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- // SPDX-License-Identifier: GPL-2.0
- /*
- * Block multiqueue core code
- *
- * Copyright (C) 2013-2014 Jens Axboe
- * Copyright (C) 2013-2014 Christoph Hellwig
- */
- #include <linux/kernel.h>
- #include <linux/module.h>
- #include <linux/backing-dev.h>
- #include <linux/bio.h>
- #include <linux/blkdev.h>
- #include <linux/kmemleak.h>
- #include <linux/mm.h>
- #include <linux/init.h>
- #include <linux/slab.h>
- #include <linux/workqueue.h>
- #include <linux/smp.h>
- #include <linux/llist.h>
- #include <linux/list_sort.h>
- #include <linux/cpu.h>
- #include <linux/cache.h>
- #include <linux/sched/sysctl.h>
- #include <linux/sched/topology.h>
- #include <linux/sched/signal.h>
- #include <linux/delay.h>
- #include <linux/crash_dump.h>
- #include <linux/prefetch.h>
- #include <linux/blk-crypto.h>
- #include <trace/events/block.h>
- #include <linux/blk-mq.h>
- #include <linux/t10-pi.h>
- #include "blk.h"
- #include "blk-mq.h"
- #include "blk-mq-debugfs.h"
- #include "blk-mq-tag.h"
- #include "blk-pm.h"
- #include "blk-stat.h"
- #include "blk-mq-sched.h"
- #include "blk-rq-qos.h"
- #include <trace/hooks/block.h>
- static DEFINE_PER_CPU(struct list_head, blk_cpu_done);
- static void blk_mq_poll_stats_start(struct request_queue *q);
- static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb);
- static int blk_mq_poll_stats_bkt(const struct request *rq)
- {
- int ddir, sectors, bucket;
- ddir = rq_data_dir(rq);
- sectors = blk_rq_stats_sectors(rq);
- bucket = ddir + 2 * ilog2(sectors);
- if (bucket < 0)
- return -1;
- else if (bucket >= BLK_MQ_POLL_STATS_BKTS)
- return ddir + BLK_MQ_POLL_STATS_BKTS - 2;
- return bucket;
- }
- /*
- * Check if any of the ctx, dispatch list or elevator
- * have pending work in this hardware queue.
- */
- static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx)
- {
- return !list_empty_careful(&hctx->dispatch) ||
- sbitmap_any_bit_set(&hctx->ctx_map) ||
- blk_mq_sched_has_work(hctx);
- }
- /*
- * Mark this ctx as having pending work in this hardware queue
- */
- static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx *hctx,
- struct blk_mq_ctx *ctx)
- {
- const int bit = ctx->index_hw[hctx->type];
- if (!sbitmap_test_bit(&hctx->ctx_map, bit))
- sbitmap_set_bit(&hctx->ctx_map, bit);
- }
- static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx,
- struct blk_mq_ctx *ctx)
- {
- const int bit = ctx->index_hw[hctx->type];
- sbitmap_clear_bit(&hctx->ctx_map, bit);
- }
- struct mq_inflight {
- struct hd_struct *part;
- unsigned int inflight[2];
- };
- static bool blk_mq_check_inflight(struct blk_mq_hw_ctx *hctx,
- struct request *rq, void *priv,
- bool reserved)
- {
- struct mq_inflight *mi = priv;
- if ((!mi->part->partno || rq->part == mi->part) &&
- blk_mq_rq_state(rq) == MQ_RQ_IN_FLIGHT)
- mi->inflight[rq_data_dir(rq)]++;
- return true;
- }
- unsigned int blk_mq_in_flight(struct request_queue *q, struct hd_struct *part)
- {
- struct mq_inflight mi = { .part = part };
- blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi);
- return mi.inflight[0] + mi.inflight[1];
- }
- void blk_mq_in_flight_rw(struct request_queue *q, struct hd_struct *part,
- unsigned int inflight[2])
- {
- struct mq_inflight mi = { .part = part };
- blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi);
- inflight[0] = mi.inflight[0];
- inflight[1] = mi.inflight[1];
- }
- void blk_freeze_queue_start(struct request_queue *q)
- {
- mutex_lock(&q->mq_freeze_lock);
- if (++q->mq_freeze_depth == 1) {
- percpu_ref_kill(&q->q_usage_counter);
- mutex_unlock(&q->mq_freeze_lock);
- if (queue_is_mq(q))
- blk_mq_run_hw_queues(q, false);
- } else {
- mutex_unlock(&q->mq_freeze_lock);
- }
- }
- EXPORT_SYMBOL_GPL(blk_freeze_queue_start);
- void blk_mq_freeze_queue_wait(struct request_queue *q)
- {
- wait_event(q->mq_freeze_wq, percpu_ref_is_zero(&q->q_usage_counter));
- }
- EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait);
- int blk_mq_freeze_queue_wait_timeout(struct request_queue *q,
- unsigned long timeout)
- {
- return wait_event_timeout(q->mq_freeze_wq,
- percpu_ref_is_zero(&q->q_usage_counter),
- timeout);
- }
- EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait_timeout);
- /*
- * Guarantee no request is in use, so we can change any data structure of
- * the queue afterward.
- */
- void blk_freeze_queue(struct request_queue *q)
- {
- /*
- * In the !blk_mq case we are only calling this to kill the
- * q_usage_counter, otherwise this increases the freeze depth
- * and waits for it to return to zero. For this reason there is
- * no blk_unfreeze_queue(), and blk_freeze_queue() is not
- * exported to drivers as the only user for unfreeze is blk_mq.
- */
- blk_freeze_queue_start(q);
- blk_mq_freeze_queue_wait(q);
- }
- void blk_mq_freeze_queue(struct request_queue *q)
- {
- /*
- * ...just an alias to keep freeze and unfreeze actions balanced
- * in the blk_mq_* namespace
- */
- blk_freeze_queue(q);
- }
- EXPORT_SYMBOL_GPL(blk_mq_freeze_queue);
- void blk_mq_unfreeze_queue(struct request_queue *q)
- {
- mutex_lock(&q->mq_freeze_lock);
- q->mq_freeze_depth--;
- WARN_ON_ONCE(q->mq_freeze_depth < 0);
- if (!q->mq_freeze_depth) {
- percpu_ref_resurrect(&q->q_usage_counter);
- wake_up_all(&q->mq_freeze_wq);
- }
- mutex_unlock(&q->mq_freeze_lock);
- }
- EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue);
- /*
- * FIXME: replace the scsi_internal_device_*block_nowait() calls in the
- * mpt3sas driver such that this function can be removed.
- */
- void blk_mq_quiesce_queue_nowait(struct request_queue *q)
- {
- blk_queue_flag_set(QUEUE_FLAG_QUIESCED, q);
- }
- EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait);
- /**
- * blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished
- * @q: request queue.
- *
- * Note: this function does not prevent that the struct request end_io()
- * callback function is invoked. Once this function is returned, we make
- * sure no dispatch can happen until the queue is unquiesced via
- * blk_mq_unquiesce_queue().
- */
- void blk_mq_quiesce_queue(struct request_queue *q)
- {
- struct blk_mq_hw_ctx *hctx;
- unsigned int i;
- bool rcu = false;
- blk_mq_quiesce_queue_nowait(q);
- queue_for_each_hw_ctx(q, hctx, i) {
- if (hctx->flags & BLK_MQ_F_BLOCKING)
- synchronize_srcu(hctx->srcu);
- else
- rcu = true;
- }
- if (rcu)
- synchronize_rcu();
- }
- EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue);
- /*
- * blk_mq_unquiesce_queue() - counterpart of blk_mq_quiesce_queue()
- * @q: request queue.
- *
- * This function recovers queue into the state before quiescing
- * which is done by blk_mq_quiesce_queue.
- */
- void blk_mq_unquiesce_queue(struct request_queue *q)
- {
- blk_queue_flag_clear(QUEUE_FLAG_QUIESCED, q);
- /* dispatch requests which are inserted during quiescing */
- blk_mq_run_hw_queues(q, true);
- }
- EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue);
- void blk_mq_wake_waiters(struct request_queue *q)
- {
- struct blk_mq_hw_ctx *hctx;
- unsigned int i;
- queue_for_each_hw_ctx(q, hctx, i)
- if (blk_mq_hw_queue_mapped(hctx))
- blk_mq_tag_wakeup_all(hctx->tags, true);
- }
- /*
- * Only need start/end time stamping if we have iostat or
- * blk stats enabled, or using an IO scheduler.
- */
- static inline bool blk_mq_need_time_stamp(struct request *rq)
- {
- return (rq->rq_flags & (RQF_IO_STAT | RQF_STATS)) || rq->q->elevator;
- }
- static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
- unsigned int tag, u64 alloc_time_ns)
- {
- struct blk_mq_tags *tags = blk_mq_tags_from_data(data);
- struct request *rq = tags->static_rqs[tag];
- if (data->q->elevator) {
- rq->tag = BLK_MQ_NO_TAG;
- rq->internal_tag = tag;
- } else {
- rq->tag = tag;
- rq->internal_tag = BLK_MQ_NO_TAG;
- }
- /* csd/requeue_work/fifo_time is initialized before use */
- rq->q = data->q;
- rq->mq_ctx = data->ctx;
- rq->mq_hctx = data->hctx;
- rq->rq_flags = 0;
- rq->cmd_flags = data->cmd_flags;
- if (data->flags & BLK_MQ_REQ_PM)
- rq->rq_flags |= RQF_PM;
- if (blk_queue_io_stat(data->q))
- rq->rq_flags |= RQF_IO_STAT;
- INIT_LIST_HEAD(&rq->queuelist);
- INIT_HLIST_NODE(&rq->hash);
- RB_CLEAR_NODE(&rq->rb_node);
- rq->rq_disk = NULL;
- rq->part = NULL;
- #ifdef CONFIG_BLK_RQ_ALLOC_TIME
- rq->alloc_time_ns = alloc_time_ns;
- #endif
- if (blk_mq_need_time_stamp(rq))
- rq->start_time_ns = ktime_get_ns();
- else
- rq->start_time_ns = 0;
- rq->io_start_time_ns = 0;
- rq->stats_sectors = 0;
- rq->nr_phys_segments = 0;
- #if defined(CONFIG_BLK_DEV_INTEGRITY)
- rq->nr_integrity_segments = 0;
- #endif
- blk_crypto_rq_set_defaults(rq);
- /* tag was already set */
- WRITE_ONCE(rq->deadline, 0);
- rq->timeout = 0;
- rq->end_io = NULL;
- rq->end_io_data = NULL;
- data->ctx->rq_dispatched[op_is_sync(data->cmd_flags)]++;
- refcount_set(&rq->ref, 1);
- if (!op_is_flush(data->cmd_flags)) {
- struct elevator_queue *e = data->q->elevator;
- rq->elv.icq = NULL;
- if (e && e->type->ops.prepare_request) {
- if (e->type->icq_cache)
- blk_mq_sched_assign_ioc(rq);
- e->type->ops.prepare_request(rq);
- rq->rq_flags |= RQF_ELVPRIV;
- }
- }
- data->hctx->queued++;
- trace_android_vh_blk_rq_ctx_init(rq, tags, data, alloc_time_ns);
- return rq;
- }
- static struct request *__blk_mq_alloc_request(struct blk_mq_alloc_data *data)
- {
- struct request_queue *q = data->q;
- struct elevator_queue *e = q->elevator;
- u64 alloc_time_ns = 0;
- unsigned int tag;
- /* alloc_time includes depth and tag waits */
- if (blk_queue_rq_alloc_time(q))
- alloc_time_ns = ktime_get_ns();
- if (data->cmd_flags & REQ_NOWAIT)
- data->flags |= BLK_MQ_REQ_NOWAIT;
- if (e) {
- /*
- * Flush requests are special and go directly to the
- * dispatch list. Don't include reserved tags in the
- * limiting, as it isn't useful.
- */
- if (!op_is_flush(data->cmd_flags) &&
- e->type->ops.limit_depth &&
- !(data->flags & BLK_MQ_REQ_RESERVED))
- e->type->ops.limit_depth(data->cmd_flags, data);
- }
- retry:
- data->ctx = blk_mq_get_ctx(q);
- data->hctx = blk_mq_map_queue(q, data->cmd_flags, data->ctx);
- if (!e)
- blk_mq_tag_busy(data->hctx);
- /*
- * Waiting allocations only fail because of an inactive hctx. In that
- * case just retry the hctx assignment and tag allocation as CPU hotplug
- * should have migrated us to an online CPU by now.
- */
- tag = blk_mq_get_tag(data);
- if (tag == BLK_MQ_NO_TAG) {
- if (data->flags & BLK_MQ_REQ_NOWAIT)
- return NULL;
- /*
- * Give up the CPU and sleep for a random short time to ensure
- * that thread using a realtime scheduling class are migrated
- * off the CPU, and thus off the hctx that is going away.
- */
- msleep(3);
- goto retry;
- }
- return blk_mq_rq_ctx_init(data, tag, alloc_time_ns);
- }
- struct request *blk_mq_alloc_request(struct request_queue *q, unsigned int op,
- blk_mq_req_flags_t flags)
- {
- struct blk_mq_alloc_data data = {
- .q = q,
- .flags = flags,
- .cmd_flags = op,
- };
- struct request *rq;
- int ret;
- ret = blk_queue_enter(q, flags);
- if (ret)
- return ERR_PTR(ret);
- rq = __blk_mq_alloc_request(&data);
- if (!rq)
- goto out_queue_exit;
- rq->__data_len = 0;
- rq->__sector = (sector_t) -1;
- rq->bio = rq->biotail = NULL;
- return rq;
- out_queue_exit:
- blk_queue_exit(q);
- return ERR_PTR(-EWOULDBLOCK);
- }
- EXPORT_SYMBOL(blk_mq_alloc_request);
- struct request *blk_mq_alloc_request_hctx(struct request_queue *q,
- unsigned int op, blk_mq_req_flags_t flags, unsigned int hctx_idx)
- {
- struct blk_mq_alloc_data data = {
- .q = q,
- .flags = flags,
- .cmd_flags = op,
- };
- u64 alloc_time_ns = 0;
- unsigned int cpu;
- unsigned int tag;
- int ret;
- /* alloc_time includes depth and tag waits */
- if (blk_queue_rq_alloc_time(q))
- alloc_time_ns = ktime_get_ns();
- /*
- * If the tag allocator sleeps we could get an allocation for a
- * different hardware context. No need to complicate the low level
- * allocator for this for the rare use case of a command tied to
- * a specific queue.
- */
- if (WARN_ON_ONCE(!(flags & (BLK_MQ_REQ_NOWAIT | BLK_MQ_REQ_RESERVED))))
- return ERR_PTR(-EINVAL);
- if (hctx_idx >= q->nr_hw_queues)
- return ERR_PTR(-EIO);
- ret = blk_queue_enter(q, flags);
- if (ret)
- return ERR_PTR(ret);
- /*
- * Check if the hardware context is actually mapped to anything.
- * If not tell the caller that it should skip this queue.
- */
- ret = -EXDEV;
- data.hctx = q->queue_hw_ctx[hctx_idx];
- if (!blk_mq_hw_queue_mapped(data.hctx))
- goto out_queue_exit;
- cpu = cpumask_first_and(data.hctx->cpumask, cpu_online_mask);
- data.ctx = __blk_mq_get_ctx(q, cpu);
- if (!q->elevator)
- blk_mq_tag_busy(data.hctx);
- ret = -EWOULDBLOCK;
- tag = blk_mq_get_tag(&data);
- if (tag == BLK_MQ_NO_TAG)
- goto out_queue_exit;
- return blk_mq_rq_ctx_init(&data, tag, alloc_time_ns);
- out_queue_exit:
- blk_queue_exit(q);
- return ERR_PTR(ret);
- }
- EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx);
- static void __blk_mq_free_request(struct request *rq)
- {
- struct request_queue *q = rq->q;
- struct blk_mq_ctx *ctx = rq->mq_ctx;
- struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
- const int sched_tag = rq->internal_tag;
- blk_crypto_free_request(rq);
- blk_pm_mark_last_busy(rq);
- rq->mq_hctx = NULL;
- if (rq->tag != BLK_MQ_NO_TAG)
- blk_mq_put_tag(hctx->tags, ctx, rq->tag);
- if (sched_tag != BLK_MQ_NO_TAG)
- blk_mq_put_tag(hctx->sched_tags, ctx, sched_tag);
- blk_mq_sched_restart(hctx);
- blk_queue_exit(q);
- }
- void blk_mq_free_request(struct request *rq)
- {
- struct request_queue *q = rq->q;
- struct elevator_queue *e = q->elevator;
- struct blk_mq_ctx *ctx = rq->mq_ctx;
- struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
- if (rq->rq_flags & RQF_ELVPRIV) {
- if (e && e->type->ops.finish_request)
- e->type->ops.finish_request(rq);
- if (rq->elv.icq) {
- put_io_context(rq->elv.icq->ioc);
- rq->elv.icq = NULL;
- }
- }
- ctx->rq_completed[rq_is_sync(rq)]++;
- if (rq->rq_flags & RQF_MQ_INFLIGHT)
- __blk_mq_dec_active_requests(hctx);
- if (unlikely(laptop_mode && !blk_rq_is_passthrough(rq)))
- laptop_io_completion(q->backing_dev_info);
- rq_qos_done(q, rq);
- WRITE_ONCE(rq->state, MQ_RQ_IDLE);
- if (refcount_dec_and_test(&rq->ref))
- __blk_mq_free_request(rq);
- }
- EXPORT_SYMBOL_GPL(blk_mq_free_request);
- inline void __blk_mq_end_request(struct request *rq, blk_status_t error)
- {
- u64 now = 0;
- if (blk_mq_need_time_stamp(rq))
- now = ktime_get_ns();
- if (rq->rq_flags & RQF_STATS) {
- blk_mq_poll_stats_start(rq->q);
- blk_stat_add(rq, now);
- }
- blk_mq_sched_completed_request(rq, now);
- blk_account_io_done(rq, now);
- if (rq->end_io) {
- rq_qos_done(rq->q, rq);
- rq->end_io(rq, error);
- } else {
- blk_mq_free_request(rq);
- }
- }
- EXPORT_SYMBOL(__blk_mq_end_request);
- void blk_mq_end_request(struct request *rq, blk_status_t error)
- {
- if (blk_update_request(rq, error, blk_rq_bytes(rq)))
- BUG();
- __blk_mq_end_request(rq, error);
- }
- EXPORT_SYMBOL(blk_mq_end_request);
- /*
- * Softirq action handler - move entries to local list and loop over them
- * while passing them to the queue registered handler.
- */
- static __latent_entropy void blk_done_softirq(struct softirq_action *h)
- {
- struct list_head *cpu_list, local_list;
- local_irq_disable();
- cpu_list = this_cpu_ptr(&blk_cpu_done);
- list_replace_init(cpu_list, &local_list);
- local_irq_enable();
- while (!list_empty(&local_list)) {
- struct request *rq;
- rq = list_entry(local_list.next, struct request, ipi_list);
- list_del_init(&rq->ipi_list);
- rq->q->mq_ops->complete(rq);
- }
- }
- static void blk_mq_trigger_softirq(struct request *rq)
- {
- struct list_head *list;
- unsigned long flags;
- local_irq_save(flags);
- list = this_cpu_ptr(&blk_cpu_done);
- list_add_tail(&rq->ipi_list, list);
- /*
- * If the list only contains our just added request, signal a raise of
- * the softirq. If there are already entries there, someone already
- * raised the irq but it hasn't run yet.
- */
- if (list->next == &rq->ipi_list)
- raise_softirq_irqoff(BLOCK_SOFTIRQ);
- local_irq_restore(flags);
- }
- static int blk_softirq_cpu_dead(unsigned int cpu)
- {
- /*
- * If a CPU goes away, splice its entries to the current CPU
- * and trigger a run of the softirq
- */
- local_irq_disable();
- list_splice_init(&per_cpu(blk_cpu_done, cpu),
- this_cpu_ptr(&blk_cpu_done));
- raise_softirq_irqoff(BLOCK_SOFTIRQ);
- local_irq_enable();
- return 0;
- }
- static void __blk_mq_complete_request_remote(void *data)
- {
- struct request *rq = data;
- /*
- * For most of single queue controllers, there is only one irq vector
- * for handling I/O completion, and the only irq's affinity is set
- * to all possible CPUs. On most of ARCHs, this affinity means the irq
- * is handled on one specific CPU.
- *
- * So complete I/O requests in softirq context in case of single queue
- * devices to avoid degrading I/O performance due to irqsoff latency.
- */
- if (rq->q->nr_hw_queues == 1)
- blk_mq_trigger_softirq(rq);
- else
- rq->q->mq_ops->complete(rq);
- }
- static inline bool blk_mq_complete_need_ipi(struct request *rq)
- {
- int cpu = raw_smp_processor_id();
- if (!IS_ENABLED(CONFIG_SMP) ||
- !test_bit(QUEUE_FLAG_SAME_COMP, &rq->q->queue_flags))
- return false;
- /* same CPU or cache domain? Complete locally */
- if (cpu == rq->mq_ctx->cpu ||
- (!test_bit(QUEUE_FLAG_SAME_FORCE, &rq->q->queue_flags) &&
- cpus_share_cache(cpu, rq->mq_ctx->cpu)))
- return false;
- /* don't try to IPI to an offline CPU */
- return cpu_online(rq->mq_ctx->cpu);
- }
- bool blk_mq_complete_request_remote(struct request *rq)
- {
- WRITE_ONCE(rq->state, MQ_RQ_COMPLETE);
- /*
- * For a polled request, always complete locallly, it's pointless
- * to redirect the completion.
- */
- if (rq->cmd_flags & REQ_HIPRI)
- return false;
- if (blk_mq_complete_need_ipi(rq)) {
- rq->csd.func = __blk_mq_complete_request_remote;
- rq->csd.info = rq;
- rq->csd.flags = 0;
- smp_call_function_single_async(rq->mq_ctx->cpu, &rq->csd);
- } else {
- if (rq->q->nr_hw_queues > 1)
- return false;
- blk_mq_trigger_softirq(rq);
- }
- return true;
- }
- EXPORT_SYMBOL_GPL(blk_mq_complete_request_remote);
- /**
- * blk_mq_complete_request - end I/O on a request
- * @rq: the request being processed
- *
- * Description:
- * Complete a request by scheduling the ->complete_rq operation.
- **/
- void blk_mq_complete_request(struct request *rq)
- {
- if (!blk_mq_complete_request_remote(rq))
- rq->q->mq_ops->complete(rq);
- }
- EXPORT_SYMBOL(blk_mq_complete_request);
- static void hctx_unlock(struct blk_mq_hw_ctx *hctx, int srcu_idx)
- __releases(hctx->srcu)
- {
- if (!(hctx->flags & BLK_MQ_F_BLOCKING))
- rcu_read_unlock();
- else
- srcu_read_unlock(hctx->srcu, srcu_idx);
- }
- static void hctx_lock(struct blk_mq_hw_ctx *hctx, int *srcu_idx)
- __acquires(hctx->srcu)
- {
- if (!(hctx->flags & BLK_MQ_F_BLOCKING)) {
- /* shut up gcc false positive */
- *srcu_idx = 0;
- rcu_read_lock();
- } else
- *srcu_idx = srcu_read_lock(hctx->srcu);
- }
- /**
- * blk_mq_start_request - Start processing a request
- * @rq: Pointer to request to be started
- *
- * Function used by device drivers to notify the block layer that a request
- * is going to be processed now, so blk layer can do proper initializations
- * such as starting the timeout timer.
- */
- void blk_mq_start_request(struct request *rq)
- {
- struct request_queue *q = rq->q;
- trace_block_rq_issue(q, rq);
- if (test_bit(QUEUE_FLAG_STATS, &q->queue_flags)) {
- rq->io_start_time_ns = ktime_get_ns();
- rq->stats_sectors = blk_rq_sectors(rq);
- rq->rq_flags |= RQF_STATS;
- rq_qos_issue(q, rq);
- }
- WARN_ON_ONCE(blk_mq_rq_state(rq) != MQ_RQ_IDLE);
- blk_add_timer(rq);
- WRITE_ONCE(rq->state, MQ_RQ_IN_FLIGHT);
- #ifdef CONFIG_BLK_DEV_INTEGRITY
- if (blk_integrity_rq(rq) && req_op(rq) == REQ_OP_WRITE)
- q->integrity.profile->prepare_fn(rq);
- #endif
- }
- EXPORT_SYMBOL(blk_mq_start_request);
- static void __blk_mq_requeue_request(struct request *rq)
- {
- struct request_queue *q = rq->q;
- blk_mq_put_driver_tag(rq);
- trace_block_rq_requeue(q, rq);
- rq_qos_requeue(q, rq);
- if (blk_mq_request_started(rq)) {
- WRITE_ONCE(rq->state, MQ_RQ_IDLE);
- rq->rq_flags &= ~RQF_TIMED_OUT;
- }
- }
- void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list)
- {
- __blk_mq_requeue_request(rq);
- /* this request will be re-inserted to io scheduler queue */
- blk_mq_sched_requeue_request(rq);
- blk_mq_add_to_requeue_list(rq, true, kick_requeue_list);
- }
- EXPORT_SYMBOL(blk_mq_requeue_request);
- static void blk_mq_requeue_work(struct work_struct *work)
- {
- struct request_queue *q =
- container_of(work, struct request_queue, requeue_work.work);
- LIST_HEAD(rq_list);
- struct request *rq, *next;
- spin_lock_irq(&q->requeue_lock);
- list_splice_init(&q->requeue_list, &rq_list);
- spin_unlock_irq(&q->requeue_lock);
- list_for_each_entry_safe(rq, next, &rq_list, queuelist) {
- if (!(rq->rq_flags & (RQF_SOFTBARRIER | RQF_DONTPREP)))
- continue;
- rq->rq_flags &= ~RQF_SOFTBARRIER;
- list_del_init(&rq->queuelist);
- /*
- * If RQF_DONTPREP, rq has contained some driver specific
- * data, so insert it to hctx dispatch list to avoid any
- * merge.
- */
- if (rq->rq_flags & RQF_DONTPREP)
- blk_mq_request_bypass_insert(rq, false, false);
- else
- blk_mq_sched_insert_request(rq, true, false, false);
- }
- while (!list_empty(&rq_list)) {
- rq = list_entry(rq_list.next, struct request, queuelist);
- list_del_init(&rq->queuelist);
- blk_mq_sched_insert_request(rq, false, false, false);
- }
- blk_mq_run_hw_queues(q, false);
- }
- void blk_mq_add_to_requeue_list(struct request *rq, bool at_head,
- bool kick_requeue_list)
- {
- struct request_queue *q = rq->q;
- unsigned long flags;
- /*
- * We abuse this flag that is otherwise used by the I/O scheduler to
- * request head insertion from the workqueue.
- */
- BUG_ON(rq->rq_flags & RQF_SOFTBARRIER);
- spin_lock_irqsave(&q->requeue_lock, flags);
- if (at_head) {
- rq->rq_flags |= RQF_SOFTBARRIER;
- list_add(&rq->queuelist, &q->requeue_list);
- } else {
- list_add_tail(&rq->queuelist, &q->requeue_list);
- }
- spin_unlock_irqrestore(&q->requeue_lock, flags);
- if (kick_requeue_list)
- blk_mq_kick_requeue_list(q);
- }
- void blk_mq_kick_requeue_list(struct request_queue *q)
- {
- kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work, 0);
- }
- EXPORT_SYMBOL(blk_mq_kick_requeue_list);
- void blk_mq_delay_kick_requeue_list(struct request_queue *q,
- unsigned long msecs)
- {
- kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work,
- msecs_to_jiffies(msecs));
- }
- EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list);
- struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag)
- {
- if (tag < tags->nr_tags) {
- prefetch(tags->rqs[tag]);
- return tags->rqs[tag];
- }
- return NULL;
- }
- EXPORT_SYMBOL(blk_mq_tag_to_rq);
- static bool blk_mq_rq_inflight(struct blk_mq_hw_ctx *hctx, struct request *rq,
- void *priv, bool reserved)
- {
- /*
- * If we find a request that isn't idle and the queue matches,
- * we know the queue is busy. Return false to stop the iteration.
- */
- if (blk_mq_request_started(rq) && rq->q == hctx->queue) {
- bool *busy = priv;
- *busy = true;
- return false;
- }
- return true;
- }
- bool blk_mq_queue_inflight(struct request_queue *q)
- {
- bool busy = false;
- blk_mq_queue_tag_busy_iter(q, blk_mq_rq_inflight, &busy);
- return busy;
- }
- EXPORT_SYMBOL_GPL(blk_mq_queue_inflight);
- static void blk_mq_rq_timed_out(struct request *req, bool reserved)
- {
- req->rq_flags |= RQF_TIMED_OUT;
- if (req->q->mq_ops->timeout) {
- enum blk_eh_timer_return ret;
- ret = req->q->mq_ops->timeout(req, reserved);
- if (ret == BLK_EH_DONE)
- return;
- WARN_ON_ONCE(ret != BLK_EH_RESET_TIMER);
- }
- blk_add_timer(req);
- }
- static bool blk_mq_req_expired(struct request *rq, unsigned long *next)
- {
- unsigned long deadline;
- if (blk_mq_rq_state(rq) != MQ_RQ_IN_FLIGHT)
- return false;
- if (rq->rq_flags & RQF_TIMED_OUT)
- return false;
- deadline = READ_ONCE(rq->deadline);
- if (time_after_eq(jiffies, deadline))
- return true;
- if (*next == 0)
- *next = deadline;
- else if (time_after(*next, deadline))
- *next = deadline;
- return false;
- }
- void blk_mq_put_rq_ref(struct request *rq)
- {
- if (is_flush_rq(rq))
- rq->end_io(rq, 0);
- else if (refcount_dec_and_test(&rq->ref))
- __blk_mq_free_request(rq);
- }
- static bool blk_mq_check_expired(struct blk_mq_hw_ctx *hctx,
- struct request *rq, void *priv, bool reserved)
- {
- unsigned long *next = priv;
- /*
- * blk_mq_queue_tag_busy_iter() has locked the request, so it cannot
- * be reallocated underneath the timeout handler's processing, then
- * the expire check is reliable. If the request is not expired, then
- * it was completed and reallocated as a new request after returning
- * from blk_mq_check_expired().
- */
- if (blk_mq_req_expired(rq, next))
- blk_mq_rq_timed_out(rq, reserved);
- return true;
- }
- static void blk_mq_timeout_work(struct work_struct *work)
- {
- struct request_queue *q =
- container_of(work, struct request_queue, timeout_work);
- unsigned long next = 0;
- struct blk_mq_hw_ctx *hctx;
- int i;
- /* A deadlock might occur if a request is stuck requiring a
- * timeout at the same time a queue freeze is waiting
- * completion, since the timeout code would not be able to
- * acquire the queue reference here.
- *
- * That's why we don't use blk_queue_enter here; instead, we use
- * percpu_ref_tryget directly, because we need to be able to
- * obtain a reference even in the short window between the queue
- * starting to freeze, by dropping the first reference in
- * blk_freeze_queue_start, and the moment the last request is
- * consumed, marked by the instant q_usage_counter reaches
- * zero.
- */
- if (!percpu_ref_tryget(&q->q_usage_counter))
- return;
- blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &next);
- if (next != 0) {
- mod_timer(&q->timeout, next);
- } else {
- /*
- * Request timeouts are handled as a forward rolling timer. If
- * we end up here it means that no requests are pending and
- * also that no request has been pending for a while. Mark
- * each hctx as idle.
- */
- queue_for_each_hw_ctx(q, hctx, i) {
- /* the hctx may be unmapped, so check it here */
- if (blk_mq_hw_queue_mapped(hctx))
- blk_mq_tag_idle(hctx);
- }
- }
- blk_queue_exit(q);
- }
- struct flush_busy_ctx_data {
- struct blk_mq_hw_ctx *hctx;
- struct list_head *list;
- };
- static bool flush_busy_ctx(struct sbitmap *sb, unsigned int bitnr, void *data)
- {
- struct flush_busy_ctx_data *flush_data = data;
- struct blk_mq_hw_ctx *hctx = flush_data->hctx;
- struct blk_mq_ctx *ctx = hctx->ctxs[bitnr];
- enum hctx_type type = hctx->type;
- spin_lock(&ctx->lock);
- list_splice_tail_init(&ctx->rq_lists[type], flush_data->list);
- sbitmap_clear_bit(sb, bitnr);
- spin_unlock(&ctx->lock);
- return true;
- }
- /*
- * Process software queues that have been marked busy, splicing them
- * to the for-dispatch
- */
- void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list)
- {
- struct flush_busy_ctx_data data = {
- .hctx = hctx,
- .list = list,
- };
- sbitmap_for_each_set(&hctx->ctx_map, flush_busy_ctx, &data);
- }
- EXPORT_SYMBOL_GPL(blk_mq_flush_busy_ctxs);
- struct dispatch_rq_data {
- struct blk_mq_hw_ctx *hctx;
- struct request *rq;
- };
- static bool dispatch_rq_from_ctx(struct sbitmap *sb, unsigned int bitnr,
- void *data)
- {
- struct dispatch_rq_data *dispatch_data = data;
- struct blk_mq_hw_ctx *hctx = dispatch_data->hctx;
- struct blk_mq_ctx *ctx = hctx->ctxs[bitnr];
- enum hctx_type type = hctx->type;
- spin_lock(&ctx->lock);
- if (!list_empty(&ctx->rq_lists[type])) {
- dispatch_data->rq = list_entry_rq(ctx->rq_lists[type].next);
- list_del_init(&dispatch_data->rq->queuelist);
- if (list_empty(&ctx->rq_lists[type]))
- sbitmap_clear_bit(sb, bitnr);
- }
- spin_unlock(&ctx->lock);
- return !dispatch_data->rq;
- }
- struct request *blk_mq_dequeue_from_ctx(struct blk_mq_hw_ctx *hctx,
- struct blk_mq_ctx *start)
- {
- unsigned off = start ? start->index_hw[hctx->type] : 0;
- struct dispatch_rq_data data = {
- .hctx = hctx,
- .rq = NULL,
- };
- __sbitmap_for_each_set(&hctx->ctx_map, off,
- dispatch_rq_from_ctx, &data);
- return data.rq;
- }
- static inline unsigned int queued_to_index(unsigned int queued)
- {
- if (!queued)
- return 0;
- return min(BLK_MQ_MAX_DISPATCH_ORDER - 1, ilog2(queued) + 1);
- }
- static bool __blk_mq_get_driver_tag(struct request *rq)
- {
- struct sbitmap_queue *bt = rq->mq_hctx->tags->bitmap_tags;
- unsigned int tag_offset = rq->mq_hctx->tags->nr_reserved_tags;
- int tag;
- blk_mq_tag_busy(rq->mq_hctx);
- if (blk_mq_tag_is_reserved(rq->mq_hctx->sched_tags, rq->internal_tag)) {
- bt = rq->mq_hctx->tags->breserved_tags;
- tag_offset = 0;
- } else {
- if (!hctx_may_queue(rq->mq_hctx, bt))
- return false;
- }
- tag = __sbitmap_queue_get(bt);
- if (tag == BLK_MQ_NO_TAG)
- return false;
- rq->tag = tag + tag_offset;
- return true;
- }
- static bool blk_mq_get_driver_tag(struct request *rq)
- {
- struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
- if (rq->tag == BLK_MQ_NO_TAG && !__blk_mq_get_driver_tag(rq))
- return false;
- if ((hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) &&
- !(rq->rq_flags & RQF_MQ_INFLIGHT)) {
- rq->rq_flags |= RQF_MQ_INFLIGHT;
- __blk_mq_inc_active_requests(hctx);
- }
- hctx->tags->rqs[rq->tag] = rq;
- return true;
- }
- static int blk_mq_dispatch_wake(wait_queue_entry_t *wait, unsigned mode,
- int flags, void *key)
- {
- struct blk_mq_hw_ctx *hctx;
- hctx = container_of(wait, struct blk_mq_hw_ctx, dispatch_wait);
- spin_lock(&hctx->dispatch_wait_lock);
- if (!list_empty(&wait->entry)) {
- struct sbitmap_queue *sbq;
- list_del_init(&wait->entry);
- sbq = hctx->tags->bitmap_tags;
- atomic_dec(&sbq->ws_active);
- }
- spin_unlock(&hctx->dispatch_wait_lock);
- blk_mq_run_hw_queue(hctx, true);
- return 1;
- }
- /*
- * Mark us waiting for a tag. For shared tags, this involves hooking us into
- * the tag wakeups. For non-shared tags, we can simply mark us needing a
- * restart. For both cases, take care to check the condition again after
- * marking us as waiting.
- */
- static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx,
- struct request *rq)
- {
- struct sbitmap_queue *sbq = hctx->tags->bitmap_tags;
- struct wait_queue_head *wq;
- wait_queue_entry_t *wait;
- bool ret;
- if (!(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED)) {
- blk_mq_sched_mark_restart_hctx(hctx);
- /*
- * It's possible that a tag was freed in the window between the
- * allocation failure and adding the hardware queue to the wait
- * queue.
- *
- * Don't clear RESTART here, someone else could have set it.
- * At most this will cost an extra queue run.
- */
- return blk_mq_get_driver_tag(rq);
- }
- wait = &hctx->dispatch_wait;
- if (!list_empty_careful(&wait->entry))
- return false;
- wq = &bt_wait_ptr(sbq, hctx)->wait;
- spin_lock_irq(&wq->lock);
- spin_lock(&hctx->dispatch_wait_lock);
- if (!list_empty(&wait->entry)) {
- spin_unlock(&hctx->dispatch_wait_lock);
- spin_unlock_irq(&wq->lock);
- return false;
- }
- atomic_inc(&sbq->ws_active);
- wait->flags &= ~WQ_FLAG_EXCLUSIVE;
- __add_wait_queue(wq, wait);
- /*
- * It's possible that a tag was freed in the window between the
- * allocation failure and adding the hardware queue to the wait
- * queue.
- */
- ret = blk_mq_get_driver_tag(rq);
- if (!ret) {
- spin_unlock(&hctx->dispatch_wait_lock);
- spin_unlock_irq(&wq->lock);
- return false;
- }
- /*
- * We got a tag, remove ourselves from the wait queue to ensure
- * someone else gets the wakeup.
- */
- list_del_init(&wait->entry);
- atomic_dec(&sbq->ws_active);
- spin_unlock(&hctx->dispatch_wait_lock);
- spin_unlock_irq(&wq->lock);
- return true;
- }
- #define BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT 8
- #define BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR 4
- /*
- * Update dispatch busy with the Exponential Weighted Moving Average(EWMA):
- * - EWMA is one simple way to compute running average value
- * - weight(7/8 and 1/8) is applied so that it can decrease exponentially
- * - take 4 as factor for avoiding to get too small(0) result, and this
- * factor doesn't matter because EWMA decreases exponentially
- */
- static void blk_mq_update_dispatch_busy(struct blk_mq_hw_ctx *hctx, bool busy)
- {
- unsigned int ewma;
- ewma = hctx->dispatch_busy;
- if (!ewma && !busy)
- return;
- ewma *= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT - 1;
- if (busy)
- ewma += 1 << BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR;
- ewma /= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT;
- hctx->dispatch_busy = ewma;
- }
- #define BLK_MQ_RESOURCE_DELAY 3 /* ms units */
- static void blk_mq_handle_dev_resource(struct request *rq,
- struct list_head *list)
- {
- struct request *next =
- list_first_entry_or_null(list, struct request, queuelist);
- /*
- * If an I/O scheduler has been configured and we got a driver tag for
- * the next request already, free it.
- */
- if (next)
- blk_mq_put_driver_tag(next);
- list_add(&rq->queuelist, list);
- __blk_mq_requeue_request(rq);
- }
- static void blk_mq_handle_zone_resource(struct request *rq,
- struct list_head *zone_list)
- {
- /*
- * If we end up here it is because we cannot dispatch a request to a
- * specific zone due to LLD level zone-write locking or other zone
- * related resource not being available. In this case, set the request
- * aside in zone_list for retrying it later.
- */
- list_add(&rq->queuelist, zone_list);
- __blk_mq_requeue_request(rq);
- }
- enum prep_dispatch {
- PREP_DISPATCH_OK,
- PREP_DISPATCH_NO_TAG,
- PREP_DISPATCH_NO_BUDGET,
- };
- static enum prep_dispatch blk_mq_prep_dispatch_rq(struct request *rq,
- bool need_budget)
- {
- struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
- if (need_budget && !blk_mq_get_dispatch_budget(rq->q)) {
- blk_mq_put_driver_tag(rq);
- return PREP_DISPATCH_NO_BUDGET;
- }
- if (!blk_mq_get_driver_tag(rq)) {
- /*
- * The initial allocation attempt failed, so we need to
- * rerun the hardware queue when a tag is freed. The
- * waitqueue takes care of that. If the queue is run
- * before we add this entry back on the dispatch list,
- * we'll re-run it below.
- */
- if (!blk_mq_mark_tag_wait(hctx, rq)) {
- /*
- * All budgets not got from this function will be put
- * together during handling partial dispatch
- */
- if (need_budget)
- blk_mq_put_dispatch_budget(rq->q);
- return PREP_DISPATCH_NO_TAG;
- }
- }
- return PREP_DISPATCH_OK;
- }
- /* release all allocated budgets before calling to blk_mq_dispatch_rq_list */
- static void blk_mq_release_budgets(struct request_queue *q,
- unsigned int nr_budgets)
- {
- int i;
- for (i = 0; i < nr_budgets; i++)
- blk_mq_put_dispatch_budget(q);
- }
- /*
- * Returns true if we did some work AND can potentially do more.
- */
- bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
- unsigned int nr_budgets)
- {
- enum prep_dispatch prep;
- struct request_queue *q = hctx->queue;
- struct request *rq, *nxt;
- int errors, queued;
- blk_status_t ret = BLK_STS_OK;
- LIST_HEAD(zone_list);
- bool needs_resource = false;
- if (list_empty(list))
- return false;
- /*
- * Now process all the entries, sending them to the driver.
- */
- errors = queued = 0;
- do {
- struct blk_mq_queue_data bd;
- rq = list_first_entry(list, struct request, queuelist);
- WARN_ON_ONCE(hctx != rq->mq_hctx);
- prep = blk_mq_prep_dispatch_rq(rq, !nr_budgets);
- if (prep != PREP_DISPATCH_OK)
- break;
- list_del_init(&rq->queuelist);
- bd.rq = rq;
- /*
- * Flag last if we have no more requests, or if we have more
- * but can't assign a driver tag to it.
- */
- if (list_empty(list))
- bd.last = true;
- else {
- nxt = list_first_entry(list, struct request, queuelist);
- bd.last = !blk_mq_get_driver_tag(nxt);
- }
- /*
- * once the request is queued to lld, no need to cover the
- * budget any more
- */
- if (nr_budgets)
- nr_budgets--;
- ret = q->mq_ops->queue_rq(hctx, &bd);
- switch (ret) {
- case BLK_STS_OK:
- queued++;
- break;
- case BLK_STS_RESOURCE:
- needs_resource = true;
- fallthrough;
- case BLK_STS_DEV_RESOURCE:
- blk_mq_handle_dev_resource(rq, list);
- goto out;
- case BLK_STS_ZONE_RESOURCE:
- /*
- * Move the request to zone_list and keep going through
- * the dispatch list to find more requests the drive can
- * accept.
- */
- blk_mq_handle_zone_resource(rq, &zone_list);
- needs_resource = true;
- break;
- default:
- errors++;
- blk_mq_end_request(rq, BLK_STS_IOERR);
- }
- } while (!list_empty(list));
- out:
- if (!list_empty(&zone_list))
- list_splice_tail_init(&zone_list, list);
- hctx->dispatched[queued_to_index(queued)]++;
- /* If we didn't flush the entire list, we could have told the driver
- * there was more coming, but that turned out to be a lie.
- */
- if ((!list_empty(list) || errors) && q->mq_ops->commit_rqs && queued)
- q->mq_ops->commit_rqs(hctx);
- /*
- * Any items that need requeuing? Stuff them into hctx->dispatch,
- * that is where we will continue on next queue run.
- */
- if (!list_empty(list)) {
- bool needs_restart;
- /* For non-shared tags, the RESTART check will suffice */
- bool no_tag = prep == PREP_DISPATCH_NO_TAG &&
- (hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED);
- blk_mq_release_budgets(q, nr_budgets);
- spin_lock(&hctx->lock);
- list_splice_tail_init(list, &hctx->dispatch);
- spin_unlock(&hctx->lock);
- /*
- * Order adding requests to hctx->dispatch and checking
- * SCHED_RESTART flag. The pair of this smp_mb() is the one
- * in blk_mq_sched_restart(). Avoid restart code path to
- * miss the new added requests to hctx->dispatch, meantime
- * SCHED_RESTART is observed here.
- */
- smp_mb();
- /*
- * If SCHED_RESTART was set by the caller of this function and
- * it is no longer set that means that it was cleared by another
- * thread and hence that a queue rerun is needed.
- *
- * If 'no_tag' is set, that means that we failed getting
- * a driver tag with an I/O scheduler attached. If our dispatch
- * waitqueue is no longer active, ensure that we run the queue
- * AFTER adding our entries back to the list.
- *
- * If no I/O scheduler has been configured it is possible that
- * the hardware queue got stopped and restarted before requests
- * were pushed back onto the dispatch list. Rerun the queue to
- * avoid starvation. Notes:
- * - blk_mq_run_hw_queue() checks whether or not a queue has
- * been stopped before rerunning a queue.
- * - Some but not all block drivers stop a queue before
- * returning BLK_STS_RESOURCE. Two exceptions are scsi-mq
- * and dm-rq.
- *
- * If driver returns BLK_STS_RESOURCE and SCHED_RESTART
- * bit is set, run queue after a delay to avoid IO stalls
- * that could otherwise occur if the queue is idle. We'll do
- * similar if we couldn't get budget or couldn't lock a zone
- * and SCHED_RESTART is set.
- */
- needs_restart = blk_mq_sched_needs_restart(hctx);
- if (prep == PREP_DISPATCH_NO_BUDGET)
- needs_resource = true;
- if (!needs_restart ||
- (no_tag && list_empty_careful(&hctx->dispatch_wait.entry)))
- blk_mq_run_hw_queue(hctx, true);
- else if (needs_restart && needs_resource)
- blk_mq_delay_run_hw_queue(hctx, BLK_MQ_RESOURCE_DELAY);
- blk_mq_update_dispatch_busy(hctx, true);
- return false;
- } else
- blk_mq_update_dispatch_busy(hctx, false);
- return (queued + errors) != 0;
- }
- /**
- * __blk_mq_run_hw_queue - Run a hardware queue.
- * @hctx: Pointer to the hardware queue to run.
- *
- * Send pending requests to the hardware.
- */
- static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx)
- {
- int srcu_idx;
- /*
- * We should be running this queue from one of the CPUs that
- * are mapped to it.
- *
- * There are at least two related races now between setting
- * hctx->next_cpu from blk_mq_hctx_next_cpu() and running
- * __blk_mq_run_hw_queue():
- *
- * - hctx->next_cpu is found offline in blk_mq_hctx_next_cpu(),
- * but later it becomes online, then this warning is harmless
- * at all
- *
- * - hctx->next_cpu is found online in blk_mq_hctx_next_cpu(),
- * but later it becomes offline, then the warning can't be
- * triggered, and we depend on blk-mq timeout handler to
- * handle dispatched requests to this hctx
- */
- if (!cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask) &&
- cpu_online(hctx->next_cpu)) {
- printk(KERN_WARNING "run queue from wrong CPU %d, hctx %s\n",
- raw_smp_processor_id(),
- cpumask_empty(hctx->cpumask) ? "inactive": "active");
- dump_stack();
- }
- /*
- * We can't run the queue inline with ints disabled. Ensure that
- * we catch bad users of this early.
- */
- WARN_ON_ONCE(in_interrupt());
- might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING);
- hctx_lock(hctx, &srcu_idx);
- blk_mq_sched_dispatch_requests(hctx);
- hctx_unlock(hctx, srcu_idx);
- }
- static inline int blk_mq_first_mapped_cpu(struct blk_mq_hw_ctx *hctx)
- {
- int cpu = cpumask_first_and(hctx->cpumask, cpu_online_mask);
- if (cpu >= nr_cpu_ids)
- cpu = cpumask_first(hctx->cpumask);
- return cpu;
- }
- /*
- * It'd be great if the workqueue API had a way to pass
- * in a mask and had some smarts for more clever placement.
- * For now we just round-robin here, switching for every
- * BLK_MQ_CPU_WORK_BATCH queued items.
- */
- static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx)
- {
- bool tried = false;
- int next_cpu = hctx->next_cpu;
- if (hctx->queue->nr_hw_queues == 1)
- return WORK_CPU_UNBOUND;
- if (--hctx->next_cpu_batch <= 0) {
- select_cpu:
- next_cpu = cpumask_next_and(next_cpu, hctx->cpumask,
- cpu_online_mask);
- if (next_cpu >= nr_cpu_ids)
- next_cpu = blk_mq_first_mapped_cpu(hctx);
- hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
- }
- /*
- * Do unbound schedule if we can't find a online CPU for this hctx,
- * and it should only happen in the path of handling CPU DEAD.
- */
- if (!cpu_online(next_cpu)) {
- if (!tried) {
- tried = true;
- goto select_cpu;
- }
- /*
- * Make sure to re-select CPU next time once after CPUs
- * in hctx->cpumask become online again.
- */
- hctx->next_cpu = next_cpu;
- hctx->next_cpu_batch = 1;
- return WORK_CPU_UNBOUND;
- }
- hctx->next_cpu = next_cpu;
- return next_cpu;
- }
- /**
- * __blk_mq_delay_run_hw_queue - Run (or schedule to run) a hardware queue.
- * @hctx: Pointer to the hardware queue to run.
- * @async: If we want to run the queue asynchronously.
- * @msecs: Microseconds of delay to wait before running the queue.
- *
- * If !@async, try to run the queue now. Else, run the queue asynchronously and
- * with a delay of @msecs.
- */
- static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async,
- unsigned long msecs)
- {
- if (unlikely(blk_mq_hctx_stopped(hctx)))
- return;
- if (!async && !(hctx->flags & BLK_MQ_F_BLOCKING)) {
- int cpu = get_cpu();
- if (cpumask_test_cpu(cpu, hctx->cpumask)) {
- __blk_mq_run_hw_queue(hctx);
- put_cpu();
- return;
- }
- put_cpu();
- }
- kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx), &hctx->run_work,
- msecs_to_jiffies(msecs));
- }
- /**
- * blk_mq_delay_run_hw_queue - Run a hardware queue asynchronously.
- * @hctx: Pointer to the hardware queue to run.
- * @msecs: Microseconds of delay to wait before running the queue.
- *
- * Run a hardware queue asynchronously with a delay of @msecs.
- */
- void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs)
- {
- __blk_mq_delay_run_hw_queue(hctx, true, msecs);
- }
- EXPORT_SYMBOL(blk_mq_delay_run_hw_queue);
- /**
- * blk_mq_run_hw_queue - Start to run a hardware queue.
- * @hctx: Pointer to the hardware queue to run.
- * @async: If we want to run the queue asynchronously.
- *
- * Check if the request queue is not in a quiesced state and if there are
- * pending requests to be sent. If this is true, run the queue to send requests
- * to hardware.
- */
- void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
- {
- int srcu_idx;
- bool need_run;
- /*
- * When queue is quiesced, we may be switching io scheduler, or
- * updating nr_hw_queues, or other things, and we can't run queue
- * any more, even __blk_mq_hctx_has_pending() can't be called safely.
- *
- * And queue will be rerun in blk_mq_unquiesce_queue() if it is
- * quiesced.
- */
- hctx_lock(hctx, &srcu_idx);
- need_run = !blk_queue_quiesced(hctx->queue) &&
- blk_mq_hctx_has_pending(hctx);
- hctx_unlock(hctx, srcu_idx);
- if (need_run)
- __blk_mq_delay_run_hw_queue(hctx, async, 0);
- }
- EXPORT_SYMBOL(blk_mq_run_hw_queue);
- /*
- * Is the request queue handled by an IO scheduler that does not respect
- * hardware queues when dispatching?
- */
- static bool blk_mq_has_sqsched(struct request_queue *q)
- {
- struct elevator_queue *e = q->elevator;
- if (e && e->type->ops.dispatch_request &&
- !(e->type->elevator_features & ELEVATOR_F_MQ_AWARE))
- return true;
- return false;
- }
- /*
- * Return prefered queue to dispatch from (if any) for non-mq aware IO
- * scheduler.
- */
- static struct blk_mq_hw_ctx *blk_mq_get_sq_hctx(struct request_queue *q)
- {
- struct blk_mq_hw_ctx *hctx;
- /*
- * If the IO scheduler does not respect hardware queues when
- * dispatching, we just don't bother with multiple HW queues and
- * dispatch from hctx for the current CPU since running multiple queues
- * just causes lock contention inside the scheduler and pointless cache
- * bouncing.
- */
- hctx = blk_mq_map_queue_type(q, HCTX_TYPE_DEFAULT,
- raw_smp_processor_id());
- if (!blk_mq_hctx_stopped(hctx))
- return hctx;
- return NULL;
- }
- /**
- * blk_mq_run_hw_queues - Run all hardware queues in a request queue.
- * @q: Pointer to the request queue to run.
- * @async: If we want to run the queue asynchronously.
- */
- void blk_mq_run_hw_queues(struct request_queue *q, bool async)
- {
- struct blk_mq_hw_ctx *hctx, *sq_hctx;
- int i;
- sq_hctx = NULL;
- if (blk_mq_has_sqsched(q))
- sq_hctx = blk_mq_get_sq_hctx(q);
- queue_for_each_hw_ctx(q, hctx, i) {
- if (blk_mq_hctx_stopped(hctx))
- continue;
- /*
- * Dispatch from this hctx either if there's no hctx preferred
- * by IO scheduler or if it has requests that bypass the
- * scheduler.
- */
- if (!sq_hctx || sq_hctx == hctx ||
- !list_empty_careful(&hctx->dispatch))
- blk_mq_run_hw_queue(hctx, async);
- }
- }
- EXPORT_SYMBOL(blk_mq_run_hw_queues);
- /**
- * blk_mq_delay_run_hw_queues - Run all hardware queues asynchronously.
- * @q: Pointer to the request queue to run.
- * @msecs: Microseconds of delay to wait before running the queues.
- */
- void blk_mq_delay_run_hw_queues(struct request_queue *q, unsigned long msecs)
- {
- struct blk_mq_hw_ctx *hctx, *sq_hctx;
- int i;
- sq_hctx = NULL;
- if (blk_mq_has_sqsched(q))
- sq_hctx = blk_mq_get_sq_hctx(q);
- queue_for_each_hw_ctx(q, hctx, i) {
- if (blk_mq_hctx_stopped(hctx))
- continue;
- /*
- * Dispatch from this hctx either if there's no hctx preferred
- * by IO scheduler or if it has requests that bypass the
- * scheduler.
- */
- if (!sq_hctx || sq_hctx == hctx ||
- !list_empty_careful(&hctx->dispatch))
- blk_mq_delay_run_hw_queue(hctx, msecs);
- }
- }
- EXPORT_SYMBOL(blk_mq_delay_run_hw_queues);
- /**
- * blk_mq_queue_stopped() - check whether one or more hctxs have been stopped
- * @q: request queue.
- *
- * The caller is responsible for serializing this function against
- * blk_mq_{start,stop}_hw_queue().
- */
- bool blk_mq_queue_stopped(struct request_queue *q)
- {
- struct blk_mq_hw_ctx *hctx;
- int i;
- queue_for_each_hw_ctx(q, hctx, i)
- if (blk_mq_hctx_stopped(hctx))
- return true;
- return false;
- }
- EXPORT_SYMBOL(blk_mq_queue_stopped);
- /*
- * This function is often used for pausing .queue_rq() by driver when
- * there isn't enough resource or some conditions aren't satisfied, and
- * BLK_STS_RESOURCE is usually returned.
- *
- * We do not guarantee that dispatch can be drained or blocked
- * after blk_mq_stop_hw_queue() returns. Please use
- * blk_mq_quiesce_queue() for that requirement.
- */
- void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx)
- {
- cancel_delayed_work(&hctx->run_work);
- set_bit(BLK_MQ_S_STOPPED, &hctx->state);
- }
- EXPORT_SYMBOL(blk_mq_stop_hw_queue);
- /*
- * This function is often used for pausing .queue_rq() by driver when
- * there isn't enough resource or some conditions aren't satisfied, and
- * BLK_STS_RESOURCE is usually returned.
- *
- * We do not guarantee that dispatch can be drained or blocked
- * after blk_mq_stop_hw_queues() returns. Please use
- * blk_mq_quiesce_queue() for that requirement.
- */
- void blk_mq_stop_hw_queues(struct request_queue *q)
- {
- struct blk_mq_hw_ctx *hctx;
- int i;
- queue_for_each_hw_ctx(q, hctx, i)
- blk_mq_stop_hw_queue(hctx);
- }
- EXPORT_SYMBOL(blk_mq_stop_hw_queues);
- void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx)
- {
- clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
- blk_mq_run_hw_queue(hctx, false);
- }
- EXPORT_SYMBOL(blk_mq_start_hw_queue);
- void blk_mq_start_hw_queues(struct request_queue *q)
- {
- struct blk_mq_hw_ctx *hctx;
- int i;
- queue_for_each_hw_ctx(q, hctx, i)
- blk_mq_start_hw_queue(hctx);
- }
- EXPORT_SYMBOL(blk_mq_start_hw_queues);
- void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
- {
- if (!blk_mq_hctx_stopped(hctx))
- return;
- clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
- blk_mq_run_hw_queue(hctx, async);
- }
- EXPORT_SYMBOL_GPL(blk_mq_start_stopped_hw_queue);
- void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async)
- {
- struct blk_mq_hw_ctx *hctx;
- int i;
- queue_for_each_hw_ctx(q, hctx, i)
- blk_mq_start_stopped_hw_queue(hctx, async);
- }
- EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues);
- static void blk_mq_run_work_fn(struct work_struct *work)
- {
- struct blk_mq_hw_ctx *hctx;
- hctx = container_of(work, struct blk_mq_hw_ctx, run_work.work);
- /*
- * If we are stopped, don't run the queue.
- */
- if (blk_mq_hctx_stopped(hctx))
- return;
- __blk_mq_run_hw_queue(hctx);
- }
- static inline void __blk_mq_insert_req_list(struct blk_mq_hw_ctx *hctx,
- struct request *rq,
- bool at_head)
- {
- struct blk_mq_ctx *ctx = rq->mq_ctx;
- enum hctx_type type = hctx->type;
- lockdep_assert_held(&ctx->lock);
- trace_block_rq_insert(hctx->queue, rq);
- if (at_head)
- list_add(&rq->queuelist, &ctx->rq_lists[type]);
- else
- list_add_tail(&rq->queuelist, &ctx->rq_lists[type]);
- }
- void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
- bool at_head)
- {
- struct blk_mq_ctx *ctx = rq->mq_ctx;
- lockdep_assert_held(&ctx->lock);
- __blk_mq_insert_req_list(hctx, rq, at_head);
- blk_mq_hctx_mark_pending(hctx, ctx);
- }
- /**
- * blk_mq_request_bypass_insert - Insert a request at dispatch list.
- * @rq: Pointer to request to be inserted.
- * @at_head: true if the request should be inserted at the head of the list.
- * @run_queue: If we should run the hardware queue after inserting the request.
- *
- * Should only be used carefully, when the caller knows we want to
- * bypass a potential IO scheduler on the target device.
- */
- void blk_mq_request_bypass_insert(struct request *rq, bool at_head,
- bool run_queue)
- {
- struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
- spin_lock(&hctx->lock);
- if (at_head)
- list_add(&rq->queuelist, &hctx->dispatch);
- else
- list_add_tail(&rq->queuelist, &hctx->dispatch);
- spin_unlock(&hctx->lock);
- if (run_queue)
- blk_mq_run_hw_queue(hctx, false);
- }
- void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx,
- struct list_head *list)
- {
- struct request *rq;
- enum hctx_type type = hctx->type;
- /*
- * preemption doesn't flush plug list, so it's possible ctx->cpu is
- * offline now
- */
- list_for_each_entry(rq, list, queuelist) {
- BUG_ON(rq->mq_ctx != ctx);
- trace_block_rq_insert(hctx->queue, rq);
- }
- spin_lock(&ctx->lock);
- list_splice_tail_init(list, &ctx->rq_lists[type]);
- blk_mq_hctx_mark_pending(hctx, ctx);
- spin_unlock(&ctx->lock);
- }
- static int plug_rq_cmp(void *priv, struct list_head *a, struct list_head *b)
- {
- struct request *rqa = container_of(a, struct request, queuelist);
- struct request *rqb = container_of(b, struct request, queuelist);
- if (rqa->mq_ctx != rqb->mq_ctx)
- return rqa->mq_ctx > rqb->mq_ctx;
- if (rqa->mq_hctx != rqb->mq_hctx)
- return rqa->mq_hctx > rqb->mq_hctx;
- return blk_rq_pos(rqa) > blk_rq_pos(rqb);
- }
- void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
- {
- LIST_HEAD(list);
- if (list_empty(&plug->mq_list))
- return;
- list_splice_init(&plug->mq_list, &list);
- if (plug->rq_count > 2 && plug->multiple_queues)
- list_sort(NULL, &list, plug_rq_cmp);
- plug->rq_count = 0;
- do {
- struct list_head rq_list;
- struct request *rq, *head_rq = list_entry_rq(list.next);
- struct list_head *pos = &head_rq->queuelist; /* skip first */
- struct blk_mq_hw_ctx *this_hctx = head_rq->mq_hctx;
- struct blk_mq_ctx *this_ctx = head_rq->mq_ctx;
- unsigned int depth = 1;
- list_for_each_continue(pos, &list) {
- rq = list_entry_rq(pos);
- BUG_ON(!rq->q);
- if (rq->mq_hctx != this_hctx || rq->mq_ctx != this_ctx)
- break;
- depth++;
- }
- list_cut_before(&rq_list, &list, pos);
- trace_block_unplug(head_rq->q, depth, !from_schedule);
- blk_mq_sched_insert_requests(this_hctx, this_ctx, &rq_list,
- from_schedule);
- } while(!list_empty(&list));
- }
- static void blk_mq_bio_to_request(struct request *rq, struct bio *bio,
- unsigned int nr_segs)
- {
- int err;
- if (bio->bi_opf & REQ_RAHEAD)
- rq->cmd_flags |= REQ_FAILFAST_MASK;
- rq->__sector = bio->bi_iter.bi_sector;
- rq->write_hint = bio->bi_write_hint;
- blk_rq_bio_prep(rq, bio, nr_segs);
- /* This can't fail, since GFP_NOIO includes __GFP_DIRECT_RECLAIM. */
- err = blk_crypto_rq_bio_prep(rq, bio, GFP_NOIO);
- WARN_ON_ONCE(err);
- blk_account_io_start(rq);
- }
- static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx,
- struct request *rq,
- blk_qc_t *cookie, bool last)
- {
- struct request_queue *q = rq->q;
- struct blk_mq_queue_data bd = {
- .rq = rq,
- .last = last,
- };
- blk_qc_t new_cookie;
- blk_status_t ret;
- new_cookie = request_to_qc_t(hctx, rq);
- /*
- * For OK queue, we are done. For error, caller may kill it.
- * Any other error (busy), just add it to our list as we
- * previously would have done.
- */
- ret = q->mq_ops->queue_rq(hctx, &bd);
- switch (ret) {
- case BLK_STS_OK:
- blk_mq_update_dispatch_busy(hctx, false);
- *cookie = new_cookie;
- break;
- case BLK_STS_RESOURCE:
- case BLK_STS_DEV_RESOURCE:
- blk_mq_update_dispatch_busy(hctx, true);
- __blk_mq_requeue_request(rq);
- break;
- default:
- blk_mq_update_dispatch_busy(hctx, false);
- *cookie = BLK_QC_T_NONE;
- break;
- }
- return ret;
- }
- static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
- struct request *rq,
- blk_qc_t *cookie,
- bool bypass_insert, bool last)
- {
- struct request_queue *q = rq->q;
- bool run_queue = true;
- /*
- * RCU or SRCU read lock is needed before checking quiesced flag.
- *
- * When queue is stopped or quiesced, ignore 'bypass_insert' from
- * blk_mq_request_issue_directly(), and return BLK_STS_OK to caller,
- * and avoid driver to try to dispatch again.
- */
- if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q)) {
- run_queue = false;
- bypass_insert = false;
- goto insert;
- }
- if (q->elevator && !bypass_insert)
- goto insert;
- if (!blk_mq_get_dispatch_budget(q))
- goto insert;
- if (!blk_mq_get_driver_tag(rq)) {
- blk_mq_put_dispatch_budget(q);
- goto insert;
- }
- return __blk_mq_issue_directly(hctx, rq, cookie, last);
- insert:
- if (bypass_insert)
- return BLK_STS_RESOURCE;
- blk_mq_sched_insert_request(rq, false, run_queue, false);
- return BLK_STS_OK;
- }
- /**
- * blk_mq_try_issue_directly - Try to send a request directly to device driver.
- * @hctx: Pointer of the associated hardware queue.
- * @rq: Pointer to request to be sent.
- * @cookie: Request queue cookie.
- *
- * If the device has enough resources to accept a new request now, send the
- * request directly to device driver. Else, insert at hctx->dispatch queue, so
- * we can try send it another time in the future. Requests inserted at this
- * queue have higher priority.
- */
- static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
- struct request *rq, blk_qc_t *cookie)
- {
- blk_status_t ret;
- int srcu_idx;
- might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING);
- hctx_lock(hctx, &srcu_idx);
- ret = __blk_mq_try_issue_directly(hctx, rq, cookie, false, true);
- if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE)
- blk_mq_request_bypass_insert(rq, false, true);
- else if (ret != BLK_STS_OK)
- blk_mq_end_request(rq, ret);
- hctx_unlock(hctx, srcu_idx);
- }
- blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last)
- {
- blk_status_t ret;
- int srcu_idx;
- blk_qc_t unused_cookie;
- struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
- hctx_lock(hctx, &srcu_idx);
- ret = __blk_mq_try_issue_directly(hctx, rq, &unused_cookie, true, last);
- hctx_unlock(hctx, srcu_idx);
- return ret;
- }
- void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
- struct list_head *list)
- {
- int queued = 0;
- int errors = 0;
- while (!list_empty(list)) {
- blk_status_t ret;
- struct request *rq = list_first_entry(list, struct request,
- queuelist);
- list_del_init(&rq->queuelist);
- ret = blk_mq_request_issue_directly(rq, list_empty(list));
- if (ret != BLK_STS_OK) {
- if (ret == BLK_STS_RESOURCE ||
- ret == BLK_STS_DEV_RESOURCE) {
- blk_mq_request_bypass_insert(rq, false,
- list_empty(list));
- break;
- }
- blk_mq_end_request(rq, ret);
- errors++;
- } else
- queued++;
- }
- /*
- * If we didn't flush the entire list, we could have told
- * the driver there was more coming, but that turned out to
- * be a lie.
- */
- if ((!list_empty(list) || errors) &&
- hctx->queue->mq_ops->commit_rqs && queued)
- hctx->queue->mq_ops->commit_rqs(hctx);
- }
- static void blk_add_rq_to_plug(struct blk_plug *plug, struct request *rq)
- {
- list_add_tail(&rq->queuelist, &plug->mq_list);
- plug->rq_count++;
- if (!plug->multiple_queues && !list_is_singular(&plug->mq_list)) {
- struct request *tmp;
- tmp = list_first_entry(&plug->mq_list, struct request,
- queuelist);
- if (tmp->q != rq->q)
- plug->multiple_queues = true;
- }
- }
- /*
- * Allow 2x BLK_MAX_REQUEST_COUNT requests on plug queue for multiple
- * queues. This is important for md arrays to benefit from merging
- * requests.
- */
- static inline unsigned short blk_plug_max_rq_count(struct blk_plug *plug)
- {
- if (plug->multiple_queues)
- return BLK_MAX_REQUEST_COUNT * 2;
- return BLK_MAX_REQUEST_COUNT;
- }
- /**
- * blk_mq_submit_bio - Create and send a request to block device.
- * @bio: Bio pointer.
- *
- * Builds up a request structure from @q and @bio and send to the device. The
- * request may not be queued directly to hardware if:
- * * This request can be merged with another one
- * * We want to place request at plug queue for possible future merging
- * * There is an IO scheduler active at this queue
- *
- * It will not queue the request if there is an error with the bio, or at the
- * request creation.
- *
- * Returns: Request queue cookie.
- */
- blk_qc_t blk_mq_submit_bio(struct bio *bio)
- {
- struct request_queue *q = bio->bi_disk->queue;
- const int is_sync = op_is_sync(bio->bi_opf);
- const int is_flush_fua = op_is_flush(bio->bi_opf);
- struct blk_mq_alloc_data data = {
- .q = q,
- };
- struct request *rq;
- struct blk_plug *plug;
- struct request *same_queue_rq = NULL;
- unsigned int nr_segs;
- blk_qc_t cookie;
- blk_status_t ret;
- blk_queue_bounce(q, &bio);
- __blk_queue_split(&bio, &nr_segs);
- if (!bio_integrity_prep(bio))
- goto queue_exit;
- if (!is_flush_fua && !blk_queue_nomerges(q) &&
- blk_attempt_plug_merge(q, bio, nr_segs, &same_queue_rq))
- goto queue_exit;
- if (blk_mq_sched_bio_merge(q, bio, nr_segs))
- goto queue_exit;
- rq_qos_throttle(q, bio);
- data.cmd_flags = bio->bi_opf;
- rq = __blk_mq_alloc_request(&data);
- if (unlikely(!rq)) {
- rq_qos_cleanup(q, bio);
- if (bio->bi_opf & REQ_NOWAIT)
- bio_wouldblock_error(bio);
- goto queue_exit;
- }
- trace_block_getrq(q, bio, bio->bi_opf);
- rq_qos_track(q, rq, bio);
- cookie = request_to_qc_t(data.hctx, rq);
- blk_mq_bio_to_request(rq, bio, nr_segs);
- ret = blk_crypto_init_request(rq);
- if (ret != BLK_STS_OK) {
- bio->bi_status = ret;
- bio_endio(bio);
- blk_mq_free_request(rq);
- return BLK_QC_T_NONE;
- }
- plug = blk_mq_plug(q, bio);
- if (unlikely(is_flush_fua)) {
- /* Bypass scheduler for flush requests */
- blk_insert_flush(rq);
- blk_mq_run_hw_queue(data.hctx, true);
- } else if (plug && (q->nr_hw_queues == 1 ||
- blk_mq_is_sbitmap_shared(rq->mq_hctx->flags) ||
- q->mq_ops->commit_rqs || !blk_queue_nonrot(q))) {
- /*
- * Use plugging if we have a ->commit_rqs() hook as well, as
- * we know the driver uses bd->last in a smart fashion.
- *
- * Use normal plugging if this disk is slow HDD, as sequential
- * IO may benefit a lot from plug merging.
- */
- unsigned int request_count = plug->rq_count;
- struct request *last = NULL;
- if (!request_count)
- trace_block_plug(q);
- else
- last = list_entry_rq(plug->mq_list.prev);
- if (request_count >= blk_plug_max_rq_count(plug) || (last &&
- blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE)) {
- blk_flush_plug_list(plug, false);
- trace_block_plug(q);
- }
- blk_add_rq_to_plug(plug, rq);
- } else if (q->elevator) {
- /* Insert the request at the IO scheduler queue */
- blk_mq_sched_insert_request(rq, false, true, true);
- } else if (plug && !blk_queue_nomerges(q)) {
- /*
- * We do limited plugging. If the bio can be merged, do that.
- * Otherwise the existing request in the plug list will be
- * issued. So the plug list will have one request at most
- * The plug list might get flushed before this. If that happens,
- * the plug list is empty, and same_queue_rq is invalid.
- */
- if (list_empty(&plug->mq_list))
- same_queue_rq = NULL;
- if (same_queue_rq) {
- list_del_init(&same_queue_rq->queuelist);
- plug->rq_count--;
- }
- blk_add_rq_to_plug(plug, rq);
- trace_block_plug(q);
- if (same_queue_rq) {
- data.hctx = same_queue_rq->mq_hctx;
- trace_block_unplug(q, 1, true);
- blk_mq_try_issue_directly(data.hctx, same_queue_rq,
- &cookie);
- }
- } else if ((q->nr_hw_queues > 1 && is_sync) ||
- !data.hctx->dispatch_busy) {
- /*
- * There is no scheduler and we can try to send directly
- * to the hardware.
- */
- blk_mq_try_issue_directly(data.hctx, rq, &cookie);
- } else {
- /* Default case. */
- blk_mq_sched_insert_request(rq, false, true, true);
- }
- return cookie;
- queue_exit:
- blk_queue_exit(q);
- return BLK_QC_T_NONE;
- }
- static size_t order_to_size(unsigned int order)
- {
- return (size_t)PAGE_SIZE << order;
- }
- /* called before freeing request pool in @tags */
- static void blk_mq_clear_rq_mapping(struct blk_mq_tag_set *set,
- struct blk_mq_tags *tags, unsigned int hctx_idx)
- {
- struct blk_mq_tags *drv_tags = set->tags[hctx_idx];
- struct page *page;
- unsigned long flags;
- list_for_each_entry(page, &tags->page_list, lru) {
- unsigned long start = (unsigned long)page_address(page);
- unsigned long end = start + order_to_size(page->private);
- int i;
- for (i = 0; i < set->queue_depth; i++) {
- struct request *rq = drv_tags->rqs[i];
- unsigned long rq_addr = (unsigned long)rq;
- if (rq_addr >= start && rq_addr < end) {
- WARN_ON_ONCE(refcount_read(&rq->ref) != 0);
- cmpxchg(&drv_tags->rqs[i], rq, NULL);
- }
- }
- }
- /*
- * Wait until all pending iteration is done.
- *
- * Request reference is cleared and it is guaranteed to be observed
- * after the ->lock is released.
- */
- spin_lock_irqsave(&drv_tags->lock, flags);
- spin_unlock_irqrestore(&drv_tags->lock, flags);
- }
- void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
- unsigned int hctx_idx)
- {
- struct page *page;
- if (tags->rqs && set->ops->exit_request) {
- int i;
- for (i = 0; i < tags->nr_tags; i++) {
- struct request *rq = tags->static_rqs[i];
- if (!rq)
- continue;
- set->ops->exit_request(set, rq, hctx_idx);
- tags->static_rqs[i] = NULL;
- }
- }
- blk_mq_clear_rq_mapping(set, tags, hctx_idx);
- while (!list_empty(&tags->page_list)) {
- page = list_first_entry(&tags->page_list, struct page, lru);
- list_del_init(&page->lru);
- /*
- * Remove kmemleak object previously allocated in
- * blk_mq_alloc_rqs().
- */
- kmemleak_free(page_address(page));
- __free_pages(page, page->private);
- }
- }
- void blk_mq_free_rq_map(struct blk_mq_tags *tags, unsigned int flags)
- {
- kfree(tags->rqs);
- tags->rqs = NULL;
- kfree(tags->static_rqs);
- tags->static_rqs = NULL;
- blk_mq_free_tags(tags, flags);
- }
- struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
- unsigned int hctx_idx,
- unsigned int nr_tags,
- unsigned int reserved_tags,
- unsigned int flags)
- {
- struct blk_mq_tags *tags;
- int node;
- node = blk_mq_hw_queue_to_node(&set->map[HCTX_TYPE_DEFAULT], hctx_idx);
- if (node == NUMA_NO_NODE)
- node = set->numa_node;
- tags = blk_mq_init_tags(nr_tags, reserved_tags, node, flags);
- if (!tags)
- return NULL;
- tags->rqs = kcalloc_node(nr_tags, sizeof(struct request *),
- GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
- node);
- if (!tags->rqs) {
- blk_mq_free_tags(tags, flags);
- return NULL;
- }
- tags->static_rqs = kcalloc_node(nr_tags, sizeof(struct request *),
- GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
- node);
- if (!tags->static_rqs) {
- kfree(tags->rqs);
- blk_mq_free_tags(tags, flags);
- return NULL;
- }
- return tags;
- }
- static int blk_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
- unsigned int hctx_idx, int node)
- {
- int ret;
- if (set->ops->init_request) {
- ret = set->ops->init_request(set, rq, hctx_idx, node);
- if (ret)
- return ret;
- }
- WRITE_ONCE(rq->state, MQ_RQ_IDLE);
- return 0;
- }
- int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
- unsigned int hctx_idx, unsigned int depth)
- {
- unsigned int i, j, entries_per_page, max_order = 4;
- size_t rq_size, left;
- int node;
- node = blk_mq_hw_queue_to_node(&set->map[HCTX_TYPE_DEFAULT], hctx_idx);
- if (node == NUMA_NO_NODE)
- node = set->numa_node;
- INIT_LIST_HEAD(&tags->page_list);
- /*
- * rq_size is the size of the request plus driver payload, rounded
- * to the cacheline size
- */
- rq_size = round_up(sizeof(struct request) + set->cmd_size,
- cache_line_size());
- trace_android_vh_blk_alloc_rqs(&rq_size, set, tags);
- left = rq_size * depth;
- for (i = 0; i < depth; ) {
- int this_order = max_order;
- struct page *page;
- int to_do;
- void *p;
- while (this_order && left < order_to_size(this_order - 1))
- this_order--;
- do {
- page = alloc_pages_node(node,
- GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY | __GFP_ZERO,
- this_order);
- if (page)
- break;
- if (!this_order--)
- break;
- if (order_to_size(this_order) < rq_size)
- break;
- } while (1);
- if (!page)
- goto fail;
- page->private = this_order;
- list_add_tail(&page->lru, &tags->page_list);
- p = page_address(page);
- /*
- * Allow kmemleak to scan these pages as they contain pointers
- * to additional allocations like via ops->init_request().
- */
- kmemleak_alloc(p, order_to_size(this_order), 1, GFP_NOIO);
- entries_per_page = order_to_size(this_order) / rq_size;
- to_do = min(entries_per_page, depth - i);
- left -= to_do * rq_size;
- for (j = 0; j < to_do; j++) {
- struct request *rq = p;
- tags->static_rqs[i] = rq;
- if (blk_mq_init_request(set, rq, hctx_idx, node)) {
- tags->static_rqs[i] = NULL;
- goto fail;
- }
- p += rq_size;
- i++;
- }
- }
- return 0;
- fail:
- blk_mq_free_rqs(set, tags, hctx_idx);
- return -ENOMEM;
- }
- struct rq_iter_data {
- struct blk_mq_hw_ctx *hctx;
- bool has_rq;
- };
- static bool blk_mq_has_request(struct request *rq, void *data, bool reserved)
- {
- struct rq_iter_data *iter_data = data;
- if (rq->mq_hctx != iter_data->hctx)
- return true;
- iter_data->has_rq = true;
- return false;
- }
- static bool blk_mq_hctx_has_requests(struct blk_mq_hw_ctx *hctx)
- {
- struct blk_mq_tags *tags = hctx->sched_tags ?
- hctx->sched_tags : hctx->tags;
- struct rq_iter_data data = {
- .hctx = hctx,
- };
- blk_mq_all_tag_iter(tags, blk_mq_has_request, &data);
- return data.has_rq;
- }
- static inline bool blk_mq_last_cpu_in_hctx(unsigned int cpu,
- struct blk_mq_hw_ctx *hctx)
- {
- if (cpumask_next_and(-1, hctx->cpumask, cpu_online_mask) != cpu)
- return false;
- if (cpumask_next_and(cpu, hctx->cpumask, cpu_online_mask) < nr_cpu_ids)
- return false;
- return true;
- }
- static int blk_mq_hctx_notify_offline(unsigned int cpu, struct hlist_node *node)
- {
- struct blk_mq_hw_ctx *hctx = hlist_entry_safe(node,
- struct blk_mq_hw_ctx, cpuhp_online);
- if (!cpumask_test_cpu(cpu, hctx->cpumask) ||
- !blk_mq_last_cpu_in_hctx(cpu, hctx))
- return 0;
- /*
- * Prevent new request from being allocated on the current hctx.
- *
- * The smp_mb__after_atomic() Pairs with the implied barrier in
- * test_and_set_bit_lock in sbitmap_get(). Ensures the inactive flag is
- * seen once we return from the tag allocator.
- */
- set_bit(BLK_MQ_S_INACTIVE, &hctx->state);
- smp_mb__after_atomic();
- /*
- * Try to grab a reference to the queue and wait for any outstanding
- * requests. If we could not grab a reference the queue has been
- * frozen and there are no requests.
- */
- if (percpu_ref_tryget(&hctx->queue->q_usage_counter)) {
- while (blk_mq_hctx_has_requests(hctx))
- msleep(5);
- percpu_ref_put(&hctx->queue->q_usage_counter);
- }
- return 0;
- }
- static int blk_mq_hctx_notify_online(unsigned int cpu, struct hlist_node *node)
- {
- struct blk_mq_hw_ctx *hctx = hlist_entry_safe(node,
- struct blk_mq_hw_ctx, cpuhp_online);
- if (cpumask_test_cpu(cpu, hctx->cpumask))
- clear_bit(BLK_MQ_S_INACTIVE, &hctx->state);
- return 0;
- }
- /*
- * 'cpu' is going away. splice any existing rq_list entries from this
- * software queue to the hw queue dispatch list, and ensure that it
- * gets run.
- */
- static int blk_mq_hctx_notify_dead(unsigned int cpu, struct hlist_node *node)
- {
- struct blk_mq_hw_ctx *hctx;
- struct blk_mq_ctx *ctx;
- LIST_HEAD(tmp);
- enum hctx_type type;
- hctx = hlist_entry_safe(node, struct blk_mq_hw_ctx, cpuhp_dead);
- if (!cpumask_test_cpu(cpu, hctx->cpumask))
- return 0;
- ctx = __blk_mq_get_ctx(hctx->queue, cpu);
- type = hctx->type;
- spin_lock(&ctx->lock);
- if (!list_empty(&ctx->rq_lists[type])) {
- list_splice_init(&ctx->rq_lists[type], &tmp);
- blk_mq_hctx_clear_pending(hctx, ctx);
- }
- spin_unlock(&ctx->lock);
- if (list_empty(&tmp))
- return 0;
- spin_lock(&hctx->lock);
- list_splice_tail_init(&tmp, &hctx->dispatch);
- spin_unlock(&hctx->lock);
- blk_mq_run_hw_queue(hctx, true);
- return 0;
- }
- static void blk_mq_remove_cpuhp(struct blk_mq_hw_ctx *hctx)
- {
- if (!(hctx->flags & BLK_MQ_F_STACKING))
- cpuhp_state_remove_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE,
- &hctx->cpuhp_online);
- cpuhp_state_remove_instance_nocalls(CPUHP_BLK_MQ_DEAD,
- &hctx->cpuhp_dead);
- }
- /*
- * Before freeing hw queue, clearing the flush request reference in
- * tags->rqs[] for avoiding potential UAF.
- */
- static void blk_mq_clear_flush_rq_mapping(struct blk_mq_tags *tags,
- unsigned int queue_depth, struct request *flush_rq)
- {
- int i;
- unsigned long flags;
- /* The hw queue may not be mapped yet */
- if (!tags)
- return;
- WARN_ON_ONCE(refcount_read(&flush_rq->ref) != 0);
- for (i = 0; i < queue_depth; i++)
- cmpxchg(&tags->rqs[i], flush_rq, NULL);
- /*
- * Wait until all pending iteration is done.
- *
- * Request reference is cleared and it is guaranteed to be observed
- * after the ->lock is released.
- */
- spin_lock_irqsave(&tags->lock, flags);
- spin_unlock_irqrestore(&tags->lock, flags);
- }
- /* hctx->ctxs will be freed in queue's release handler */
- static void blk_mq_exit_hctx(struct request_queue *q,
- struct blk_mq_tag_set *set,
- struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
- {
- struct request *flush_rq = hctx->fq->flush_rq;
- if (blk_mq_hw_queue_mapped(hctx))
- blk_mq_tag_idle(hctx);
- blk_mq_clear_flush_rq_mapping(set->tags[hctx_idx],
- set->queue_depth, flush_rq);
- if (set->ops->exit_request)
- set->ops->exit_request(set, flush_rq, hctx_idx);
- if (set->ops->exit_hctx)
- set->ops->exit_hctx(hctx, hctx_idx);
- blk_mq_remove_cpuhp(hctx);
- spin_lock(&q->unused_hctx_lock);
- list_add(&hctx->hctx_list, &q->unused_hctx_list);
- spin_unlock(&q->unused_hctx_lock);
- }
- static void blk_mq_exit_hw_queues(struct request_queue *q,
- struct blk_mq_tag_set *set, int nr_queue)
- {
- struct blk_mq_hw_ctx *hctx;
- unsigned int i;
- queue_for_each_hw_ctx(q, hctx, i) {
- if (i == nr_queue)
- break;
- blk_mq_debugfs_unregister_hctx(hctx);
- blk_mq_exit_hctx(q, set, hctx, i);
- }
- }
- static int blk_mq_hw_ctx_size(struct blk_mq_tag_set *tag_set)
- {
- int hw_ctx_size = sizeof(struct blk_mq_hw_ctx);
- BUILD_BUG_ON(ALIGN(offsetof(struct blk_mq_hw_ctx, srcu),
- __alignof__(struct blk_mq_hw_ctx)) !=
- sizeof(struct blk_mq_hw_ctx));
- if (tag_set->flags & BLK_MQ_F_BLOCKING)
- hw_ctx_size += sizeof(struct srcu_struct);
- return hw_ctx_size;
- }
- static int blk_mq_init_hctx(struct request_queue *q,
- struct blk_mq_tag_set *set,
- struct blk_mq_hw_ctx *hctx, unsigned hctx_idx)
- {
- hctx->queue_num = hctx_idx;
- if (!(hctx->flags & BLK_MQ_F_STACKING))
- cpuhp_state_add_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE,
- &hctx->cpuhp_online);
- cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD, &hctx->cpuhp_dead);
- hctx->tags = set->tags[hctx_idx];
- if (set->ops->init_hctx &&
- set->ops->init_hctx(hctx, set->driver_data, hctx_idx))
- goto unregister_cpu_notifier;
- if (blk_mq_init_request(set, hctx->fq->flush_rq, hctx_idx,
- hctx->numa_node))
- goto exit_hctx;
- return 0;
- exit_hctx:
- if (set->ops->exit_hctx)
- set->ops->exit_hctx(hctx, hctx_idx);
- unregister_cpu_notifier:
- blk_mq_remove_cpuhp(hctx);
- return -1;
- }
- static struct blk_mq_hw_ctx *
- blk_mq_alloc_hctx(struct request_queue *q, struct blk_mq_tag_set *set,
- int node)
- {
- struct blk_mq_hw_ctx *hctx;
- gfp_t gfp = GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY;
- hctx = kzalloc_node(blk_mq_hw_ctx_size(set), gfp, node);
- if (!hctx)
- goto fail_alloc_hctx;
- if (!zalloc_cpumask_var_node(&hctx->cpumask, gfp, node))
- goto free_hctx;
- atomic_set(&hctx->nr_active, 0);
- if (node == NUMA_NO_NODE)
- node = set->numa_node;
- hctx->numa_node = node;
- INIT_DELAYED_WORK(&hctx->run_work, blk_mq_run_work_fn);
- spin_lock_init(&hctx->lock);
- INIT_LIST_HEAD(&hctx->dispatch);
- hctx->queue = q;
- hctx->flags = set->flags & ~BLK_MQ_F_TAG_QUEUE_SHARED;
- INIT_LIST_HEAD(&hctx->hctx_list);
- /*
- * Allocate space for all possible cpus to avoid allocation at
- * runtime
- */
- hctx->ctxs = kmalloc_array_node(nr_cpu_ids, sizeof(void *),
- gfp, node);
- if (!hctx->ctxs)
- goto free_cpumask;
- if (sbitmap_init_node(&hctx->ctx_map, nr_cpu_ids, ilog2(8),
- gfp, node))
- goto free_ctxs;
- hctx->nr_ctx = 0;
- spin_lock_init(&hctx->dispatch_wait_lock);
- init_waitqueue_func_entry(&hctx->dispatch_wait, blk_mq_dispatch_wake);
- INIT_LIST_HEAD(&hctx->dispatch_wait.entry);
- hctx->fq = blk_alloc_flush_queue(hctx->numa_node, set->cmd_size, gfp);
- if (!hctx->fq)
- goto free_bitmap;
- if (hctx->flags & BLK_MQ_F_BLOCKING)
- init_srcu_struct(hctx->srcu);
- blk_mq_hctx_kobj_init(hctx);
- return hctx;
- free_bitmap:
- sbitmap_free(&hctx->ctx_map);
- free_ctxs:
- kfree(hctx->ctxs);
- free_cpumask:
- free_cpumask_var(hctx->cpumask);
- free_hctx:
- kfree(hctx);
- fail_alloc_hctx:
- return NULL;
- }
- static void blk_mq_init_cpu_queues(struct request_queue *q,
- unsigned int nr_hw_queues)
- {
- struct blk_mq_tag_set *set = q->tag_set;
- unsigned int i, j;
- for_each_possible_cpu(i) {
- struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i);
- struct blk_mq_hw_ctx *hctx;
- int k;
- __ctx->cpu = i;
- spin_lock_init(&__ctx->lock);
- for (k = HCTX_TYPE_DEFAULT; k < HCTX_MAX_TYPES; k++)
- INIT_LIST_HEAD(&__ctx->rq_lists[k]);
- __ctx->queue = q;
- /*
- * Set local node, IFF we have more than one hw queue. If
- * not, we remain on the home node of the device
- */
- for (j = 0; j < set->nr_maps; j++) {
- hctx = blk_mq_map_queue_type(q, j, i);
- if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE)
- hctx->numa_node = cpu_to_node(i);
- }
- }
- }
- static bool __blk_mq_alloc_map_and_request(struct blk_mq_tag_set *set,
- int hctx_idx)
- {
- unsigned int flags = set->flags;
- int ret = 0;
- set->tags[hctx_idx] = blk_mq_alloc_rq_map(set, hctx_idx,
- set->queue_depth, set->reserved_tags, flags);
- if (!set->tags[hctx_idx])
- return false;
- ret = blk_mq_alloc_rqs(set, set->tags[hctx_idx], hctx_idx,
- set->queue_depth);
- if (!ret)
- return true;
- blk_mq_free_rq_map(set->tags[hctx_idx], flags);
- set->tags[hctx_idx] = NULL;
- return false;
- }
- static void blk_mq_free_map_and_requests(struct blk_mq_tag_set *set,
- unsigned int hctx_idx)
- {
- unsigned int flags = set->flags;
- if (set->tags && set->tags[hctx_idx]) {
- blk_mq_free_rqs(set, set->tags[hctx_idx], hctx_idx);
- blk_mq_free_rq_map(set->tags[hctx_idx], flags);
- set->tags[hctx_idx] = NULL;
- }
- }
- static void blk_mq_map_swqueue(struct request_queue *q)
- {
- unsigned int i, j, hctx_idx;
- struct blk_mq_hw_ctx *hctx;
- struct blk_mq_ctx *ctx;
- struct blk_mq_tag_set *set = q->tag_set;
- queue_for_each_hw_ctx(q, hctx, i) {
- cpumask_clear(hctx->cpumask);
- hctx->nr_ctx = 0;
- hctx->dispatch_from = NULL;
- }
- /*
- * Map software to hardware queues.
- *
- * If the cpu isn't present, the cpu is mapped to first hctx.
- */
- for_each_possible_cpu(i) {
- ctx = per_cpu_ptr(q->queue_ctx, i);
- for (j = 0; j < set->nr_maps; j++) {
- if (!set->map[j].nr_queues) {
- ctx->hctxs[j] = blk_mq_map_queue_type(q,
- HCTX_TYPE_DEFAULT, i);
- continue;
- }
- hctx_idx = set->map[j].mq_map[i];
- /* unmapped hw queue can be remapped after CPU topo changed */
- if (!set->tags[hctx_idx] &&
- !__blk_mq_alloc_map_and_request(set, hctx_idx)) {
- /*
- * If tags initialization fail for some hctx,
- * that hctx won't be brought online. In this
- * case, remap the current ctx to hctx[0] which
- * is guaranteed to always have tags allocated
- */
- set->map[j].mq_map[i] = 0;
- }
- hctx = blk_mq_map_queue_type(q, j, i);
- ctx->hctxs[j] = hctx;
- /*
- * If the CPU is already set in the mask, then we've
- * mapped this one already. This can happen if
- * devices share queues across queue maps.
- */
- if (cpumask_test_cpu(i, hctx->cpumask))
- continue;
- cpumask_set_cpu(i, hctx->cpumask);
- hctx->type = j;
- ctx->index_hw[hctx->type] = hctx->nr_ctx;
- hctx->ctxs[hctx->nr_ctx++] = ctx;
- /*
- * If the nr_ctx type overflows, we have exceeded the
- * amount of sw queues we can support.
- */
- BUG_ON(!hctx->nr_ctx);
- }
- for (; j < HCTX_MAX_TYPES; j++)
- ctx->hctxs[j] = blk_mq_map_queue_type(q,
- HCTX_TYPE_DEFAULT, i);
- }
- queue_for_each_hw_ctx(q, hctx, i) {
- /*
- * If no software queues are mapped to this hardware queue,
- * disable it and free the request entries.
- */
- if (!hctx->nr_ctx) {
- /* Never unmap queue 0. We need it as a
- * fallback in case of a new remap fails
- * allocation
- */
- if (i && set->tags[i])
- blk_mq_free_map_and_requests(set, i);
- hctx->tags = NULL;
- continue;
- }
- hctx->tags = set->tags[i];
- WARN_ON(!hctx->tags);
- /*
- * Set the map size to the number of mapped software queues.
- * This is more accurate and more efficient than looping
- * over all possibly mapped software queues.
- */
- sbitmap_resize(&hctx->ctx_map, hctx->nr_ctx);
- /*
- * Initialize batch roundrobin counts
- */
- hctx->next_cpu = blk_mq_first_mapped_cpu(hctx);
- hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
- }
- }
- /*
- * Caller needs to ensure that we're either frozen/quiesced, or that
- * the queue isn't live yet.
- */
- static void queue_set_hctx_shared(struct request_queue *q, bool shared)
- {
- struct blk_mq_hw_ctx *hctx;
- int i;
- queue_for_each_hw_ctx(q, hctx, i) {
- if (shared)
- hctx->flags |= BLK_MQ_F_TAG_QUEUE_SHARED;
- else
- hctx->flags &= ~BLK_MQ_F_TAG_QUEUE_SHARED;
- }
- }
- static void blk_mq_update_tag_set_shared(struct blk_mq_tag_set *set,
- bool shared)
- {
- struct request_queue *q;
- lockdep_assert_held(&set->tag_list_lock);
- list_for_each_entry(q, &set->tag_list, tag_set_list) {
- blk_mq_freeze_queue(q);
- queue_set_hctx_shared(q, shared);
- blk_mq_unfreeze_queue(q);
- }
- }
- static void blk_mq_del_queue_tag_set(struct request_queue *q)
- {
- struct blk_mq_tag_set *set = q->tag_set;
- mutex_lock(&set->tag_list_lock);
- list_del(&q->tag_set_list);
- if (list_is_singular(&set->tag_list)) {
- /* just transitioned to unshared */
- set->flags &= ~BLK_MQ_F_TAG_QUEUE_SHARED;
- /* update existing queue */
- blk_mq_update_tag_set_shared(set, false);
- }
- mutex_unlock(&set->tag_list_lock);
- INIT_LIST_HEAD(&q->tag_set_list);
- }
- static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set,
- struct request_queue *q)
- {
- mutex_lock(&set->tag_list_lock);
- /*
- * Check to see if we're transitioning to shared (from 1 to 2 queues).
- */
- if (!list_empty(&set->tag_list) &&
- !(set->flags & BLK_MQ_F_TAG_QUEUE_SHARED)) {
- set->flags |= BLK_MQ_F_TAG_QUEUE_SHARED;
- /* update existing queue */
- blk_mq_update_tag_set_shared(set, true);
- }
- if (set->flags & BLK_MQ_F_TAG_QUEUE_SHARED)
- queue_set_hctx_shared(q, true);
- list_add_tail(&q->tag_set_list, &set->tag_list);
- mutex_unlock(&set->tag_list_lock);
- }
- /* All allocations will be freed in release handler of q->mq_kobj */
- static int blk_mq_alloc_ctxs(struct request_queue *q)
- {
- struct blk_mq_ctxs *ctxs;
- int cpu;
- ctxs = kzalloc(sizeof(*ctxs), GFP_KERNEL);
- if (!ctxs)
- return -ENOMEM;
- ctxs->queue_ctx = alloc_percpu(struct blk_mq_ctx);
- if (!ctxs->queue_ctx)
- goto fail;
- for_each_possible_cpu(cpu) {
- struct blk_mq_ctx *ctx = per_cpu_ptr(ctxs->queue_ctx, cpu);
- ctx->ctxs = ctxs;
- }
- q->mq_kobj = &ctxs->kobj;
- q->queue_ctx = ctxs->queue_ctx;
- return 0;
- fail:
- kfree(ctxs);
- return -ENOMEM;
- }
- /*
- * It is the actual release handler for mq, but we do it from
- * request queue's release handler for avoiding use-after-free
- * and headache because q->mq_kobj shouldn't have been introduced,
- * but we can't group ctx/kctx kobj without it.
- */
- void blk_mq_release(struct request_queue *q)
- {
- struct blk_mq_hw_ctx *hctx, *next;
- int i;
- queue_for_each_hw_ctx(q, hctx, i)
- WARN_ON_ONCE(hctx && list_empty(&hctx->hctx_list));
- /* all hctx are in .unused_hctx_list now */
- list_for_each_entry_safe(hctx, next, &q->unused_hctx_list, hctx_list) {
- list_del_init(&hctx->hctx_list);
- kobject_put(&hctx->kobj);
- }
- kfree(q->queue_hw_ctx);
- /*
- * release .mq_kobj and sw queue's kobject now because
- * both share lifetime with request queue.
- */
- blk_mq_sysfs_deinit(q);
- }
- struct request_queue *blk_mq_init_queue_data(struct blk_mq_tag_set *set,
- void *queuedata)
- {
- struct request_queue *uninit_q, *q;
- uninit_q = blk_alloc_queue(set->numa_node);
- if (!uninit_q)
- return ERR_PTR(-ENOMEM);
- uninit_q->queuedata = queuedata;
- /*
- * Initialize the queue without an elevator. device_add_disk() will do
- * the initialization.
- */
- q = blk_mq_init_allocated_queue(set, uninit_q, false);
- if (IS_ERR(q))
- blk_cleanup_queue(uninit_q);
- return q;
- }
- EXPORT_SYMBOL_GPL(blk_mq_init_queue_data);
- struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set)
- {
- return blk_mq_init_queue_data(set, NULL);
- }
- EXPORT_SYMBOL(blk_mq_init_queue);
- /*
- * Helper for setting up a queue with mq ops, given queue depth, and
- * the passed in mq ops flags.
- */
- struct request_queue *blk_mq_init_sq_queue(struct blk_mq_tag_set *set,
- const struct blk_mq_ops *ops,
- unsigned int queue_depth,
- unsigned int set_flags)
- {
- struct request_queue *q;
- int ret;
- memset(set, 0, sizeof(*set));
- set->ops = ops;
- set->nr_hw_queues = 1;
- set->nr_maps = 1;
- set->queue_depth = queue_depth;
- set->numa_node = NUMA_NO_NODE;
- set->flags = set_flags;
- ret = blk_mq_alloc_tag_set(set);
- if (ret)
- return ERR_PTR(ret);
- q = blk_mq_init_queue(set);
- if (IS_ERR(q)) {
- blk_mq_free_tag_set(set);
- return q;
- }
- return q;
- }
- EXPORT_SYMBOL(blk_mq_init_sq_queue);
- static struct blk_mq_hw_ctx *blk_mq_alloc_and_init_hctx(
- struct blk_mq_tag_set *set, struct request_queue *q,
- int hctx_idx, int node)
- {
- struct blk_mq_hw_ctx *hctx = NULL, *tmp;
- /* reuse dead hctx first */
- spin_lock(&q->unused_hctx_lock);
- list_for_each_entry(tmp, &q->unused_hctx_list, hctx_list) {
- if (tmp->numa_node == node) {
- hctx = tmp;
- break;
- }
- }
- if (hctx)
- list_del_init(&hctx->hctx_list);
- spin_unlock(&q->unused_hctx_lock);
- if (!hctx)
- hctx = blk_mq_alloc_hctx(q, set, node);
- if (!hctx)
- goto fail;
- if (blk_mq_init_hctx(q, set, hctx, hctx_idx))
- goto free_hctx;
- return hctx;
- free_hctx:
- kobject_put(&hctx->kobj);
- fail:
- return NULL;
- }
- static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
- struct request_queue *q)
- {
- int i, j, end;
- struct blk_mq_hw_ctx **hctxs = q->queue_hw_ctx;
- if (q->nr_hw_queues < set->nr_hw_queues) {
- struct blk_mq_hw_ctx **new_hctxs;
- new_hctxs = kcalloc_node(set->nr_hw_queues,
- sizeof(*new_hctxs), GFP_KERNEL,
- set->numa_node);
- if (!new_hctxs)
- return;
- if (hctxs)
- memcpy(new_hctxs, hctxs, q->nr_hw_queues *
- sizeof(*hctxs));
- q->queue_hw_ctx = new_hctxs;
- kfree(hctxs);
- hctxs = new_hctxs;
- }
- /* protect against switching io scheduler */
- mutex_lock(&q->sysfs_lock);
- for (i = 0; i < set->nr_hw_queues; i++) {
- int node;
- struct blk_mq_hw_ctx *hctx;
- node = blk_mq_hw_queue_to_node(&set->map[HCTX_TYPE_DEFAULT], i);
- /*
- * If the hw queue has been mapped to another numa node,
- * we need to realloc the hctx. If allocation fails, fallback
- * to use the previous one.
- */
- if (hctxs[i] && (hctxs[i]->numa_node == node))
- continue;
- hctx = blk_mq_alloc_and_init_hctx(set, q, i, node);
- if (hctx) {
- if (hctxs[i])
- blk_mq_exit_hctx(q, set, hctxs[i], i);
- hctxs[i] = hctx;
- } else {
- if (hctxs[i])
- pr_warn("Allocate new hctx on node %d fails,\
- fallback to previous one on node %d\n",
- node, hctxs[i]->numa_node);
- else
- break;
- }
- }
- /*
- * Increasing nr_hw_queues fails. Free the newly allocated
- * hctxs and keep the previous q->nr_hw_queues.
- */
- if (i != set->nr_hw_queues) {
- j = q->nr_hw_queues;
- end = i;
- } else {
- j = i;
- end = q->nr_hw_queues;
- q->nr_hw_queues = set->nr_hw_queues;
- }
- for (; j < end; j++) {
- struct blk_mq_hw_ctx *hctx = hctxs[j];
- if (hctx) {
- if (hctx->tags)
- blk_mq_free_map_and_requests(set, j);
- blk_mq_exit_hctx(q, set, hctx, j);
- hctxs[j] = NULL;
- }
- }
- mutex_unlock(&q->sysfs_lock);
- }
- struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
- struct request_queue *q,
- bool elevator_init)
- {
- /* mark the queue as mq asap */
- q->mq_ops = set->ops;
- q->poll_cb = blk_stat_alloc_callback(blk_mq_poll_stats_fn,
- blk_mq_poll_stats_bkt,
- BLK_MQ_POLL_STATS_BKTS, q);
- if (!q->poll_cb)
- goto err_exit;
- if (blk_mq_alloc_ctxs(q))
- goto err_poll;
- /* init q->mq_kobj and sw queues' kobjects */
- blk_mq_sysfs_init(q);
- INIT_LIST_HEAD(&q->unused_hctx_list);
- spin_lock_init(&q->unused_hctx_lock);
- blk_mq_realloc_hw_ctxs(set, q);
- if (!q->nr_hw_queues)
- goto err_hctxs;
- INIT_WORK(&q->timeout_work, blk_mq_timeout_work);
- blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ);
- q->tag_set = set;
- q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT;
- if (set->nr_maps > HCTX_TYPE_POLL &&
- set->map[HCTX_TYPE_POLL].nr_queues)
- blk_queue_flag_set(QUEUE_FLAG_POLL, q);
- q->sg_reserved_size = INT_MAX;
- INIT_DELAYED_WORK(&q->requeue_work, blk_mq_requeue_work);
- INIT_LIST_HEAD(&q->requeue_list);
- spin_lock_init(&q->requeue_lock);
- q->nr_requests = set->queue_depth;
- /*
- * Default to classic polling
- */
- q->poll_nsec = BLK_MQ_POLL_CLASSIC;
- blk_mq_init_cpu_queues(q, set->nr_hw_queues);
- blk_mq_add_queue_tag_set(set, q);
- blk_mq_map_swqueue(q);
- if (elevator_init)
- elevator_init_mq(q);
- return q;
- err_hctxs:
- kfree(q->queue_hw_ctx);
- q->nr_hw_queues = 0;
- blk_mq_sysfs_deinit(q);
- err_poll:
- blk_stat_free_callback(q->poll_cb);
- q->poll_cb = NULL;
- err_exit:
- q->mq_ops = NULL;
- return ERR_PTR(-ENOMEM);
- }
- EXPORT_SYMBOL(blk_mq_init_allocated_queue);
- /* tags can _not_ be used after returning from blk_mq_exit_queue */
- void blk_mq_exit_queue(struct request_queue *q)
- {
- struct blk_mq_tag_set *set = q->tag_set;
- /* Checks hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED. */
- blk_mq_exit_hw_queues(q, set, set->nr_hw_queues);
- /* May clear BLK_MQ_F_TAG_QUEUE_SHARED in hctx->flags. */
- blk_mq_del_queue_tag_set(q);
- }
- static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
- {
- int i;
- for (i = 0; i < set->nr_hw_queues; i++) {
- if (!__blk_mq_alloc_map_and_request(set, i))
- goto out_unwind;
- cond_resched();
- }
- return 0;
- out_unwind:
- while (--i >= 0)
- blk_mq_free_map_and_requests(set, i);
- return -ENOMEM;
- }
- /*
- * Allocate the request maps associated with this tag_set. Note that this
- * may reduce the depth asked for, if memory is tight. set->queue_depth
- * will be updated to reflect the allocated depth.
- */
- static int blk_mq_alloc_map_and_requests(struct blk_mq_tag_set *set)
- {
- unsigned int depth;
- int err;
- depth = set->queue_depth;
- do {
- err = __blk_mq_alloc_rq_maps(set);
- if (!err)
- break;
- set->queue_depth >>= 1;
- if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) {
- err = -ENOMEM;
- break;
- }
- } while (set->queue_depth);
- if (!set->queue_depth || err) {
- pr_err("blk-mq: failed to allocate request map\n");
- return -ENOMEM;
- }
- if (depth != set->queue_depth)
- pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
- depth, set->queue_depth);
- return 0;
- }
- static int blk_mq_update_queue_map(struct blk_mq_tag_set *set)
- {
- /*
- * blk_mq_map_queues() and multiple .map_queues() implementations
- * expect that set->map[HCTX_TYPE_DEFAULT].nr_queues is set to the
- * number of hardware queues.
- */
- if (set->nr_maps == 1)
- set->map[HCTX_TYPE_DEFAULT].nr_queues = set->nr_hw_queues;
- if (set->ops->map_queues && !is_kdump_kernel()) {
- int i;
- /*
- * transport .map_queues is usually done in the following
- * way:
- *
- * for (queue = 0; queue < set->nr_hw_queues; queue++) {
- * mask = get_cpu_mask(queue)
- * for_each_cpu(cpu, mask)
- * set->map[x].mq_map[cpu] = queue;
- * }
- *
- * When we need to remap, the table has to be cleared for
- * killing stale mapping since one CPU may not be mapped
- * to any hw queue.
- */
- for (i = 0; i < set->nr_maps; i++)
- blk_mq_clear_mq_map(&set->map[i]);
- return set->ops->map_queues(set);
- } else {
- BUG_ON(set->nr_maps > 1);
- return blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
- }
- }
- static int blk_mq_realloc_tag_set_tags(struct blk_mq_tag_set *set,
- int cur_nr_hw_queues, int new_nr_hw_queues)
- {
- struct blk_mq_tags **new_tags;
- if (cur_nr_hw_queues >= new_nr_hw_queues)
- return 0;
- new_tags = kcalloc_node(new_nr_hw_queues, sizeof(struct blk_mq_tags *),
- GFP_KERNEL, set->numa_node);
- if (!new_tags)
- return -ENOMEM;
- if (set->tags)
- memcpy(new_tags, set->tags, cur_nr_hw_queues *
- sizeof(*set->tags));
- kfree(set->tags);
- set->tags = new_tags;
- set->nr_hw_queues = new_nr_hw_queues;
- return 0;
- }
- /*
- * Alloc a tag set to be associated with one or more request queues.
- * May fail with EINVAL for various error conditions. May adjust the
- * requested depth down, if it's too large. In that case, the set
- * value will be stored in set->queue_depth.
- */
- int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
- {
- int i, ret;
- BUILD_BUG_ON(BLK_MQ_MAX_DEPTH > 1 << BLK_MQ_UNIQUE_TAG_BITS);
- if (!set->nr_hw_queues)
- return -EINVAL;
- if (!set->queue_depth)
- return -EINVAL;
- if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN)
- return -EINVAL;
- if (!set->ops->queue_rq)
- return -EINVAL;
- if (!set->ops->get_budget ^ !set->ops->put_budget)
- return -EINVAL;
- if (set->queue_depth > BLK_MQ_MAX_DEPTH) {
- pr_info("blk-mq: reduced tag depth to %u\n",
- BLK_MQ_MAX_DEPTH);
- set->queue_depth = BLK_MQ_MAX_DEPTH;
- }
- if (!set->nr_maps)
- set->nr_maps = 1;
- else if (set->nr_maps > HCTX_MAX_TYPES)
- return -EINVAL;
- /*
- * If a crashdump is active, then we are potentially in a very
- * memory constrained environment. Limit us to 1 queue and
- * 64 tags to prevent using too much memory.
- */
- if (is_kdump_kernel()) {
- set->nr_hw_queues = 1;
- set->nr_maps = 1;
- set->queue_depth = min(64U, set->queue_depth);
- }
- /*
- * There is no use for more h/w queues than cpus if we just have
- * a single map
- */
- if (set->nr_maps == 1 && set->nr_hw_queues > nr_cpu_ids)
- set->nr_hw_queues = nr_cpu_ids;
- if (blk_mq_realloc_tag_set_tags(set, 0, set->nr_hw_queues) < 0)
- return -ENOMEM;
- ret = -ENOMEM;
- for (i = 0; i < set->nr_maps; i++) {
- set->map[i].mq_map = kcalloc_node(nr_cpu_ids,
- sizeof(set->map[i].mq_map[0]),
- GFP_KERNEL, set->numa_node);
- if (!set->map[i].mq_map)
- goto out_free_mq_map;
- set->map[i].nr_queues = is_kdump_kernel() ? 1 : set->nr_hw_queues;
- }
- ret = blk_mq_update_queue_map(set);
- if (ret)
- goto out_free_mq_map;
- ret = blk_mq_alloc_map_and_requests(set);
- if (ret)
- goto out_free_mq_map;
- if (blk_mq_is_sbitmap_shared(set->flags)) {
- atomic_set(&set->active_queues_shared_sbitmap, 0);
- if (blk_mq_init_shared_sbitmap(set, set->flags)) {
- ret = -ENOMEM;
- goto out_free_mq_rq_maps;
- }
- }
- mutex_init(&set->tag_list_lock);
- INIT_LIST_HEAD(&set->tag_list);
- return 0;
- out_free_mq_rq_maps:
- for (i = 0; i < set->nr_hw_queues; i++)
- blk_mq_free_map_and_requests(set, i);
- out_free_mq_map:
- for (i = 0; i < set->nr_maps; i++) {
- kfree(set->map[i].mq_map);
- set->map[i].mq_map = NULL;
- }
- kfree(set->tags);
- set->tags = NULL;
- return ret;
- }
- EXPORT_SYMBOL(blk_mq_alloc_tag_set);
- void blk_mq_free_tag_set(struct blk_mq_tag_set *set)
- {
- int i, j;
- for (i = 0; i < set->nr_hw_queues; i++)
- blk_mq_free_map_and_requests(set, i);
- if (blk_mq_is_sbitmap_shared(set->flags))
- blk_mq_exit_shared_sbitmap(set);
- for (j = 0; j < set->nr_maps; j++) {
- kfree(set->map[j].mq_map);
- set->map[j].mq_map = NULL;
- }
- kfree(set->tags);
- set->tags = NULL;
- }
- EXPORT_SYMBOL(blk_mq_free_tag_set);
- int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
- {
- struct blk_mq_tag_set *set = q->tag_set;
- struct blk_mq_hw_ctx *hctx;
- int i, ret;
- if (!set)
- return -EINVAL;
- if (q->nr_requests == nr)
- return 0;
- blk_mq_freeze_queue(q);
- blk_mq_quiesce_queue(q);
- ret = 0;
- queue_for_each_hw_ctx(q, hctx, i) {
- if (!hctx->tags)
- continue;
- /*
- * If we're using an MQ scheduler, just update the scheduler
- * queue depth. This is similar to what the old code would do.
- */
- if (!hctx->sched_tags) {
- ret = blk_mq_tag_update_depth(hctx, &hctx->tags, nr,
- false);
- if (!ret && blk_mq_is_sbitmap_shared(set->flags))
- blk_mq_tag_resize_shared_sbitmap(set, nr);
- } else {
- ret = blk_mq_tag_update_depth(hctx, &hctx->sched_tags,
- nr, true);
- }
- if (ret)
- break;
- if (q->elevator && q->elevator->type->ops.depth_updated)
- q->elevator->type->ops.depth_updated(hctx);
- }
- if (!ret)
- q->nr_requests = nr;
- blk_mq_unquiesce_queue(q);
- blk_mq_unfreeze_queue(q);
- return ret;
- }
- /*
- * request_queue and elevator_type pair.
- * It is just used by __blk_mq_update_nr_hw_queues to cache
- * the elevator_type associated with a request_queue.
- */
- struct blk_mq_qe_pair {
- struct list_head node;
- struct request_queue *q;
- struct elevator_type *type;
- };
- /*
- * Cache the elevator_type in qe pair list and switch the
- * io scheduler to 'none'
- */
- static bool blk_mq_elv_switch_none(struct list_head *head,
- struct request_queue *q)
- {
- struct blk_mq_qe_pair *qe;
- if (!q->elevator)
- return true;
- qe = kmalloc(sizeof(*qe), GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY);
- if (!qe)
- return false;
- INIT_LIST_HEAD(&qe->node);
- qe->q = q;
- qe->type = q->elevator->type;
- list_add(&qe->node, head);
- mutex_lock(&q->sysfs_lock);
- /*
- * After elevator_switch_mq, the previous elevator_queue will be
- * released by elevator_release. The reference of the io scheduler
- * module get by elevator_get will also be put. So we need to get
- * a reference of the io scheduler module here to prevent it to be
- * removed.
- */
- __module_get(qe->type->elevator_owner);
- elevator_switch_mq(q, NULL);
- mutex_unlock(&q->sysfs_lock);
- return true;
- }
- static void blk_mq_elv_switch_back(struct list_head *head,
- struct request_queue *q)
- {
- struct blk_mq_qe_pair *qe;
- struct elevator_type *t = NULL;
- list_for_each_entry(qe, head, node)
- if (qe->q == q) {
- t = qe->type;
- break;
- }
- if (!t)
- return;
- list_del(&qe->node);
- kfree(qe);
- mutex_lock(&q->sysfs_lock);
- elevator_switch_mq(q, t);
- mutex_unlock(&q->sysfs_lock);
- }
- static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set,
- int nr_hw_queues)
- {
- struct request_queue *q;
- LIST_HEAD(head);
- int prev_nr_hw_queues;
- lockdep_assert_held(&set->tag_list_lock);
- if (set->nr_maps == 1 && nr_hw_queues > nr_cpu_ids)
- nr_hw_queues = nr_cpu_ids;
- if (nr_hw_queues < 1)
- return;
- if (set->nr_maps == 1 && nr_hw_queues == set->nr_hw_queues)
- return;
- list_for_each_entry(q, &set->tag_list, tag_set_list)
- blk_mq_freeze_queue(q);
- /*
- * Switch IO scheduler to 'none', cleaning up the data associated
- * with the previous scheduler. We will switch back once we are done
- * updating the new sw to hw queue mappings.
- */
- list_for_each_entry(q, &set->tag_list, tag_set_list)
- if (!blk_mq_elv_switch_none(&head, q))
- goto switch_back;
- list_for_each_entry(q, &set->tag_list, tag_set_list) {
- blk_mq_debugfs_unregister_hctxs(q);
- blk_mq_sysfs_unregister(q);
- }
- prev_nr_hw_queues = set->nr_hw_queues;
- if (blk_mq_realloc_tag_set_tags(set, set->nr_hw_queues, nr_hw_queues) <
- 0)
- goto reregister;
- set->nr_hw_queues = nr_hw_queues;
- fallback:
- blk_mq_update_queue_map(set);
- list_for_each_entry(q, &set->tag_list, tag_set_list) {
- blk_mq_realloc_hw_ctxs(set, q);
- if (q->nr_hw_queues != set->nr_hw_queues) {
- pr_warn("Increasing nr_hw_queues to %d fails, fallback to %d\n",
- nr_hw_queues, prev_nr_hw_queues);
- set->nr_hw_queues = prev_nr_hw_queues;
- blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
- goto fallback;
- }
- blk_mq_map_swqueue(q);
- }
- reregister:
- list_for_each_entry(q, &set->tag_list, tag_set_list) {
- blk_mq_sysfs_register(q);
- blk_mq_debugfs_register_hctxs(q);
- }
- switch_back:
- list_for_each_entry(q, &set->tag_list, tag_set_list)
- blk_mq_elv_switch_back(&head, q);
- list_for_each_entry(q, &set->tag_list, tag_set_list)
- blk_mq_unfreeze_queue(q);
- }
- void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues)
- {
- mutex_lock(&set->tag_list_lock);
- __blk_mq_update_nr_hw_queues(set, nr_hw_queues);
- mutex_unlock(&set->tag_list_lock);
- }
- EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues);
- /* Enable polling stats and return whether they were already enabled. */
- static bool blk_poll_stats_enable(struct request_queue *q)
- {
- if (test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags) ||
- blk_queue_flag_test_and_set(QUEUE_FLAG_POLL_STATS, q))
- return true;
- blk_stat_add_callback(q, q->poll_cb);
- return false;
- }
- static void blk_mq_poll_stats_start(struct request_queue *q)
- {
- /*
- * We don't arm the callback if polling stats are not enabled or the
- * callback is already active.
- */
- if (!test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags) ||
- blk_stat_is_active(q->poll_cb))
- return;
- blk_stat_activate_msecs(q->poll_cb, 100);
- }
- static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb)
- {
- struct request_queue *q = cb->data;
- int bucket;
- for (bucket = 0; bucket < BLK_MQ_POLL_STATS_BKTS; bucket++) {
- if (cb->stat[bucket].nr_samples)
- q->poll_stat[bucket] = cb->stat[bucket];
- }
- }
- static unsigned long blk_mq_poll_nsecs(struct request_queue *q,
- struct request *rq)
- {
- unsigned long ret = 0;
- int bucket;
- /*
- * If stats collection isn't on, don't sleep but turn it on for
- * future users
- */
- if (!blk_poll_stats_enable(q))
- return 0;
- /*
- * As an optimistic guess, use half of the mean service time
- * for this type of request. We can (and should) make this smarter.
- * For instance, if the completion latencies are tight, we can
- * get closer than just half the mean. This is especially
- * important on devices where the completion latencies are longer
- * than ~10 usec. We do use the stats for the relevant IO size
- * if available which does lead to better estimates.
- */
- bucket = blk_mq_poll_stats_bkt(rq);
- if (bucket < 0)
- return ret;
- if (q->poll_stat[bucket].nr_samples)
- ret = (q->poll_stat[bucket].mean + 1) / 2;
- return ret;
- }
- static bool blk_mq_poll_hybrid_sleep(struct request_queue *q,
- struct request *rq)
- {
- struct hrtimer_sleeper hs;
- enum hrtimer_mode mode;
- unsigned int nsecs;
- ktime_t kt;
- if (rq->rq_flags & RQF_MQ_POLL_SLEPT)
- return false;
- /*
- * If we get here, hybrid polling is enabled. Hence poll_nsec can be:
- *
- * 0: use half of prev avg
- * >0: use this specific value
- */
- if (q->poll_nsec > 0)
- nsecs = q->poll_nsec;
- else
- nsecs = blk_mq_poll_nsecs(q, rq);
- if (!nsecs)
- return false;
- rq->rq_flags |= RQF_MQ_POLL_SLEPT;
- /*
- * This will be replaced with the stats tracking code, using
- * 'avg_completion_time / 2' as the pre-sleep target.
- */
- kt = nsecs;
- mode = HRTIMER_MODE_REL;
- hrtimer_init_sleeper_on_stack(&hs, CLOCK_MONOTONIC, mode);
- hrtimer_set_expires(&hs.timer, kt);
- do {
- if (blk_mq_rq_state(rq) == MQ_RQ_COMPLETE)
- break;
- set_current_state(TASK_UNINTERRUPTIBLE);
- hrtimer_sleeper_start_expires(&hs, mode);
- if (hs.task)
- io_schedule();
- hrtimer_cancel(&hs.timer);
- mode = HRTIMER_MODE_ABS;
- } while (hs.task && !signal_pending(current));
- __set_current_state(TASK_RUNNING);
- destroy_hrtimer_on_stack(&hs.timer);
- return true;
- }
- static bool blk_mq_poll_hybrid(struct request_queue *q,
- struct blk_mq_hw_ctx *hctx, blk_qc_t cookie)
- {
- struct request *rq;
- if (q->poll_nsec == BLK_MQ_POLL_CLASSIC)
- return false;
- if (!blk_qc_t_is_internal(cookie))
- rq = blk_mq_tag_to_rq(hctx->tags, blk_qc_t_to_tag(cookie));
- else {
- rq = blk_mq_tag_to_rq(hctx->sched_tags, blk_qc_t_to_tag(cookie));
- /*
- * With scheduling, if the request has completed, we'll
- * get a NULL return here, as we clear the sched tag when
- * that happens. The request still remains valid, like always,
- * so we should be safe with just the NULL check.
- */
- if (!rq)
- return false;
- }
- return blk_mq_poll_hybrid_sleep(q, rq);
- }
- /**
- * blk_poll - poll for IO completions
- * @q: the queue
- * @cookie: cookie passed back at IO submission time
- * @spin: whether to spin for completions
- *
- * Description:
- * Poll for completions on the passed in queue. Returns number of
- * completed entries found. If @spin is true, then blk_poll will continue
- * looping until at least one completion is found, unless the task is
- * otherwise marked running (or we need to reschedule).
- */
- int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin)
- {
- struct blk_mq_hw_ctx *hctx;
- long state;
- if (!blk_qc_t_valid(cookie) ||
- !test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
- return 0;
- if (current->plug)
- blk_flush_plug_list(current->plug, false);
- hctx = q->queue_hw_ctx[blk_qc_t_to_queue_num(cookie)];
- /*
- * If we sleep, have the caller restart the poll loop to reset
- * the state. Like for the other success return cases, the
- * caller is responsible for checking if the IO completed. If
- * the IO isn't complete, we'll get called again and will go
- * straight to the busy poll loop.
- */
- if (blk_mq_poll_hybrid(q, hctx, cookie))
- return 1;
- hctx->poll_considered++;
- state = current->state;
- do {
- int ret;
- hctx->poll_invoked++;
- ret = q->mq_ops->poll(hctx);
- if (ret > 0) {
- hctx->poll_success++;
- __set_current_state(TASK_RUNNING);
- return ret;
- }
- if (signal_pending_state(state, current))
- __set_current_state(TASK_RUNNING);
- if (current->state == TASK_RUNNING)
- return 1;
- if (ret < 0 || !spin)
- break;
- cpu_relax();
- } while (!need_resched());
- __set_current_state(TASK_RUNNING);
- return 0;
- }
- EXPORT_SYMBOL_GPL(blk_poll);
- unsigned int blk_mq_rq_cpu(struct request *rq)
- {
- return rq->mq_ctx->cpu;
- }
- EXPORT_SYMBOL(blk_mq_rq_cpu);
- static int __init blk_mq_init(void)
- {
- int i;
- for_each_possible_cpu(i)
- INIT_LIST_HEAD(&per_cpu(blk_cpu_done, i));
- open_softirq(BLOCK_SOFTIRQ, blk_done_softirq);
- cpuhp_setup_state_nocalls(CPUHP_BLOCK_SOFTIRQ_DEAD,
- "block/softirq:dead", NULL,
- blk_softirq_cpu_dead);
- cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD, "block/mq:dead", NULL,
- blk_mq_hctx_notify_dead);
- cpuhp_setup_state_multi(CPUHP_AP_BLK_MQ_ONLINE, "block/mq:online",
- blk_mq_hctx_notify_online,
- blk_mq_hctx_notify_offline);
- return 0;
- }
- subsys_initcall(blk_mq_init);
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