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- // SPDX-License-Identifier: GPL-2.0-only
- //#define DEBUG
- #include <linux/spinlock.h>
- #include <linux/slab.h>
- #include <linux/blkdev.h>
- #include <linux/hdreg.h>
- #include <linux/module.h>
- #include <linux/mutex.h>
- #include <linux/interrupt.h>
- #include <linux/virtio.h>
- #include <linux/virtio_blk.h>
- #include <linux/scatterlist.h>
- #include <linux/string_helpers.h>
- #include <linux/idr.h>
- #include <linux/blk-mq.h>
- #include <linux/blk-mq-virtio.h>
- #include <linux/numa.h>
- #include <uapi/linux/virtio_ring.h>
- #define PART_BITS 4
- #define VQ_NAME_LEN 16
- #define MAX_DISCARD_SEGMENTS 256u
- static int major;
- static DEFINE_IDA(vd_index_ida);
- static struct workqueue_struct *virtblk_wq;
- struct virtio_blk_vq {
- struct virtqueue *vq;
- spinlock_t lock;
- char name[VQ_NAME_LEN];
- } ____cacheline_aligned_in_smp;
- struct virtio_blk {
- /*
- * This mutex must be held by anything that may run after
- * virtblk_remove() sets vblk->vdev to NULL.
- *
- * blk-mq, virtqueue processing, and sysfs attribute code paths are
- * shut down before vblk->vdev is set to NULL and therefore do not need
- * to hold this mutex.
- */
- struct mutex vdev_mutex;
- struct virtio_device *vdev;
- /* The disk structure for the kernel. */
- struct gendisk *disk;
- /* Block layer tags. */
- struct blk_mq_tag_set tag_set;
- /* Process context for config space updates */
- struct work_struct config_work;
- /*
- * Tracks references from block_device_operations open/release and
- * virtio_driver probe/remove so this object can be freed once no
- * longer in use.
- */
- refcount_t refs;
- /* What host tells us, plus 2 for header & tailer. */
- unsigned int sg_elems;
- /* Ida index - used to track minor number allocations. */
- int index;
- /* num of vqs */
- int num_vqs;
- struct virtio_blk_vq *vqs;
- };
- struct virtblk_req {
- struct virtio_blk_outhdr out_hdr;
- u8 status;
- struct scatterlist sg[];
- };
- static inline blk_status_t virtblk_result(struct virtblk_req *vbr)
- {
- switch (vbr->status) {
- case VIRTIO_BLK_S_OK:
- return BLK_STS_OK;
- case VIRTIO_BLK_S_UNSUPP:
- return BLK_STS_NOTSUPP;
- default:
- return BLK_STS_IOERR;
- }
- }
- static int virtblk_add_req(struct virtqueue *vq, struct virtblk_req *vbr,
- struct scatterlist *data_sg, bool have_data)
- {
- struct scatterlist hdr, status, *sgs[3];
- unsigned int num_out = 0, num_in = 0;
- sg_init_one(&hdr, &vbr->out_hdr, sizeof(vbr->out_hdr));
- sgs[num_out++] = &hdr;
- if (have_data) {
- if (vbr->out_hdr.type & cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_OUT))
- sgs[num_out++] = data_sg;
- else
- sgs[num_out + num_in++] = data_sg;
- }
- sg_init_one(&status, &vbr->status, sizeof(vbr->status));
- sgs[num_out + num_in++] = &status;
- return virtqueue_add_sgs(vq, sgs, num_out, num_in, vbr, GFP_ATOMIC);
- }
- static int virtblk_setup_discard_write_zeroes(struct request *req, bool unmap)
- {
- unsigned short segments = blk_rq_nr_discard_segments(req);
- unsigned short n = 0;
- struct virtio_blk_discard_write_zeroes *range;
- struct bio *bio;
- u32 flags = 0;
- if (unmap)
- flags |= VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP;
- range = kmalloc_array(segments, sizeof(*range), GFP_ATOMIC);
- if (!range)
- return -ENOMEM;
- /*
- * Single max discard segment means multi-range discard isn't
- * supported, and block layer only runs contiguity merge like
- * normal RW request. So we can't reply on bio for retrieving
- * each range info.
- */
- if (queue_max_discard_segments(req->q) == 1) {
- range[0].flags = cpu_to_le32(flags);
- range[0].num_sectors = cpu_to_le32(blk_rq_sectors(req));
- range[0].sector = cpu_to_le64(blk_rq_pos(req));
- n = 1;
- } else {
- __rq_for_each_bio(bio, req) {
- u64 sector = bio->bi_iter.bi_sector;
- u32 num_sectors = bio->bi_iter.bi_size >> SECTOR_SHIFT;
- range[n].flags = cpu_to_le32(flags);
- range[n].num_sectors = cpu_to_le32(num_sectors);
- range[n].sector = cpu_to_le64(sector);
- n++;
- }
- }
- WARN_ON_ONCE(n != segments);
- req->special_vec.bv_page = virt_to_page(range);
- req->special_vec.bv_offset = offset_in_page(range);
- req->special_vec.bv_len = sizeof(*range) * segments;
- req->rq_flags |= RQF_SPECIAL_PAYLOAD;
- return 0;
- }
- static inline void virtblk_request_done(struct request *req)
- {
- struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
- if (req->rq_flags & RQF_SPECIAL_PAYLOAD) {
- kfree(page_address(req->special_vec.bv_page) +
- req->special_vec.bv_offset);
- }
- blk_mq_end_request(req, virtblk_result(vbr));
- }
- static void virtblk_done(struct virtqueue *vq)
- {
- struct virtio_blk *vblk = vq->vdev->priv;
- bool req_done = false;
- int qid = vq->index;
- struct virtblk_req *vbr;
- unsigned long flags;
- unsigned int len;
- spin_lock_irqsave(&vblk->vqs[qid].lock, flags);
- do {
- virtqueue_disable_cb(vq);
- while ((vbr = virtqueue_get_buf(vblk->vqs[qid].vq, &len)) != NULL) {
- struct request *req = blk_mq_rq_from_pdu(vbr);
- if (likely(!blk_should_fake_timeout(req->q)))
- blk_mq_complete_request(req);
- req_done = true;
- }
- if (unlikely(virtqueue_is_broken(vq)))
- break;
- } while (!virtqueue_enable_cb(vq));
- /* In case queue is stopped waiting for more buffers. */
- if (req_done)
- blk_mq_start_stopped_hw_queues(vblk->disk->queue, true);
- spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
- }
- static void virtio_commit_rqs(struct blk_mq_hw_ctx *hctx)
- {
- struct virtio_blk *vblk = hctx->queue->queuedata;
- struct virtio_blk_vq *vq = &vblk->vqs[hctx->queue_num];
- bool kick;
- spin_lock_irq(&vq->lock);
- kick = virtqueue_kick_prepare(vq->vq);
- spin_unlock_irq(&vq->lock);
- if (kick)
- virtqueue_notify(vq->vq);
- }
- static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx,
- const struct blk_mq_queue_data *bd)
- {
- struct virtio_blk *vblk = hctx->queue->queuedata;
- struct request *req = bd->rq;
- struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
- unsigned long flags;
- unsigned int num;
- int qid = hctx->queue_num;
- int err;
- bool notify = false;
- bool unmap = false;
- u32 type;
- switch (req_op(req)) {
- case REQ_OP_READ:
- case REQ_OP_WRITE:
- type = 0;
- break;
- case REQ_OP_FLUSH:
- type = VIRTIO_BLK_T_FLUSH;
- break;
- case REQ_OP_DISCARD:
- type = VIRTIO_BLK_T_DISCARD;
- break;
- case REQ_OP_WRITE_ZEROES:
- type = VIRTIO_BLK_T_WRITE_ZEROES;
- unmap = !(req->cmd_flags & REQ_NOUNMAP);
- break;
- case REQ_OP_DRV_IN:
- type = VIRTIO_BLK_T_GET_ID;
- break;
- default:
- WARN_ON_ONCE(1);
- return BLK_STS_IOERR;
- }
- BUG_ON(type != VIRTIO_BLK_T_DISCARD &&
- type != VIRTIO_BLK_T_WRITE_ZEROES &&
- (req->nr_phys_segments + 2 > vblk->sg_elems));
- vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, type);
- vbr->out_hdr.sector = type ?
- 0 : cpu_to_virtio64(vblk->vdev, blk_rq_pos(req));
- vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(req));
- blk_mq_start_request(req);
- if (type == VIRTIO_BLK_T_DISCARD || type == VIRTIO_BLK_T_WRITE_ZEROES) {
- err = virtblk_setup_discard_write_zeroes(req, unmap);
- if (err)
- return BLK_STS_RESOURCE;
- }
- num = blk_rq_map_sg(hctx->queue, req, vbr->sg);
- if (num) {
- if (rq_data_dir(req) == WRITE)
- vbr->out_hdr.type |= cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_OUT);
- else
- vbr->out_hdr.type |= cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_IN);
- }
- spin_lock_irqsave(&vblk->vqs[qid].lock, flags);
- err = virtblk_add_req(vblk->vqs[qid].vq, vbr, vbr->sg, num);
- if (err) {
- virtqueue_kick(vblk->vqs[qid].vq);
- /* Don't stop the queue if -ENOMEM: we may have failed to
- * bounce the buffer due to global resource outage.
- */
- if (err == -ENOSPC)
- blk_mq_stop_hw_queue(hctx);
- spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
- switch (err) {
- case -ENOSPC:
- return BLK_STS_DEV_RESOURCE;
- case -ENOMEM:
- return BLK_STS_RESOURCE;
- default:
- return BLK_STS_IOERR;
- }
- }
- if (bd->last && virtqueue_kick_prepare(vblk->vqs[qid].vq))
- notify = true;
- spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
- if (notify)
- virtqueue_notify(vblk->vqs[qid].vq);
- return BLK_STS_OK;
- }
- /* return id (s/n) string for *disk to *id_str
- */
- static int virtblk_get_id(struct gendisk *disk, char *id_str)
- {
- struct virtio_blk *vblk = disk->private_data;
- struct request_queue *q = vblk->disk->queue;
- struct request *req;
- int err;
- req = blk_get_request(q, REQ_OP_DRV_IN, 0);
- if (IS_ERR(req))
- return PTR_ERR(req);
- err = blk_rq_map_kern(q, req, id_str, VIRTIO_BLK_ID_BYTES, GFP_KERNEL);
- if (err)
- goto out;
- blk_execute_rq(vblk->disk->queue, vblk->disk, req, false);
- err = blk_status_to_errno(virtblk_result(blk_mq_rq_to_pdu(req)));
- out:
- blk_put_request(req);
- return err;
- }
- static void virtblk_get(struct virtio_blk *vblk)
- {
- refcount_inc(&vblk->refs);
- }
- static void virtblk_put(struct virtio_blk *vblk)
- {
- if (refcount_dec_and_test(&vblk->refs)) {
- ida_simple_remove(&vd_index_ida, vblk->index);
- mutex_destroy(&vblk->vdev_mutex);
- kfree(vblk);
- }
- }
- static int virtblk_open(struct block_device *bd, fmode_t mode)
- {
- struct virtio_blk *vblk = bd->bd_disk->private_data;
- int ret = 0;
- mutex_lock(&vblk->vdev_mutex);
- if (vblk->vdev)
- virtblk_get(vblk);
- else
- ret = -ENXIO;
- mutex_unlock(&vblk->vdev_mutex);
- return ret;
- }
- static void virtblk_release(struct gendisk *disk, fmode_t mode)
- {
- struct virtio_blk *vblk = disk->private_data;
- virtblk_put(vblk);
- }
- /* We provide getgeo only to please some old bootloader/partitioning tools */
- static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo)
- {
- struct virtio_blk *vblk = bd->bd_disk->private_data;
- int ret = 0;
- mutex_lock(&vblk->vdev_mutex);
- if (!vblk->vdev) {
- ret = -ENXIO;
- goto out;
- }
- /* see if the host passed in geometry config */
- if (virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_GEOMETRY)) {
- virtio_cread(vblk->vdev, struct virtio_blk_config,
- geometry.cylinders, &geo->cylinders);
- virtio_cread(vblk->vdev, struct virtio_blk_config,
- geometry.heads, &geo->heads);
- virtio_cread(vblk->vdev, struct virtio_blk_config,
- geometry.sectors, &geo->sectors);
- } else {
- /* some standard values, similar to sd */
- geo->heads = 1 << 6;
- geo->sectors = 1 << 5;
- geo->cylinders = get_capacity(bd->bd_disk) >> 11;
- }
- out:
- mutex_unlock(&vblk->vdev_mutex);
- return ret;
- }
- static const struct block_device_operations virtblk_fops = {
- .owner = THIS_MODULE,
- .open = virtblk_open,
- .release = virtblk_release,
- .getgeo = virtblk_getgeo,
- };
- static int index_to_minor(int index)
- {
- return index << PART_BITS;
- }
- static int minor_to_index(int minor)
- {
- return minor >> PART_BITS;
- }
- static ssize_t serial_show(struct device *dev,
- struct device_attribute *attr, char *buf)
- {
- struct gendisk *disk = dev_to_disk(dev);
- int err;
- /* sysfs gives us a PAGE_SIZE buffer */
- BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES);
- buf[VIRTIO_BLK_ID_BYTES] = '\0';
- err = virtblk_get_id(disk, buf);
- if (!err)
- return strlen(buf);
- if (err == -EIO) /* Unsupported? Make it empty. */
- return 0;
- return err;
- }
- static DEVICE_ATTR_RO(serial);
- /* The queue's logical block size must be set before calling this */
- static void virtblk_update_capacity(struct virtio_blk *vblk, bool resize)
- {
- struct virtio_device *vdev = vblk->vdev;
- struct request_queue *q = vblk->disk->queue;
- char cap_str_2[10], cap_str_10[10];
- unsigned long long nblocks;
- u64 capacity;
- /* Host must always specify the capacity. */
- virtio_cread(vdev, struct virtio_blk_config, capacity, &capacity);
- /* If capacity is too big, truncate with warning. */
- if ((sector_t)capacity != capacity) {
- dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
- (unsigned long long)capacity);
- capacity = (sector_t)-1;
- }
- nblocks = DIV_ROUND_UP_ULL(capacity, queue_logical_block_size(q) >> 9);
- string_get_size(nblocks, queue_logical_block_size(q),
- STRING_UNITS_2, cap_str_2, sizeof(cap_str_2));
- string_get_size(nblocks, queue_logical_block_size(q),
- STRING_UNITS_10, cap_str_10, sizeof(cap_str_10));
- dev_notice(&vdev->dev,
- "[%s] %s%llu %d-byte logical blocks (%s/%s)\n",
- vblk->disk->disk_name,
- resize ? "new size: " : "",
- nblocks,
- queue_logical_block_size(q),
- cap_str_10,
- cap_str_2);
- set_capacity_revalidate_and_notify(vblk->disk, capacity, true);
- }
- static void virtblk_config_changed_work(struct work_struct *work)
- {
- struct virtio_blk *vblk =
- container_of(work, struct virtio_blk, config_work);
- virtblk_update_capacity(vblk, true);
- }
- static void virtblk_config_changed(struct virtio_device *vdev)
- {
- struct virtio_blk *vblk = vdev->priv;
- queue_work(virtblk_wq, &vblk->config_work);
- }
- static int init_vq(struct virtio_blk *vblk)
- {
- int err;
- int i;
- vq_callback_t **callbacks;
- const char **names;
- struct virtqueue **vqs;
- unsigned short num_vqs;
- struct virtio_device *vdev = vblk->vdev;
- struct irq_affinity desc = { 0, };
- err = virtio_cread_feature(vdev, VIRTIO_BLK_F_MQ,
- struct virtio_blk_config, num_queues,
- &num_vqs);
- if (err)
- num_vqs = 1;
- num_vqs = min_t(unsigned int, nr_cpu_ids, num_vqs);
- vblk->vqs = kmalloc_array(num_vqs, sizeof(*vblk->vqs), GFP_KERNEL);
- if (!vblk->vqs)
- return -ENOMEM;
- names = kmalloc_array(num_vqs, sizeof(*names), GFP_KERNEL);
- callbacks = kmalloc_array(num_vqs, sizeof(*callbacks), GFP_KERNEL);
- vqs = kmalloc_array(num_vqs, sizeof(*vqs), GFP_KERNEL);
- if (!names || !callbacks || !vqs) {
- err = -ENOMEM;
- goto out;
- }
- for (i = 0; i < num_vqs; i++) {
- callbacks[i] = virtblk_done;
- snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req.%d", i);
- names[i] = vblk->vqs[i].name;
- }
- /* Discover virtqueues and write information to configuration. */
- err = virtio_find_vqs(vdev, num_vqs, vqs, callbacks, names, &desc);
- if (err)
- goto out;
- for (i = 0; i < num_vqs; i++) {
- spin_lock_init(&vblk->vqs[i].lock);
- vblk->vqs[i].vq = vqs[i];
- }
- vblk->num_vqs = num_vqs;
- out:
- kfree(vqs);
- kfree(callbacks);
- kfree(names);
- if (err)
- kfree(vblk->vqs);
- return err;
- }
- /*
- * Legacy naming scheme used for virtio devices. We are stuck with it for
- * virtio blk but don't ever use it for any new driver.
- */
- static int virtblk_name_format(char *prefix, int index, char *buf, int buflen)
- {
- const int base = 'z' - 'a' + 1;
- char *begin = buf + strlen(prefix);
- char *end = buf + buflen;
- char *p;
- int unit;
- p = end - 1;
- *p = '\0';
- unit = base;
- do {
- if (p == begin)
- return -EINVAL;
- *--p = 'a' + (index % unit);
- index = (index / unit) - 1;
- } while (index >= 0);
- memmove(begin, p, end - p);
- memcpy(buf, prefix, strlen(prefix));
- return 0;
- }
- static int virtblk_get_cache_mode(struct virtio_device *vdev)
- {
- u8 writeback;
- int err;
- err = virtio_cread_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE,
- struct virtio_blk_config, wce,
- &writeback);
- /*
- * If WCE is not configurable and flush is not available,
- * assume no writeback cache is in use.
- */
- if (err)
- writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH);
- return writeback;
- }
- static void virtblk_update_cache_mode(struct virtio_device *vdev)
- {
- u8 writeback = virtblk_get_cache_mode(vdev);
- struct virtio_blk *vblk = vdev->priv;
- blk_queue_write_cache(vblk->disk->queue, writeback, false);
- revalidate_disk_size(vblk->disk, true);
- }
- static const char *const virtblk_cache_types[] = {
- "write through", "write back"
- };
- static ssize_t
- cache_type_store(struct device *dev, struct device_attribute *attr,
- const char *buf, size_t count)
- {
- struct gendisk *disk = dev_to_disk(dev);
- struct virtio_blk *vblk = disk->private_data;
- struct virtio_device *vdev = vblk->vdev;
- int i;
- BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE));
- i = sysfs_match_string(virtblk_cache_types, buf);
- if (i < 0)
- return i;
- virtio_cwrite8(vdev, offsetof(struct virtio_blk_config, wce), i);
- virtblk_update_cache_mode(vdev);
- return count;
- }
- static ssize_t
- cache_type_show(struct device *dev, struct device_attribute *attr, char *buf)
- {
- struct gendisk *disk = dev_to_disk(dev);
- struct virtio_blk *vblk = disk->private_data;
- u8 writeback = virtblk_get_cache_mode(vblk->vdev);
- BUG_ON(writeback >= ARRAY_SIZE(virtblk_cache_types));
- return snprintf(buf, 40, "%s\n", virtblk_cache_types[writeback]);
- }
- static DEVICE_ATTR_RW(cache_type);
- static struct attribute *virtblk_attrs[] = {
- &dev_attr_serial.attr,
- &dev_attr_cache_type.attr,
- NULL,
- };
- static umode_t virtblk_attrs_are_visible(struct kobject *kobj,
- struct attribute *a, int n)
- {
- struct device *dev = kobj_to_dev(kobj);
- struct gendisk *disk = dev_to_disk(dev);
- struct virtio_blk *vblk = disk->private_data;
- struct virtio_device *vdev = vblk->vdev;
- if (a == &dev_attr_cache_type.attr &&
- !virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE))
- return S_IRUGO;
- return a->mode;
- }
- static const struct attribute_group virtblk_attr_group = {
- .attrs = virtblk_attrs,
- .is_visible = virtblk_attrs_are_visible,
- };
- static const struct attribute_group *virtblk_attr_groups[] = {
- &virtblk_attr_group,
- NULL,
- };
- static int virtblk_init_request(struct blk_mq_tag_set *set, struct request *rq,
- unsigned int hctx_idx, unsigned int numa_node)
- {
- struct virtio_blk *vblk = set->driver_data;
- struct virtblk_req *vbr = blk_mq_rq_to_pdu(rq);
- sg_init_table(vbr->sg, vblk->sg_elems);
- return 0;
- }
- static int virtblk_map_queues(struct blk_mq_tag_set *set)
- {
- struct virtio_blk *vblk = set->driver_data;
- return blk_mq_virtio_map_queues(&set->map[HCTX_TYPE_DEFAULT],
- vblk->vdev, 0);
- }
- static const struct blk_mq_ops virtio_mq_ops = {
- .queue_rq = virtio_queue_rq,
- .commit_rqs = virtio_commit_rqs,
- .complete = virtblk_request_done,
- .init_request = virtblk_init_request,
- .map_queues = virtblk_map_queues,
- };
- static unsigned int virtblk_queue_depth;
- module_param_named(queue_depth, virtblk_queue_depth, uint, 0444);
- static int virtblk_probe(struct virtio_device *vdev)
- {
- struct virtio_blk *vblk;
- struct request_queue *q;
- int err, index;
- u32 v, blk_size, max_size, sg_elems, opt_io_size;
- u16 min_io_size;
- u8 physical_block_exp, alignment_offset;
- if (!vdev->config->get) {
- dev_err(&vdev->dev, "%s failure: config access disabled\n",
- __func__);
- return -EINVAL;
- }
- err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS),
- GFP_KERNEL);
- if (err < 0)
- goto out;
- index = err;
- /* We need to know how many segments before we allocate. */
- err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SEG_MAX,
- struct virtio_blk_config, seg_max,
- &sg_elems);
- /* We need at least one SG element, whatever they say. */
- if (err || !sg_elems)
- sg_elems = 1;
- /* We need an extra sg elements at head and tail. */
- sg_elems += 2;
- vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL);
- if (!vblk) {
- err = -ENOMEM;
- goto out_free_index;
- }
- /* This reference is dropped in virtblk_remove(). */
- refcount_set(&vblk->refs, 1);
- mutex_init(&vblk->vdev_mutex);
- vblk->vdev = vdev;
- vblk->sg_elems = sg_elems;
- INIT_WORK(&vblk->config_work, virtblk_config_changed_work);
- err = init_vq(vblk);
- if (err)
- goto out_free_vblk;
- /* FIXME: How many partitions? How long is a piece of string? */
- vblk->disk = alloc_disk(1 << PART_BITS);
- if (!vblk->disk) {
- err = -ENOMEM;
- goto out_free_vq;
- }
- /* Default queue sizing is to fill the ring. */
- if (!virtblk_queue_depth) {
- virtblk_queue_depth = vblk->vqs[0].vq->num_free;
- /* ... but without indirect descs, we use 2 descs per req */
- if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC))
- virtblk_queue_depth /= 2;
- }
- memset(&vblk->tag_set, 0, sizeof(vblk->tag_set));
- vblk->tag_set.ops = &virtio_mq_ops;
- vblk->tag_set.queue_depth = virtblk_queue_depth;
- vblk->tag_set.numa_node = NUMA_NO_NODE;
- vblk->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
- vblk->tag_set.cmd_size =
- sizeof(struct virtblk_req) +
- sizeof(struct scatterlist) * sg_elems;
- vblk->tag_set.driver_data = vblk;
- vblk->tag_set.nr_hw_queues = vblk->num_vqs;
- err = blk_mq_alloc_tag_set(&vblk->tag_set);
- if (err)
- goto out_put_disk;
- q = blk_mq_init_queue(&vblk->tag_set);
- if (IS_ERR(q)) {
- err = -ENOMEM;
- goto out_free_tags;
- }
- vblk->disk->queue = q;
- q->queuedata = vblk;
- virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN);
- vblk->disk->major = major;
- vblk->disk->first_minor = index_to_minor(index);
- vblk->disk->private_data = vblk;
- vblk->disk->fops = &virtblk_fops;
- vblk->disk->flags |= GENHD_FL_EXT_DEVT;
- vblk->index = index;
- /* configure queue flush support */
- virtblk_update_cache_mode(vdev);
- /* If disk is read-only in the host, the guest should obey */
- if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
- set_disk_ro(vblk->disk, 1);
- /* We can handle whatever the host told us to handle. */
- blk_queue_max_segments(q, vblk->sg_elems-2);
- /* No real sector limit. */
- blk_queue_max_hw_sectors(q, -1U);
- max_size = virtio_max_dma_size(vdev);
- /* Host can optionally specify maximum segment size and number of
- * segments. */
- err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX,
- struct virtio_blk_config, size_max, &v);
- if (!err)
- max_size = min(max_size, v);
- blk_queue_max_segment_size(q, max_size);
- /* Host can optionally specify the block size of the device */
- err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE,
- struct virtio_blk_config, blk_size,
- &blk_size);
- if (!err) {
- err = blk_validate_block_size(blk_size);
- if (err) {
- dev_err(&vdev->dev,
- "virtio_blk: invalid block size: 0x%x\n",
- blk_size);
- goto out_cleanup_disk;
- }
- blk_queue_logical_block_size(q, blk_size);
- } else
- blk_size = queue_logical_block_size(q);
- /* Use topology information if available */
- err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
- struct virtio_blk_config, physical_block_exp,
- &physical_block_exp);
- if (!err && physical_block_exp)
- blk_queue_physical_block_size(q,
- blk_size * (1 << physical_block_exp));
- err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
- struct virtio_blk_config, alignment_offset,
- &alignment_offset);
- if (!err && alignment_offset)
- blk_queue_alignment_offset(q, blk_size * alignment_offset);
- err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
- struct virtio_blk_config, min_io_size,
- &min_io_size);
- if (!err && min_io_size)
- blk_queue_io_min(q, blk_size * min_io_size);
- err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
- struct virtio_blk_config, opt_io_size,
- &opt_io_size);
- if (!err && opt_io_size)
- blk_queue_io_opt(q, blk_size * opt_io_size);
- if (virtio_has_feature(vdev, VIRTIO_BLK_F_DISCARD)) {
- q->limits.discard_granularity = blk_size;
- virtio_cread(vdev, struct virtio_blk_config,
- discard_sector_alignment, &v);
- q->limits.discard_alignment = v ? v << SECTOR_SHIFT : 0;
- virtio_cread(vdev, struct virtio_blk_config,
- max_discard_sectors, &v);
- blk_queue_max_discard_sectors(q, v ? v : UINT_MAX);
- virtio_cread(vdev, struct virtio_blk_config, max_discard_seg,
- &v);
- /*
- * max_discard_seg == 0 is out of spec but we always
- * handled it.
- */
- if (!v)
- v = sg_elems - 2;
- blk_queue_max_discard_segments(q,
- min(v, MAX_DISCARD_SEGMENTS));
- blk_queue_flag_set(QUEUE_FLAG_DISCARD, q);
- }
- if (virtio_has_feature(vdev, VIRTIO_BLK_F_WRITE_ZEROES)) {
- virtio_cread(vdev, struct virtio_blk_config,
- max_write_zeroes_sectors, &v);
- blk_queue_max_write_zeroes_sectors(q, v ? v : UINT_MAX);
- }
- virtblk_update_capacity(vblk, false);
- virtio_device_ready(vdev);
- device_add_disk(&vdev->dev, vblk->disk, virtblk_attr_groups);
- return 0;
- out_cleanup_disk:
- blk_cleanup_queue(vblk->disk->queue);
- out_free_tags:
- blk_mq_free_tag_set(&vblk->tag_set);
- out_put_disk:
- put_disk(vblk->disk);
- out_free_vq:
- vdev->config->del_vqs(vdev);
- kfree(vblk->vqs);
- out_free_vblk:
- kfree(vblk);
- out_free_index:
- ida_simple_remove(&vd_index_ida, index);
- out:
- return err;
- }
- static void virtblk_remove(struct virtio_device *vdev)
- {
- struct virtio_blk *vblk = vdev->priv;
- /* Make sure no work handler is accessing the device. */
- flush_work(&vblk->config_work);
- del_gendisk(vblk->disk);
- blk_cleanup_queue(vblk->disk->queue);
- blk_mq_free_tag_set(&vblk->tag_set);
- mutex_lock(&vblk->vdev_mutex);
- /* Stop all the virtqueues. */
- vdev->config->reset(vdev);
- /* Virtqueues are stopped, nothing can use vblk->vdev anymore. */
- vblk->vdev = NULL;
- put_disk(vblk->disk);
- vdev->config->del_vqs(vdev);
- kfree(vblk->vqs);
- mutex_unlock(&vblk->vdev_mutex);
- virtblk_put(vblk);
- }
- #ifdef CONFIG_PM_SLEEP
- static int virtblk_freeze(struct virtio_device *vdev)
- {
- struct virtio_blk *vblk = vdev->priv;
- /* Ensure we don't receive any more interrupts */
- vdev->config->reset(vdev);
- /* Make sure no work handler is accessing the device. */
- flush_work(&vblk->config_work);
- blk_mq_quiesce_queue(vblk->disk->queue);
- vdev->config->del_vqs(vdev);
- kfree(vblk->vqs);
- return 0;
- }
- static int virtblk_restore(struct virtio_device *vdev)
- {
- struct virtio_blk *vblk = vdev->priv;
- int ret;
- ret = init_vq(vdev->priv);
- if (ret)
- return ret;
- virtio_device_ready(vdev);
- blk_mq_unquiesce_queue(vblk->disk->queue);
- return 0;
- }
- #endif
- static const struct virtio_device_id id_table[] = {
- { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
- { 0 },
- };
- static unsigned int features_legacy[] = {
- VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
- VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
- VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
- VIRTIO_BLK_F_MQ, VIRTIO_BLK_F_DISCARD, VIRTIO_BLK_F_WRITE_ZEROES,
- }
- ;
- static unsigned int features[] = {
- VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
- VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
- VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
- VIRTIO_BLK_F_MQ, VIRTIO_BLK_F_DISCARD, VIRTIO_BLK_F_WRITE_ZEROES,
- };
- static struct virtio_driver virtio_blk = {
- .feature_table = features,
- .feature_table_size = ARRAY_SIZE(features),
- .feature_table_legacy = features_legacy,
- .feature_table_size_legacy = ARRAY_SIZE(features_legacy),
- .driver.name = KBUILD_MODNAME,
- .driver.owner = THIS_MODULE,
- .id_table = id_table,
- .probe = virtblk_probe,
- .remove = virtblk_remove,
- .config_changed = virtblk_config_changed,
- #ifdef CONFIG_PM_SLEEP
- .freeze = virtblk_freeze,
- .restore = virtblk_restore,
- #endif
- };
- static int __init init(void)
- {
- int error;
- virtblk_wq = alloc_workqueue("virtio-blk", 0, 0);
- if (!virtblk_wq)
- return -ENOMEM;
- major = register_blkdev(0, "virtblk");
- if (major < 0) {
- error = major;
- goto out_destroy_workqueue;
- }
- error = register_virtio_driver(&virtio_blk);
- if (error)
- goto out_unregister_blkdev;
- return 0;
- out_unregister_blkdev:
- unregister_blkdev(major, "virtblk");
- out_destroy_workqueue:
- destroy_workqueue(virtblk_wq);
- return error;
- }
- static void __exit fini(void)
- {
- unregister_virtio_driver(&virtio_blk);
- unregister_blkdev(major, "virtblk");
- destroy_workqueue(virtblk_wq);
- }
- module_init(init);
- module_exit(fini);
- MODULE_DEVICE_TABLE(virtio, id_table);
- MODULE_DESCRIPTION("Virtio block driver");
- MODULE_LICENSE("GPL");
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