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- // SPDX-License-Identifier: GPL-2.0
- /*
- * virtio-fs: Virtio Filesystem
- * Copyright (C) 2018 Red Hat, Inc.
- */
- #include <linux/fs.h>
- #include <linux/dax.h>
- #include <linux/pci.h>
- #include <linux/pfn_t.h>
- #include <linux/module.h>
- #include <linux/virtio.h>
- #include <linux/virtio_fs.h>
- #include <linux/delay.h>
- #include <linux/fs_context.h>
- #include <linux/fs_parser.h>
- #include <linux/highmem.h>
- #include <linux/uio.h>
- #include "fuse_i.h"
- /* List of virtio-fs device instances and a lock for the list. Also provides
- * mutual exclusion in device removal and mounting path
- */
- static DEFINE_MUTEX(virtio_fs_mutex);
- static LIST_HEAD(virtio_fs_instances);
- enum {
- VQ_HIPRIO,
- VQ_REQUEST
- };
- #define VQ_NAME_LEN 24
- /* Per-virtqueue state */
- struct virtio_fs_vq {
- spinlock_t lock;
- struct virtqueue *vq; /* protected by ->lock */
- struct work_struct done_work;
- struct list_head queued_reqs;
- struct list_head end_reqs; /* End these requests */
- struct delayed_work dispatch_work;
- struct fuse_dev *fud;
- bool connected;
- long in_flight;
- struct completion in_flight_zero; /* No inflight requests */
- char name[VQ_NAME_LEN];
- } ____cacheline_aligned_in_smp;
- /* A virtio-fs device instance */
- struct virtio_fs {
- struct kref refcount;
- struct list_head list; /* on virtio_fs_instances */
- char *tag;
- struct virtio_fs_vq *vqs;
- unsigned int nvqs; /* number of virtqueues */
- unsigned int num_request_queues; /* number of request queues */
- struct dax_device *dax_dev;
- /* DAX memory window where file contents are mapped */
- void *window_kaddr;
- phys_addr_t window_phys_addr;
- size_t window_len;
- };
- struct virtio_fs_forget_req {
- struct fuse_in_header ih;
- struct fuse_forget_in arg;
- };
- struct virtio_fs_forget {
- /* This request can be temporarily queued on virt queue */
- struct list_head list;
- struct virtio_fs_forget_req req;
- };
- struct virtio_fs_req_work {
- struct fuse_req *req;
- struct virtio_fs_vq *fsvq;
- struct work_struct done_work;
- };
- static int virtio_fs_enqueue_req(struct virtio_fs_vq *fsvq,
- struct fuse_req *req, bool in_flight);
- enum {
- OPT_DAX,
- };
- static const struct fs_parameter_spec virtio_fs_parameters[] = {
- fsparam_flag("dax", OPT_DAX),
- {}
- };
- static int virtio_fs_parse_param(struct fs_context *fc,
- struct fs_parameter *param)
- {
- struct fs_parse_result result;
- struct fuse_fs_context *ctx = fc->fs_private;
- int opt;
- opt = fs_parse(fc, virtio_fs_parameters, param, &result);
- if (opt < 0)
- return opt;
- switch (opt) {
- case OPT_DAX:
- ctx->dax = 1;
- break;
- default:
- return -EINVAL;
- }
- return 0;
- }
- static void virtio_fs_free_fc(struct fs_context *fc)
- {
- struct fuse_fs_context *ctx = fc->fs_private;
- kfree(ctx);
- }
- static inline struct virtio_fs_vq *vq_to_fsvq(struct virtqueue *vq)
- {
- struct virtio_fs *fs = vq->vdev->priv;
- return &fs->vqs[vq->index];
- }
- static inline struct fuse_pqueue *vq_to_fpq(struct virtqueue *vq)
- {
- return &vq_to_fsvq(vq)->fud->pq;
- }
- /* Should be called with fsvq->lock held. */
- static inline void inc_in_flight_req(struct virtio_fs_vq *fsvq)
- {
- fsvq->in_flight++;
- }
- /* Should be called with fsvq->lock held. */
- static inline void dec_in_flight_req(struct virtio_fs_vq *fsvq)
- {
- WARN_ON(fsvq->in_flight <= 0);
- fsvq->in_flight--;
- if (!fsvq->in_flight)
- complete(&fsvq->in_flight_zero);
- }
- static void release_virtio_fs_obj(struct kref *ref)
- {
- struct virtio_fs *vfs = container_of(ref, struct virtio_fs, refcount);
- kfree(vfs->vqs);
- kfree(vfs);
- }
- /* Make sure virtiofs_mutex is held */
- static void virtio_fs_put(struct virtio_fs *fs)
- {
- kref_put(&fs->refcount, release_virtio_fs_obj);
- }
- static void virtio_fs_fiq_release(struct fuse_iqueue *fiq)
- {
- struct virtio_fs *vfs = fiq->priv;
- mutex_lock(&virtio_fs_mutex);
- virtio_fs_put(vfs);
- mutex_unlock(&virtio_fs_mutex);
- }
- static void virtio_fs_drain_queue(struct virtio_fs_vq *fsvq)
- {
- WARN_ON(fsvq->in_flight < 0);
- /* Wait for in flight requests to finish.*/
- spin_lock(&fsvq->lock);
- if (fsvq->in_flight) {
- /* We are holding virtio_fs_mutex. There should not be any
- * waiters waiting for completion.
- */
- reinit_completion(&fsvq->in_flight_zero);
- spin_unlock(&fsvq->lock);
- wait_for_completion(&fsvq->in_flight_zero);
- } else {
- spin_unlock(&fsvq->lock);
- }
- flush_work(&fsvq->done_work);
- flush_delayed_work(&fsvq->dispatch_work);
- }
- static void virtio_fs_drain_all_queues_locked(struct virtio_fs *fs)
- {
- struct virtio_fs_vq *fsvq;
- int i;
- for (i = 0; i < fs->nvqs; i++) {
- fsvq = &fs->vqs[i];
- virtio_fs_drain_queue(fsvq);
- }
- }
- static void virtio_fs_drain_all_queues(struct virtio_fs *fs)
- {
- /* Provides mutual exclusion between ->remove and ->kill_sb
- * paths. We don't want both of these draining queue at the
- * same time. Current completion logic reinits completion
- * and that means there should not be any other thread
- * doing reinit or waiting for completion already.
- */
- mutex_lock(&virtio_fs_mutex);
- virtio_fs_drain_all_queues_locked(fs);
- mutex_unlock(&virtio_fs_mutex);
- }
- static void virtio_fs_start_all_queues(struct virtio_fs *fs)
- {
- struct virtio_fs_vq *fsvq;
- int i;
- for (i = 0; i < fs->nvqs; i++) {
- fsvq = &fs->vqs[i];
- spin_lock(&fsvq->lock);
- fsvq->connected = true;
- spin_unlock(&fsvq->lock);
- }
- }
- /* Add a new instance to the list or return -EEXIST if tag name exists*/
- static int virtio_fs_add_instance(struct virtio_fs *fs)
- {
- struct virtio_fs *fs2;
- bool duplicate = false;
- mutex_lock(&virtio_fs_mutex);
- list_for_each_entry(fs2, &virtio_fs_instances, list) {
- if (strcmp(fs->tag, fs2->tag) == 0)
- duplicate = true;
- }
- if (!duplicate)
- list_add_tail(&fs->list, &virtio_fs_instances);
- mutex_unlock(&virtio_fs_mutex);
- if (duplicate)
- return -EEXIST;
- return 0;
- }
- /* Return the virtio_fs with a given tag, or NULL */
- static struct virtio_fs *virtio_fs_find_instance(const char *tag)
- {
- struct virtio_fs *fs;
- mutex_lock(&virtio_fs_mutex);
- list_for_each_entry(fs, &virtio_fs_instances, list) {
- if (strcmp(fs->tag, tag) == 0) {
- kref_get(&fs->refcount);
- goto found;
- }
- }
- fs = NULL; /* not found */
- found:
- mutex_unlock(&virtio_fs_mutex);
- return fs;
- }
- static void virtio_fs_free_devs(struct virtio_fs *fs)
- {
- unsigned int i;
- for (i = 0; i < fs->nvqs; i++) {
- struct virtio_fs_vq *fsvq = &fs->vqs[i];
- if (!fsvq->fud)
- continue;
- fuse_dev_free(fsvq->fud);
- fsvq->fud = NULL;
- }
- }
- /* Read filesystem name from virtio config into fs->tag (must kfree()). */
- static int virtio_fs_read_tag(struct virtio_device *vdev, struct virtio_fs *fs)
- {
- char tag_buf[sizeof_field(struct virtio_fs_config, tag)];
- char *end;
- size_t len;
- virtio_cread_bytes(vdev, offsetof(struct virtio_fs_config, tag),
- &tag_buf, sizeof(tag_buf));
- end = memchr(tag_buf, '\0', sizeof(tag_buf));
- if (end == tag_buf)
- return -EINVAL; /* empty tag */
- if (!end)
- end = &tag_buf[sizeof(tag_buf)];
- len = end - tag_buf;
- fs->tag = devm_kmalloc(&vdev->dev, len + 1, GFP_KERNEL);
- if (!fs->tag)
- return -ENOMEM;
- memcpy(fs->tag, tag_buf, len);
- fs->tag[len] = '\0';
- return 0;
- }
- /* Work function for hiprio completion */
- static void virtio_fs_hiprio_done_work(struct work_struct *work)
- {
- struct virtio_fs_vq *fsvq = container_of(work, struct virtio_fs_vq,
- done_work);
- struct virtqueue *vq = fsvq->vq;
- /* Free completed FUSE_FORGET requests */
- spin_lock(&fsvq->lock);
- do {
- unsigned int len;
- void *req;
- virtqueue_disable_cb(vq);
- while ((req = virtqueue_get_buf(vq, &len)) != NULL) {
- kfree(req);
- dec_in_flight_req(fsvq);
- }
- } while (!virtqueue_enable_cb(vq) && likely(!virtqueue_is_broken(vq)));
- spin_unlock(&fsvq->lock);
- }
- static void virtio_fs_request_dispatch_work(struct work_struct *work)
- {
- struct fuse_req *req;
- struct virtio_fs_vq *fsvq = container_of(work, struct virtio_fs_vq,
- dispatch_work.work);
- int ret;
- pr_debug("virtio-fs: worker %s called.\n", __func__);
- while (1) {
- spin_lock(&fsvq->lock);
- req = list_first_entry_or_null(&fsvq->end_reqs, struct fuse_req,
- list);
- if (!req) {
- spin_unlock(&fsvq->lock);
- break;
- }
- list_del_init(&req->list);
- spin_unlock(&fsvq->lock);
- fuse_request_end(req);
- }
- /* Dispatch pending requests */
- while (1) {
- spin_lock(&fsvq->lock);
- req = list_first_entry_or_null(&fsvq->queued_reqs,
- struct fuse_req, list);
- if (!req) {
- spin_unlock(&fsvq->lock);
- return;
- }
- list_del_init(&req->list);
- spin_unlock(&fsvq->lock);
- ret = virtio_fs_enqueue_req(fsvq, req, true);
- if (ret < 0) {
- if (ret == -ENOMEM || ret == -ENOSPC) {
- spin_lock(&fsvq->lock);
- list_add_tail(&req->list, &fsvq->queued_reqs);
- schedule_delayed_work(&fsvq->dispatch_work,
- msecs_to_jiffies(1));
- spin_unlock(&fsvq->lock);
- return;
- }
- req->out.h.error = ret;
- spin_lock(&fsvq->lock);
- dec_in_flight_req(fsvq);
- spin_unlock(&fsvq->lock);
- pr_err("virtio-fs: virtio_fs_enqueue_req() failed %d\n",
- ret);
- fuse_request_end(req);
- }
- }
- }
- /*
- * Returns 1 if queue is full and sender should wait a bit before sending
- * next request, 0 otherwise.
- */
- static int send_forget_request(struct virtio_fs_vq *fsvq,
- struct virtio_fs_forget *forget,
- bool in_flight)
- {
- struct scatterlist sg;
- struct virtqueue *vq;
- int ret = 0;
- bool notify;
- struct virtio_fs_forget_req *req = &forget->req;
- spin_lock(&fsvq->lock);
- if (!fsvq->connected) {
- if (in_flight)
- dec_in_flight_req(fsvq);
- kfree(forget);
- goto out;
- }
- sg_init_one(&sg, req, sizeof(*req));
- vq = fsvq->vq;
- dev_dbg(&vq->vdev->dev, "%s\n", __func__);
- ret = virtqueue_add_outbuf(vq, &sg, 1, forget, GFP_ATOMIC);
- if (ret < 0) {
- if (ret == -ENOMEM || ret == -ENOSPC) {
- pr_debug("virtio-fs: Could not queue FORGET: err=%d. Will try later\n",
- ret);
- list_add_tail(&forget->list, &fsvq->queued_reqs);
- schedule_delayed_work(&fsvq->dispatch_work,
- msecs_to_jiffies(1));
- if (!in_flight)
- inc_in_flight_req(fsvq);
- /* Queue is full */
- ret = 1;
- } else {
- pr_debug("virtio-fs: Could not queue FORGET: err=%d. Dropping it.\n",
- ret);
- kfree(forget);
- if (in_flight)
- dec_in_flight_req(fsvq);
- }
- goto out;
- }
- if (!in_flight)
- inc_in_flight_req(fsvq);
- notify = virtqueue_kick_prepare(vq);
- spin_unlock(&fsvq->lock);
- if (notify)
- virtqueue_notify(vq);
- return ret;
- out:
- spin_unlock(&fsvq->lock);
- return ret;
- }
- static void virtio_fs_hiprio_dispatch_work(struct work_struct *work)
- {
- struct virtio_fs_forget *forget;
- struct virtio_fs_vq *fsvq = container_of(work, struct virtio_fs_vq,
- dispatch_work.work);
- pr_debug("virtio-fs: worker %s called.\n", __func__);
- while (1) {
- spin_lock(&fsvq->lock);
- forget = list_first_entry_or_null(&fsvq->queued_reqs,
- struct virtio_fs_forget, list);
- if (!forget) {
- spin_unlock(&fsvq->lock);
- return;
- }
- list_del(&forget->list);
- spin_unlock(&fsvq->lock);
- if (send_forget_request(fsvq, forget, true))
- return;
- }
- }
- /* Allocate and copy args into req->argbuf */
- static int copy_args_to_argbuf(struct fuse_req *req)
- {
- struct fuse_args *args = req->args;
- unsigned int offset = 0;
- unsigned int num_in;
- unsigned int num_out;
- unsigned int len;
- unsigned int i;
- num_in = args->in_numargs - args->in_pages;
- num_out = args->out_numargs - args->out_pages;
- len = fuse_len_args(num_in, (struct fuse_arg *) args->in_args) +
- fuse_len_args(num_out, args->out_args);
- req->argbuf = kmalloc(len, GFP_ATOMIC);
- if (!req->argbuf)
- return -ENOMEM;
- for (i = 0; i < num_in; i++) {
- memcpy(req->argbuf + offset,
- args->in_args[i].value,
- args->in_args[i].size);
- offset += args->in_args[i].size;
- }
- return 0;
- }
- /* Copy args out of and free req->argbuf */
- static void copy_args_from_argbuf(struct fuse_args *args, struct fuse_req *req)
- {
- unsigned int remaining;
- unsigned int offset;
- unsigned int num_in;
- unsigned int num_out;
- unsigned int i;
- remaining = req->out.h.len - sizeof(req->out.h);
- num_in = args->in_numargs - args->in_pages;
- num_out = args->out_numargs - args->out_pages;
- offset = fuse_len_args(num_in, (struct fuse_arg *)args->in_args);
- for (i = 0; i < num_out; i++) {
- unsigned int argsize = args->out_args[i].size;
- if (args->out_argvar &&
- i == args->out_numargs - 1 &&
- argsize > remaining) {
- argsize = remaining;
- }
- memcpy(args->out_args[i].value, req->argbuf + offset, argsize);
- offset += argsize;
- if (i != args->out_numargs - 1)
- remaining -= argsize;
- }
- /* Store the actual size of the variable-length arg */
- if (args->out_argvar)
- args->out_args[args->out_numargs - 1].size = remaining;
- kfree(req->argbuf);
- req->argbuf = NULL;
- }
- /* Work function for request completion */
- static void virtio_fs_request_complete(struct fuse_req *req,
- struct virtio_fs_vq *fsvq)
- {
- struct fuse_pqueue *fpq = &fsvq->fud->pq;
- struct fuse_args *args;
- struct fuse_args_pages *ap;
- unsigned int len, i, thislen;
- struct page *page;
- /*
- * TODO verify that server properly follows FUSE protocol
- * (oh.uniq, oh.len)
- */
- args = req->args;
- copy_args_from_argbuf(args, req);
- if (args->out_pages && args->page_zeroing) {
- len = args->out_args[args->out_numargs - 1].size;
- ap = container_of(args, typeof(*ap), args);
- for (i = 0; i < ap->num_pages; i++) {
- thislen = ap->descs[i].length;
- if (len < thislen) {
- WARN_ON(ap->descs[i].offset);
- page = ap->pages[i];
- zero_user_segment(page, len, thislen);
- len = 0;
- } else {
- len -= thislen;
- }
- }
- }
- spin_lock(&fpq->lock);
- clear_bit(FR_SENT, &req->flags);
- spin_unlock(&fpq->lock);
- fuse_request_end(req);
- spin_lock(&fsvq->lock);
- dec_in_flight_req(fsvq);
- spin_unlock(&fsvq->lock);
- }
- static void virtio_fs_complete_req_work(struct work_struct *work)
- {
- struct virtio_fs_req_work *w =
- container_of(work, typeof(*w), done_work);
- virtio_fs_request_complete(w->req, w->fsvq);
- kfree(w);
- }
- static void virtio_fs_requests_done_work(struct work_struct *work)
- {
- struct virtio_fs_vq *fsvq = container_of(work, struct virtio_fs_vq,
- done_work);
- struct fuse_pqueue *fpq = &fsvq->fud->pq;
- struct virtqueue *vq = fsvq->vq;
- struct fuse_req *req;
- struct fuse_req *next;
- unsigned int len;
- LIST_HEAD(reqs);
- /* Collect completed requests off the virtqueue */
- spin_lock(&fsvq->lock);
- do {
- virtqueue_disable_cb(vq);
- while ((req = virtqueue_get_buf(vq, &len)) != NULL) {
- spin_lock(&fpq->lock);
- list_move_tail(&req->list, &reqs);
- spin_unlock(&fpq->lock);
- }
- } while (!virtqueue_enable_cb(vq) && likely(!virtqueue_is_broken(vq)));
- spin_unlock(&fsvq->lock);
- /* End requests */
- list_for_each_entry_safe(req, next, &reqs, list) {
- list_del_init(&req->list);
- /* blocking async request completes in a worker context */
- if (req->args->may_block) {
- struct virtio_fs_req_work *w;
- w = kzalloc(sizeof(*w), GFP_NOFS | __GFP_NOFAIL);
- INIT_WORK(&w->done_work, virtio_fs_complete_req_work);
- w->fsvq = fsvq;
- w->req = req;
- schedule_work(&w->done_work);
- } else {
- virtio_fs_request_complete(req, fsvq);
- }
- }
- }
- /* Virtqueue interrupt handler */
- static void virtio_fs_vq_done(struct virtqueue *vq)
- {
- struct virtio_fs_vq *fsvq = vq_to_fsvq(vq);
- dev_dbg(&vq->vdev->dev, "%s %s\n", __func__, fsvq->name);
- schedule_work(&fsvq->done_work);
- }
- static void virtio_fs_init_vq(struct virtio_fs_vq *fsvq, char *name,
- int vq_type)
- {
- strncpy(fsvq->name, name, VQ_NAME_LEN);
- spin_lock_init(&fsvq->lock);
- INIT_LIST_HEAD(&fsvq->queued_reqs);
- INIT_LIST_HEAD(&fsvq->end_reqs);
- init_completion(&fsvq->in_flight_zero);
- if (vq_type == VQ_REQUEST) {
- INIT_WORK(&fsvq->done_work, virtio_fs_requests_done_work);
- INIT_DELAYED_WORK(&fsvq->dispatch_work,
- virtio_fs_request_dispatch_work);
- } else {
- INIT_WORK(&fsvq->done_work, virtio_fs_hiprio_done_work);
- INIT_DELAYED_WORK(&fsvq->dispatch_work,
- virtio_fs_hiprio_dispatch_work);
- }
- }
- /* Initialize virtqueues */
- static int virtio_fs_setup_vqs(struct virtio_device *vdev,
- struct virtio_fs *fs)
- {
- struct virtqueue **vqs;
- vq_callback_t **callbacks;
- const char **names;
- unsigned int i;
- int ret = 0;
- virtio_cread_le(vdev, struct virtio_fs_config, num_request_queues,
- &fs->num_request_queues);
- if (fs->num_request_queues == 0)
- return -EINVAL;
- fs->nvqs = VQ_REQUEST + fs->num_request_queues;
- fs->vqs = kcalloc(fs->nvqs, sizeof(fs->vqs[VQ_HIPRIO]), GFP_KERNEL);
- if (!fs->vqs)
- return -ENOMEM;
- vqs = kmalloc_array(fs->nvqs, sizeof(vqs[VQ_HIPRIO]), GFP_KERNEL);
- callbacks = kmalloc_array(fs->nvqs, sizeof(callbacks[VQ_HIPRIO]),
- GFP_KERNEL);
- names = kmalloc_array(fs->nvqs, sizeof(names[VQ_HIPRIO]), GFP_KERNEL);
- if (!vqs || !callbacks || !names) {
- ret = -ENOMEM;
- goto out;
- }
- /* Initialize the hiprio/forget request virtqueue */
- callbacks[VQ_HIPRIO] = virtio_fs_vq_done;
- virtio_fs_init_vq(&fs->vqs[VQ_HIPRIO], "hiprio", VQ_HIPRIO);
- names[VQ_HIPRIO] = fs->vqs[VQ_HIPRIO].name;
- /* Initialize the requests virtqueues */
- for (i = VQ_REQUEST; i < fs->nvqs; i++) {
- char vq_name[VQ_NAME_LEN];
- snprintf(vq_name, VQ_NAME_LEN, "requests.%u", i - VQ_REQUEST);
- virtio_fs_init_vq(&fs->vqs[i], vq_name, VQ_REQUEST);
- callbacks[i] = virtio_fs_vq_done;
- names[i] = fs->vqs[i].name;
- }
- ret = virtio_find_vqs(vdev, fs->nvqs, vqs, callbacks, names, NULL);
- if (ret < 0)
- goto out;
- for (i = 0; i < fs->nvqs; i++)
- fs->vqs[i].vq = vqs[i];
- virtio_fs_start_all_queues(fs);
- out:
- kfree(names);
- kfree(callbacks);
- kfree(vqs);
- if (ret)
- kfree(fs->vqs);
- return ret;
- }
- /* Free virtqueues (device must already be reset) */
- static void virtio_fs_cleanup_vqs(struct virtio_device *vdev,
- struct virtio_fs *fs)
- {
- vdev->config->del_vqs(vdev);
- }
- /* Map a window offset to a page frame number. The window offset will have
- * been produced by .iomap_begin(), which maps a file offset to a window
- * offset.
- */
- static long virtio_fs_direct_access(struct dax_device *dax_dev, pgoff_t pgoff,
- long nr_pages, void **kaddr, pfn_t *pfn)
- {
- struct virtio_fs *fs = dax_get_private(dax_dev);
- phys_addr_t offset = PFN_PHYS(pgoff);
- size_t max_nr_pages = fs->window_len/PAGE_SIZE - pgoff;
- if (kaddr)
- *kaddr = fs->window_kaddr + offset;
- if (pfn)
- *pfn = phys_to_pfn_t(fs->window_phys_addr + offset,
- PFN_DEV | PFN_MAP);
- return nr_pages > max_nr_pages ? max_nr_pages : nr_pages;
- }
- static size_t virtio_fs_copy_from_iter(struct dax_device *dax_dev,
- pgoff_t pgoff, void *addr,
- size_t bytes, struct iov_iter *i)
- {
- return copy_from_iter(addr, bytes, i);
- }
- static size_t virtio_fs_copy_to_iter(struct dax_device *dax_dev,
- pgoff_t pgoff, void *addr,
- size_t bytes, struct iov_iter *i)
- {
- return copy_to_iter(addr, bytes, i);
- }
- static int virtio_fs_zero_page_range(struct dax_device *dax_dev,
- pgoff_t pgoff, size_t nr_pages)
- {
- long rc;
- void *kaddr;
- rc = dax_direct_access(dax_dev, pgoff, nr_pages, &kaddr, NULL);
- if (rc < 0)
- return rc;
- memset(kaddr, 0, nr_pages << PAGE_SHIFT);
- dax_flush(dax_dev, kaddr, nr_pages << PAGE_SHIFT);
- return 0;
- }
- static const struct dax_operations virtio_fs_dax_ops = {
- .direct_access = virtio_fs_direct_access,
- .copy_from_iter = virtio_fs_copy_from_iter,
- .copy_to_iter = virtio_fs_copy_to_iter,
- .zero_page_range = virtio_fs_zero_page_range,
- };
- static void virtio_fs_cleanup_dax(void *data)
- {
- struct dax_device *dax_dev = data;
- kill_dax(dax_dev);
- put_dax(dax_dev);
- }
- static int virtio_fs_setup_dax(struct virtio_device *vdev, struct virtio_fs *fs)
- {
- struct virtio_shm_region cache_reg;
- struct dev_pagemap *pgmap;
- bool have_cache;
- if (!IS_ENABLED(CONFIG_FUSE_DAX))
- return 0;
- /* Get cache region */
- have_cache = virtio_get_shm_region(vdev, &cache_reg,
- (u8)VIRTIO_FS_SHMCAP_ID_CACHE);
- if (!have_cache) {
- dev_notice(&vdev->dev, "%s: No cache capability\n", __func__);
- return 0;
- }
- if (!devm_request_mem_region(&vdev->dev, cache_reg.addr, cache_reg.len,
- dev_name(&vdev->dev))) {
- dev_warn(&vdev->dev, "could not reserve region addr=0x%llx len=0x%llx\n",
- cache_reg.addr, cache_reg.len);
- return -EBUSY;
- }
- dev_notice(&vdev->dev, "Cache len: 0x%llx @ 0x%llx\n", cache_reg.len,
- cache_reg.addr);
- pgmap = devm_kzalloc(&vdev->dev, sizeof(*pgmap), GFP_KERNEL);
- if (!pgmap)
- return -ENOMEM;
- pgmap->type = MEMORY_DEVICE_FS_DAX;
- /* Ideally we would directly use the PCI BAR resource but
- * devm_memremap_pages() wants its own copy in pgmap. So
- * initialize a struct resource from scratch (only the start
- * and end fields will be used).
- */
- pgmap->range = (struct range) {
- .start = (phys_addr_t) cache_reg.addr,
- .end = (phys_addr_t) cache_reg.addr + cache_reg.len - 1,
- };
- pgmap->nr_range = 1;
- fs->window_kaddr = devm_memremap_pages(&vdev->dev, pgmap);
- if (IS_ERR(fs->window_kaddr))
- return PTR_ERR(fs->window_kaddr);
- fs->window_phys_addr = (phys_addr_t) cache_reg.addr;
- fs->window_len = (phys_addr_t) cache_reg.len;
- dev_dbg(&vdev->dev, "%s: window kaddr 0x%px phys_addr 0x%llx len 0x%llx\n",
- __func__, fs->window_kaddr, cache_reg.addr, cache_reg.len);
- fs->dax_dev = alloc_dax(fs, NULL, &virtio_fs_dax_ops, 0);
- if (IS_ERR(fs->dax_dev))
- return PTR_ERR(fs->dax_dev);
- return devm_add_action_or_reset(&vdev->dev, virtio_fs_cleanup_dax,
- fs->dax_dev);
- }
- static int virtio_fs_probe(struct virtio_device *vdev)
- {
- struct virtio_fs *fs;
- int ret;
- fs = kzalloc(sizeof(*fs), GFP_KERNEL);
- if (!fs)
- return -ENOMEM;
- kref_init(&fs->refcount);
- vdev->priv = fs;
- ret = virtio_fs_read_tag(vdev, fs);
- if (ret < 0)
- goto out;
- ret = virtio_fs_setup_vqs(vdev, fs);
- if (ret < 0)
- goto out;
- /* TODO vq affinity */
- ret = virtio_fs_setup_dax(vdev, fs);
- if (ret < 0)
- goto out_vqs;
- /* Bring the device online in case the filesystem is mounted and
- * requests need to be sent before we return.
- */
- virtio_device_ready(vdev);
- ret = virtio_fs_add_instance(fs);
- if (ret < 0)
- goto out_vqs;
- return 0;
- out_vqs:
- vdev->config->reset(vdev);
- virtio_fs_cleanup_vqs(vdev, fs);
- kfree(fs->vqs);
- out:
- vdev->priv = NULL;
- kfree(fs);
- return ret;
- }
- static void virtio_fs_stop_all_queues(struct virtio_fs *fs)
- {
- struct virtio_fs_vq *fsvq;
- int i;
- for (i = 0; i < fs->nvqs; i++) {
- fsvq = &fs->vqs[i];
- spin_lock(&fsvq->lock);
- fsvq->connected = false;
- spin_unlock(&fsvq->lock);
- }
- }
- static void virtio_fs_remove(struct virtio_device *vdev)
- {
- struct virtio_fs *fs = vdev->priv;
- mutex_lock(&virtio_fs_mutex);
- /* This device is going away. No one should get new reference */
- list_del_init(&fs->list);
- virtio_fs_stop_all_queues(fs);
- virtio_fs_drain_all_queues_locked(fs);
- vdev->config->reset(vdev);
- virtio_fs_cleanup_vqs(vdev, fs);
- vdev->priv = NULL;
- /* Put device reference on virtio_fs object */
- virtio_fs_put(fs);
- mutex_unlock(&virtio_fs_mutex);
- }
- #ifdef CONFIG_PM_SLEEP
- static int virtio_fs_freeze(struct virtio_device *vdev)
- {
- /* TODO need to save state here */
- pr_warn("virtio-fs: suspend/resume not yet supported\n");
- return -EOPNOTSUPP;
- }
- static int virtio_fs_restore(struct virtio_device *vdev)
- {
- /* TODO need to restore state here */
- return 0;
- }
- #endif /* CONFIG_PM_SLEEP */
- static const struct virtio_device_id id_table[] = {
- { VIRTIO_ID_FS, VIRTIO_DEV_ANY_ID },
- {},
- };
- static const unsigned int feature_table[] = {};
- static struct virtio_driver virtio_fs_driver = {
- .driver.name = KBUILD_MODNAME,
- .driver.owner = THIS_MODULE,
- .id_table = id_table,
- .feature_table = feature_table,
- .feature_table_size = ARRAY_SIZE(feature_table),
- .probe = virtio_fs_probe,
- .remove = virtio_fs_remove,
- #ifdef CONFIG_PM_SLEEP
- .freeze = virtio_fs_freeze,
- .restore = virtio_fs_restore,
- #endif
- };
- static void virtio_fs_wake_forget_and_unlock(struct fuse_iqueue *fiq)
- __releases(fiq->lock)
- {
- struct fuse_forget_link *link;
- struct virtio_fs_forget *forget;
- struct virtio_fs_forget_req *req;
- struct virtio_fs *fs;
- struct virtio_fs_vq *fsvq;
- u64 unique;
- link = fuse_dequeue_forget(fiq, 1, NULL);
- unique = fuse_get_unique(fiq);
- fs = fiq->priv;
- fsvq = &fs->vqs[VQ_HIPRIO];
- spin_unlock(&fiq->lock);
- /* Allocate a buffer for the request */
- forget = kmalloc(sizeof(*forget), GFP_NOFS | __GFP_NOFAIL);
- req = &forget->req;
- req->ih = (struct fuse_in_header){
- .opcode = FUSE_FORGET,
- .nodeid = link->forget_one.nodeid,
- .unique = unique,
- .len = sizeof(*req),
- };
- req->arg = (struct fuse_forget_in){
- .nlookup = link->forget_one.nlookup,
- };
- send_forget_request(fsvq, forget, false);
- kfree(link);
- }
- static void virtio_fs_wake_interrupt_and_unlock(struct fuse_iqueue *fiq)
- __releases(fiq->lock)
- {
- /*
- * TODO interrupts.
- *
- * Normal fs operations on a local filesystems aren't interruptible.
- * Exceptions are blocking lock operations; for example fcntl(F_SETLKW)
- * with shared lock between host and guest.
- */
- spin_unlock(&fiq->lock);
- }
- /* Count number of scatter-gather elements required */
- static unsigned int sg_count_fuse_pages(struct fuse_page_desc *page_descs,
- unsigned int num_pages,
- unsigned int total_len)
- {
- unsigned int i;
- unsigned int this_len;
- for (i = 0; i < num_pages && total_len; i++) {
- this_len = min(page_descs[i].length, total_len);
- total_len -= this_len;
- }
- return i;
- }
- /* Return the number of scatter-gather list elements required */
- static unsigned int sg_count_fuse_req(struct fuse_req *req)
- {
- struct fuse_args *args = req->args;
- struct fuse_args_pages *ap = container_of(args, typeof(*ap), args);
- unsigned int size, total_sgs = 1 /* fuse_in_header */;
- if (args->in_numargs - args->in_pages)
- total_sgs += 1;
- if (args->in_pages) {
- size = args->in_args[args->in_numargs - 1].size;
- total_sgs += sg_count_fuse_pages(ap->descs, ap->num_pages,
- size);
- }
- if (!test_bit(FR_ISREPLY, &req->flags))
- return total_sgs;
- total_sgs += 1 /* fuse_out_header */;
- if (args->out_numargs - args->out_pages)
- total_sgs += 1;
- if (args->out_pages) {
- size = args->out_args[args->out_numargs - 1].size;
- total_sgs += sg_count_fuse_pages(ap->descs, ap->num_pages,
- size);
- }
- return total_sgs;
- }
- /* Add pages to scatter-gather list and return number of elements used */
- static unsigned int sg_init_fuse_pages(struct scatterlist *sg,
- struct page **pages,
- struct fuse_page_desc *page_descs,
- unsigned int num_pages,
- unsigned int total_len)
- {
- unsigned int i;
- unsigned int this_len;
- for (i = 0; i < num_pages && total_len; i++) {
- sg_init_table(&sg[i], 1);
- this_len = min(page_descs[i].length, total_len);
- sg_set_page(&sg[i], pages[i], this_len, page_descs[i].offset);
- total_len -= this_len;
- }
- return i;
- }
- /* Add args to scatter-gather list and return number of elements used */
- static unsigned int sg_init_fuse_args(struct scatterlist *sg,
- struct fuse_req *req,
- struct fuse_arg *args,
- unsigned int numargs,
- bool argpages,
- void *argbuf,
- unsigned int *len_used)
- {
- struct fuse_args_pages *ap = container_of(req->args, typeof(*ap), args);
- unsigned int total_sgs = 0;
- unsigned int len;
- len = fuse_len_args(numargs - argpages, args);
- if (len)
- sg_init_one(&sg[total_sgs++], argbuf, len);
- if (argpages)
- total_sgs += sg_init_fuse_pages(&sg[total_sgs],
- ap->pages, ap->descs,
- ap->num_pages,
- args[numargs - 1].size);
- if (len_used)
- *len_used = len;
- return total_sgs;
- }
- /* Add a request to a virtqueue and kick the device */
- static int virtio_fs_enqueue_req(struct virtio_fs_vq *fsvq,
- struct fuse_req *req, bool in_flight)
- {
- /* requests need at least 4 elements */
- struct scatterlist *stack_sgs[6];
- struct scatterlist stack_sg[ARRAY_SIZE(stack_sgs)];
- struct scatterlist **sgs = stack_sgs;
- struct scatterlist *sg = stack_sg;
- struct virtqueue *vq;
- struct fuse_args *args = req->args;
- unsigned int argbuf_used = 0;
- unsigned int out_sgs = 0;
- unsigned int in_sgs = 0;
- unsigned int total_sgs;
- unsigned int i;
- int ret;
- bool notify;
- struct fuse_pqueue *fpq;
- /* Does the sglist fit on the stack? */
- total_sgs = sg_count_fuse_req(req);
- if (total_sgs > ARRAY_SIZE(stack_sgs)) {
- sgs = kmalloc_array(total_sgs, sizeof(sgs[0]), GFP_ATOMIC);
- sg = kmalloc_array(total_sgs, sizeof(sg[0]), GFP_ATOMIC);
- if (!sgs || !sg) {
- ret = -ENOMEM;
- goto out;
- }
- }
- /* Use a bounce buffer since stack args cannot be mapped */
- ret = copy_args_to_argbuf(req);
- if (ret < 0)
- goto out;
- /* Request elements */
- sg_init_one(&sg[out_sgs++], &req->in.h, sizeof(req->in.h));
- out_sgs += sg_init_fuse_args(&sg[out_sgs], req,
- (struct fuse_arg *)args->in_args,
- args->in_numargs, args->in_pages,
- req->argbuf, &argbuf_used);
- /* Reply elements */
- if (test_bit(FR_ISREPLY, &req->flags)) {
- sg_init_one(&sg[out_sgs + in_sgs++],
- &req->out.h, sizeof(req->out.h));
- in_sgs += sg_init_fuse_args(&sg[out_sgs + in_sgs], req,
- args->out_args, args->out_numargs,
- args->out_pages,
- req->argbuf + argbuf_used, NULL);
- }
- WARN_ON(out_sgs + in_sgs != total_sgs);
- for (i = 0; i < total_sgs; i++)
- sgs[i] = &sg[i];
- spin_lock(&fsvq->lock);
- if (!fsvq->connected) {
- spin_unlock(&fsvq->lock);
- ret = -ENOTCONN;
- goto out;
- }
- vq = fsvq->vq;
- ret = virtqueue_add_sgs(vq, sgs, out_sgs, in_sgs, req, GFP_ATOMIC);
- if (ret < 0) {
- spin_unlock(&fsvq->lock);
- goto out;
- }
- /* Request successfully sent. */
- fpq = &fsvq->fud->pq;
- spin_lock(&fpq->lock);
- list_add_tail(&req->list, fpq->processing);
- spin_unlock(&fpq->lock);
- set_bit(FR_SENT, &req->flags);
- /* matches barrier in request_wait_answer() */
- smp_mb__after_atomic();
- if (!in_flight)
- inc_in_flight_req(fsvq);
- notify = virtqueue_kick_prepare(vq);
- spin_unlock(&fsvq->lock);
- if (notify)
- virtqueue_notify(vq);
- out:
- if (ret < 0 && req->argbuf) {
- kfree(req->argbuf);
- req->argbuf = NULL;
- }
- if (sgs != stack_sgs) {
- kfree(sgs);
- kfree(sg);
- }
- return ret;
- }
- static void virtio_fs_wake_pending_and_unlock(struct fuse_iqueue *fiq)
- __releases(fiq->lock)
- {
- unsigned int queue_id = VQ_REQUEST; /* TODO multiqueue */
- struct virtio_fs *fs;
- struct fuse_req *req;
- struct virtio_fs_vq *fsvq;
- int ret;
- WARN_ON(list_empty(&fiq->pending));
- req = list_last_entry(&fiq->pending, struct fuse_req, list);
- clear_bit(FR_PENDING, &req->flags);
- list_del_init(&req->list);
- WARN_ON(!list_empty(&fiq->pending));
- spin_unlock(&fiq->lock);
- fs = fiq->priv;
- pr_debug("%s: opcode %u unique %#llx nodeid %#llx in.len %u out.len %u\n",
- __func__, req->in.h.opcode, req->in.h.unique,
- req->in.h.nodeid, req->in.h.len,
- fuse_len_args(req->args->out_numargs, req->args->out_args));
- fsvq = &fs->vqs[queue_id];
- ret = virtio_fs_enqueue_req(fsvq, req, false);
- if (ret < 0) {
- if (ret == -ENOMEM || ret == -ENOSPC) {
- /*
- * Virtqueue full. Retry submission from worker
- * context as we might be holding fc->bg_lock.
- */
- spin_lock(&fsvq->lock);
- list_add_tail(&req->list, &fsvq->queued_reqs);
- inc_in_flight_req(fsvq);
- schedule_delayed_work(&fsvq->dispatch_work,
- msecs_to_jiffies(1));
- spin_unlock(&fsvq->lock);
- return;
- }
- req->out.h.error = ret;
- pr_err("virtio-fs: virtio_fs_enqueue_req() failed %d\n", ret);
- /* Can't end request in submission context. Use a worker */
- spin_lock(&fsvq->lock);
- list_add_tail(&req->list, &fsvq->end_reqs);
- schedule_delayed_work(&fsvq->dispatch_work, 0);
- spin_unlock(&fsvq->lock);
- return;
- }
- }
- static const struct fuse_iqueue_ops virtio_fs_fiq_ops = {
- .wake_forget_and_unlock = virtio_fs_wake_forget_and_unlock,
- .wake_interrupt_and_unlock = virtio_fs_wake_interrupt_and_unlock,
- .wake_pending_and_unlock = virtio_fs_wake_pending_and_unlock,
- .release = virtio_fs_fiq_release,
- };
- static inline void virtio_fs_ctx_set_defaults(struct fuse_fs_context *ctx)
- {
- ctx->rootmode = S_IFDIR;
- ctx->default_permissions = 1;
- ctx->allow_other = 1;
- ctx->max_read = UINT_MAX;
- ctx->blksize = 512;
- ctx->destroy = true;
- ctx->no_control = true;
- ctx->no_force_umount = true;
- }
- static int virtio_fs_fill_super(struct super_block *sb, struct fs_context *fsc)
- {
- struct fuse_mount *fm = get_fuse_mount_super(sb);
- struct fuse_conn *fc = fm->fc;
- struct virtio_fs *fs = fc->iq.priv;
- struct fuse_fs_context *ctx = fsc->fs_private;
- unsigned int i;
- int err;
- virtio_fs_ctx_set_defaults(ctx);
- mutex_lock(&virtio_fs_mutex);
- /* After holding mutex, make sure virtiofs device is still there.
- * Though we are holding a reference to it, drive ->remove might
- * still have cleaned up virtual queues. In that case bail out.
- */
- err = -EINVAL;
- if (list_empty(&fs->list)) {
- pr_info("virtio-fs: tag <%s> not found\n", fs->tag);
- goto err;
- }
- err = -ENOMEM;
- /* Allocate fuse_dev for hiprio and notification queues */
- for (i = 0; i < fs->nvqs; i++) {
- struct virtio_fs_vq *fsvq = &fs->vqs[i];
- fsvq->fud = fuse_dev_alloc();
- if (!fsvq->fud)
- goto err_free_fuse_devs;
- }
- /* virtiofs allocates and installs its own fuse devices */
- ctx->fudptr = NULL;
- if (ctx->dax) {
- if (!fs->dax_dev) {
- err = -EINVAL;
- pr_err("virtio-fs: dax can't be enabled as filesystem"
- " device does not support it.\n");
- goto err_free_fuse_devs;
- }
- ctx->dax_dev = fs->dax_dev;
- }
- err = fuse_fill_super_common(sb, ctx);
- if (err < 0)
- goto err_free_fuse_devs;
- for (i = 0; i < fs->nvqs; i++) {
- struct virtio_fs_vq *fsvq = &fs->vqs[i];
- fuse_dev_install(fsvq->fud, fc);
- }
- /* Previous unmount will stop all queues. Start these again */
- virtio_fs_start_all_queues(fs);
- fuse_send_init(fm);
- mutex_unlock(&virtio_fs_mutex);
- return 0;
- err_free_fuse_devs:
- virtio_fs_free_devs(fs);
- err:
- mutex_unlock(&virtio_fs_mutex);
- return err;
- }
- static void virtio_fs_conn_destroy(struct fuse_mount *fm)
- {
- struct fuse_conn *fc = fm->fc;
- struct virtio_fs *vfs = fc->iq.priv;
- struct virtio_fs_vq *fsvq = &vfs->vqs[VQ_HIPRIO];
- /* Stop dax worker. Soon evict_inodes() will be called which
- * will free all memory ranges belonging to all inodes.
- */
- if (IS_ENABLED(CONFIG_FUSE_DAX))
- fuse_dax_cancel_work(fc);
- /* Stop forget queue. Soon destroy will be sent */
- spin_lock(&fsvq->lock);
- fsvq->connected = false;
- spin_unlock(&fsvq->lock);
- virtio_fs_drain_all_queues(vfs);
- fuse_conn_destroy(fm);
- /* fuse_conn_destroy() must have sent destroy. Stop all queues
- * and drain one more time and free fuse devices. Freeing fuse
- * devices will drop their reference on fuse_conn and that in
- * turn will drop its reference on virtio_fs object.
- */
- virtio_fs_stop_all_queues(vfs);
- virtio_fs_drain_all_queues(vfs);
- virtio_fs_free_devs(vfs);
- }
- static void virtio_kill_sb(struct super_block *sb)
- {
- struct fuse_mount *fm = get_fuse_mount_super(sb);
- bool last;
- /* If mount failed, we can still be called without any fc */
- if (fm) {
- last = fuse_mount_remove(fm);
- if (last)
- virtio_fs_conn_destroy(fm);
- }
- kill_anon_super(sb);
- }
- static int virtio_fs_test_super(struct super_block *sb,
- struct fs_context *fsc)
- {
- struct fuse_mount *fsc_fm = fsc->s_fs_info;
- struct fuse_mount *sb_fm = get_fuse_mount_super(sb);
- return fsc_fm->fc->iq.priv == sb_fm->fc->iq.priv;
- }
- static int virtio_fs_set_super(struct super_block *sb,
- struct fs_context *fsc)
- {
- int err;
- err = get_anon_bdev(&sb->s_dev);
- if (!err)
- fuse_mount_get(fsc->s_fs_info);
- return err;
- }
- static int virtio_fs_get_tree(struct fs_context *fsc)
- {
- struct virtio_fs *fs;
- struct super_block *sb;
- struct fuse_conn *fc;
- struct fuse_mount *fm;
- int err;
- /* This gets a reference on virtio_fs object. This ptr gets installed
- * in fc->iq->priv. Once fuse_conn is going away, it calls ->put()
- * to drop the reference to this object.
- */
- fs = virtio_fs_find_instance(fsc->source);
- if (!fs) {
- pr_info("virtio-fs: tag <%s> not found\n", fsc->source);
- return -EINVAL;
- }
- fc = kzalloc(sizeof(struct fuse_conn), GFP_KERNEL);
- if (!fc) {
- mutex_lock(&virtio_fs_mutex);
- virtio_fs_put(fs);
- mutex_unlock(&virtio_fs_mutex);
- return -ENOMEM;
- }
- fm = kzalloc(sizeof(struct fuse_mount), GFP_KERNEL);
- if (!fm) {
- mutex_lock(&virtio_fs_mutex);
- virtio_fs_put(fs);
- mutex_unlock(&virtio_fs_mutex);
- kfree(fc);
- return -ENOMEM;
- }
- fuse_conn_init(fc, fm, fsc->user_ns, &virtio_fs_fiq_ops, fs);
- fc->release = fuse_free_conn;
- fc->delete_stale = true;
- fc->auto_submounts = true;
- fsc->s_fs_info = fm;
- sb = sget_fc(fsc, virtio_fs_test_super, virtio_fs_set_super);
- fuse_mount_put(fm);
- if (IS_ERR(sb))
- return PTR_ERR(sb);
- if (!sb->s_root) {
- err = virtio_fs_fill_super(sb, fsc);
- if (err) {
- fuse_mount_put(fm);
- sb->s_fs_info = NULL;
- deactivate_locked_super(sb);
- return err;
- }
- sb->s_flags |= SB_ACTIVE;
- }
- WARN_ON(fsc->root);
- fsc->root = dget(sb->s_root);
- return 0;
- }
- static const struct fs_context_operations virtio_fs_context_ops = {
- .free = virtio_fs_free_fc,
- .parse_param = virtio_fs_parse_param,
- .get_tree = virtio_fs_get_tree,
- };
- static int virtio_fs_init_fs_context(struct fs_context *fsc)
- {
- struct fuse_fs_context *ctx;
- ctx = kzalloc(sizeof(struct fuse_fs_context), GFP_KERNEL);
- if (!ctx)
- return -ENOMEM;
- fsc->fs_private = ctx;
- fsc->ops = &virtio_fs_context_ops;
- return 0;
- }
- static struct file_system_type virtio_fs_type = {
- .owner = THIS_MODULE,
- .name = "virtiofs",
- .init_fs_context = virtio_fs_init_fs_context,
- .kill_sb = virtio_kill_sb,
- };
- static int __init virtio_fs_init(void)
- {
- int ret;
- ret = register_virtio_driver(&virtio_fs_driver);
- if (ret < 0)
- return ret;
- ret = register_filesystem(&virtio_fs_type);
- if (ret < 0) {
- unregister_virtio_driver(&virtio_fs_driver);
- return ret;
- }
- return 0;
- }
- module_init(virtio_fs_init);
- static void __exit virtio_fs_exit(void)
- {
- unregister_filesystem(&virtio_fs_type);
- unregister_virtio_driver(&virtio_fs_driver);
- }
- module_exit(virtio_fs_exit);
- MODULE_AUTHOR("Stefan Hajnoczi <stefanha@redhat.com>");
- MODULE_DESCRIPTION("Virtio Filesystem");
- MODULE_LICENSE("GPL");
- MODULE_ALIAS_FS(KBUILD_MODNAME);
- MODULE_DEVICE_TABLE(virtio, id_table);
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