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-rw-r--r--drivers/block/virtio_blk.c1314
1 files changed, 1314 insertions, 0 deletions
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
new file mode 100644
index 000000000..3124837aa
--- /dev/null
+++ b/drivers/block/virtio_blk.c
@@ -0,0 +1,1314 @@
+// 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
+
+/* The maximum number of sg elements that fit into a virtqueue */
+#define VIRTIO_BLK_MAX_SG_ELEMS 32768
+
+#ifdef CONFIG_ARCH_NO_SG_CHAIN
+#define VIRTIO_BLK_INLINE_SG_CNT 0
+#else
+#define VIRTIO_BLK_INLINE_SG_CNT 2
+#endif
+
+static unsigned int num_request_queues;
+module_param(num_request_queues, uint, 0644);
+MODULE_PARM_DESC(num_request_queues,
+ "Limit the number of request queues to use for blk device. "
+ "0 for no limit. "
+ "Values > nr_cpu_ids truncated to nr_cpu_ids.");
+
+static unsigned int poll_queues;
+module_param(poll_queues, uint, 0644);
+MODULE_PARM_DESC(poll_queues, "The number of dedicated virtqueues for polling I/O");
+
+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;
+
+ /* Ida index - used to track minor number allocations. */
+ int index;
+
+ /* num of vqs */
+ int num_vqs;
+ int io_queues[HCTX_MAX_TYPES];
+ struct virtio_blk_vq *vqs;
+};
+
+struct virtblk_req {
+ struct virtio_blk_outhdr out_hdr;
+ u8 status;
+ struct sg_table sg_table;
+ 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 inline struct virtio_blk_vq *get_virtio_blk_vq(struct blk_mq_hw_ctx *hctx)
+{
+ struct virtio_blk *vblk = hctx->queue->queuedata;
+ struct virtio_blk_vq *vq = &vblk->vqs[hctx->queue_num];
+
+ return vq;
+}
+
+static int virtblk_add_req(struct virtqueue *vq, struct virtblk_req *vbr)
+{
+ 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 (vbr->sg_table.nents) {
+ if (vbr->out_hdr.type & cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_OUT))
+ sgs[num_out++] = vbr->sg_table.sgl;
+ else
+ sgs[num_out + num_in++] = vbr->sg_table.sgl;
+ }
+
+ 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_erase(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 void virtblk_unmap_data(struct request *req, struct virtblk_req *vbr)
+{
+ if (blk_rq_nr_phys_segments(req))
+ sg_free_table_chained(&vbr->sg_table,
+ VIRTIO_BLK_INLINE_SG_CNT);
+}
+
+static int virtblk_map_data(struct blk_mq_hw_ctx *hctx, struct request *req,
+ struct virtblk_req *vbr)
+{
+ int err;
+
+ if (!blk_rq_nr_phys_segments(req))
+ return 0;
+
+ vbr->sg_table.sgl = vbr->sg;
+ err = sg_alloc_table_chained(&vbr->sg_table,
+ blk_rq_nr_phys_segments(req),
+ vbr->sg_table.sgl,
+ VIRTIO_BLK_INLINE_SG_CNT);
+ if (unlikely(err))
+ return -ENOMEM;
+
+ return blk_rq_map_sg(hctx->queue, req, vbr->sg_table.sgl);
+}
+
+static void virtblk_cleanup_cmd(struct request *req)
+{
+ if (req->rq_flags & RQF_SPECIAL_PAYLOAD)
+ kfree(bvec_virt(&req->special_vec));
+}
+
+static blk_status_t virtblk_setup_cmd(struct virtio_device *vdev,
+ struct request *req,
+ struct virtblk_req *vbr)
+{
+ bool unmap = false;
+ u32 type;
+
+ vbr->out_hdr.sector = 0;
+
+ switch (req_op(req)) {
+ case REQ_OP_READ:
+ type = VIRTIO_BLK_T_IN;
+ vbr->out_hdr.sector = cpu_to_virtio64(vdev,
+ blk_rq_pos(req));
+ break;
+ case REQ_OP_WRITE:
+ type = VIRTIO_BLK_T_OUT;
+ vbr->out_hdr.sector = cpu_to_virtio64(vdev,
+ blk_rq_pos(req));
+ 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_SECURE_ERASE:
+ type = VIRTIO_BLK_T_SECURE_ERASE;
+ break;
+ case REQ_OP_DRV_IN:
+ type = VIRTIO_BLK_T_GET_ID;
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ return BLK_STS_IOERR;
+ }
+
+ vbr->out_hdr.type = cpu_to_virtio32(vdev, type);
+ vbr->out_hdr.ioprio = cpu_to_virtio32(vdev, req_get_ioprio(req));
+
+ if (type == VIRTIO_BLK_T_DISCARD || type == VIRTIO_BLK_T_WRITE_ZEROES ||
+ type == VIRTIO_BLK_T_SECURE_ERASE) {
+ if (virtblk_setup_discard_write_zeroes_erase(req, unmap))
+ return BLK_STS_RESOURCE;
+ }
+
+ return 0;
+}
+
+static inline void virtblk_request_done(struct request *req)
+{
+ struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
+
+ virtblk_unmap_data(req, vbr);
+ virtblk_cleanup_cmd(req);
+ 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 virtblk_fail_to_queue(struct request *req, int rc)
+{
+ virtblk_cleanup_cmd(req);
+ switch (rc) {
+ case -ENOSPC:
+ return BLK_STS_DEV_RESOURCE;
+ case -ENOMEM:
+ return BLK_STS_RESOURCE;
+ default:
+ return BLK_STS_IOERR;
+ }
+}
+
+static blk_status_t virtblk_prep_rq(struct blk_mq_hw_ctx *hctx,
+ struct virtio_blk *vblk,
+ struct request *req,
+ struct virtblk_req *vbr)
+{
+ blk_status_t status;
+ int num;
+
+ status = virtblk_setup_cmd(vblk->vdev, req, vbr);
+ if (unlikely(status))
+ return status;
+
+ num = virtblk_map_data(hctx, req, vbr);
+ if (unlikely(num < 0))
+ return virtblk_fail_to_queue(req, -ENOMEM);
+ vbr->sg_table.nents = num;
+
+ blk_mq_start_request(req);
+
+ return BLK_STS_OK;
+}
+
+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;
+ int qid = hctx->queue_num;
+ bool notify = false;
+ blk_status_t status;
+ int err;
+
+ status = virtblk_prep_rq(hctx, vblk, req, vbr);
+ if (unlikely(status))
+ return status;
+
+ spin_lock_irqsave(&vblk->vqs[qid].lock, flags);
+ err = virtblk_add_req(vblk->vqs[qid].vq, vbr);
+ 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);
+ virtblk_unmap_data(req, vbr);
+ return virtblk_fail_to_queue(req, err);
+ }
+
+ 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;
+}
+
+static bool virtblk_prep_rq_batch(struct request *req)
+{
+ struct virtio_blk *vblk = req->mq_hctx->queue->queuedata;
+ struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
+
+ req->mq_hctx->tags->rqs[req->tag] = req;
+
+ return virtblk_prep_rq(req->mq_hctx, vblk, req, vbr) == BLK_STS_OK;
+}
+
+static bool virtblk_add_req_batch(struct virtio_blk_vq *vq,
+ struct request **rqlist)
+{
+ unsigned long flags;
+ int err;
+ bool kick;
+
+ spin_lock_irqsave(&vq->lock, flags);
+
+ while (!rq_list_empty(*rqlist)) {
+ struct request *req = rq_list_pop(rqlist);
+ struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
+
+ err = virtblk_add_req(vq->vq, vbr);
+ if (err) {
+ virtblk_unmap_data(req, vbr);
+ virtblk_cleanup_cmd(req);
+ blk_mq_requeue_request(req, true);
+ }
+ }
+
+ kick = virtqueue_kick_prepare(vq->vq);
+ spin_unlock_irqrestore(&vq->lock, flags);
+
+ return kick;
+}
+
+static void virtio_queue_rqs(struct request **rqlist)
+{
+ struct request *req, *next, *prev = NULL;
+ struct request *requeue_list = NULL;
+
+ rq_list_for_each_safe(rqlist, req, next) {
+ struct virtio_blk_vq *vq = get_virtio_blk_vq(req->mq_hctx);
+ bool kick;
+
+ if (!virtblk_prep_rq_batch(req)) {
+ rq_list_move(rqlist, &requeue_list, req, prev);
+ req = prev;
+ if (!req)
+ continue;
+ }
+
+ if (!next || req->mq_hctx != next->mq_hctx) {
+ req->rq_next = NULL;
+ kick = virtblk_add_req_batch(vq, rqlist);
+ if (kick)
+ virtqueue_notify(vq->vq);
+
+ *rqlist = next;
+ prev = NULL;
+ } else
+ prev = req;
+ }
+
+ *rqlist = requeue_list;
+}
+
+/* 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_mq_alloc_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(req, false);
+ err = blk_status_to_errno(virtblk_result(blk_mq_rq_to_pdu(req)));
+out:
+ blk_mq_free_request(req);
+ return err;
+}
+
+/* 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 void virtblk_free_disk(struct gendisk *disk)
+{
+ struct virtio_blk *vblk = disk->private_data;
+
+ ida_simple_remove(&vd_index_ida, vblk->index);
+ mutex_destroy(&vblk->vdev_mutex);
+ kfree(vblk);
+}
+
+static const struct block_device_operations virtblk_fops = {
+ .owner = THIS_MODULE,
+ .getgeo = virtblk_getgeo,
+ .free_disk = virtblk_free_disk,
+};
+
+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);
+
+ 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_and_notify(vblk->disk, capacity);
+}
+
+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;
+ unsigned short i;
+ vq_callback_t **callbacks;
+ const char **names;
+ struct virtqueue **vqs;
+ unsigned short num_vqs;
+ unsigned short num_poll_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;
+
+ if (!err && !num_vqs) {
+ dev_err(&vdev->dev, "MQ advertised but zero queues reported\n");
+ return -EINVAL;
+ }
+
+ num_vqs = min_t(unsigned int,
+ min_not_zero(num_request_queues, nr_cpu_ids),
+ num_vqs);
+
+ num_poll_vqs = min_t(unsigned int, poll_queues, num_vqs - 1);
+
+ vblk->io_queues[HCTX_TYPE_DEFAULT] = num_vqs - num_poll_vqs;
+ vblk->io_queues[HCTX_TYPE_READ] = 0;
+ vblk->io_queues[HCTX_TYPE_POLL] = num_poll_vqs;
+
+ dev_info(&vdev->dev, "%d/%d/%d default/read/poll queues\n",
+ vblk->io_queues[HCTX_TYPE_DEFAULT],
+ vblk->io_queues[HCTX_TYPE_READ],
+ vblk->io_queues[HCTX_TYPE_POLL]);
+
+ 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 - num_poll_vqs; i++) {
+ callbacks[i] = virtblk_done;
+ snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req.%u", i);
+ names[i] = vblk->vqs[i].name;
+ }
+
+ for (; i < num_vqs; i++) {
+ callbacks[i] = NULL;
+ snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req_poll.%u", 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);
+}
+
+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 sysfs_emit(buf, "%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 void virtblk_map_queues(struct blk_mq_tag_set *set)
+{
+ struct virtio_blk *vblk = set->driver_data;
+ int i, qoff;
+
+ for (i = 0, qoff = 0; i < set->nr_maps; i++) {
+ struct blk_mq_queue_map *map = &set->map[i];
+
+ map->nr_queues = vblk->io_queues[i];
+ map->queue_offset = qoff;
+ qoff += map->nr_queues;
+
+ if (map->nr_queues == 0)
+ continue;
+
+ /*
+ * Regular queues have interrupts and hence CPU affinity is
+ * defined by the core virtio code, but polling queues have
+ * no interrupts so we let the block layer assign CPU affinity.
+ */
+ if (i == HCTX_TYPE_POLL)
+ blk_mq_map_queues(&set->map[i]);
+ else
+ blk_mq_virtio_map_queues(&set->map[i], vblk->vdev, 0);
+ }
+}
+
+static void virtblk_complete_batch(struct io_comp_batch *iob)
+{
+ struct request *req;
+
+ rq_list_for_each(&iob->req_list, req) {
+ virtblk_unmap_data(req, blk_mq_rq_to_pdu(req));
+ virtblk_cleanup_cmd(req);
+ }
+ blk_mq_end_request_batch(iob);
+}
+
+static int virtblk_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob)
+{
+ struct virtio_blk *vblk = hctx->queue->queuedata;
+ struct virtio_blk_vq *vq = get_virtio_blk_vq(hctx);
+ struct virtblk_req *vbr;
+ unsigned long flags;
+ unsigned int len;
+ int found = 0;
+
+ spin_lock_irqsave(&vq->lock, flags);
+
+ while ((vbr = virtqueue_get_buf(vq->vq, &len)) != NULL) {
+ struct request *req = blk_mq_rq_from_pdu(vbr);
+
+ found++;
+ if (!blk_mq_add_to_batch(req, iob, vbr->status,
+ virtblk_complete_batch))
+ blk_mq_complete_request(req);
+ }
+
+ if (found)
+ blk_mq_start_stopped_hw_queues(vblk->disk->queue, true);
+
+ spin_unlock_irqrestore(&vq->lock, flags);
+
+ return found;
+}
+
+static const struct blk_mq_ops virtio_mq_ops = {
+ .queue_rq = virtio_queue_rq,
+ .queue_rqs = virtio_queue_rqs,
+ .commit_rqs = virtio_commit_rqs,
+ .complete = virtblk_request_done,
+ .map_queues = virtblk_map_queues,
+ .poll = virtblk_poll,
+};
+
+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;
+ u32 max_discard_segs = 0;
+ u32 discard_granularity = 0;
+ u16 min_io_size;
+ u8 physical_block_exp, alignment_offset;
+ unsigned int queue_depth;
+ size_t max_dma_size;
+
+ 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;
+
+ /* Prevent integer overflows and honor max vq size */
+ sg_elems = min_t(u32, sg_elems, VIRTIO_BLK_MAX_SG_ELEMS - 2);
+
+ vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL);
+ if (!vblk) {
+ err = -ENOMEM;
+ goto out_free_index;
+ }
+
+ mutex_init(&vblk->vdev_mutex);
+
+ vblk->vdev = vdev;
+
+ INIT_WORK(&vblk->config_work, virtblk_config_changed_work);
+
+ err = init_vq(vblk);
+ if (err)
+ goto out_free_vblk;
+
+ /* Default queue sizing is to fill the ring. */
+ if (!virtblk_queue_depth) {
+ 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))
+ queue_depth /= 2;
+ } else {
+ queue_depth = virtblk_queue_depth;
+ }
+
+ memset(&vblk->tag_set, 0, sizeof(vblk->tag_set));
+ vblk->tag_set.ops = &virtio_mq_ops;
+ vblk->tag_set.queue_depth = 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) * VIRTIO_BLK_INLINE_SG_CNT;
+ vblk->tag_set.driver_data = vblk;
+ vblk->tag_set.nr_hw_queues = vblk->num_vqs;
+ vblk->tag_set.nr_maps = 1;
+ if (vblk->io_queues[HCTX_TYPE_POLL])
+ vblk->tag_set.nr_maps = 3;
+
+ err = blk_mq_alloc_tag_set(&vblk->tag_set);
+ if (err)
+ goto out_free_vq;
+
+ vblk->disk = blk_mq_alloc_disk(&vblk->tag_set, vblk);
+ if (IS_ERR(vblk->disk)) {
+ err = PTR_ERR(vblk->disk);
+ goto out_free_tags;
+ }
+ q = vblk->disk->queue;
+
+ 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->minors = 1 << PART_BITS;
+ vblk->disk->private_data = vblk;
+ vblk->disk->fops = &virtblk_fops;
+ 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, sg_elems);
+
+ /* No real sector limit. */
+ blk_queue_max_hw_sectors(q, -1U);
+
+ max_dma_size = virtio_max_dma_size(vdev);
+ max_size = max_dma_size > U32_MAX ? U32_MAX : max_dma_size;
+
+ /* 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)) {
+ virtio_cread(vdev, struct virtio_blk_config,
+ discard_sector_alignment, &discard_granularity);
+
+ 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,
+ &max_discard_segs);
+ }
+
+ 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);
+ }
+
+ /* The discard and secure erase limits are combined since the Linux
+ * block layer uses the same limit for both commands.
+ *
+ * If both VIRTIO_BLK_F_SECURE_ERASE and VIRTIO_BLK_F_DISCARD features
+ * are negotiated, we will use the minimum between the limits.
+ *
+ * discard sector alignment is set to the minimum between discard_sector_alignment
+ * and secure_erase_sector_alignment.
+ *
+ * max discard sectors is set to the minimum between max_discard_seg and
+ * max_secure_erase_seg.
+ */
+ if (virtio_has_feature(vdev, VIRTIO_BLK_F_SECURE_ERASE)) {
+
+ virtio_cread(vdev, struct virtio_blk_config,
+ secure_erase_sector_alignment, &v);
+
+ /* secure_erase_sector_alignment should not be zero, the device should set a
+ * valid number of sectors.
+ */
+ if (!v) {
+ dev_err(&vdev->dev,
+ "virtio_blk: secure_erase_sector_alignment can't be 0\n");
+ err = -EINVAL;
+ goto out_cleanup_disk;
+ }
+
+ discard_granularity = min_not_zero(discard_granularity, v);
+
+ virtio_cread(vdev, struct virtio_blk_config,
+ max_secure_erase_sectors, &v);
+
+ /* max_secure_erase_sectors should not be zero, the device should set a
+ * valid number of sectors.
+ */
+ if (!v) {
+ dev_err(&vdev->dev,
+ "virtio_blk: max_secure_erase_sectors can't be 0\n");
+ err = -EINVAL;
+ goto out_cleanup_disk;
+ }
+
+ blk_queue_max_secure_erase_sectors(q, v);
+
+ virtio_cread(vdev, struct virtio_blk_config,
+ max_secure_erase_seg, &v);
+
+ /* max_secure_erase_seg should not be zero, the device should set a
+ * valid number of segments
+ */
+ if (!v) {
+ dev_err(&vdev->dev,
+ "virtio_blk: max_secure_erase_seg can't be 0\n");
+ err = -EINVAL;
+ goto out_cleanup_disk;
+ }
+
+ max_discard_segs = min_not_zero(max_discard_segs, v);
+ }
+
+ if (virtio_has_feature(vdev, VIRTIO_BLK_F_DISCARD) ||
+ virtio_has_feature(vdev, VIRTIO_BLK_F_SECURE_ERASE)) {
+ /* max_discard_seg and discard_granularity will be 0 only
+ * if max_discard_seg and discard_sector_alignment fields in the virtio
+ * config are 0 and VIRTIO_BLK_F_SECURE_ERASE feature is not negotiated.
+ * In this case, we use default values.
+ */
+ if (!max_discard_segs)
+ max_discard_segs = sg_elems;
+
+ blk_queue_max_discard_segments(q,
+ min(max_discard_segs, MAX_DISCARD_SEGMENTS));
+
+ if (discard_granularity)
+ q->limits.discard_granularity = discard_granularity << SECTOR_SHIFT;
+ else
+ q->limits.discard_granularity = blk_size;
+ }
+
+ virtblk_update_capacity(vblk, false);
+ virtio_device_ready(vdev);
+
+ err = device_add_disk(&vdev->dev, vblk->disk, virtblk_attr_groups);
+ if (err)
+ goto out_cleanup_disk;
+
+ return 0;
+
+out_cleanup_disk:
+ put_disk(vblk->disk);
+out_free_tags:
+ blk_mq_free_tag_set(&vblk->tag_set);
+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_mq_free_tag_set(&vblk->tag_set);
+
+ mutex_lock(&vblk->vdev_mutex);
+
+ /* Stop all the virtqueues. */
+ virtio_reset_device(vdev);
+
+ /* Virtqueues are stopped, nothing can use vblk->vdev anymore. */
+ vblk->vdev = NULL;
+
+ vdev->config->del_vqs(vdev);
+ kfree(vblk->vqs);
+
+ mutex_unlock(&vblk->vdev_mutex);
+
+ put_disk(vblk->disk);
+}
+
+#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 */
+ virtio_reset_device(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,
+ VIRTIO_BLK_F_SECURE_ERASE,
+}
+;
+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,
+ VIRTIO_BLK_F_SECURE_ERASE,
+};
+
+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 virtio_blk_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 virtio_blk_fini(void)
+{
+ unregister_virtio_driver(&virtio_blk);
+ unregister_blkdev(major, "virtblk");
+ destroy_workqueue(virtblk_wq);
+}
+module_init(virtio_blk_init);
+module_exit(virtio_blk_fini);
+
+MODULE_DEVICE_TABLE(virtio, id_table);
+MODULE_DESCRIPTION("Virtio block driver");
+MODULE_LICENSE("GPL");