| // 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 <scsi/scsi_cmnd.h> |
| #include <linux/idr.h> |
| #include <linux/blk-mq.h> |
| #include <linux/blk-mq-virtio.h> |
| #include <linux/numa.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 { |
| #ifdef CONFIG_VIRTIO_BLK_SCSI |
| struct scsi_request sreq; /* for SCSI passthrough, must be first */ |
| u8 sense[SCSI_SENSE_BUFFERSIZE]; |
| struct virtio_scsi_inhdr in_hdr; |
| #endif |
| 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; |
| } |
| } |
| |
| /* |
| * If this is a packet command we need a couple of additional headers. Behind |
| * the normal outhdr we put a segment with the scsi command block, and before |
| * the normal inhdr we put the sense data and the inhdr with additional status |
| * information. |
| */ |
| #ifdef CONFIG_VIRTIO_BLK_SCSI |
| static int virtblk_add_req_scsi(struct virtqueue *vq, struct virtblk_req *vbr, |
| struct scatterlist *data_sg, bool have_data) |
| { |
| struct scatterlist hdr, status, cmd, sense, inhdr, *sgs[6]; |
| unsigned int num_out = 0, num_in = 0; |
| |
| sg_init_one(&hdr, &vbr->out_hdr, sizeof(vbr->out_hdr)); |
| sgs[num_out++] = &hdr; |
| sg_init_one(&cmd, vbr->sreq.cmd, vbr->sreq.cmd_len); |
| sgs[num_out++] = &cmd; |
| |
| 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(&sense, vbr->sense, SCSI_SENSE_BUFFERSIZE); |
| sgs[num_out + num_in++] = &sense; |
| sg_init_one(&inhdr, &vbr->in_hdr, sizeof(vbr->in_hdr)); |
| sgs[num_out + num_in++] = &inhdr; |
| 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 inline void virtblk_scsi_request_done(struct request *req) |
| { |
| struct virtblk_req *vbr = blk_mq_rq_to_pdu(req); |
| struct virtio_blk *vblk = req->q->queuedata; |
| struct scsi_request *sreq = &vbr->sreq; |
| |
| sreq->resid_len = virtio32_to_cpu(vblk->vdev, vbr->in_hdr.residual); |
| sreq->sense_len = virtio32_to_cpu(vblk->vdev, vbr->in_hdr.sense_len); |
| sreq->result = virtio32_to_cpu(vblk->vdev, vbr->in_hdr.errors); |
| } |
| |
| static int virtblk_ioctl(struct block_device *bdev, fmode_t mode, |
| unsigned int cmd, unsigned long data) |
| { |
| struct gendisk *disk = bdev->bd_disk; |
| struct virtio_blk *vblk = disk->private_data; |
| |
| /* |
| * Only allow the generic SCSI ioctls if the host can support it. |
| */ |
| if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_SCSI)) |
| return -ENOTTY; |
| |
| return scsi_cmd_blk_ioctl(bdev, mode, cmd, |
| (void __user *)data); |
| } |
| #else |
| static inline int virtblk_add_req_scsi(struct virtqueue *vq, |
| struct virtblk_req *vbr, struct scatterlist *data_sg, |
| bool have_data) |
| { |
| return -EIO; |
| } |
| static inline void virtblk_scsi_request_done(struct request *req) |
| { |
| } |
| #define virtblk_ioctl NULL |
| #endif /* CONFIG_VIRTIO_BLK_SCSI */ |
| |
| 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); |
| } |
| |
| switch (req_op(req)) { |
| case REQ_OP_SCSI_IN: |
| case REQ_OP_SCSI_OUT: |
| virtblk_scsi_request_done(req); |
| break; |
| } |
| |
| 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); |
| |
| 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_SCSI_IN: |
| case REQ_OP_SCSI_OUT: |
| type = VIRTIO_BLK_T_SCSI_CMD; |
| 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); |
| if (blk_rq_is_scsi(req)) |
| err = virtblk_add_req_scsi(vblk->vqs[qid].vq, vbr, vbr->sg, num); |
| else |
| 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 = { |
| .ioctl = virtblk_ioctl, |
| .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(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); |
| char *envp[] = { "RESIZE=1", NULL }; |
| |
| virtblk_update_capacity(vblk, true); |
| revalidate_disk(vblk->disk); |
| kobject_uevent_env(&disk_to_dev(vblk->disk)->kobj, KOBJ_CHANGE, envp); |
| } |
| |
| 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(vblk->disk); |
| } |
| |
| 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 = container_of(kobj, struct device, 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); |
| |
| #ifdef CONFIG_VIRTIO_BLK_SCSI |
| vbr->sreq.sense = vbr->sense; |
| #endif |
| 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); |
| } |
| |
| #ifdef CONFIG_VIRTIO_BLK_SCSI |
| static void virtblk_initialize_rq(struct request *req) |
| { |
| struct virtblk_req *vbr = blk_mq_rq_to_pdu(req); |
| |
| scsi_req_init(&vbr->sreq); |
| } |
| #endif |
| |
| 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, |
| #ifdef CONFIG_VIRTIO_BLK_SCSI |
| .initialize_rq_fn = virtblk_initialize_rq, |
| #endif |
| .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_free_tags; |
| } |
| |
| 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, &v); |
| if (v) |
| q->limits.discard_granularity = v << SECTOR_SHIFT; |
| else |
| q->limits.discard_granularity = blk_size; |
| |
| 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_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 no requests in virtqueues before deleting vqs. */ |
| blk_mq_freeze_queue(vblk->disk->queue); |
| |
| /* 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); |
| |
| 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_unfreeze_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, |
| #ifdef CONFIG_VIRTIO_BLK_SCSI |
| VIRTIO_BLK_F_SCSI, |
| #endif |
| 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"); |