in virtio_blk.c [751:963]
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;
unsigned int queue_depth;
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);
/* We need 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;
/* 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;
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, vblk->sg_elems-2);
/* No real sector limit. */
blk_queue_max_hw_sectors(q, -1U);
max_size = virtio_max_dma_size(vdev);
/* Host can optionally specify maximum segment size and number of
* segments. */
err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX,
struct virtio_blk_config, size_max, &v);
if (!err)
max_size = min(max_size, v);
blk_queue_max_segment_size(q, max_size);
/* Host can optionally specify the block size of the device */
err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE,
struct virtio_blk_config, blk_size,
&blk_size);
if (!err) {
err = blk_validate_block_size(blk_size);
if (err) {
dev_err(&vdev->dev,
"virtio_blk: invalid block size: 0x%x\n",
blk_size);
goto out_cleanup_disk;
}
blk_queue_logical_block_size(q, blk_size);
} else
blk_size = queue_logical_block_size(q);
/* Use topology information if available */
err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
struct virtio_blk_config, physical_block_exp,
&physical_block_exp);
if (!err && physical_block_exp)
blk_queue_physical_block_size(q,
blk_size * (1 << physical_block_exp));
err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
struct virtio_blk_config, alignment_offset,
&alignment_offset);
if (!err && alignment_offset)
blk_queue_alignment_offset(q, blk_size * alignment_offset);
err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
struct virtio_blk_config, min_io_size,
&min_io_size);
if (!err && min_io_size)
blk_queue_io_min(q, blk_size * min_io_size);
err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
struct virtio_blk_config, opt_io_size,
&opt_io_size);
if (!err && opt_io_size)
blk_queue_io_opt(q, blk_size * opt_io_size);
if (virtio_has_feature(vdev, VIRTIO_BLK_F_DISCARD)) {
q->limits.discard_granularity = blk_size;
virtio_cread(vdev, struct virtio_blk_config,
discard_sector_alignment, &v);
q->limits.discard_alignment = v ? v << SECTOR_SHIFT : 0;
virtio_cread(vdev, struct virtio_blk_config,
max_discard_sectors, &v);
blk_queue_max_discard_sectors(q, v ? v : UINT_MAX);
virtio_cread(vdev, struct virtio_blk_config, max_discard_seg,
&v);
blk_queue_max_discard_segments(q,
min_not_zero(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);
err = device_add_disk(&vdev->dev, vblk->disk, virtblk_attr_groups);
if (err)
goto out_cleanup_disk;
return 0;
out_cleanup_disk:
blk_cleanup_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;
}