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path: root/drivers/block/virtio_blk.c
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Diffstat (limited to 'drivers/block/virtio_blk.c')
-rw-r--r--drivers/block/virtio_blk.c20
1 files changed, 17 insertions, 3 deletions
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 0eace43cea11..6d8a87f252de 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -158,6 +158,7 @@ static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req)
unsigned long flags;
unsigned int num;
const bool last = (req->cmd_flags & REQ_END) != 0;
+ int err;
BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems);
@@ -198,11 +199,16 @@ static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req)
}
spin_lock_irqsave(&vblk->vq_lock, flags);
- if (__virtblk_add_req(vblk->vq, vbr, vbr->sg, num) < 0) {
+ err = __virtblk_add_req(vblk->vq, vbr, vbr->sg, num);
+ if (err) {
virtqueue_kick(vblk->vq);
spin_unlock_irqrestore(&vblk->vq_lock, flags);
blk_mq_stop_hw_queue(hctx);
- return BLK_MQ_RQ_QUEUE_BUSY;
+ /* Out of mem doesn't actually happen, since we fall back
+ * to direct descriptors */
+ if (err == -ENOMEM || err == -ENOSPC)
+ return BLK_MQ_RQ_QUEUE_BUSY;
+ return BLK_MQ_RQ_QUEUE_ERROR;
}
if (last)
@@ -485,10 +491,11 @@ static struct blk_mq_ops virtio_mq_ops = {
static struct blk_mq_reg virtio_mq_reg = {
.ops = &virtio_mq_ops,
.nr_hw_queues = 1,
- .queue_depth = 64,
+ .queue_depth = 0, /* Set in virtblk_probe */
.numa_node = NUMA_NO_NODE,
.flags = BLK_MQ_F_SHOULD_MERGE,
};
+module_param_named(queue_depth, virtio_mq_reg.queue_depth, uint, 0444);
static int virtblk_init_vbr(void *data, struct blk_mq_hw_ctx *hctx,
struct request *rq, unsigned int nr)
@@ -553,6 +560,13 @@ static int virtblk_probe(struct virtio_device *vdev)
goto out_free_vq;
}
+ /* Default queue sizing is to fill the ring. */
+ if (!virtio_mq_reg.queue_depth) {
+ virtio_mq_reg.queue_depth = vblk->vq->num_free;
+ /* ... but without indirect descs, we use 2 descs per req */
+ if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC))
+ virtio_mq_reg.queue_depth /= 2;
+ }
virtio_mq_reg.cmd_size =
sizeof(struct virtblk_req) +
sizeof(struct scatterlist) * sg_elems;