[SRU][Xenial][PATCH 1/1] UBUNTU: SAUCE: (no-up) virtio-scsi: Increment reqs counter.
Joseph Salisbury
joseph.salisbury at canonical.com
Fri Jun 8 17:48:27 UTC 2018
From: Felipe Franciosi <felipe at nutanix.com>
BugLink: http://bugs.launchpad.net/bugs/1775235
virtio-scsi itself is broken in a way that it doesn't increment the
'reqs' counter when submitting requests on MQ in certain conditions.
That caused the counter to go to -1 (on the completion of the first
request) and the CPU to hang indefinitely.
Fixes: f1f609d8015e ("UBUNTU: SAUCE: (no-up) virtio-scsi: Fix race in
target free")
Signed-off-by: Felipe Franciosi <felipe at nutanix.com>
Signed-off-by: Joseph Salisbury <joseph.salisbury at canonical.com>
---
drivers/scsi/virtio_scsi.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index e2da312..b4a41d5 100644
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -588,11 +588,12 @@ static int virtscsi_queuecommand_single(struct Scsi_Host *sh,
}
static struct virtio_scsi_vq *virtscsi_pick_vq_mq(struct virtio_scsi *vscsi,
- struct scsi_cmnd *sc)
+ struct virtio_scsi_target_state *tgt, struct scsi_cmnd *sc)
{
u32 tag = blk_mq_unique_tag(sc->request);
u16 hwq = blk_mq_unique_tag_to_hwq(tag);
+ atomic_inc(&tgt->reqs);
return &vscsi->req_vqs[hwq];
}
@@ -642,7 +643,7 @@ static int virtscsi_queuecommand_multi(struct Scsi_Host *sh,
struct virtio_scsi_vq *req_vq;
if (shost_use_blk_mq(sh))
- req_vq = virtscsi_pick_vq_mq(vscsi, sc);
+ req_vq = virtscsi_pick_vq_mq(vscsi, tgt, sc);
else
req_vq = virtscsi_pick_vq(vscsi, tgt);
--
2.7.4
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