[PATCH 3.18 099/183] storvsc: ring buffer failures may result in I/O freeze

Greg Kroah-Hartman
2015-01-25T18:43:16Z

From: Long Li <longli@microsoft.com>

commit e86fb5e8ab95f10ec5f2e9430119d5d35020c951 upstream.

When ring buffer returns an error indicating retry, storvsc may not
return a proper error code to SCSI when bounce buffer is not used.
This has introduced I/O freeze on RAID running atop storvsc devices.
This patch fixes it by always returning a proper error code.

Signed-off-by: Long Li <longli@microsoft.com>
Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/scsi/storvsc_drv.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -1688,13 +1688,12 @@ static int storvsc_queuecommand(struct S
if (ret == -EAGAIN) {
/* no more space */

- if (cmd_request->bounce_sgl_count) {
+ if (cmd_request->bounce_sgl_count)
destroy_bounce_buffer(cmd_request->bounce_sgl,
cmd_request->bounce_sgl_count);

- ret = SCSI_MLQUEUE_DEVICE_BUSY;
- goto queue_error;
- }
+ ret = SCSI_MLQUEUE_DEVICE_BUSY;
+ goto queue_error;
}

return 0;