[PATCH REPOST] scsi: don't count non-failure CHECK_CONDITION as error

[Tejun Heo <tj@kernel.org>]

SCSI command completion path bumps ioerr_cnt whenever scsi_cmd->result
isn't zero; unfortunately, this means that non-error sense reporting
bumps the counter too.  This is pronounced with ATA passthrough
commands because most of them explicitly request the resulting
taskfile to be transported via sense data bumping the count
unconditionally.

Don't bump the counter if scsi_cmd->result simply indicates that sense
data is available.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Dave Jones <dsj@fb.com>
---
Hello,

Reposting because the email address listed under "SCSI SUBSYSTEM",
JBottomley@odin.com, bounced.  James, can you please update the entry?

Thanks.

 drivers/scsi/scsi_lib.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index fa6b2c4..e90e3f7 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1622,7 +1622,8 @@ static void scsi_softirq_done(struct request *rq)
 	INIT_LIST_HEAD(&cmd->eh_entry);
 
 	atomic_inc(&cmd->device->iodone_cnt);
-	if (cmd->result)
+	if (cmd->result &&
+	    cmd->result != ((DRIVER_SENSE << 24) | SAM_STAT_CHECK_CONDITION))
 		atomic_inc(&cmd->device->ioerr_cnt);
 
 	disposition = scsi_decide_disposition(cmd);