[SCSI] sd: Fix handling of NO_SENSE check condition

The current handling of NO_SENSE check condition is the same as
RECOVERED_ERROR, and assumes that in both cases, the I/O was fully
transferred.

We have seen cases of arrays returning with NO_SENSE (no error), but
the I/O was not completely transferred, thus residual set.  Thus,
rather than return good_bytes as the entire transfer, set good_bytes
to 0, so that the midlayer then applies the residual in calculating
the transfer, and for sd, will fail the I/O and fall into a retry
path.

Signed-off-by: Jamie Wellnitz <Jamie.Wellnitz@emulex.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 7c4d2e68df1c..55e6ed4b886d 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1054,7 +1054,6 @@ static int sd_done(struct scsi_cmnd *SCpnt)
                 good_bytes = sd_completed_bytes(SCpnt);
                 break;
         case RECOVERED_ERROR:
-        case NO_SENSE:
                 /* Inform the user, but make sure that it's not treated
                  * as a hard error.
                  */
@@ -1063,6 +1062,15 @@ static int sd_done(struct scsi_cmnd *SCpnt)
                 memset(SCpnt->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
                 good_bytes = scsi_bufflen(SCpnt);
                 break;
+        case NO_SENSE:
+                /* This indicates a false check condition, so ignore it.  An
+                 * unknown amount of data was transferred so treat it as an
+                 * error.
+                 */
+                scsi_print_sense("sd", SCpnt);
+                SCpnt->result = 0;
+                memset(SCpnt->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
+                break;
         case ABORTED_COMMAND:
                 if (sshdr.asc == 0x10) { /* DIF: Disk detected corruption */
                         scsi_print_result(SCpnt);