1) If the device reports an uncorrectable MEDIUM ERROR, such
as SK MEDIUM ERROR, ASC UNRECOVERED READ ERR, AMNF DATA
FIELD or RECORD NOT FOUND, then: In scsi_check_sense()
return SUCCESS so as to not retry -- the error is
uncorrectable -- this speeds up total processing time.
2) In scsi_io_completion(), retry if and only if there was
at least one byte completed, i.e. good_bytes != 0. If
good_bytes == 0, don't try to retry.
Without this patch, SCSI Core gets hung reading sector 0
forever, for example when reading the partition table of a
(newly discovered) device.
Signed-off-by: Luben Tuikov <ltuikov@xxxxxxxxx>
---
drivers/scsi/scsi_error.c | 5 +++++
drivers/scsi/scsi_lib.c | 3 ++-
2 files changed, 7 insertions(+), 1 deletions(-)
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index aff1b0c..011dd32 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -359,6 +359,11 @@ static int scsi_check_sense(struct scsi_cmnd *scmd)
return SUCCESS;
case MEDIUM_ERROR:
+ if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */
+ sshdr.asc == 0x13 || /* AMNF DATA FIELD */
+ sshdr.asc == 0x14) { /* RECORD NOT FOUND */
+ return SUCCESS;
+ }
return NEEDS_RETRY;
case HARDWARE_ERROR:
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 8b208b4..c5fa329 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -866,7 +866,8 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
* are leftovers and there is some kind of error
* (result != 0), retry the rest.
*/
- if (scsi_end_request(cmd, 1, good_bytes, !!result) == NULL)
+ if (good_bytes &&
+ scsi_end_request(cmd, 1, good_bytes, !!result) == NULL)
return;
/* good_bytes = 0, or (inclusive) there were leftovers and
--
1.4.4.1.g7a0e
