This has read_capacity_10 have scsi-ml retry errors instead of driving
them itself.
There are two behavior changes:
1. We no longer retry when scsi_execute_cmd returns < 0, but we should be
ok. We don't need to retry for failures like the queue being removed, and
for the case where there are no tags/reqs the block layer waits/retries
for us. For possible memory allocation failures from blk_rq_map_kern we
use GFP_NOIO, so retrying will probably not help.
2. For device reset UAs, we would retry READ_CAPACITY_RETRIES_ON_RESET
times, then once those are used up we would hit the main do loops retry
counter and get 3 more retries. We now only get
READ_CAPACITY_RETRIES_ON_RESET retries.
Signed-off-by: Mike Christie <michael.christie@xxxxxxxxxx>
---
drivers/scsi/sd.c | 64 +++++++++++++++++++++++++++++------------------
1 file changed, 39 insertions(+), 25 deletions(-)
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index ba1970283966..8fe97a9f8a4f 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2447,42 +2447,56 @@ static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp,
static int read_capacity_10(struct scsi_disk *sdkp, struct scsi_device *sdp,
unsigned char *buffer)
{
- unsigned char cmd[16];
+ static const u8 cmd[10] = { READ_CAPACITY };
struct scsi_sense_hdr sshdr;
+ struct scsi_failure failures[] = {
+ /* Fail immediately for Medium Not Present */
+ {
+ .sense = UNIT_ATTENTION,
+ .asc = 0x3A,
+ .ascq = 0x0,
+ .allowed = 0,
+ .result = SAM_STAT_CHECK_CONDITION,
+ },
+ {
+ .sense = NOT_READY,
+ .asc = 0x3A,
+ .ascq = 0x0,
+ .allowed = 0,
+ .result = SAM_STAT_CHECK_CONDITION,
+ },
+ {
+ .sense = UNIT_ATTENTION,
+ .asc = 0x29,
+ .ascq = 0,
+ /* Device reset might occur several times */
+ .allowed = READ_CAPACITY_RETRIES_ON_RESET,
+ .result = SAM_STAT_CHECK_CONDITION,
+ },
+ /* Any other error not listed above retry */
+ {
+ .result = SCMD_FAILURE_RESULT_ANY,
+ .allowed = 3,
+ },
+ {},
+ };
const struct scsi_exec_args exec_args = {
.sshdr = &sshdr,
+ .failures = failures,
};
int sense_valid = 0;
int the_result;
- int retries = 3, reset_retries = READ_CAPACITY_RETRIES_ON_RESET;
sector_t lba;
unsigned sector_size;
- do {
- cmd[0] = READ_CAPACITY;
- memset(&cmd[1], 0, 9);
- memset(buffer, 0, 8);
-
- the_result = scsi_execute_cmd(sdp, cmd, REQ_OP_DRV_IN, buffer,
- 8, SD_TIMEOUT, sdkp->max_retries,
- &exec_args);
+ memset(buffer, 0, 8);
- if (media_not_present(sdkp, &sshdr))
- return -ENODEV;
-
- if (the_result > 0) {
- sense_valid = scsi_sense_valid(&sshdr);
- if (sense_valid &&
- sshdr.sense_key == UNIT_ATTENTION &&
- sshdr.asc == 0x29 && sshdr.ascq == 0x00)
- /* Device reset might occur several times,
- * give it one more chance */
- if (--reset_retries > 0)
- continue;
- }
- retries--;
+ the_result = scsi_execute_cmd(sdp, cmd, REQ_OP_DRV_IN, buffer,
+ 8, SD_TIMEOUT, sdkp->max_retries,
+ &exec_args);
- } while (the_result && retries);
+ if (media_not_present(sdkp, &sshdr))
+ return -ENODEV;
if (the_result) {
sd_print_result(sdkp, "Read Capacity(10) failed", the_result);
--
2.25.1
