[PATCH v12 04/20] scsi: sd: Have scsi-ml retry read_capacity_16 errors

Mike Christie
2023-11-14T01:38:30Z

This has read_capacity_16 have scsi-ml retry errors instead of driving
them itself.

There are 2 behavior changes with this patch:
1. There is one behavior change where 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 since 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 the specific UAs we checked for and retried, we would get
READ_CAPACITY_RETRIES_ON_RESET retries plus whatever retries were left
from the main loop's retries. Each UA now gets
READ_CAPACITY_RETRIES_ON_RESET reties, and the other errors get up to 3
retries. This is most likely ok, because READ_CAPACITY_RETRIES_ON_RESET
is already 10 and is not based on anything specific like a spec or
device, so the extra 3 we got from the main loop was probably just an
accident and is not going to help.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
---
drivers/scsi/sd.c | 108 ++++++++++++++++++++++++++++++----------------
1 file changed, 71 insertions(+), 37 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index fa00dd503cbf..1af04b01e1df 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2453,55 +2453,89 @@ static void read_capacity_error(struct scsi_disk *sdkp, struct scsi_device *sdp,
static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp,
unsigned char *buffer)
{
- unsigned char cmd[16];
- struct scsi_sense_hdr sshdr;
- const struct scsi_exec_args exec_args = {
- .sshdr = &sshdr,
+ static const u8 cmd[16] = {
+ [0] = SERVICE_ACTION_IN_16,
+ [1] = SAI_READ_CAPACITY_16,
+ [13] = RC16_LEN,
};
+ struct scsi_sense_hdr sshdr;
int sense_valid = 0;
int the_result;
- int retries = 3, reset_retries = READ_CAPACITY_RETRIES_ON_RESET;
unsigned int alignment;
unsigned long long lba;
unsigned sector_size;
+ struct scsi_failure failure_defs[] = {
+ /*
+ * Do not retry Invalid Command Operation Code or Invalid
+ * Field in CDB.
+ */
+ {
+ .sense = ILLEGAL_REQUEST,
+ .asc = 0x20,
+ .result = SAM_STAT_CHECK_CONDITION,
+ },
+ {
+ .sense = ILLEGAL_REQUEST,
+ .asc = 0x24,
+ .result = SAM_STAT_CHECK_CONDITION,
+ },
+ /* Do not retry Medium Not Present */
+ {
+ .sense = UNIT_ATTENTION,
+ .asc = 0x3A,
+ .result = SAM_STAT_CHECK_CONDITION,
+ },
+ {
+ .sense = NOT_READY,
+ .asc = 0x3A,
+ .result = SAM_STAT_CHECK_CONDITION,
+ },
+ /* Device reset might occur several times so retry a lot */
+ {
+ .sense = UNIT_ATTENTION,
+ .asc = 0x29,
+ .allowed = READ_CAPACITY_RETRIES_ON_RESET,
+ .result = SAM_STAT_CHECK_CONDITION,
+ },
+ /* Any other error not listed above retry 3 times */
+ {
+ .result = SCMD_FAILURE_RESULT_ANY,
+ .allowed = 3,
+ },
+ {}
+ };
+ struct scsi_failures failures = {
+ .failure_definitions = failure_defs,
+ };
+ const struct scsi_exec_args exec_args = {
+ .sshdr = &sshdr,
+ .failures = &failures,
+ };

if (sdp->no_read_capacity_16)
return -EINVAL;

- do {
- memset(cmd, 0, 16);
- cmd[0] = SERVICE_ACTION_IN_16;
- cmd[1] = SAI_READ_CAPACITY_16;
- cmd[13] = RC16_LEN;
- memset(buffer, 0, RC16_LEN);
-
- the_result = scsi_execute_cmd(sdp, cmd, REQ_OP_DRV_IN,
- buffer, RC16_LEN, SD_TIMEOUT,
- sdkp->max_retries, &exec_args);
- if (the_result > 0) {
- if (media_not_present(sdkp, &sshdr))
- return -ENODEV;
+ memset(buffer, 0, RC16_LEN);

- sense_valid = scsi_sense_valid(&sshdr);
- if (sense_valid &&
- sshdr.sense_key == ILLEGAL_REQUEST &&
- (sshdr.asc == 0x20 || sshdr.asc == 0x24) &&
- sshdr.ascq == 0x00)
- /* Invalid Command Operation Code or
- * Invalid Field in CDB, just retry
- * silently with RC10 */
- return -EINVAL;
- 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,
+ RC16_LEN, SD_TIMEOUT, sdkp->max_retries,
+ &exec_args);

- } while (the_result && retries);
+ if (the_result > 0) {
+ if (media_not_present(sdkp, &sshdr))
+ return -ENODEV;
+
+ sense_valid = scsi_sense_valid(&sshdr);
+ if (sense_valid && sshdr.sense_key == ILLEGAL_REQUEST &&
+ (sshdr.asc == 0x20 || sshdr.asc == 0x24) &&
+ sshdr.ascq == 0x00) {
+ /*
+ * Invalid Command Operation Code or Invalid Field in
+ * CDB, just retry silently with RC10
+ */
+ return -EINVAL;
+ }
+ }

if (the_result) {
sd_print_result(sdkp, "Read Capacity(16) failed", the_result);
--
2.34.1