[PATCH v11 19/34] scsi: sd: Have scsi-ml retry sd_sync_cache errors

Mike Christie
2023-09-05T23:21:27Z

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

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 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.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Garry <john.g.garry@oracle.com>
---
drivers/scsi/sd.c | 32 ++++++++++++++------------------
1 file changed, 14 insertions(+), 18 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 1f6cc24d633b..8efd5d8e46e8 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1566,36 +1566,32 @@ static unsigned int sd_check_events(struct gendisk *disk, unsigned int clearing)

static int sd_sync_cache(struct scsi_disk *sdkp)
{
- int retries, res;
+ int res;
struct scsi_device *sdp = sdkp->device;
const int timeout = sdp->request_queue->rq_timeout
* SD_FLUSH_TIMEOUT_MULTIPLIER;
+ /* Leave the rest of the command zero to indicate flush everything. */
+ const unsigned char cmd[16] = { sdp->use_16_for_sync ?
+ SYNCHRONIZE_CACHE_16 : SYNCHRONIZE_CACHE };
struct scsi_sense_hdr sshdr;
+ struct scsi_failure failures[] = {
+ {
+ .allowed = 3,
+ .result = SCMD_FAILURE_RESULT_ANY,
+ },
+ {}
+ };
const struct scsi_exec_args exec_args = {
.req_flags = BLK_MQ_REQ_PM,
.sshdr = &sshdr,
+ .failures = failures,
};

if (!scsi_device_online(sdp))
return -ENODEV;

- for (retries = 3; retries > 0; --retries) {
- unsigned char cmd[16] = { 0 };
-
- if (sdp->use_16_for_sync)
- cmd[0] = SYNCHRONIZE_CACHE_16;
- else
- cmd[0] = SYNCHRONIZE_CACHE;
- /*
- * Leave the rest of the command zero to indicate
- * flush everything.
- */
- res = scsi_execute_cmd(sdp, cmd, REQ_OP_DRV_IN, NULL, 0,
- timeout, sdkp->max_retries, &exec_args);
- if (res == 0)
- break;
- }
-
+ res = scsi_execute_cmd(sdp, cmd, REQ_OP_DRV_IN, NULL, 0, timeout,
+ sdkp->max_retries, &exec_args);
if (res) {
sd_print_result(sdkp, "Synchronize Cache(10) failed", res);

--
2.34.1