diff mbox series

[v11,24/34] scsi: Have scsi-ml retry scsi_report_lun_scan errors

Message ID 20230905231547.83945-25-michael.christie@oracle.com
State Superseded
Headers show
Series [v11,01/34] scsi: Add helper to prep sense during error handling | expand

Commit Message

Mike Christie Sept. 5, 2023, 11:15 p.m. UTC 
This has scsi_report_lun_scan 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/scsi_scan.c | 56 +++++++++++++++++++++++-----------------
 1 file changed, 32 insertions(+), 24 deletions(-)

Comments

Martin Wilck Sept. 15, 2023, 9:17 p.m. UTC | #1 
On Tue, 2023-09-05 at 18:15 -0500, Mike Christie wrote:
> This has scsi_report_lun_scan 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.

Another minor behavior change is that we may now get up to 3 retries
for UAs plus up to 3 retries for non-CC errors. Anyway,

> 
> 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>

Reviewed-by: Martin Wilck <mwilck@suse.com>
diff mbox series

Patch

diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index c27b64a1b239..b29c47c2a5c6 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -1412,14 +1412,33 @@  static int scsi_report_lun_scan(struct scsi_target *starget, blist_flags_t bflag
 	unsigned int length;
 	u64 lun;
 	unsigned int num_luns;
-	unsigned int retries;
 	int result;
 	struct scsi_lun *lunp, *lun_data;
-	struct scsi_sense_hdr sshdr;
 	struct scsi_device *sdev;
 	struct Scsi_Host *shost = dev_to_shost(&starget->dev);
+	struct scsi_failure failures[] = {
+		{
+			.sense = UNIT_ATTENTION,
+			.asc = SCMD_FAILURE_ASC_ANY,
+			.ascq = SCMD_FAILURE_ASCQ_ANY,
+			.allowed = 3,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		/* Fail all CCs except the UA above */
+		{
+			.sense = SCMD_FAILURE_SENSE_ANY,
+			.allowed = 0,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		/* Retry any oher errors not listed above */
+		{
+			.result = SCMD_FAILURE_RESULT_ANY,
+			.allowed = 3,
+		},
+		{}
+	};
 	const struct scsi_exec_args exec_args = {
-		.sshdr = &sshdr,
+		.failures = failures,
 	};
 	int ret = 0;
 
@@ -1490,29 +1509,18 @@  static int scsi_report_lun_scan(struct scsi_target *starget, blist_flags_t bflag
 	 * should come through as a check condition, and will not generate
 	 * a retry.
 	 */
-	for (retries = 0; retries < 3; retries++) {
-		SCSI_LOG_SCAN_BUS(3, sdev_printk (KERN_INFO, sdev,
-				"scsi scan: Sending REPORT LUNS to (try %d)\n",
-				retries));
-
-		result = scsi_execute_cmd(sdev, scsi_cmd, REQ_OP_DRV_IN,
-					  lun_data, length,
-					  SCSI_REPORT_LUNS_TIMEOUT, 3,
-					  &exec_args);
+	scsi_reset_failures(failures);
 
-		SCSI_LOG_SCAN_BUS(3, sdev_printk (KERN_INFO, sdev,
-				"scsi scan: REPORT LUNS"
-				" %s (try %d) result 0x%x\n",
-				result ?  "failed" : "successful",
-				retries, result));
-		if (result == 0)
-			break;
-		else if (scsi_sense_valid(&sshdr)) {
-			if (sshdr.sense_key != UNIT_ATTENTION)
-				break;
-		}
-	}
+	SCSI_LOG_SCAN_BUS(3, sdev_printk (KERN_INFO, sdev,
+			  "scsi scan: Sending REPORT LUNS\n"));
+
+	result = scsi_execute_cmd(sdev, scsi_cmd, REQ_OP_DRV_IN, lun_data,
+				  length, SCSI_REPORT_LUNS_TIMEOUT, 3,
+				  &exec_args);
 
+	SCSI_LOG_SCAN_BUS(3, sdev_printk (KERN_INFO, sdev,
+			  "scsi scan: REPORT LUNS  %s result 0x%x\n",
+			  result ?  "failed" : "successful", result));
 	if (result) {
 		/*
 		 * The device probably does not support a REPORT LUN command