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

[Mike Christie <michael.christie@oracle.com>]

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