[PATCH v7 20/22] scsi: sr: Have scsi-ml retry get_sectorsize errors

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

This has get_sectorsize 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>
---
 drivers/scsi/sr.c | 35 +++++++++++++++++------------------
 1 file changed, 17 insertions(+), 18 deletions(-)

diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index 9e51dcd30bfd..81802a080189 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -721,27 +721,26 @@ static int sr_probe(struct device *dev)
 
 static void get_sectorsize(struct scsi_cd *cd)
 {
-	unsigned char cmd[10];
-	unsigned char buffer[8];
-	int the_result, retries = 3;
+	static const u8 cmd[10] = { READ_CAPACITY };
+	unsigned char buffer[8] = { };
+	int the_result;
 	int sector_size;
 	struct request_queue *queue;
+	struct scsi_failure failures[] = {
+		{
+			.result = SCMD_FAILURE_RESULT_ANY,
+			.allowed = 3,
+		},
+		{},
+	};
+	const struct scsi_exec_args exec_args = {
+		.failures = failures,
+	};
 
-	do {
-		cmd[0] = READ_CAPACITY;
-		memset((void *) &cmd[1], 0, 9);
-		memset(buffer, 0, sizeof(buffer));
-
-		/* Do the command and wait.. */
-		the_result = scsi_execute_cmd(cd->device, cmd, REQ_OP_DRV_IN,
-					      buffer, sizeof(buffer),
-					      SR_TIMEOUT, MAX_RETRIES, NULL);
-
-		retries--;
-
-	} while (the_result && retries);
-
-
+	/* Do the command and wait.. */
+	the_result = scsi_execute_cmd(cd->device, cmd, REQ_OP_DRV_IN, buffer,
+				      sizeof(buffer), SR_TIMEOUT, MAX_RETRIES,
+				      &exec_args);
 	if (the_result) {
 		cd->capacity = 0x1fffff;
 		sector_size = 2048;	/* A guess, just in case */
-- 
2.25.1