[PATCH v6 19/35] scsi: Have scsi-ml retry scsi_probe_lun errors

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

This has scsi_probe_lun ask scsi-ml to retry UAs instead of driving them
itself.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/scsi/scsi_scan.c | 51 ++++++++++++++++++++++++----------------
 1 file changed, 31 insertions(+), 20 deletions(-)

diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 58edd5d641f8..ffdb043bda5f 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -653,8 +653,29 @@ static int scsi_probe_lun(struct scsi_device *sdev, unsigned char *inq_result,
 	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
 	int first_inquiry_len, try_inquiry_len, next_inquiry_len;
 	int response_len = 0;
-	int pass, count, result;
-	struct scsi_sense_hdr sshdr;
+	int pass, count, result, i;
+	/*
+	 * not-ready to ready transition [asc/ascq=0x28/0x0] or power-on,
+	 * reset [asc/ascq=0x29/0x0], continue. INQUIRY should not yield
+	 * UNIT_ATTENTION but many buggy devices do so anyway.
+	 */
+	struct scsi_failure failures[] = {
+		{
+			.sense = UNIT_ATTENTION,
+			.asc = 0x28,
+			.ascq = 0,
+			.allowed = 3,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{
+			.sense = UNIT_ATTENTION,
+			.asc = 0x29,
+			.ascq = 0,
+			.allowed = 3,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{},
+	};
 
 	*bflags = 0;
 
@@ -671,6 +692,11 @@ static int scsi_probe_lun(struct scsi_device *sdev, unsigned char *inq_result,
 				pass, try_inquiry_len));
 
 	/* Each pass gets up to three chances to ignore Unit Attention */
+	for (i = 0; i < ARRAY_SIZE(failures); i++) {
+		if (failures[i].sense == UNIT_ATTENTION)
+			failures[i].retries = 0;
+	}
+
 	for (count = 0; count < 3; ++count) {
 		int resid;
 
@@ -686,32 +712,17 @@ static int scsi_probe_lun(struct scsi_device *sdev, unsigned char *inq_result,
 						.data_dir = DMA_FROM_DEVICE,
 						.buf = inq_result,
 						.buf_len = try_inquiry_len,
-						.sshdr = &sshdr,
 						.timeout = HZ / 2 +
 							HZ * scsi_inq_timeout,
 						.retries = 3,
-						.resid = &resid }));
+						.resid = &resid,
+						.failures = failures }));
 
 		SCSI_LOG_SCAN_BUS(3, sdev_printk(KERN_INFO, sdev,
 				"scsi scan: INQUIRY %s with code 0x%x\n",
 				result ? "failed" : "successful", result));
 
-		if (result > 0) {
-			/*
-			 * not-ready to ready transition [asc/ascq=0x28/0x0]
-			 * or power-on, reset [asc/ascq=0x29/0x0], continue.
-			 * INQUIRY should not yield UNIT_ATTENTION
-			 * but many buggy devices do so anyway. 
-			 */
-			if (scsi_status_is_check_condition(result) &&
-			    scsi_sense_valid(&sshdr)) {
-				if ((sshdr.sense_key == UNIT_ATTENTION) &&
-				    ((sshdr.asc == 0x28) ||
-				     (sshdr.asc == 0x29)) &&
-				    (sshdr.ascq == 0))
-					continue;
-			}
-		} else if (result == 0) {
+		if (result == 0) {
 			/*
 			 * if nothing was transferred, we try
 			 * again. It's a workaround for some USB
-- 
2.25.1