[SCSI] scsi_dh_rdac: Retry for NOT_READY(02/04/01) in rdac device handler

During device discovery read capacity fails with 0x020401 and sets the
device size to 0. As a reason any I/O submitted to this path gets
killed at sd_prep_fn with BLKPREP_KILL. This patch is to retry for
0x020401. NEED_RETRY in scsi_decide_disposition does not give
sufficient time for the device to become ready.

Signed-off-by: Vijay Chauhan <[e-mail]>
Signed-off-by: James Bottomley <[e-mail]>

drivers/scsi/device_handler/scsi_dh_rdac.c

···
 	struct rdac_dh_data *h = get_rdac_data(sdev);
 	switch (sense_hdr->sense_key) {
 	case NOT_READY:
+		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x01)
+			/* LUN Not Ready - Logical Unit Not Ready and is in
+			* the process of becoming ready
+			* Just retry.
+			*/
+			return ADD_TO_MLQUEUE;
 		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x81)
 			/* LUN Not Ready - Storage firmware incompatible
 			 * Manual code synchonisation required.