[SCSI] scsi_error.c: Add EH Start Unit retry

Currently, the scsi error handler will issue a START_UNIT
command if the drive indicates it needs its motor started
and the allow_restart flag is set in the scsi_device. If,
after the scsi error handler invokes a host adapter reset
due to error recovery, a device is in a unit attention
state AND also needs a START_UNIT, that device will be placed
offline. The disk array devices on an ipr RAID adapter
will do exactly this when in a dual initiator configuration.
This patch adds a single retry to the EH initiated
START_UNIT.

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>

Patch modified and
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/scsi_error.c

@@ -932,10 +932,12 @@ static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
 	static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
 
 	if (scmd->device->allow_restart) {
-		int rtn;
+		int i, rtn = NEEDS_RETRY;
+
+		for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
+			rtn = scsi_send_eh_cmnd(scmd, stu_command, 6,
+						START_UNIT_TIMEOUT, 0);
 
-		rtn = scsi_send_eh_cmnd(scmd, stu_command, 6,
-					START_UNIT_TIMEOUT, 0);
 		if (rtn == SUCCESS)
 			return 0;
 	}