[PATCH] libata-dev: Minor fix for ata_hsm_move() to work with ata_host_intr()

Minor fix for ata_hsm_move() to work with ata_host_intr().
Changes:
- WARN_ON() and comment fix
- Make the HSM_ST_LAST device status checking more rigid.
- Treat unknown HSM state as BUG().

Signed-off-by: Albert Lee <albertcc@tw.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/scsi/libata-core.c

@@ -3808,6 +3808,8 @@ static void ata_pio_error(struct ata_port *ap)
 static void ata_hsm_move(struct ata_port *ap, struct ata_queued_cmd *qc,
 			 u8 status)
 {
+	WARN_ON((qc->flags & ATA_QCFLAG_ACTIVE) == 0);
+
 	/* check error */
 	if (unlikely(status & (ATA_ERR | ATA_DF))) {
 		qc->err_mask |= AC_ERR_DEV;
@@ -3817,10 +3819,6 @@ static void ata_hsm_move(struct ata_port *ap, struct ata_queued_cmd *qc,
 fsm_start:
 	switch (ap->hsm_task_state) {
 	case HSM_ST_FIRST:
-		/* Some pre-ATAPI-4 devices assert INTRQ
-		 * at this state when ready to receive CDB.
-		 */
-
 		/* check device status */
 		if (unlikely((status & (ATA_BUSY | ATA_DRQ)) != ATA_DRQ)) {
 			/* Wrong status. Let EH handle this */
@@ -3873,9 +3871,8 @@ fsm_start:
 		break;
 
 	case HSM_ST_LAST:
-		if (unlikely(status & ATA_DRQ)) {
-			/* handle DRQ=1 as error */
-			qc->err_mask |= AC_ERR_HSM;
+		if (unlikely(!ata_ok(status))) {
+			qc->err_mask |= __ac_err_mask(status);
 			ap->hsm_task_state = HSM_ST_ERR;
 			goto fsm_start;
 		}
@@ -3884,17 +3881,18 @@ fsm_start:
 		DPRINTK("ata%u: command complete, drv_stat 0x%x\n",
 			ap->id, status);
 
+		WARN_ON(qc->err_mask);
+
 		ap->hsm_task_state = HSM_ST_IDLE;
 
 		/* complete taskfile transaction */
-		qc->err_mask |= ac_err_mask(status);
 		ata_qc_complete(qc);
 		break;
 
 	case HSM_ST_ERR:
 		if (qc->tf.command != ATA_CMD_PACKET)
-			printk(KERN_ERR "ata%u: command error, drv_stat 0x%x host_stat 0x%x\n",
-			       ap->id, status, host_stat);
+			printk(KERN_ERR "ata%u: command error, drv_stat 0x%x\n",
+			       ap->id, status);
 
 		/* make sure qc->err_mask is available to
 		 * know what's wrong and recover
@@ -3905,7 +3903,7 @@ fsm_start:
 		ata_qc_complete(qc);
 		break;
 	default:
-		goto idle_irq;
+		BUG();
 	}
 
 }
@@ -4371,6 +4369,10 @@ inline unsigned int ata_host_intr (struct ata_port *ap,
 	/* Check whether we are expecting interrupt in this state */
 	switch (ap->hsm_task_state) {
 	case HSM_ST_FIRST:
+		/* Some pre-ATAPI-4 devices assert INTRQ
+		 * at this state when ready to receive CDB.
+		 */
+
 		/* Check the ATA_DFLAG_CDB_INTR flag is enough here.
 		 * The flag was turned on only for atapi devices.
 		 * No need to check is_atapi_taskfile(&qc->tf) again.