[libata] REQUEST SENSE handling fixes

- Move ATAPI check-condition handling out of the timeout handler
- Use multi-qc-issue feature to issue REQUEST SENSE ATAPI PACKET
  command upon receiving an ATAPI check-condition.

This cleans things up a lot, and eliminates a nasty recursion bug.

drivers/scsi/libata-core.c

@@ -3284,32 +3284,11 @@ static void ata_qc_timeout(struct ata_queued_cmd *qc)
 {
 	struct ata_port *ap = qc->ap;
 	struct ata_host_set *host_set = ap->host_set;
-	struct ata_device *dev = qc->dev;
 	u8 host_stat = 0, drv_stat;
 	unsigned long flags;
 
 	DPRINTK("ENTER\n");
 
-	/* FIXME: doesn't this conflict with timeout handling? */
-	if (qc->dev->class == ATA_DEV_ATAPI && qc->scsicmd) {
-		struct scsi_cmnd *cmd = qc->scsicmd;
-
-		if (!(cmd->eh_eflags & SCSI_EH_CANCEL_CMD)) {
-
-			/* finish completing original command */
-			spin_lock_irqsave(&host_set->lock, flags);
-			__ata_qc_complete(qc);
-			spin_unlock_irqrestore(&host_set->lock, flags);
-
-			atapi_request_sense(ap, dev, cmd);
-
-			cmd->result = (CHECK_CONDITION << 1) | (DID_OK << 16);
-			scsi_finish_command(cmd);
-
-			goto out;
-		}
-	}
-
 	spin_lock_irqsave(&host_set->lock, flags);
 
 	/* hack alert!  We cannot use the supplied completion
@@ -3348,7 +3327,6 @@ static void ata_qc_timeout(struct ata_queued_cmd *qc)
 
 	spin_unlock_irqrestore(&host_set->lock, flags);
 
-out:
 	DPRINTK("EXIT\n");
 }
 

drivers/scsi/libata-scsi.c

@@ -1955,22 +1955,44 @@ void ata_scsi_badcmd(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *), u8
 	done(cmd);
 }
 
-void atapi_request_sense(struct ata_port *ap, struct ata_device *dev,
-			 struct scsi_cmnd *cmd)
+static int atapi_sense_complete(struct ata_queued_cmd *qc,unsigned int err_mask)
 {
-	DECLARE_COMPLETION(wait);
-	struct ata_queued_cmd *qc;
-	unsigned long flags;
-	int rc;
+	if (err_mask && ((err_mask & AC_ERR_DEV) == 0))
+		/* FIXME: not quite right; we don't want the
+		 * translation of taskfile registers into
+		 * a sense descriptors, since that's only
+		 * correct for ATA, not ATAPI
+		 */
+		ata_gen_ata_desc_sense(qc);
 
-	DPRINTK("ATAPI request sense\n");
+	qc->scsidone(qc->scsicmd);
+	return 0;
+}
 
-	qc = ata_qc_new_init(ap, dev);
-	BUG_ON(qc == NULL);
+/* is it pointless to prefer PIO for "safety reasons"? */
+static inline int ata_pio_use_silly(struct ata_port *ap)
+{
+	return (ap->flags & ATA_FLAG_PIO_DMA);
+}
+
+static void atapi_request_sense(struct ata_queued_cmd *qc)
+{
+	struct ata_port *ap = qc->ap;
+	struct scsi_cmnd *cmd = qc->scsicmd;
+
+	DPRINTK("ATAPI request sense\n");
 
 	/* FIXME: is this needed? */
 	memset(cmd->sense_buffer, 0, sizeof(cmd->sense_buffer));
 
+	ap->ops->tf_read(ap, &qc->tf);
+
+	/* fill these in, for the case where they are -not- overwritten */
+	cmd->sense_buffer[0] = 0x70;
+	cmd->sense_buffer[2] = qc->tf.feature >> 4;
+
+	ata_qc_reinit(qc);
+
 	ata_sg_init_one(qc, cmd->sense_buffer, sizeof(cmd->sense_buffer));
 	qc->dma_dir = DMA_FROM_DEVICE;
 
@@ -1981,22 +2003,20 @@ void atapi_request_sense(struct ata_port *ap, struct ata_device *dev,
 	qc->tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
 	qc->tf.command = ATA_CMD_PACKET;
 
+	if (ata_pio_use_silly(ap)) {
+		qc->tf.protocol = ATA_PROT_ATAPI_DMA;
+		qc->tf.feature |= ATAPI_PKT_DMA;
+	} else {
 		qc->tf.protocol = ATA_PROT_ATAPI;
 		qc->tf.lbam = (8 * 1024) & 0xff;
 		qc->tf.lbah = (8 * 1024) >> 8;
+	}
 	qc->nbytes = SCSI_SENSE_BUFFERSIZE;
 
-	qc->waiting = &wait;
-	qc->complete_fn = ata_qc_complete_noop;
+	qc->complete_fn = atapi_sense_complete;
 
-	spin_lock_irqsave(&ap->host_set->lock, flags);
-	rc = ata_qc_issue(qc);
-	spin_unlock_irqrestore(&ap->host_set->lock, flags);
-
-	if (rc)
-		ata_port_disable(ap);
-	else
-		wait_for_completion(&wait);
+	if (ata_qc_issue(qc))
+		ata_qc_complete(qc, AC_ERR_OTHER);
 
 	DPRINTK("EXIT\n");
 }
@@ -2008,19 +2028,8 @@ static int atapi_qc_complete(struct ata_queued_cmd *qc, unsigned int err_mask)
 	VPRINTK("ENTER, err_mask 0x%X\n", err_mask);
 
 	if (unlikely(err_mask & AC_ERR_DEV)) {
-		DPRINTK("request check condition\n");
-
-		/* FIXME: command completion with check condition
-		 * but no sense causes the error handler to run,
-		 * which then issues REQUEST SENSE, fills in the sense 
-		 * buffer, and completes the command (for the second
-		 * time).  We need to issue REQUEST SENSE some other
-		 * way, to avoid completing the command twice.
-		 */
 		cmd->result = SAM_STAT_CHECK_CONDITION;
-
-		qc->scsidone(cmd);
-
+		atapi_request_sense(qc);
 		return 1;
 	}
 

drivers/scsi/libata.h

@@ -54,8 +54,6 @@ extern int ata_cmd_ioctl(struct scsi_device *scsidev, void __user *arg);
 
 
 /* libata-scsi.c */
-extern void atapi_request_sense(struct ata_port *ap, struct ata_device *dev,
-			 struct scsi_cmnd *cmd);
 extern void ata_scsi_scan_host(struct ata_port *ap);
 extern int ata_scsi_error(struct Scsi_Host *host);
 extern unsigned int ata_scsiop_inq_std(struct ata_scsi_args *args, u8 *rbuf,