1 files changed, 56 insertions, 29 deletions

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index c228df298bd..12ac0b511f7 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -2384,11 +2384,6 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc)
 	int using_pio = (dev->flags & ATA_DFLAG_PIO);
 	int nodata = (scmd->sc_data_direction == DMA_NONE);
 
-	if (!using_pio)
-		/* Check whether ATAPI DMA is safe */
-		if (ata_check_atapi_dma(qc))
-			using_pio = 1;
-
 	memset(qc->cdb, 0, dev->cdb_len);
 	memcpy(qc->cdb, scmd->cmnd, scmd->cmd_len);
 
@@ -2401,19 +2396,22 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc)
 	}
 
 	qc->tf.command = ATA_CMD_PACKET;
+	qc->nbytes = scmd->request_bufflen;
+
+	/* check whether ATAPI DMA is safe */
+	if (!using_pio && ata_check_atapi_dma(qc))
+		using_pio = 1;
 
-	/* no data, or PIO data xfer */
 	if (using_pio || nodata) {
+		/* no data, or PIO data xfer */
 		if (nodata)
 			qc->tf.protocol = ATA_PROT_ATAPI_NODATA;
 		else
 			qc->tf.protocol = ATA_PROT_ATAPI;
 		qc->tf.lbam = (8 * 1024) & 0xff;
 		qc->tf.lbah = (8 * 1024) >> 8;
-	}
-
-	/* DMA data xfer */
-	else {
+	} else {
+		/* DMA data xfer */
 		qc->tf.protocol = ATA_PROT_ATAPI_DMA;
 		qc->tf.feature |= ATAPI_PKT_DMA;
 
@@ -2422,8 +2420,6 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc)
 			qc->tf.feature |= ATAPI_DMADIR;
 	}
 
-	qc->nbytes = scmd->request_bufflen;
-
 	return 0;
 }
 
@@ -2624,7 +2620,7 @@ static unsigned int ata_scsi_pass_thru(struct ata_queued_cmd *qc)
 			ata_dev_printk(dev, KERN_WARNING,
 				       "invalid multi_count %u ignored\n",
 				       multi_count);
-	}	
+	}
 
 	/* READ/WRITE LONG use a non-standard sect_size */
 	qc->sect_size = ATA_SECT_SIZE;
@@ -2951,17 +2947,22 @@ int ata_scsi_add_hosts(struct ata_host *host, struct scsi_host_template *sht)
 	return rc;
 }
 
-void ata_scsi_scan_host(struct ata_port *ap)
+void ata_scsi_scan_host(struct ata_port *ap, int sync)
 {
+	int tries = 5;
+	struct ata_device *last_failed_dev = NULL;
+	struct ata_device *dev;
 	unsigned int i;
 
 	if (ap->flags & ATA_FLAG_DISABLED)
 		return;
 
+ repeat:
 	for (i = 0; i < ATA_MAX_DEVICES; i++) {
-		struct ata_device *dev = &ap->device[i];
 		struct scsi_device *sdev;
 
+		dev = &ap->device[i];
+
 		if (!ata_dev_enabled(dev) || dev->sdev)
 			continue;
 
@@ -2971,6 +2972,45 @@ void ata_scsi_scan_host(struct ata_port *ap)
 			scsi_device_put(sdev);
 		}
 	}
+
+	/* If we scanned while EH was in progress or allocation
+	 * failure occurred, scan would have failed silently.  Check
+	 * whether all devices are attached.
+	 */
+	for (i = 0; i < ATA_MAX_DEVICES; i++) {
+		dev = &ap->device[i];
+		if (ata_dev_enabled(dev) && !dev->sdev)
+			break;
+	}
+	if (i == ATA_MAX_DEVICES)
+		return;
+
+	/* we're missing some SCSI devices */
+	if (sync) {
+		/* If caller requested synchrnous scan && we've made
+		 * any progress, sleep briefly and repeat.
+		 */
+		if (dev != last_failed_dev) {
+			msleep(100);
+			last_failed_dev = dev;
+			goto repeat;
+		}
+
+		/* We might be failing to detect boot device, give it
+		 * a few more chances.
+		 */
+		if (--tries) {
+			msleep(100);
+			goto repeat;
+		}
+
+		ata_port_printk(ap, KERN_ERR, "WARNING: synchronous SCSI scan "
+				"failed without making any progress,\n"
+				"                  switching to async\n");
+	}
+
+	queue_delayed_work(ata_aux_wq, &ap->hotplug_task,
+			   round_jiffies_relative(HZ));
 }
 
 /**
@@ -3097,20 +3137,7 @@ void ata_scsi_hotplug(struct work_struct *work)
 	}
 
 	/* scan for new ones */
-	ata_scsi_scan_host(ap);
-
-	/* If we scanned while EH was in progress, scan would have
-	 * failed silently.  Requeue if there are enabled but
-	 * unattached devices.
-	 */
-	for (i = 0; i < ATA_MAX_DEVICES; i++) {
-		struct ata_device *dev = &ap->device[i];
-		if (ata_dev_enabled(dev) && !dev->sdev) {
-			queue_delayed_work(ata_aux_wq, &ap->hotplug_task,
-				round_jiffies_relative(HZ));
-			break;
-		}
-	}
+	ata_scsi_scan_host(ap, 0);
 
 	DPRINTK("EXIT\n");
 }