diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 0b5d3a5b7ed..ee9b96da841 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -1253,11 +1253,11 @@ void __sata_phy_reset(struct ata_port *ap)
 	unsigned long timeout = jiffies + (HZ * 5);
 
 	if (ap->flags & ATA_FLAG_SATA_RESET) {
-		scr_write(ap, SCR_CONTROL, 0x301); /* issue phy wake/reset */
-		scr_read(ap, SCR_STATUS);	/* dummy read; flush */
+		/* issue phy wake/reset */
+		scr_write_flush(ap, SCR_CONTROL, 0x301);
 		udelay(400);			/* FIXME: a guess */
 	}
-	scr_write(ap, SCR_CONTROL, 0x300);	/* issue phy wake/clear reset */
+	scr_write_flush(ap, SCR_CONTROL, 0x300); /* phy wake/clear reset */
 
 	/* wait for phy to become ready, if necessary */
 	do {
@@ -2539,7 +2539,7 @@ static void atapi_request_sense(struct ata_port *ap, struct ata_device *dev,
 	ata_sg_init_one(qc, cmd->sense_buffer, sizeof(cmd->sense_buffer));
 	qc->dma_dir = DMA_FROM_DEVICE;
 
-	memset(&qc->cdb, 0, sizeof(ap->cdb_len));
+	memset(&qc->cdb, 0, ap->cdb_len);
 	qc->cdb[0] = REQUEST_SENSE;
 	qc->cdb[4] = SCSI_SENSE_BUFFERSIZE;
 
@@ -2811,6 +2811,7 @@ void ata_qc_complete(struct ata_queued_cmd *qc, u8 drv_stat)
 
 	/* call completion callback */
 	rc = qc->complete_fn(qc, drv_stat);
+	qc->flags &= ~ATA_QCFLAG_ACTIVE;
 
 	/* if callback indicates not to complete command (non-zero),
 	 * return immediately
@@ -3229,7 +3230,8 @@ irqreturn_t ata_interrupt (int irq, void *dev_instance, struct pt_regs *regs)
 			struct ata_queued_cmd *qc;
 
 			qc = ata_qc_from_tag(ap, ap->active_tag);
-			if (qc && (!(qc->tf.ctl & ATA_NIEN)))
+			if (qc && (!(qc->tf.ctl & ATA_NIEN)) &&
+			    (qc->flags & ATA_QCFLAG_ACTIVE))
 				handled |= ata_host_intr(ap, qc);
 		}
 	}
diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
index 4c96df060c3..416ba67ba9e 100644
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -347,7 +347,10 @@ int ata_scsi_slave_config(struct scsi_device *sdev)
 		 */
 		if ((dev->flags & ATA_DFLAG_LBA48) &&
 		    ((dev->flags & ATA_DFLAG_LOCK_SECTORS) == 0)) {
-			sdev->host->max_sectors = 2048;
+			/*
+			 * do not overwrite sdev->host->max_sectors, since
+			 * other drives on this host may not support LBA48
+			 */
 			blk_queue_max_sectors(sdev->request_queue, 2048);
 		}
 	}
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 505160ab472..1f7e2039a04 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -584,6 +584,13 @@ static inline void scr_write(struct ata_port *ap, unsigned int reg, u32 val)
 	ap->ops->scr_write(ap, reg, val);
 }
 
+static inline void scr_write_flush(struct ata_port *ap, unsigned int reg, 
+				   u32 val)
+{
+	ap->ops->scr_write(ap, reg, val);
+	(void) ap->ops->scr_read(ap, reg);
+}
+
 static inline unsigned int sata_dev_present(struct ata_port *ap)
 {
 	return ((scr_read(ap, SCR_STATUS) & 0xf) == 0x3) ? 1 : 0;