1 files changed, 29 insertions, 35 deletions

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index d81db3a3d4b..ba1eb8b38e0 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -1263,7 +1263,7 @@ retry:
 	}
 
 	/* ATAPI-specific feature tests */
-	else {
+	else if (dev->class == ATA_DEV_ATAPI) {
 		if (ata_id_is_ata(dev->id))		/* sanity check */
 			goto err_out_nosup;
 
@@ -2399,7 +2399,7 @@ static void ata_sg_clean(struct ata_queued_cmd *qc)
 	if (qc->flags & ATA_QCFLAG_SINGLE)
 		assert(qc->n_elem == 1);
 
-	DPRINTK("unmapping %u sg elements\n", qc->n_elem);
+	VPRINTK("unmapping %u sg elements\n", qc->n_elem);
 
 	/* if we padded the buffer out to 32-bit bound, and data
 	 * xfer direction is from-device, we must copy from the
@@ -2409,7 +2409,8 @@ static void ata_sg_clean(struct ata_queued_cmd *qc)
 		pad_buf = ap->pad + (qc->tag * ATA_DMA_PAD_SZ);
 
 	if (qc->flags & ATA_QCFLAG_SG) {
-		dma_unmap_sg(ap->host_set->dev, sg, qc->n_elem, dir);
+		if (qc->n_elem)
+			dma_unmap_sg(ap->host_set->dev, sg, qc->n_elem, dir);
 		/* restore last sg */
 		sg[qc->orig_n_elem - 1].length += qc->pad_len;
 		if (pad_buf) {
@@ -2419,8 +2420,10 @@ static void ata_sg_clean(struct ata_queued_cmd *qc)
 			kunmap_atomic(psg->page, KM_IRQ0);
 		}
 	} else {
-		dma_unmap_single(ap->host_set->dev, sg_dma_address(&sg[0]),
-				 sg_dma_len(&sg[0]), dir);
+		if (sg_dma_len(&sg[0]) > 0)
+			dma_unmap_single(ap->host_set->dev,
+				sg_dma_address(&sg[0]), sg_dma_len(&sg[0]),
+				dir);
 		/* restore sg */
 		sg->length += qc->pad_len;
 		if (pad_buf)
@@ -2619,6 +2622,11 @@ static int ata_sg_setup_one(struct ata_queued_cmd *qc)
 			sg->length, qc->pad_len);
 	}
 
+	if (!sg->length) {
+		sg_dma_address(sg) = 0;
+		goto skip_map;
+	}
+
 	dma_address = dma_map_single(ap->host_set->dev, qc->buf_virt,
 				     sg->length, dir);
 	if (dma_mapping_error(dma_address)) {
@@ -2628,6 +2636,7 @@ static int ata_sg_setup_one(struct ata_queued_cmd *qc)
 	}
 
 	sg_dma_address(sg) = dma_address;
+skip_map:
 	sg_dma_len(sg) = sg->length;
 
 	DPRINTK("mapped buffer of %d bytes for %s\n", sg_dma_len(sg),
@@ -2655,7 +2664,7 @@ static int ata_sg_setup(struct ata_queued_cmd *qc)
 	struct ata_port *ap = qc->ap;
 	struct scatterlist *sg = qc->__sg;
 	struct scatterlist *lsg = &sg[qc->n_elem - 1];
-	int n_elem, dir;
+	int n_elem, pre_n_elem, dir, trim_sg = 0;
 
 	VPRINTK("ENTER, ata%u\n", ap->id);
 	assert(qc->flags & ATA_QCFLAG_SG);
@@ -2689,13 +2698,24 @@ static int ata_sg_setup(struct ata_queued_cmd *qc)
 		sg_dma_len(psg) = ATA_DMA_PAD_SZ;
 		/* trim last sg */
 		lsg->length -= qc->pad_len;
+		if (lsg->length == 0)
+			trim_sg = 1;
 
 		DPRINTK("padding done, sg[%d].length=%u pad_len=%u\n",
 			qc->n_elem - 1, lsg->length, qc->pad_len);
 	}
 
+	pre_n_elem = qc->n_elem;
+	if (trim_sg && pre_n_elem)
+		pre_n_elem--;
+
+	if (!pre_n_elem) {
+		n_elem = 0;
+		goto skip_map;
+	}
+
 	dir = qc->dma_dir;
-	n_elem = dma_map_sg(ap->host_set->dev, sg, qc->n_elem, dir);
+	n_elem = dma_map_sg(ap->host_set->dev, sg, pre_n_elem, dir);
 	if (n_elem < 1) {
 		/* restore last sg */
 		lsg->length += qc->pad_len;
@@ -2704,6 +2724,7 @@ static int ata_sg_setup(struct ata_queued_cmd *qc)
 
 	DPRINTK("%d sg elements mapped\n", n_elem);
 
+skip_map:
 	qc->n_elem = n_elem;
 
 	return 0;
@@ -3263,32 +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
@@ -3327,7 +3327,6 @@ static void ata_qc_timeout(struct ata_queued_cmd *qc)
 
 	spin_unlock_irqrestore(&host_set->lock, flags);
 
-out:
 	DPRINTK("EXIT\n");
 }
 
@@ -3411,16 +3410,11 @@ struct ata_queued_cmd *ata_qc_new_init(struct ata_port *ap,
 
 	qc = ata_qc_new(ap);
 	if (qc) {
-		qc->__sg = NULL;
-		qc->flags = 0;
 		qc->scsicmd = NULL;
 		qc->ap = ap;
 		qc->dev = dev;
-		qc->cursect = qc->cursg = qc->cursg_ofs = 0;
-		qc->nsect = 0;
-		qc->nbytes = qc->curbytes = 0;
 
-		ata_tf_init(ap, &qc->tf, dev->devno);
+		ata_qc_reinit(qc);
 	}
 
 	return qc;