1 files changed, 29 insertions, 35 deletions

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index d81db3a3d4b9..ba1eb8b38e00 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;