5 files changed, 111 insertions, 77 deletions

diff --git a/drivers/scsi/ahci.c b/drivers/scsi/ahci.c
index 4e96ec5f2ff9..894e7113e0b3 100644
--- a/drivers/scsi/ahci.c
+++ b/drivers/scsi/ahci.c
@@ -565,6 +565,17 @@ static void ahci_intr_error(struct ata_port *ap, u32 irq_stat)
         u32 tmp;
         int work;
 
+        printk(KERN_WARNING "ata%u: port reset, "
+               "p_is %x is %x pis %x cmd %x tf %x ss %x se %x\n",
+                ap->id,
+                irq_stat,
+                readl(mmio + HOST_IRQ_STAT),
+                readl(port_mmio + PORT_IRQ_STAT),
+                readl(port_mmio + PORT_CMD),
+                readl(port_mmio + PORT_TFDATA),
+                readl(port_mmio + PORT_SCR_STAT),
+                readl(port_mmio + PORT_SCR_ERR));
+
         /* stop DMA */
         tmp = readl(port_mmio + PORT_CMD);
         tmp &= ~PORT_CMD_START;
@@ -602,8 +613,6 @@ static void ahci_intr_error(struct ata_port *ap, u32 irq_stat)
         tmp |= PORT_CMD_START;
         writel(tmp, port_mmio + PORT_CMD);
         readl(port_mmio + PORT_CMD); /* flush */
-
-        printk(KERN_WARNING "ata%u: error occurred, port reset\n", ap->id);
 }
 
 static void ahci_eng_timeout(struct ata_port *ap)
@@ -614,17 +623,17 @@ static void ahci_eng_timeout(struct ata_port *ap)
         struct ata_queued_cmd *qc;
         unsigned long flags;
 
-        DPRINTK("ENTER\n");
+        printk(KERN_WARNING "ata%u: handling error/timeout\n", ap->id);
 
         spin_lock_irqsave(&host_set->lock, flags);
 
-        ahci_intr_error(ap, readl(port_mmio + PORT_IRQ_STAT));
-
         qc = ata_qc_from_tag(ap, ap->active_tag);
         if (!qc) {
                 printk(KERN_ERR "ata%u: BUG: timeout without command\n",
                        ap->id);
         } else {
+                ahci_intr_error(ap, readl(port_mmio + PORT_IRQ_STAT));
+
                 /* hack alert!  We cannot use the supplied completion
                  * function from inside the ->eh_strategy_handler() thread.
                  * libata is the only user of ->eh_strategy_handler() in
@@ -659,9 +668,19 @@ static inline int ahci_host_intr(struct ata_port *ap, struct ata_queued_cmd *qc)
         }
 
         if (status & PORT_IRQ_FATAL) {
+                unsigned int err_mask;
+                if (status & PORT_IRQ_TF_ERR)
+                        err_mask = AC_ERR_DEV;
+                else if (status & PORT_IRQ_IF_ERR)
+                        err_mask = AC_ERR_ATA_BUS;
+                else
+                        err_mask = AC_ERR_HOST_BUS;
+
+                /* command processing has stopped due to error; restart */
                 ahci_intr_error(ap, status);
+
                 if (qc)
-                        ata_qc_complete(qc, AC_ERR_OTHER);
+                        ata_qc_complete(qc, err_mask);
         }
 
         return 1;
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--;