libata: fix ATAPI DMA alignment issues

ATAPI needs to be padded to next 4 byte boundary, if misaligned.

Original work by me, many fixes from Tejun Heo.

1 files changed, 6 insertions, 7 deletions

diff --git a/drivers/scsi/sata_sx4.c b/drivers/scsi/sata_sx4.c
index 540a85191172..79fdbbab513e 100644
--- a/drivers/scsi/sata_sx4.c
+++ b/drivers/scsi/sata_sx4.c
@@ -449,14 +449,14 @@ static inline void pdc20621_host_pkt(struct ata_taskfile *tf, u8 *buf,
 
 static void pdc20621_dma_prep(struct ata_queued_cmd *qc)
 {
-        struct scatterlist *sg = qc->sg;
+        struct scatterlist *sg;
         struct ata_port *ap = qc->ap;
         struct pdc_port_priv *pp = ap->private_data;
         void __iomem *mmio = ap->host_set->mmio_base;
         struct pdc_host_priv *hpriv = ap->host_set->private_data;
         void __iomem *dimm_mmio = hpriv->dimm_mmio;
         unsigned int portno = ap->port_no;
-        unsigned int i, last, idx, total_len = 0, sgt_len;
+        unsigned int i, idx, total_len = 0, sgt_len;
         u32 *buf = (u32 *) &pp->dimm_buf[PDC_DIMM_HEADER_SZ];
 
         assert(qc->flags & ATA_QCFLAG_DMAMAP);
@@ -469,12 +469,11 @@ static void pdc20621_dma_prep(struct ata_queued_cmd *qc)
         /*
          * Build S/G table
          */
-        last = qc->n_elem;
         idx = 0;
-        for (i = 0; i < last; i++) {
-                buf[idx++] = cpu_to_le32(sg_dma_address(&sg[i]));
-                buf[idx++] = cpu_to_le32(sg_dma_len(&sg[i]));
-                total_len += sg_dma_len(&sg[i]);
+        ata_for_each_sg(sg, qc) {
+                buf[idx++] = cpu_to_le32(sg_dma_address(sg));
+                buf[idx++] = cpu_to_le32(sg_dma_len(sg));
+                total_len += sg_dma_len(sg);
         }
         buf[idx - 1] |= cpu_to_le32(ATA_PRD_EOT);
         sgt_len = idx * 4;