libata: add ata_sg_is_last() helper, use it in several drivers

diff --git a/drivers/scsi/pdc_adma.c b/drivers/scsi/pdc_adma.c
index 53b8db4be1a9e3700218741c9b899e4722951081..c6825da6ae20a875832031b2bbc96cc60131118d 100644 (file)
--- a/drivers/scsi/pdc_adma.c
+++ b/drivers/scsi/pdc_adma.c
@@ -293,14 +293,14 @@ static void adma_eng_timeout(struct ata_port *ap)
 
 static int adma_fill_sg(struct ata_queued_cmd *qc)
 {
-       struct scatterlist *sg = qc->sg;
+       struct scatterlist *sg;
        struct ata_port *ap = qc->ap;
        struct adma_port_priv *pp = ap->private_data;
        u8  *buf = pp->pkt;
-       int nelem, i = (2 + buf[3]) * 8;
+       int i = (2 + buf[3]) * 8;
        u8 pFLAGS = pORD | ((qc->tf.flags & ATA_TFLAG_WRITE) ? pDIRO : 0);
 
-       for (nelem = 0; nelem < qc->n_elem; nelem++,sg++) {
+       ata_for_each_sg(sg, qc) {
                u32 addr;
                u32 len;
 
@@ -312,7 +312,7 @@ static int adma_fill_sg(struct ata_queued_cmd *qc)
                *(__le32 *)(buf + i) = cpu_to_le32(len);
                i += 4;
 
-               if ((nelem + 1) == qc->n_elem)
+               if (ata_sg_is_last(sg, qc))
                        pFLAGS |= pEND;
                buf[i++] = pFLAGS;
                buf[i++] = qc->dev->dma_mode & 0xf;

diff --git a/drivers/scsi/sata_mv.c b/drivers/scsi/sata_mv.c
index d457f5673476890732aa3f7d39adadf832dcc6f0..be7c378dcd365ae6162b6e119e002051e475ad4d 100644 (file)
--- a/drivers/scsi/sata_mv.c
+++ b/drivers/scsi/sata_mv.c
@@ -785,22 +785,24 @@ static void mv_port_stop(struct ata_port *ap)
 static void mv_fill_sg(struct ata_queued_cmd *qc)
 {
        struct mv_port_priv *pp = qc->ap->private_data;
-       unsigned int i;
+       unsigned int i = 0;
+       struct scatterlist *sg;
 
-       for (i = 0; i < qc->n_elem; i++) {
+       ata_for_each_sg(sg, qc) {
                u32 sg_len;
                dma_addr_t addr;
 
-               addr = sg_dma_address(&qc->sg[i]);
-               sg_len = sg_dma_len(&qc->sg[i]);
+               addr = sg_dma_address(sg);
+               sg_len = sg_dma_len(sg);
 
                pp->sg_tbl[i].addr = cpu_to_le32(addr & 0xffffffff);
                pp->sg_tbl[i].addr_hi = cpu_to_le32((addr >> 16) >> 16);
                assert(0 == (sg_len & ~MV_DMA_BOUNDARY));
                pp->sg_tbl[i].flags_size = cpu_to_le32(sg_len);
-       }
-       if (0 < qc->n_elem) {
-               pp->sg_tbl[qc->n_elem - 1].flags_size |= EPRD_FLAG_END_OF_TBL;
+               if (ata_sg_is_last(sg, qc))
+                       pp->sg_tbl[i].flags_size |= cpu_to_le32(EPRD_FLAG_END_OF_TBL);
+
+               i++;
        }
 }
 

diff --git a/drivers/scsi/sata_sil24.c b/drivers/scsi/sata_sil24.c
index 19857814d69fbe25874b19565b58115896cc4128..e16d1815cda0ebf253f312dbbd68dc7db6699567 100644 (file)
--- a/drivers/scsi/sata_sil24.c
+++ b/drivers/scsi/sata_sil24.c
@@ -416,15 +416,20 @@ static void sil24_phy_reset(struct ata_port *ap)
 static inline void sil24_fill_sg(struct ata_queued_cmd *qc,
                                 struct sil24_cmd_block *cb)
 {
-       struct scatterlist *sg = qc->sg;
        struct sil24_sge *sge = cb->sge;
-       unsigned i;
+       struct scatterlist *sg;
+       unsigned int idx = 0;
 
-       for (i = 0; i < qc->n_elem; i++, sg++, sge++) {
+       ata_for_each_sg(sg, qc) {
                sge->addr = cpu_to_le64(sg_dma_address(sg));
                sge->cnt = cpu_to_le32(sg_dma_len(sg));
-               sge->flags = 0;
-               sge->flags = i < qc->n_elem - 1 ? 0 : cpu_to_le32(SGE_TRM);
+               if (ata_sg_is_last(sg, qc))
+                       sge->flags = cpu_to_le32(SGE_TRM);
+               else
+                       sge->flags = 0;
+
+               sge++;
+               idx++;
        }
 }
 

diff --git a/include/linux/libata.h b/include/linux/libata.h
index d3f58a796c3a371f1497af11c581e541e7862908..d3dfefefabece15cb9ffded87297966da842b943 100644 (file)
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -480,6 +480,18 @@ extern int pci_test_config_bits(struct pci_dev *pdev, struct pci_bits *bits);
 #endif /* CONFIG_PCI */
 
 
+static inline int
+ata_sg_is_last(struct scatterlist *sg, struct ata_queued_cmd *qc)
+{
+       if (sg == &qc->pad_sgent)
+               return 1;
+       if (qc->pad_len)
+               return 0;
+       if (((sg - qc->__sg) + 1) == qc->n_elem)
+               return 1;
+       return 0;
+}
+
 static inline struct scatterlist *
 ata_qc_next_sg(struct scatterlist *sg, struct ata_queued_cmd *qc)
 {