libata: convert to using sg helpers

This converts libata to using the sg helpers for looking up sg
elements, instead of doing it manually.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 10 insertions, 6 deletions

diff --git a/include/linux/libata.h b/include/linux/libata.h
index 229a9ff9f924..377e6d4d9be3 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -29,7 +29,7 @@
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/dma-mapping.h>
-#include <asm/scatterlist.h>
+#include <linux/scatterlist.h>
 #include <linux/io.h>
 #include <linux/ata.h>
 #include <linux/workqueue.h>
@@ -416,6 +416,7 @@ struct ata_queued_cmd {
         unsigned long           flags;          /* ATA_QCFLAG_xxx */
         unsigned int            tag;
         unsigned int            n_elem;
+        unsigned int            n_iter;
         unsigned int            orig_n_elem;
 
         int                     dma_dir;
@@ -426,7 +427,7 @@ struct ata_queued_cmd {
         unsigned int            nbytes;
         unsigned int            curbytes;
 
-        unsigned int            cursg;
+        struct scatterlist      *cursg;
         unsigned int            cursg_ofs;
 
         struct scatterlist      sgent;
@@ -1043,7 +1044,7 @@ ata_sg_is_last(struct scatterlist *sg, struct ata_queued_cmd *qc)
                 return 1;
         if (qc->pad_len)
                 return 0;
-        if (((sg - qc->__sg) + 1) == qc->n_elem)
+        if (qc->n_iter == qc->n_elem)
                 return 1;
         return 0;
 }
@@ -1051,6 +1052,7 @@ ata_sg_is_last(struct scatterlist *sg, struct ata_queued_cmd *qc)
 static inline struct scatterlist *
 ata_qc_first_sg(struct ata_queued_cmd *qc)
 {
+        qc->n_iter = 0;
         if (qc->n_elem)
                 return qc->__sg;
         if (qc->pad_len)
@@ -1063,8 +1065,8 @@ ata_qc_next_sg(struct scatterlist *sg, struct ata_queued_cmd *qc)
 {
         if (sg == &qc->pad_sgent)
                 return NULL;
-        if (++sg - qc->__sg < qc->n_elem)
-                return sg;
+        if (++qc->n_iter < qc->n_elem)
+                return sg_next(sg);
         if (qc->pad_len)
                 return &qc->pad_sgent;
         return NULL;
@@ -1309,9 +1311,11 @@ static inline void ata_qc_reinit(struct ata_queued_cmd *qc)
         qc->dma_dir = DMA_NONE;
         qc->__sg = NULL;
         qc->flags = 0;
-        qc->cursg = qc->cursg_ofs = 0;
+        qc->cursg = NULL;
+        qc->cursg_ofs = 0;
         qc->nbytes = qc->curbytes = 0;
         qc->n_elem = 0;
+        qc->n_iter = 0;
         qc->err_mask = 0;
         qc->pad_len = 0;
         qc->sect_size = ATA_SECT_SIZE;