scsi: convert to using sg helpers

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

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

2 files changed, 15 insertions, 10 deletions

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 207f1aa08869..960f949b8f8f 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -17,6 +17,7 @@
 #include <linux/pci.h>
 #include <linux/delay.h>
 #include <linux/hardirq.h>
+#include <linux/scatterlist.h>
 
 #include <scsi/scsi.h>
 #include <scsi/scsi_cmnd.h>
@@ -289,14 +290,16 @@ static int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl,
         struct request_queue *q = rq->q;
         int nr_pages = (bufflen + sgl[0].offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
         unsigned int data_len = bufflen, len, bytes, off;
+        struct scatterlist *sg;
         struct page *page;
         struct bio *bio = NULL;
         int i, err, nr_vecs = 0;
 
-        for (i = 0; i < nsegs; i++) {
-                page = sgl[i].page;
-                off = sgl[i].offset;
-                len = sgl[i].length;
+        for_each_sg(sgl, sg, nsegs, i) {
+                page = sg->page;
+                off = sg->offset;
+                len = sg->length;
+                data_len += len;
 
                 while (len > 0 && data_len > 0) {
                         /*
@@ -2193,18 +2196,19 @@ EXPORT_SYMBOL_GPL(scsi_target_unblock);
  *
  * Returns virtual address of the start of the mapped page
  */
-void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count,
+void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
                           size_t *offset, size_t *len)
 {
         int i;
         size_t sg_len = 0, len_complete = 0;
+        struct scatterlist *sg;
         struct page *page;
 
         WARN_ON(!irqs_disabled());
 
-        for (i = 0; i < sg_count; i++) {
+        for_each_sg(sgl, sg, sg_count, i) {
                 len_complete = sg_len; /* Complete sg-entries */
-                sg_len += sg[i].length;
+                sg_len += sg->length;
                 if (sg_len > *offset)
                         break;
         }
@@ -2218,10 +2222,10 @@ void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count,
         }
 
         /* Offset starting from the beginning of first page in this sg-entry */
-        *offset = *offset - len_complete + sg[i].offset;
+        *offset = *offset - len_complete + sg->offset;
 
         /* Assumption: contiguous pages can be accessed as "page + i" */
-        page = nth_page(sg[i].page, (*offset >> PAGE_SHIFT));
+        page = nth_page(sg->page, (*offset >> PAGE_SHIFT));
         *offset &= ~PAGE_MASK;
 
         /* Bytes in this sg-entry from *offset to the end of the page */
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index 65ab5145a09b..3b0bb6680e62 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -5,6 +5,7 @@
 #include <linux/list.h>
 #include <linux/types.h>
 #include <linux/timer.h>
+#include <linux/scatterlist.h>
 
 struct request;
 struct scatterlist;
@@ -148,6 +149,6 @@ static inline int scsi_get_resid(struct scsi_cmnd *cmd)
 }
 
 #define scsi_for_each_sg(cmd, sg, nseg, __i)                    \
-        for (__i = 0, sg = scsi_sglist(cmd); __i < (nseg); __i++, (sg)++)
+        for_each_sg(scsi_sglist(cmd), sg, nseg, __i)
 
 #endif /* _SCSI_SCSI_CMND_H */