[PATCH 5/13] scsi: convert to using sg helpers

Jens Axboe
2007-05-10T10:24:24Z

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>
---
drivers/scsi/scsi_lib.c | 20 +++++++++++---------
1 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 1f5a07b..f944690 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -302,14 +302,15 @@ 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 = 0, 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) {
@@ -2240,18 +2241,19 @@ 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;
}
@@ -2265,10 +2267,10 @@ 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 */
--
1.5.2.rc1