block: convert to using sg helpers
Convert the main rq mapper (blk_rq_map_sg()) to the sg helper setup.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 4df7d02..36d2051 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -30,6 +30,7 @@
#include <linux/cpu.h>
#include <linux/blktrace_api.h>
#include <linux/fault-inject.h>
+#include <linux/scatterlist.h>
/*
* for max sense size
@@ -1318,9 +1319,10 @@
* must make sure sg can hold rq->nr_phys_segments entries
*/
int blk_rq_map_sg(struct request_queue *q, struct request *rq,
- struct scatterlist *sg)
+ struct scatterlist *sglist)
{
struct bio_vec *bvec, *bvprv;
+ struct scatterlist *next_sg, *sg;
struct req_iterator iter;
int nsegs, cluster;
@@ -1331,11 +1333,12 @@
* for each bio in rq
*/
bvprv = NULL;
+ sg = next_sg = &sglist[0];
rq_for_each_segment(bvec, rq, iter) {
int nbytes = bvec->bv_len;
if (bvprv && cluster) {
- if (sg[nsegs - 1].length + nbytes > q->max_segment_size)
+ if (sg->length + nbytes > q->max_segment_size)
goto new_segment;
if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec))
@@ -1343,14 +1346,15 @@
if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bvec))
goto new_segment;
- sg[nsegs - 1].length += nbytes;
+ sg->length += nbytes;
} else {
new_segment:
- memset(&sg[nsegs],0,sizeof(struct scatterlist));
- sg[nsegs].page = bvec->bv_page;
- sg[nsegs].length = nbytes;
- sg[nsegs].offset = bvec->bv_offset;
+ sg = next_sg;
+ next_sg = sg_next(sg);
+ sg->page = bvec->bv_page;
+ sg->length = nbytes;
+ sg->offset = bvec->bv_offset;
nsegs++;
}
bvprv = bvec;