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authorJens Axboe <jens.axboe@oracle.com>2007-10-17 21:34:11 +0400
committerJens Axboe <jens.axboe@oracle.com>2007-10-17 21:34:11 +0400
commitba951841ceb7fa5b06ad48caa5270cc2ae17941e (patch)
treefda194f4506fb2af93895d3aac1902051678e8e0
parenta3bec5c5aea0da263111c4d8f8eabc1f8560d7bf (diff)
downloadlinux-ba951841ceb7fa5b06ad48caa5270cc2ae17941e.tar.xz
[BLOCK] blk_rq_map_sg() next_sg fixup
Don't ever use sg_next() on the last entry, it may not be valid! Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
-rw-r--r--block/ll_rw_blk.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 9e3f3cc85d0d..3935469e3662 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -1322,8 +1322,8 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq,
struct scatterlist *sglist)
{
struct bio_vec *bvec, *bvprv;
- struct scatterlist *next_sg, *sg;
struct req_iterator iter;
+ struct scatterlist *sg;
int nsegs, cluster;
nsegs = 0;
@@ -1333,7 +1333,7 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq,
* for each bio in rq
*/
bvprv = NULL;
- sg = next_sg = &sglist[0];
+ sg = NULL;
rq_for_each_segment(bvec, rq, iter) {
int nbytes = bvec->bv_len;
@@ -1349,8 +1349,10 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq,
sg->length += nbytes;
} else {
new_segment:
- sg = next_sg;
- next_sg = sg_next(sg);
+ if (!sg)
+ sg = sglist;
+ else
+ sg = sg_next(sg);
memset(sg, 0, sizeof(*sg));
sg->page = bvec->bv_page;