@@ -109,7 +109,6 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
bool do_split = true;
struct bio *new = NULL;
const unsigned max_sectors = get_max_io_size(q, bio);
- unsigned advance = 0;
bio_for_each_segment(bv, bio, iter) {
/*
@@ -133,32 +132,12 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
}
if (bvprvp && blk_queue_cluster(q)) {
+ if (seg_size + bv.bv_len > queue_max_segment_size(q))
+ goto new_segment;
if (!BIOVEC_PHYS_MERGEABLE(bvprvp, &bv))
goto new_segment;
if (!BIOVEC_SEG_BOUNDARY(q, bvprvp, &bv))
goto new_segment;
- if (seg_size + bv.bv_len > queue_max_segment_size(q)) {
- /*
- * One assumption is that initial value of
- * @seg_size(equals to bv.bv_len) won't be
- * bigger than max segment size, but this
- * becomes false after multipage bvecs.
- */
- advance = queue_max_segment_size(q) - seg_size;
-
- if (advance > 0) {
- seg_size += advance;
- sectors += advance >> 9;
- bv.bv_len -= advance;
- bv.bv_offset += advance;
- }
-
- /*
- * Still need to put remainder of current
- * bvec into a new segment.
- */
- goto new_segment;
- }
seg_size += bv.bv_len;
bvprv = bv;
@@ -180,12 +159,6 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
seg_size = bv.bv_len;
sectors += bv.bv_len >> 9;
- /* restore the bvec for iterator */
- if (advance) {
- bv.bv_len += advance;
- bv.bv_offset -= advance;
- advance = 0;
- }
}
do_split = false;
@@ -386,29 +359,16 @@ __blk_segment_map_sg(struct request_queue *q, struct bio_vec *bvec,
{
int nbytes = bvec->bv_len;
- unsigned advance = 0;
if (*sg && *cluster) {
+ if ((*sg)->length + nbytes > queue_max_segment_size(q))
+ goto new_segment;
+
if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec))
goto new_segment;
if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bvec))
goto new_segment;
- /*
- * try best to merge part of the bvec into previous
- * segment and follow same policy with
- * blk_bio_segment_split()
- */
- if ((*sg)->length + nbytes > queue_max_segment_size(q)) {
- advance = queue_max_segment_size(q) - (*sg)->length;
- if (advance) {
- (*sg)->length += advance;
- bvec->bv_offset += advance;
- bvec->bv_len -= advance;
- }
- goto new_segment;
- }
-
(*sg)->length += nbytes;
} else {
new_segment:
@@ -431,10 +391,6 @@ __blk_segment_map_sg(struct request_queue *q, struct bio_vec *bvec,
sg_set_page(*sg, bvec->bv_page, nbytes, bvec->bv_offset);
(*nsegs)++;
-
- /* for making iterator happy */
- bvec->bv_offset -= advance;
- bvec->bv_len += advance;
}
*bvprv = *bvec;
}
This reverts commit a2d37968d784363842f87820a21e106741d28004. If max segment size isn't 512-aligned, this patch won't work well. Also once multipage bvec is enabled, adjacent bvecs won't be physically contiguous if page is added via bio_add_page(), so we don't need this kind of complicated logic. Reported-by: Dmitry Osipenko <digetx@gmail.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> --- block/blk-merge.c | 54 +++++------------------------------------------------- 1 file changed, 5 insertions(+), 49 deletions(-)