[PATCH 13/13] block: don't check for BIO_MAX_PAGES in blk_bio_segment_split()
From: NeilBrown <hidden>
Date: 2017-05-02 03:47:17
Also in:
lkml
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
blk_bio_segment_split() makes sure bios have no more than BIO_MAX_PAGES entries in the bi_io_vec. This was done because bio_clone_bioset() (when given a mempool bioset) could not handle larger io_vecs. No driver uses bio_clone_bioset() any more, they all use bio_clone_fast() if anything, and bio_clone_fast() doesn't clone the bi_io_vec. The main user of of bio_clone_bioset() at this level is bounce.c, and bouncing now happens before blk_bio_segment_split(), so that is not of concern. So remove the big helpful comment and the code. Signed-off-by: NeilBrown <redacted> --- block/blk-merge.c | 16 ---------------- 1 file changed, 16 deletions(-)
diff --git a/block/blk-merge.c b/block/blk-merge.c
index e7862e9dcc39..cea544ec5d96 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c@@ -108,25 +108,9 @@ 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 bvecs = 0; bio_for_each_segment(bv, bio, iter) { /* - * With arbitrary bio size, the incoming bio may be very - * big. We have to split the bio into small bios so that - * each holds at most BIO_MAX_PAGES bvecs because - * bio_clone_bioset() can fail to allocate big bvecs. - * - * Those drivers which will need to use bio_clone_bioset() - * should tell us in some way. For now, impose the - * BIO_MAX_PAGES limit on all queues. - * - * TODO: handle users of bio_clone_bioset() differently. - */ - if (bvecs++ >= BIO_MAX_PAGES) - goto split; - - /* * If the queue doesn't support SG gaps and adding this * offset would create a gap, disallow it. */