From 14cb0dc6479dc5ebc63b3a459a5d89a2f1b39fed Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Mon, 18 Dec 2017 15:40:43 +0800 Subject: block: don't let passthrough IO go into .make_request_fn() Commit a8821f3f3("block: Improvements to bounce-buffer handling") tries to make sure that the bio to .make_request_fn won't exceed BIO_MAX_PAGES, but ignores that passthrough I/O can use blk_queue_bounce() too. Especially, passthrough IO may not be sector-aligned, and the check of 'sectors < bio_sectors(*bio_orig)' inside __blk_queue_bounce() may become true even though the max bvec number doesn't exceed BIO_MAX_PAGES, then cause the bio splitted, and the original passthrough bio is submited to generic_make_request(). This patch fixes this issue by checking if the bio is passthrough IO, and use bio_kmalloc() to allocate the cloned passthrough bio. Cc: NeilBrown Fixes: a8821f3f3("block: Improvements to bounce-buffer handling") Tested-by: Michele Ballabio Signed-off-by: Ming Lei Signed-off-by: Jens Axboe --- block/bounce.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'block/bounce.c') diff --git a/block/bounce.c b/block/bounce.c index fceb1a96480bf..1d05c422c932a 100644 --- a/block/bounce.c +++ b/block/bounce.c @@ -200,6 +200,7 @@ static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig, unsigned i = 0; bool bounce = false; int sectors = 0; + bool passthrough = bio_is_passthrough(*bio_orig); bio_for_each_segment(from, *bio_orig, iter) { if (i++ < BIO_MAX_PAGES) @@ -210,13 +211,14 @@ static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig, if (!bounce) return; - if (sectors < bio_sectors(*bio_orig)) { + if (!passthrough && sectors < bio_sectors(*bio_orig)) { bio = bio_split(*bio_orig, sectors, GFP_NOIO, bounce_bio_split); bio_chain(bio, *bio_orig); generic_make_request(*bio_orig); *bio_orig = bio; } - bio = bio_clone_bioset(*bio_orig, GFP_NOIO, bounce_bio_set); + bio = bio_clone_bioset(*bio_orig, GFP_NOIO, passthrough ? NULL : + bounce_bio_set); bio_for_each_segment_all(to, bio, i) { struct page *page = to->bv_page; -- cgit v1.2.3