From f908ee9463b09ddd05e1c1a0111132212dc05fac Mon Sep 17 00:00:00 2001 From: Bernd Schubert Date: Fri, 11 May 2012 16:36:44 +0200 Subject: [PATCH] bio allocation failure due to bio_get_nr_vecs() The number of bio_get_nr_vecs() is passed down via bio_alloc() to bvec_alloc_bs(), which fails the bio allocation if nr_iovecs > BIO_MAX_PAGES. For the underlying caller this causes an unexpected bio allocation failure. Limiting to queue_max_segments() is not sufficient, as max_segments also might be very large. bvec_alloc_bs(gfp_mask, nr_iovecs, ) => NULL when nr_iovecs > BIO_MAX_PAGES bio_alloc_bioset(gfp_mask, nr_iovecs, ...) bio_alloc(GFP_NOIO, nvecs) xfs_alloc_ioend_bio() Signed-off-by: Bernd Schubert Cc: stable@kernel.org Signed-off-by: Jens Axboe --- fs/bio.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/bio.c b/fs/bio.c index e453924036e9..84da88539046 100644 --- a/fs/bio.c +++ b/fs/bio.c @@ -505,9 +505,14 @@ EXPORT_SYMBOL(bio_clone); int bio_get_nr_vecs(struct block_device *bdev) { struct request_queue *q = bdev_get_queue(bdev); - return min_t(unsigned, + int nr_pages; + + nr_pages = min_t(unsigned, queue_max_segments(q), queue_max_sectors(q) / (PAGE_SIZE >> 9) + 1); + + return min_t(unsigned, nr_pages, BIO_MAX_PAGES); + } EXPORT_SYMBOL(bio_get_nr_vecs); -- 2.39.5