From: Bernd Schubert Date: Fri, 11 May 2012 14:36:44 +0000 (+0200) Subject: bio allocation failure due to bio_get_nr_vecs() X-Git-Tag: v3.2.19~108 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=6609c1cd5ca261eadaddaca83d71977a8dfb4032;p=karo-tx-linux.git bio allocation failure due to bio_get_nr_vecs() commit f908ee9463b09ddd05e1c1a0111132212dc05fac upstream. 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 Signed-off-by: Jens Axboe Signed-off-by: Ben Hutchings --- diff --git a/fs/bio.c b/fs/bio.c index b980ecde026a..4fc4dbb079a9 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);