From: Al Viro viro@zeniv.linux.org.uk

commit 2b04e8f6bbb196cab4b232af0f8d48ff2c7a8058 upstream.

we need to take care of failure exit as well - pages already in bio should be dropped by analogue of bio_unmap_pages(), since their refcounts had been bumped only once per reference in bio.

Cc: stable@vger.kernel.org Signed-off-by: Al Viro viro@zeniv.linux.org.uk Signed-off-by: Guenter Roeck linux@roeck-us.net --- Fixed conflicts. Intended for v4.4.y. Does not apply to v3.18.y or older kernels.

block/bio.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/block/bio.c b/block/bio.c index 68bbc835bacc..63363a689922 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1268,6 +1268,7 @@ struct bio *bio_map_user_iov(struct request_queue *q, int ret, offset; struct iov_iter i; struct iovec iov; + struct bio_vec *bvec;

iov_for_each(iov, i, *iter) { unsigned long uaddr = (unsigned long) iov.iov_base; @@ -1312,7 +1313,12 @@ struct bio *bio_map_user_iov(struct request_queue *q, ret = get_user_pages_fast(uaddr, local_nr_pages, (iter->type & WRITE) != WRITE, &pages[cur_page]); - if (ret < local_nr_pages) { + if (unlikely(ret < local_nr_pages)) { + for (j = cur_page; j < page_limit; j++) { + if (!pages[j]) + break; + put_page(pages[j]); + } ret = -EFAULT; goto out_unmap; } @@ -1374,10 +1380,8 @@ struct bio *bio_map_user_iov(struct request_queue *q, return bio;

out_unmap: - for (j = 0; j < nr_pages; j++) { - if (!pages[j]) - break; - page_cache_release(pages[j]); + bio_for_each_segment_all(bvec, bio, j) { + put_page(bvec->bv_page); } out: kfree(pages);