more bio_map_user_iov() leak fixes

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>

1 files changed, 9 insertions, 5 deletions

diff --git a/block/bio.c b/block/bio.c
index 0d6439e89acb..9e9606d26cc6 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1331,6 +1331,7 @@ 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;
@@ -1375,7 +1376,12 @@ 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;
                 }
@@ -1431,10 +1437,8 @@ 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;
-                put_page(pages[j]);
+        bio_for_each_segment_all(bvec, bio, j) {
+                put_page(bvec->bv_page);
         }
  out:
         kfree(pages);