more bio_map_user_iov() leak fixes

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.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[bwh: Backported to 3.2: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/fs/bio.c b/fs/bio.c
index 1fa6b825240d89f180e4f0958bb1058b2a1c296b..081747c89b6274cace9bc6f34586b4ffa834969d 100644 (file)
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -976,6 +976,7 @@ static struct bio *__bio_map_user_iov(struct request_queue *q,
        struct bio *bio;
        int cur_page = 0;
        int ret, offset;
+       struct bio_vec *bvec;
 
        for (i = 0; i < iov_count; i++) {
                unsigned long uaddr = (unsigned long)iov[i].iov_base;
@@ -1019,7 +1020,12 @@ static struct bio *__bio_map_user_iov(struct request_queue *q,
 
                ret = get_user_pages_fast(uaddr, local_nr_pages,
                                write_to_vm, &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;
                }
@@ -1074,10 +1080,8 @@ static struct bio *__bio_map_user_iov(struct request_queue *q,
        return bio;
 
  out_unmap:
-       for (i = 0; i < nr_pages; i++) {
-               if(!pages[i])
-                       break;
-               page_cache_release(pages[i]);
+       bio_for_each_segment_all(bvec, bio, j) {
+               put_page(bvec->bv_page);
        }
  out:
        kfree(pages);