refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@xxxxxxxxx>
Signed-off-by: Hans Liljestrand <ishkamiel@xxxxxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: David Windsor <dwindsor@xxxxxxxxx>
---
fs/btrfs/compression.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index c7721a6..10e6b28 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -44,7 +44,7 @@
struct compressed_bio {
/* number of bios pending for this compressed extent */
- atomic_t pending_bios;
+ refcount_t pending_bios;
/* the pages with the compressed data on them */
struct page **compressed_pages;
@@ -161,7 +161,7 @@ static void end_compressed_bio_read(struct bio *bio)
/* if there are more bios still pending for this compressed
* extent, just exit
*/
- if (!atomic_dec_and_test(&cb->pending_bios))
+ if (!refcount_dec_and_test(&cb->pending_bios))
goto out;
inode = cb->inode;
@@ -274,7 +274,7 @@ static void end_compressed_bio_write(struct bio *bio)
/* if there are more bios still pending for this compressed
* extent, just exit
*/
- if (!atomic_dec_and_test(&cb->pending_bios))
+ if (!refcount_dec_and_test(&cb->pending_bios))
goto out;
/* ok, we're the last bio for this extent, step one is to
@@ -342,7 +342,7 @@ int btrfs_submit_compressed_write(struct inode *inode, u64 start,
cb = kmalloc(compressed_bio_size(fs_info, compressed_len), GFP_NOFS);
if (!cb)
return -ENOMEM;
- atomic_set(&cb->pending_bios, 0);
+ refcount_set(&cb->pending_bios, 0);
cb->errors = 0;
cb->inode = inode;
cb->start = start;
@@ -363,7 +363,7 @@ int btrfs_submit_compressed_write(struct inode *inode, u64 start,
bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
bio->bi_private = cb;
bio->bi_end_io = end_compressed_bio_write;
- atomic_inc(&cb->pending_bios);
+ refcount_set(&cb->pending_bios, 1);
/* create and submit bios for the compressed pages */
bytes_left = compressed_len;
@@ -388,7 +388,7 @@ int btrfs_submit_compressed_write(struct inode *inode, u64 start,
* we inc the count. Otherwise, the cb might get
* freed before we're done setting it up
*/
- atomic_inc(&cb->pending_bios);
+ refcount_inc(&cb->pending_bios);
ret = btrfs_bio_wq_end_io(fs_info, bio,
BTRFS_WQ_ENDIO_DATA);
BUG_ON(ret); /* -ENOMEM */
@@ -607,7 +607,7 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
if (!cb)
goto out;
- atomic_set(&cb->pending_bios, 0);
+ refcount_set(&cb->pending_bios, 0);
cb->errors = 0;
cb->inode = inode;
cb->mirror_num = mirror_num;
@@ -656,7 +656,7 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
bio_set_op_attrs (comp_bio, REQ_OP_READ, 0);
comp_bio->bi_private = cb;
comp_bio->bi_end_io = end_compressed_bio_read;
- atomic_inc(&cb->pending_bios);
+ refcount_set(&cb->pending_bios, 1);
for (pg_index = 0; pg_index < nr_pages; pg_index++) {
page = cb->compressed_pages[pg_index];
@@ -685,7 +685,7 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
* we inc the count. Otherwise, the cb might get
* freed before we're done setting it up
*/
- atomic_inc(&cb->pending_bios);
+ refcount_inc(&cb->pending_bios);
if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
ret = btrfs_lookup_bio_sums(inode, comp_bio,
--
2.7.4
