diff options
| author | Gustavo A. R. Silva | 2020-03-06 10:49:12 -0600 |
|---|---|---|
| committer | David Sterba | 2020-03-23 17:01:53 +0100 |
| commit | 17b238acf7c665e5c1eb44a31be10299fcbf8858 (patch) | |
| tree | 9c71866e46d30bdb7c53c83a53c6e6bab7ab247b /fs | |
| parent | 29566c9c773456467933ee22bbca1c2b72a3506c (diff) | |
btrfs: delayed-inode: Replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array
member[1][2], introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by this
change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero." [1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/delayed-inode.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/btrfs/delayed-inode.h b/fs/btrfs/delayed-inode.h index 74ae226ffaf0..ca96ef007d8f 100644 --- a/fs/btrfs/delayed-inode.h +++ b/fs/btrfs/delayed-inode.h @@ -70,7 +70,7 @@ struct btrfs_delayed_item { refcount_t refs; int ins_or_del; u32 data_len; - char data[0]; + char data[]; }; static inline void btrfs_init_delayed_root( |