Avoid a VLA[1] by using a real constant expression instead of a variable. The compiler should be able to optimize the original code and avoid using an actual VLA. Anyway this change is useful because it will avoid a false positive with -Wvla, it might also help the compiler generating better code.
[1] https://lkml.org/lkml/2018/3/7/621 Signed-off-by: Salvatore Mesoraca <s.mesorac...@gmail.com> --- fs/btrfs/disk-io.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 21f34ad..88cef92 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -403,8 +403,7 @@ static int btrfs_check_super_csum(struct btrfs_fs_info *fs_info, if (csum_type == BTRFS_CSUM_TYPE_CRC32) { u32 crc = ~(u32)0; - const int csum_size = sizeof(crc); - char result[csum_size]; + char result[sizeof(crc)]; /* * The super_block structure does not span the whole @@ -415,7 +414,7 @@ static int btrfs_check_super_csum(struct btrfs_fs_info *fs_info, crc, BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE); btrfs_csum_final(crc, result); - if (memcmp(raw_disk_sb, result, csum_size)) + if (memcmp(raw_disk_sb, result, sizeof(result))) ret = 1; } -- 1.9.1
