| Message ID | 1520970622-19535-1-git-send-email-s.mesoraca16@gmail.com (mailing list archive) |
|---|---|
| State | Rejected |
| Headers | show |
On Tue, Mar 13, 2018 at 08:50:22PM +0100, Salvatore Mesoraca wrote: > 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.mesoraca16@gmail.com> We already have a patch for that from a few days ago, but thanks anyway. https://patchwork.kernel.org/patch/10277901/
2018-03-14 16:42 GMT+01:00 David Sterba <dsterba@suse.cz>: > We already have a patch for that from a few days ago, but thanks anyway. > > https://patchwork.kernel.org/patch/10277901/ Oh.. OK Best regards, Salvatore
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; }
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.mesoraca16@gmail.com> --- fs/btrfs/disk-io.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)