btrfs: drop redundant bflags initialization when allocating extent buffer

When allocating an extent buffer, at __alloc_extent_buffer(), there's no
point in explicitly assigning zero to the bflags field of the new extent
buffer because we allocated it with kmem_cache_zalloc().

So just remove the redundant initialization, it saves one mov instruction
in the generated assembly code for x86_64 ("movq $0x0,0x10(%rax)").

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 56a9f59..3192f09 100644 (file)
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4266,7 +4266,6 @@ __alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
        eb->start = start;
        eb->len = len;
        eb->fs_info = fs_info;
-       eb->bflags = 0;
        init_rwsem(&eb->lock);
 
        btrfs_leak_debug_add_eb(eb);