diff mbox series

[v2,07/19] btrfs: drop pointless memset when cloning extent buffer

Message ID 624ea4cace0e7dc7ec9fd3983159121a8311d8fc.1665490018.git.fdmanana@suse.com (mailing list archive)
State New, archived
Headers show
Series btrfs: fixes, cleanups and optimizations around fiemap | expand

Commit Message

Filipe Manana Oct. 11, 2022, 12:16 p.m. UTC 
From: Filipe Manana <fdmanana@suse.com>

At btrfs_clone_extent_buffer(), before allocating the pages array for the
new extent buffer we are calling memset() to zero out the pages array of
the extent buffer. This is pointless however, because the extent buffer
already has every element in its pages array pointing to NULL, as it was
allocated with kmem_cache_zalloc(). The memset() was introduced with
commit dd137dd1f2d719 ("btrfs: factor out allocating an array of pages"),
but even before that commit we already depended on the pages array being
initialized to NULL for the error paths that need to call
btrfs_release_extent_buffer().

So remove the memset(), it's useless and slightly increases the object
text size.

Before this change:

   $ size fs/btrfs/extent_io.o
      text	   data	    bss	    dec	    hex	filename
     70580	   5469	     40	  76089	  12939	fs/btrfs/extent_io.o

After this change:

   $ size fs/btrfs/extent_io.o
      text	   data	    bss	    dec	    hex	filename
     70564	   5469	     40	  76073	  12929	fs/btrfs/extent_io.o

Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
 fs/btrfs/extent_io.c | 1 -
 1 file changed, 1 deletion(-)
diff mbox series

Patch

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 1eae68fbae21..c9a9f784d21c 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4302,7 +4302,6 @@  struct extent_buffer *btrfs_clone_extent_buffer(const struct extent_buffer *src)
 	 */
 	set_bit(EXTENT_BUFFER_UNMAPPED, &new->bflags);
 
-	memset(new->pages, 0, sizeof(*new->pages) * num_pages);
 	ret = btrfs_alloc_page_array(num_pages, new->pages);
 	if (ret) {
 		btrfs_release_extent_buffer(new);