mirrors/linux
2
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-05-09 19:51:25 -04:00
Code Issues Packages Projects Releases Wiki Activity

btrfs: send: drop unnecessary backref context field initializations

Browse Source 
At find_extent_clone() we are initializing to zero the 'found_itself' and
'found' fields of the backref context before we use it but we have already
initialized the structure to zeroes when we declared it on stack, so it's
pointless to initialize those fields and they are unnecessarily increasing
the object text size with two "mov" instructions (x86_64).

Similarly make the 'extent_len' initialization more clear by using an if-
-then-else instead of a double assignment to it in case the extent's end
crosses the i_size boundary.

Before this change:

   $ size fs/btrfs/send.o
      text	   data	    bss	    dec	    hex	filename
     68694	   4252	     16	  72962	  11d02	fs/btrfs/send.o

After this change:

   $ size fs/btrfs/send.o
      text	   data	    bss	    dec	    hex	filename
     68678	   4252	     16	  72946	  11cf2	fs/btrfs/send.o

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Filipe Manana
2022-11-01 16:15:43 +00:00
committed by David Sterba
parent d3f41317f0
commit 344174a1a6
1 changed files with 2 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
fs/btrfs/send.c
View File

@@ -1432,11 +1432,8 @@ static int find_extent_clone(struct send_ctx *sctx,
}
backref_ctx.sctx = sctx;
backref_ctx.found = 0;
backref_ctx.cur_objectid = ino;
backref_ctx.cur_offset = data_offset;
backref_ctx.found_itself = 0;
backref_ctx.extent_len = num_bytes;
/*
* The last extent of a file may be too large due to page alignment.
@@ -1445,6 +1442,8 @@ static int find_extent_clone(struct send_ctx *sctx,
*/
if (data_offset + num_bytes >= ino_size)
backref_ctx.extent_len = ino_size - data_offset;
else
backref_ctx.extent_len = num_bytes;
/*
* Now collect all backrefs.