| commit | f4cb1cc18f364d761d5614eb6293cccc6647f259 | |
| author | Fenghua Yu <fenghua.yu@intel.com> | |
| Sat, 16 Nov 2013 20:37:01 +0000 (16 12:37 -0800) | ||
| committer | H. Peter Anvin <hpa@linux.intel.com> | |
| Sun, 17 Nov 2013 02:00:58 +0000 (16 18:00 -0800) | ||
| tree | af6be6a073d887171d49401ba9dddaed9a537a99 | treesnapshot (tar.gz zip) |
| parent | 1213959d4ad2f523290d0d7c94f712edef63852c | commitdiff |
x86-64, copy_user: Remove zero byte check before copy user buffer.
Operation of rep movsb instruction handles zero byte copy. As pointed out by
Linus, there is no need to check zero size in kernel. Removing this redundant
check saves a few cycles in copy user functions.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1384634221-6006-1-git-send-email-fenghua.yu@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Operation of rep movsb instruction handles zero byte copy. As pointed out by
Linus, there is no need to check zero size in kernel. Removing this redundant
check saves a few cycles in copy user functions.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1384634221-6006-1-git-send-email-fenghua.yu@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| arch/x86/lib/copy_user_64.S | diffblobblamehistory |