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Subject[tip:x86/asm] x86/uaccess: Add unlikely() to __chk_range_not_ok() failure paths
Commit-ID:  7e0f51cb445be8d3aee80e433ed8da4a33ad0157
Gitweb: http://git.kernel.org/tip/7e0f51cb445be8d3aee80e433ed8da4a33ad0157
Author: Andy Lutomirski <luto@kernel.org>
AuthorDate: Mon, 5 Oct 2015 17:47:50 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 7 Oct 2015 11:34:06 +0200

x86/uaccess: Add unlikely() to __chk_range_not_ok() failure paths

This should improve code quality a bit. It also shrinks the kernel text:

Before:
text data bss dec filename
21828379 5194760 1277952 28301091 vmlinux

After:
text data bss dec filename
21827997 5194760 1277952 28300709 vmlinux

... by 382 bytes.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/f427b8002d932e5deab9055e0074bb4e7e80ee39.1444091584.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/uaccess.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 3e911c6..09b1b0a 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -51,13 +51,13 @@ static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, un
* limit, not add it to the address).
*/
if (__builtin_constant_p(size))
- return addr > limit - size;
+ return unlikely(addr > limit - size);

/* Arbitrary sizes? Be careful about overflow */
addr += size;
- if (addr < size)
+ if (unlikely(addr < size))
return true;
- return addr > limit;
+ return unlikely(addr > limit);
}

#define __range_not_ok(addr, size, limit) \

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