linux-kernel - [tip:x86/asm] x86/uaccess: Add unlikely() to __chk_range_not

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Date:	Wed, 7 Oct 2015 09:16:14 -0700
From:	tip-bot for Andy Lutomirski <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	bp@...en8.de, luto@...capital.net, peterz@...radead.org,
	linux-kernel@...r.kernel.org, tglx@...utronix.de, mingo@...nel.org,
	torvalds@...ux-foundation.org, luto@...nel.org, hpa@...or.com,
	brgerst@...il.com, dvlasenk@...hat.com
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@...nel.org>
AuthorDate: Mon, 5 Oct 2015 17:47:50 -0700
Committer:  Ingo Molnar <mingo@...nel.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@...nel.org>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: linux-kernel@...r.kernel.org
Link: http://lkml.kernel.org/r/f427b8002d932e5deab9055e0074bb4e7e80ee39.1444091584.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@...nel.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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