lkml.org 
[lkml]   [2007]   [Dec]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH 1/3] arch/x86: Use offsetof
From: Julia Lawall <julia@diku.dk>

In the patch cc154ac64aa8d3396b187f64cef01ce67f433324, Al Viro observed
that the proper way to compute the distance between two structure fields is
to use offsetof() or a cast to a pointer to character. The same change can
be applied to a few more files.

The change was made using the following semantic patch
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@r@
type T;
T s;
type T1, T2;
identifier fld1, fld2;
typedef uint8_t;
typedef u8;
@@

(
(char *)&s.fld1 - (char *)&s.fld2
|
(uint8_t *)&s.fld1 - (uint8_t *)&s.fld2
|
(u8 *)&s.fld1 - (u8 *)&s.fld2
|
- (T1)&s.fld1 - (T2)&s.fld2
+ offsetof(T,fld1) - offsetof(T,fld2)
)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
---

diff -u -p a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
--- a/arch/x86/kernel/vm86_32.c 2007-10-22 11:25:00.000000000 +0200
+++ b/arch/x86/kernel/vm86_32.c 2007-12-26 16:27:15.000000000 +0100
@@ -215,7 +215,9 @@ asmlinkage int sys_vm86old(struct pt_reg
ret = -EFAULT;
if (tmp)
goto out;
- memset(&info.vm86plus, 0, (int)&info.regs32 - (int)&info.vm86plus);
+ memset(&info.vm86plus, 0,
+ offsetof(struct kernel_vm86_struct, regs32) -
+ offsetof(struct kernel_vm86_struct, vm86plus));
info.regs32 = &regs;
tsk->thread.vm86_info = v86;
do_sys_vm86(&info, tsk);

\
 
 \ /
  Last update: 2007-12-26 17:17    [W:0.060 / U:0.520 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site