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authorEric Dumazet <dada1@cosmosbay.com>2007-05-02 19:27:11 +0200
committerAndi Kleen <andi@basil.nowhere.org>2007-05-02 19:27:11 +0200
commit272a3713bb9e302e0455c894c41180a482d2c8a3 (patch)
tree2dad036c75c0523db5f5f0f9618f4f3b9f21e28c
parentbd8559c38ee5be40ce2c57a80fd3c3e978cca267 (diff)
[PATCH] x86-64: fix vtime() vsyscall
There is a tiny probability that the return value from vtime(time_t *t) is Signed-off-by: Andi Kleen <ak@suse.de> different than the value stored in *t Using a temporary variable solves the problem and gives a faster code. 17: 48 85 ff test %rdi,%rdi 1a: 48 8b 05 00 00 00 00 mov 0(%rip),%rax # __vsyscall_gtod_data.wall_time_tv.tv_sec 21: 74 03 je 26 23: 48 89 07 mov %rax,(%rdi) 26: c9 leaveq 27: c3 retq Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
-rw-r--r--arch/x86_64/kernel/vsyscall.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/x86_64/kernel/vsyscall.c b/arch/x86_64/kernel/vsyscall.c
index d14cbb3e0eb..ba330f87067 100644
--- a/arch/x86_64/kernel/vsyscall.c
+++ b/arch/x86_64/kernel/vsyscall.c
@@ -156,11 +156,13 @@ int __vsyscall(0) vgettimeofday(struct timeval * tv, struct timezone * tz)
* unlikely */
time_t __vsyscall(1) vtime(time_t *t)
{
+ time_t result;
if (unlikely(!__vsyscall_gtod_data.sysctl_enabled))
return time_syscall(t);
- else if (t)
- *t = __vsyscall_gtod_data.wall_time_tv.tv_sec;
- return __vsyscall_gtod_data.wall_time_tv.tv_sec;
+ result = __vsyscall_gtod_data.wall_time_tv.tv_sec;
+ if (t)
+ *t = result;
+ return result;
}
/* Fast way to get current CPU and node.