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authorThomas Gleixner <tglx@linutronix.de>2012-02-28 19:46:04 +0000
committerJohn Stultz <john.stultz@linaro.org>2012-03-15 18:17:58 -0700
commit2ab516575f2f273b19d95140d02c54612201e80a (patch)
tree26db92249e65754d99759af21fd207507a81cec8 /arch/x86/kernel/vsyscall_64.c
parent6c260d586343f7f78239d90aa9e2cfed02f74ff3 (diff)
x86: vdso: Use seqcount instead of seqlock
The update of the vdso data happens under xtime_lock, so adding a nested lock is pointless. Just use a seqcount to sync the readers. Reviewed-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
Diffstat (limited to 'arch/x86/kernel/vsyscall_64.c')
-rw-r--r--arch/x86/kernel/vsyscall_64.c11
1 files changed, 3 insertions, 8 deletions
diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c
index 33385c18e5d3..cdc95a707cd1 100644
--- a/arch/x86/kernel/vsyscall_64.c
+++ b/arch/x86/kernel/vsyscall_64.c
@@ -52,10 +52,7 @@
#include "vsyscall_trace.h"
DEFINE_VVAR(int, vgetcpu_mode);
-DEFINE_VVAR(struct vsyscall_gtod_data, vsyscall_gtod_data) =
-{
- .lock = __SEQLOCK_UNLOCKED(__vsyscall_gtod_data.lock),
-};
+DEFINE_VVAR(struct vsyscall_gtod_data, vsyscall_gtod_data);
static enum { EMULATE, NATIVE, NONE } vsyscall_mode = EMULATE;
@@ -86,9 +83,7 @@ void update_vsyscall_tz(void)
void update_vsyscall(struct timespec *wall_time, struct timespec *wtm,
struct clocksource *clock, u32 mult)
{
- unsigned long flags;
-
- write_seqlock_irqsave(&vsyscall_gtod_data.lock, flags);
+ write_seqcount_begin(&vsyscall_gtod_data.seq);
/* copy vsyscall data */
vsyscall_gtod_data.clock.vclock_mode = clock->archdata.vclock_mode;
@@ -101,7 +96,7 @@ void update_vsyscall(struct timespec *wall_time, struct timespec *wtm,
vsyscall_gtod_data.wall_to_monotonic = *wtm;
vsyscall_gtod_data.wall_time_coarse = __current_kernel_time();
- write_sequnlock_irqrestore(&vsyscall_gtod_data.lock, flags);
+ write_seqcount_end(&vsyscall_gtod_data.seq);
}
static void warn_bad_vsyscall(const char *level, struct pt_regs *regs,