From 7ecb344ae80bc03397ded3b004e06ecfe32becf9 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Mon, 7 Dec 2009 12:51:44 +0100 Subject: [PATCH] [S390] Improve notify_page_fault implementation. notify_page_fault does a preempt_disable/preempt_enable for each fault generated by a kernel access to user space. If kprobes is not active that is unnecessary since the interrupts are not reenabled yet. To play safe repeat the kprobe_running check after preempt_disable(). Signed-off-by: Martin Schwidefsky --- arch/s390/mm/fault.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index 77108e34fc1a..fd72c269cdb4 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -52,11 +52,11 @@ extern int sysctl_userprocess_debug; #endif -#ifdef CONFIG_KPROBES -static inline int notify_page_fault(struct pt_regs *regs, long err) +static inline int notify_page_fault(struct pt_regs *regs) { int ret = 0; +#ifdef CONFIG_KPROBES /* kprobe_running() needs smp_processor_id() */ if (!user_mode(regs)) { preempt_disable(); @@ -64,15 +64,9 @@ static inline int notify_page_fault(struct pt_regs *regs, long err) ret = 1; preempt_enable(); } - +#endif return ret; } -#else -static inline int notify_page_fault(struct pt_regs *regs, long err) -{ - return 0; -} -#endif /* @@ -274,7 +268,7 @@ do_exception(struct pt_regs *regs, unsigned long error_code, int write, int si_code; int fault; - if (notify_page_fault(regs, error_code)) + if (notify_page_fault(regs)) return; tsk = current;