diff options
| author | Peter Zijlstra <[email protected]> | 2013-11-20 16:52:19 +0100 |
|---|---|---|
| committer | Ingo Molnar <[email protected]> | 2014-01-13 13:47:37 +0100 |
| commit | 62b94a08da1bae9d187d49dfcd6665af393750f8 (patch) | |
| tree | c3e66c87005da3aa35e367523ee869d5c3902e70 | |
| parent | 9ea4c380066fbe23fe0da7f4abfabc444f2467f4 (diff) | |
sched/preempt: Take away preempt_enable_no_resched() from modules
Discourage drivers/modules to be creative with preemption.
Sadly all is implemented in macros and inline so if they want to do
evil they still can, but at least try and discourage some.
Reviewed-by: Thomas Gleixner <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Cc: Eliezer Tamir <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Mike Galbraith <[email protected]>
Cc: [email protected]
Cc: Rusty Russell <[email protected]>
Cc: Arjan van de Ven <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Linus Torvalds <[email protected]>
Cc: Andrew Morton <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
| -rw-r--r-- | include/linux/preempt.h | 22 | ||||
| -rw-r--r-- | include/linux/uaccess.h | 5 |
2 files changed, 24 insertions, 3 deletions
diff --git a/include/linux/preempt.h b/include/linux/preempt.h index a3d9dc8c2c00..dd9ddf8af205 100644 --- a/include/linux/preempt.h +++ b/include/linux/preempt.h @@ -64,7 +64,11 @@ do { \ } while (0) #else -#define preempt_enable() preempt_enable_no_resched() +#define preempt_enable() \ +do { \ + barrier(); \ + preempt_count_dec(); \ +} while (0) #define preempt_check_resched() do { } while (0) #endif @@ -93,7 +97,11 @@ do { \ __preempt_schedule_context(); \ } while (0) #else -#define preempt_enable_notrace() preempt_enable_no_resched_notrace() +#define preempt_enable_notrace() \ +do { \ + barrier(); \ + __preempt_count_dec(); \ +} while (0) #endif #else /* !CONFIG_PREEMPT_COUNT */ @@ -116,6 +124,16 @@ do { \ #endif /* CONFIG_PREEMPT_COUNT */ +#ifdef MODULE +/* + * Modules have no business playing preemption tricks. + */ +#undef sched_preempt_enable_no_resched +#undef preempt_enable_no_resched +#undef preempt_enable_no_resched_notrace +#undef preempt_check_resched +#endif + #ifdef CONFIG_PREEMPT_NOTIFIERS struct preempt_notifier; diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h index 9d8cf056e661..ecd3319dac33 100644 --- a/include/linux/uaccess.h +++ b/include/linux/uaccess.h @@ -25,13 +25,16 @@ static inline void pagefault_disable(void) static inline void pagefault_enable(void) { +#ifndef CONFIG_PREEMPT /* * make sure to issue those last loads/stores before enabling * the pagefault handler again. */ barrier(); preempt_count_dec(); - preempt_check_resched(); +#else + preempt_enable(); +#endif } #ifndef ARCH_HAS_NOCACHE_UACCESS |