Commit-ID: 62b94a08da1bae9d187d49dfcd6665af393750f8 Gitweb: http://git.kernel.org/tip/62b94a08da1bae9d187d49dfcd6665af393750f8 Author: Peter Zijlstra <pet...@infradead.org> AuthorDate: Wed, 20 Nov 2013 16:52:19 +0100 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Mon, 13 Jan 2014 13:47:37 +0100
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 <t...@linutronix.de> Signed-off-by: Peter Zijlstra <pet...@infradead.org> Cc: Eliezer Tamir <eliezer.ta...@linux.intel.com> Cc: rui.zh...@intel.com Cc: jacob.jun....@linux.intel.com Cc: Mike Galbraith <bitbuc...@online.de> Cc: h...@zytor.com Cc: Rusty Russell <ru...@rustcorp.com.au> Cc: Arjan van de Ven <ar...@linux.intel.com> Cc: l...@kernel.org Cc: r...@rjwysocki.net Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Andrew Morton <a...@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-fn7h6vu8wtgxk0ih402qc...@git.kernel.org Signed-off-by: Ingo Molnar <mi...@kernel.org> --- include/linux/preempt.h | 22 ++++++++++++++++++++-- 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 a3d9dc8..dd9ddf8 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 9d8cf05..ecd3319 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
