sched/preempt: Take away preempt_enable_no_resched() from modules (62b94a08) · Commits · 戴 / test

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 <tglx@linutronix.de> Signed-off-by:

Peter Zijlstra <peterz@infradead.org> Cc: Eliezer Tamir <eliezer.tamir@linux.intel.com> Cc: rui.zhang@intel.com Cc: jacob.jun.pan@linux.intel.com Cc: Mike Galbraith <bitbucket@online.de> Cc: hpa@zytor.com Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: lenb@kernel.org Cc: rjw@rjwysocki.net Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-fn7h6vu8wtgxk0ih402qcijx@git.kernel.org Signed-off-by:

Ingo Molnar <mingo@kernel.org>

include/linux/preempt.h

+20 −2

Original line number	Diff line number	Diff line
		@@ -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;

include/linux/uaccess.h

+4 −1

Original line number	Diff line number	Diff line
		@@ -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

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