in_atomic(): document why it is unsuitable for general use (8c703d35) · Commits · 戴 / test

Discourage people from inappropriately using in_atomic() Signed-off-by:

include/linux/hardirq.h

+7 −0

Original line number	Diff line number	Diff line
		@@ -72,6 +72,13 @@
		#define in_softirq() (softirq_count())
		#define in_interrupt() (irq_count())

		/*
		* Are we running in atomic context? WARNING: this macro cannot
		* always detect atomic context; in particular, it cannot know about
		* held spinlocks in non-preemptible kernels. Thus it should not be
		* used in the general case to determine whether sleeping is possible.
		* Do not use in_atomic() in driver code.
		*/
		#define in_atomic() ((preempt_count() & ~PREEMPT_ACTIVE) != 0)

		#ifdef CONFIG_PREEMPT