in_atomic(): document why it is unsuitable for general use

Discourage people from inappropriately using in_atomic()

Signed-off-by: Jonathan Corbet <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Jonathan Corbet 2008-03-28 14:15:49 -07:00 • committed by Linus Torvalds
commit 8c703d35fa

View file

@ -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