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| author | Jonathan Corbet <corbet@lwn.net> | 2008-03-28 14:15:49 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-03-28 14:45:21 -0700 |
| commit | 8c703d35fa91911dd92a18c31a718853f483ad80 (patch) | |
| tree | 13b63c9754ad202cc7f4528ee94c7c54f3f88bba | |
| parent | f67e74ca690d9f168cc468b7d714caad492740a6 (diff) | |
| download | linux-8c703d35fa91911dd92a18c31a718853f483ad80.tar.bz2 | |
in_atomic(): document why it is unsuitable for general use
Discourage people from inappropriately using in_atomic()
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/hardirq.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h index 49829988bfa0..897f723bd222 100644 --- a/include/linux/hardirq.h +++ b/include/linux/hardirq.h @@ -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 |