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| author | Peter Zijlstra <peterz@infradead.org> | 2014-04-18 15:07:17 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-04-18 16:40:08 -0700 |
| commit | 8b32201de1f87878ace971bfdc2846a4f3a5bb2b (patch) | |
| tree | 7f9bf1d69e618d47591786b1e39262251eba5119 /include/linux/wait.h | |
| parent | 9cc236827fde5e254fd995a0023c05c5ee3a3ba6 (diff) | |
| download | lwn-8b32201de1f87878ace971bfdc2846a4f3a5bb2b.tar.gz lwn-8b32201de1f87878ace971bfdc2846a4f3a5bb2b.zip | |
wait: explain the shadowing and type inconsistencies
Stick in a comment before someone else tries to fix the sparse warning
this generates.
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-o2ro6f3vkxklni0bc8f7m68s@git.kernel.org
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/wait.h')
| -rw-r--r-- | include/linux/wait.h | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/include/linux/wait.h b/include/linux/wait.h index e7d9d9ed14f5..bd68819f0815 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -191,11 +191,23 @@ wait_queue_head_t *bit_waitqueue(void *, int); (!__builtin_constant_p(state) || \ state == TASK_INTERRUPTIBLE || state == TASK_KILLABLE) \ +/* + * The below macro ___wait_event() has an explicit shadow of the __ret + * variable when used from the wait_event_*() macros. + * + * This is so that both can use the ___wait_cond_timeout() construct + * to wrap the condition. + * + * The type inconsistency of the wait_event_*() __ret variable is also + * on purpose; we use long where we can return timeout values and int + * otherwise. + */ + #define ___wait_event(wq, condition, state, exclusive, ret, cmd) \ ({ \ __label__ __out; \ wait_queue_t __wait; \ - long __ret = ret; \ + long __ret = ret; /* explicit shadow */ \ \ INIT_LIST_HEAD(&__wait.task_list); \ if (exclusive) \ |