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authorShaohua Li <shli@kernel.org>2013-11-14 08:16:16 +0400
committerNeilBrown <neilb@suse.de>2013-11-14 08:16:16 +0400
commit82e06c811163c4d853ed335d56c3378088bc89cc (patch)
tree83ca8da3fcda9ebb1ec6ce5bb275533d8d4bd952 /include/linux/wait.h
parentba8805b97320416e7c5bb8f55d2bd06d5c319e7d (diff)
downloadlinux-82e06c811163c4d853ed335d56c3378088bc89cc.tar.xz
wait: add wait_event_cmd()
Add a new API wait_event_cmd(). It's a variant of wait_even() with two commands executed. One is executed before sleep, another after sleep. Modified to match use wait.h approach based on suggestion by Peter Zijlstra <peterz@infradead.org> - neilb Signed-off-by: Shaohua Li <shli@fusionio.com> Signed-off-by: NeilBrown <neilb@suse.de>
Diffstat (limited to 'include/linux/wait.h')
-rw-r--r--include/linux/wait.h25
1 files changed, 25 insertions, 0 deletions
diff --git a/include/linux/wait.h b/include/linux/wait.h
index 61939ba30aa0..eaa00b10abaa 100644
--- a/include/linux/wait.h
+++ b/include/linux/wait.h
@@ -278,6 +278,31 @@ do { \
__ret; \
})
+#define __wait_event_cmd(wq, condition, cmd1, cmd2) \
+ (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0, \
+ cmd1; schedule(); cmd2)
+
+/**
+ * wait_event_cmd - sleep until a condition gets true
+ * @wq: the waitqueue to wait on
+ * @condition: a C expression for the event to wait for
+ * cmd1: the command will be executed before sleep
+ * cmd2: the command will be executed after sleep
+ *
+ * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the
+ * @condition evaluates to true. The @condition is checked each time
+ * the waitqueue @wq is woken up.
+ *
+ * wake_up() has to be called after changing any variable that could
+ * change the result of the wait condition.
+ */
+#define wait_event_cmd(wq, condition, cmd1, cmd2) \
+do { \
+ if (condition) \
+ break; \
+ __wait_event_cmd(wq, condition, cmd1, cmd2); \
+} while (0)
+
#define __wait_event_interruptible(wq, condition) \
___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0, \
schedule())