From 82e06c811163c4d853ed335d56c3378088bc89cc Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Thu, 14 Nov 2013 15:16:16 +1100 Subject: [PATCH] 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 - neilb Signed-off-by: Shaohua Li Signed-off-by: NeilBrown --- include/linux/wait.h | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/include/linux/wait.h b/include/linux/wait.h index 61939ba..eaa00b1 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()) -- 2.7.4