On 09/30, Oleg Nesterov wrote:
>
> On 09/30, Peter Zijlstra wrote:
> >
> > On Mon, Sep 30, 2013 at 07:40:54PM +0200, Oleg Nesterov wrote:
> > > Once again, of course I do not blame this series, but
> > > wait_event_timeout(wq, true, 0) still returns 0.
> >
> > So we have:
> >
> > [...snip...]
>
> > So wait_event_timeout(wq, true, 0) turns into:
>
> Not really, because of fast-path check,
>
>       #define wait_event_timeout(wq, condition, timeout)                      
> \
>       ({                                                                      
> \
>               long __ret = timeout;                                           
> \
>               if (!(condition))                                               
> \
>                       __ret = __wait_event_timeout(wq, condition, timeout);   
> \
>               __ret;                                                          
> \
>       })
>
> we do not even call __wait_event_timeout() if "condition" is already
> true at the start.

But somehow I didn't realize that ___wait_cond_timeout() can be used
as is, so the simple patch below should work?

Oleg.

--- x/include/linux/wait.h
+++ x/include/linux/wait.h
@@ -270,7 +270,7 @@ do {                                                        
                \
 #define wait_event_timeout(wq, condition, timeout)                     \
 ({                                                                     \
        long __ret = timeout;                                           \
-       if (!(condition))                                               \
+       if (!___wait_cond_timeout(condition))                           \
                __ret = __wait_event_timeout(wq, condition, timeout);   \
        __ret;                                                          \
 })
@@ -328,7 +328,7 @@ do {                                                        
                \
 #define wait_event_interruptible_timeout(wq, condition, timeout)       \
 ({                                                                     \
        long __ret = timeout;                                           \
-       if (!(condition))                                               \
+       if (!___wait_cond_timeout(condition))                           \
                __ret = __wait_event_interruptible_timeout(wq,          \
                                                condition, timeout);    \
        __ret;                                                          \
@@ -770,7 +770,7 @@ do {                                                        
                \
                                                  timeout)              \
 ({                                                                     \
        long __ret = timeout;                                           \
-       if (!(condition))                                               \
+       if (!___wait_cond_timeout(condition))                           \
                __ret = __wait_event_interruptible_lock_irq_timeout(    \
                                        wq, condition, lock, timeout);  \
        __ret;                                                          \

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