Thanks Jan,
So the only different thing my function does from
wait_event_interruptible is that it does not check for a signal pending for
the current process, right ? So yes correct i must use
wait_event_interruptible.
Amit
Jan Hudec <bulb@ucw.cz>@vagabond.light.src> on 06/08/2004 06:20:15 PM
Sent by: Jan Hudec <bulb@vagabond.light.src>
To: Amit Kumar Singh/HSS@HSS
cc:
Subject: Re: schedule()
On Tue, Jun 08, 2004 at 15:53:36 +0530, aksingh@hss.hns.com wrote:
>
>
>
>
> Hi,
>
> This is the way I intend to block the read call on my char device, if
> there is no data to be read.
>
> void block() {
> DECLARE_WAITQUEUE(w, current);
> __add_wait_queue(&some_wait_queue, &w);
> current->state=TASK_INTERRUPTIBLE;
> if (!isready())
> schedule();
> current->state=TASK_RUNNING;
> remove_wait_queue(&some_wait_queue, &w);
> }
Oh, and now I noticed you sleed in TASK_INTERRUPTIBLE state and don't
check for signals. Now, THAT is a BUG! You should do:
void block() {
int ret = 0;
wait_event_interruptible(some_wait_queue, isready(), ret);
return ret; /* Will be -ERESTARTSYS if you wake up due tu signal */
}
-------------------------------------------------------------------------------
Jan 'Bulb' Hudec <bulb@ucw.cz>
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