[PATCH] pcmcia/cs: fix possible missed wakeup

[Andrew Morton]

Daniel Ritz <daniel.ritz at gmx.ch> wrote:
>
> hi andrew, dominik, andreas
> 
> the patch fixes one of the problems andreas steinmetz reported a while ago.
> akmp, please queue up in -mm, andreas please test. should fix the last
> testcase in your test script:
> http://marc.theaimsgroup.com/?l=linux-kernel&m=112293392628128&w=4
> 

Did we hear back on the testing results of this one?

Thanks.

> 
> [PATCH] pcmcia/cs: fix possible missed wakeup
> 
> - thread_done should only be completed when the wait_queue is installed.
> - all wake up conditions should be checked before schedule()
> 
> this fixes a hang of rmmod in the sequence modprobe yenta_socket; rmmod yenta_socket
> as reported by Andreas Steinmetz. w/o this rmmod yenta_socket can hang on 
> wait_for_completion() in pcmcia_unregister_socket()
> 
> Signed-off-by: Daniel Ritz <daniel.ritz at gmx.ch>
> 
> diff --git a/drivers/pcmcia/cs.c b/drivers/pcmcia/cs.c
> --- a/drivers/pcmcia/cs.c
> +++ b/drivers/pcmcia/cs.c
> @@ -654,9 +654,10 @@ static int pccardd(void *__skt)
>  		skt->thread = NULL;
>  		complete_and_exit(&skt->thread_done, 0);
>  	}
> -	complete(&skt->thread_done);
>  
>  	add_wait_queue(&skt->thread_wait, &wait);
> +	complete(&skt->thread_done);
> +
>  	for (;;) {
>  		unsigned long flags;
>  		unsigned int events;
> @@ -682,11 +683,11 @@ static int pccardd(void *__skt)
>  			continue;
>  		}
>  
> -		schedule();
> -		try_to_freeze();
> -
>  		if (!skt->thread)
>  			break;
> +
> +		schedule();
> +		try_to_freeze();
>  	}
>  	remove_wait_queue(&skt->thread_wait, &wait);
>