[alsa-devel] [PATCH] snd-usb-us122l: Fix missing NULL checks

[Takashi Iwai]

At Tue, 4 Jan 2011 01:20:37 +0100,
Karsten Wiese wrote:
> 
> Fix missing NULL checks in usb_stream_hwdep_poll() and usb_stream_hwdep_ioctl().
> Wake up poll waiters before returning from usb_stream_hwdep_ioctl().
> 
> Signed-off-by: Karsten Wiese <fzu at wemgehoertderstaat.de>
> Cc: stable at kernel.org

Applied.  Thanks.


Takashi

> ---
>  sound/usb/usx2y/us122l.c |   41 ++++++++++++++++++++---------------------
>  1 files changed, 20 insertions(+), 21 deletions(-)
> 
> diff --git a/sound/usb/usx2y/us122l.c b/sound/usb/usx2y/us122l.c
> index 91bb296..7abda8d 100644
> --- a/sound/usb/usx2y/us122l.c
> +++ b/sound/usb/usx2y/us122l.c
> @@ -269,29 +269,26 @@ static unsigned int usb_stream_hwdep_poll(struct snd_hwdep *hw,
>  					  struct file *file, poll_table *wait)
>  {
>  	struct us122l	*us122l = hw->private_data;
> -	struct usb_stream *s = us122l->sk.s;
>  	unsigned	*polled;
>  	unsigned int	mask;
>  
>  	poll_wait(file, &us122l->sk.sleep, wait);
>  
> -	switch (s->state) {
> -	case usb_stream_ready:
> -		if (us122l->first == file)
> -			polled = &s->periods_polled;
> -		else
> -			polled = &us122l->second_periods_polled;
> -		if (*polled != s->periods_done) {
> -			*polled = s->periods_done;
> -			mask = POLLIN | POLLOUT | POLLWRNORM;
> -			break;
> +	mask = POLLIN | POLLOUT | POLLWRNORM | POLLERR;
> +	if (mutex_trylock(&us122l->mutex)) {
> +		struct usb_stream *s = us122l->sk.s;
> +		if (s && s->state == usb_stream_ready) {
> +			if (us122l->first == file)
> +				polled = &s->periods_polled;
> +			else
> +				polled = &us122l->second_periods_polled;
> +			if (*polled != s->periods_done) {
> +				*polled = s->periods_done;
> +				mask = POLLIN | POLLOUT | POLLWRNORM;
> +			} else
> +				mask = 0;
>  		}
> -		/* Fall through */
> -		mask = 0;
> -		break;
> -	default:
> -		mask = POLLIN | POLLOUT | POLLWRNORM | POLLERR;
> -		break;
> +		mutex_unlock(&us122l->mutex);
>  	}
>  	return mask;
>  }
> @@ -377,6 +374,7 @@ static int usb_stream_hwdep_ioctl(struct snd_hwdep *hw, struct file *file,
>  {
>  	struct usb_stream_config *cfg;
>  	struct us122l *us122l = hw->private_data;
> +	struct usb_stream *s;
>  	unsigned min_period_frames;
>  	int err = 0;
>  	bool high_speed;
> @@ -422,18 +420,18 @@ static int usb_stream_hwdep_ioctl(struct snd_hwdep *hw, struct file *file,
>  	snd_power_wait(hw->card, SNDRV_CTL_POWER_D0);
>  
>  	mutex_lock(&us122l->mutex);
> +	s = us122l->sk.s;
>  	if (!us122l->master)
>  		us122l->master = file;
>  	else if (us122l->master != file) {
> -		if (memcmp(cfg, &us122l->sk.s->cfg, sizeof(*cfg))) {
> +		if (!s || memcmp(cfg, &s->cfg, sizeof(*cfg))) {
>  			err = -EIO;
>  			goto unlock;
>  		}
>  		us122l->slave = file;
>  	}
> -	if (!us122l->sk.s ||
> -	    memcmp(cfg, &us122l->sk.s->cfg, sizeof(*cfg)) ||
> -	    us122l->sk.s->state == usb_stream_xrun) {
> +	if (!s || memcmp(cfg, &s->cfg, sizeof(*cfg)) ||
> +	    s->state == usb_stream_xrun) {
>  		us122l_stop(us122l);
>  		if (!us122l_start(us122l, cfg->sample_rate, cfg->period_frames))
>  			err = -EIO;
> @@ -444,6 +442,7 @@ unlock:
>  	mutex_unlock(&us122l->mutex);
>  free:
>  	kfree(cfg);
> +	wake_up_all(&us122l->sk.sleep);
>  	return err;
>  }
>  
> -- 
> 1.7.2.3
> 
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