Hello,
Thanks for your reply! It is very helpful!
Should I submit a patch as you suggested for safety?
Best wishes,
Tuo Li
On Mon, Jun 26, 2023 at 3:33 PM Takashi Iwai <tiwai@xxxxxxx> wrote:
> On Mon, 26 Jun 2023 09:31:18 +0200,
> Tuo Li wrote:
> >
> >
> > Hello,
> >
> > Thank you for your reply!
>
> FWIW, the simplest fix would be something like below, just extending
> the mutex coverage. But it'll serialize the all calls, so it might
> influence on the performance, while it's the safest way.
>
>
> Takashi
>
> --- a/sound/core/pcm_memory.c
> +++ b/sound/core/pcm_memory.c
> @@ -37,20 +37,22 @@ static int do_alloc_pages(struct snd_card *card, int
> type, struct device *dev,
> enum dma_data_direction dir;
> int err;
>
> + mutex_lock(&card->memory_mutex);
> if (max_alloc_per_card &&
> - card->total_pcm_alloc_bytes + size > max_alloc_per_card)
> - return -ENOMEM;
> + card->total_pcm_alloc_bytes + size > max_alloc_per_card) {
> + err = -ENOMEM;
> + goto unlock;
> + }
>
> if (str == SNDRV_PCM_STREAM_PLAYBACK)
> dir = DMA_TO_DEVICE;
> else
> dir = DMA_FROM_DEVICE;
> err = snd_dma_alloc_dir_pages(type, dev, dir, size, dmab);
> - if (!err) {
> - mutex_lock(&card->memory_mutex);
> + if (!err)
> card->total_pcm_alloc_bytes += dmab->bytes;
> - mutex_unlock(&card->memory_mutex);
> - }
> + unlock:
> + mutex_unlock(&card->memory_mutex);
> return err;
> }
>
>
