[alsa-devel] [PATCH 1/2] ALSA: pcm: Warn if doubly preallocated

[Takashi Iwai]

Warn if snd_pcm_lib_preallocate_pages*() is applied to the stream that
has already the preallocated buffers and skip the allocation.  It's a
clearly a driver bug.

Signed-off-by: Takashi Iwai <tiwai at suse.de>
---
 sound/core/pcm_memory.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sound/core/pcm_memory.c b/sound/core/pcm_memory.c
index 7600dcdf5fd4..19407f79b638 100644
--- a/sound/core/pcm_memory.c
+++ b/sound/core/pcm_memory.c
@@ -221,6 +221,8 @@ void snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream,
 				  int type, struct device *data,
 				  size_t size, size_t max)
 {
+	if (snd_BUG_ON(substream->dma_buffer.dev.type))
+		return;
 	substream->dma_buffer.dev.type = type;
 	substream->dma_buffer.dev.dev = data;
 	snd_pcm_lib_preallocate_pages1(substream, size, max);
-- 
2.16.4