The recent refactoring of mmap handling caused Oops on some devices that don't use the standard memory allocations. This patch addresses it by allowing snd_dma_buffer_mmap() helper to receive the NULL pointer dmab argument (and return an error appropriately).

Fixes: a202bd1ad86d ("ALSA: core: Move mmap handler into memalloc ops") Cc: stable@vger.kernel.org Signed-off-by: Takashi Iwai tiwai@suse.de --- sound/core/memalloc.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/sound/core/memalloc.c b/sound/core/memalloc.c index 0145dabda56d..de7e9d2df39d 100644 --- a/sound/core/memalloc.c +++ b/sound/core/memalloc.c @@ -183,8 +183,11 @@ EXPORT_SYMBOL_GPL(snd_devm_alloc_dir_pages); int snd_dma_buffer_mmap(struct snd_dma_buffer *dmab, struct vm_area_struct *area) { - const struct snd_malloc_ops *ops = snd_dma_get_ops(dmab); + const struct snd_malloc_ops *ops;

+ if (!dmab) + return -ENOENT; + ops = snd_dma_get_ops(dmab); if (ops && ops->mmap) return ops->mmap(dmab, area); else