When a driver needs to deal with a special buffer like a SG or a vmalloc buffer, it has to set up the PCM page ops explicitly for the corresponding helper function. This is rather error-prone and many people forgot or incorrectly used it.
For simplifying the call patterns and avoiding such a potential bug, this patch enhances the PCM default mmap handler to check the (pre-)allocated buffer type and handles the page gracefully depending on the buffer type. If the PCM page ops is given, the ops is still used in a higher priority. The new code path is only for the default (NULL page ops) case.
Signed-off-by: Takashi Iwai tiwai@suse.de --- sound/core/pcm_native.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c index c3a139436ac2..998c63192ae4 100644 --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -13,6 +13,7 @@ #include <linux/pm_qos.h> #include <linux/io.h> #include <linux/dma-mapping.h> +#include <linux/vmalloc.h> #include <sound/core.h> #include <sound/control.h> #include <sound/info.h> @@ -3335,7 +3336,18 @@ static inline struct page * snd_pcm_default_page_ops(struct snd_pcm_substream *substream, unsigned long ofs) { void *vaddr = substream->runtime->dma_area + ofs; - return virt_to_page(vaddr); + + switch (substream->dma_buffer.dev.type) { +#ifdef CONFIG_SND_DMA_SGBUF + case SNDRV_DMA_TYPE_DEV_SG: + case SNDRV_DMA_TYPE_DEV_UC_SG: + return snd_pcm_sgbuf_ops_page(substream, ofs); +#endif /* CONFIG_SND_DMA_SGBUF */ + case SNDRV_DMA_TYPE_VMALLOC: + return vmalloc_to_page(vaddr); + default: + return virt_to_page(vaddr); + } }
/*