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@xxxxxxx>
---
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);
+ }
}
/*
--
2.16.4
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