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sound: pcm: add vmalloc buffer helper functions 

There are now five copies of the code to allocate a PCM buffer using
vmalloc().  Add a sixth in the core so that the others can be removed.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Clemens Ladisch 2009-12-18 09:29:00 +01:00 committed by Takashi Iwai
parent 14d44e2c2c
commit 681b84e177
2 changed files with 92 additions and 0 deletions
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38
include/sound/pcm.h
View File

@ -905,6 +905,44 @@ int snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm,
int snd_pcm_lib_malloc_pages(struct snd_pcm_substream *substream, size_t size);
int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream);
int _snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream *substream,
size_t size, gfp_t gfp_flags);
int snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream *substream);
struct page *snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream *substream,
unsigned long offset);
#if 0 /* for kernel-doc */
/**
* snd_pcm_lib_alloc_vmalloc_buffer - allocate virtual DMA buffer
* @substream: the substream to allocate the buffer to
* @size: the requested buffer size, in bytes
*
* Allocates the PCM substream buffer using vmalloc(), i.e., the memory is
* contiguous in kernel virtual space, but not in physical memory. Use this
* if the buffer is accessed by kernel code but not by device DMA.
*
* Returns 1 if the buffer was changed, 0 if not changed, or a negative error
* code.
*/
static int snd_pcm_lib_alloc_vmalloc_buffer
(struct snd_pcm_substream *substream, size_t size);
/**
* snd_pcm_lib_alloc_vmalloc_32_buffer - allocate 32-bit-addressable buffer
* @substream: the substream to allocate the buffer to
* @size: the requested buffer size, in bytes
*
* This function works like snd_pcm_lib_alloc_vmalloc_buffer(), but uses
* vmalloc_32(), i.e., the pages are allocated from 32-bit-addressable memory.
*/
static int snd_pcm_lib_alloc_vmalloc_32_buffer
(struct snd_pcm_substream *substream, size_t size);
#endif
#define snd_pcm_lib_alloc_vmalloc_buffer(subs, size) \
_snd_pcm_lib_alloc_vmalloc_buffer \
(subs, size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO)
#define snd_pcm_lib_alloc_vmalloc_32_buffer(subs, size) \
_snd_pcm_lib_alloc_vmalloc_buffer \
(subs, size, GFP_KERNEL | GFP_DMA32 | __GFP_ZERO)
#ifdef CONFIG_SND_DMA_SGBUF
/*
* SG-buffer handling

54
sound/core/pcm_memory.c
View File

@ -434,3 +434,57 @@ int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream)
}
EXPORT_SYMBOL(snd_pcm_lib_free_pages);
int _snd_pcm_lib_alloc_vmalloc_buffer(struct snd_pcm_substream *substream,
size_t size, gfp_t gfp_flags)
{
struct snd_pcm_runtime *runtime;
if (PCM_RUNTIME_CHECK(substream))
return -EINVAL;
runtime = substream->runtime;
if (runtime->dma_area) {
if (runtime->dma_bytes >= size)
return 0; /* already large enough */
vfree(runtime->dma_area);
}
runtime->dma_area = __vmalloc(size, gfp_flags, PAGE_KERNEL);
if (!runtime->dma_area)
return -ENOMEM;
runtime->dma_bytes = size;
return 1;
}
EXPORT_SYMBOL(_snd_pcm_lib_alloc_vmalloc_buffer);
/**
* snd_pcm_lib_free_vmalloc_buffer - free vmalloc buffer
* @substream: the substream with a buffer allocated by
* snd_pcm_lib_alloc_vmalloc_buffer()
*/
int snd_pcm_lib_free_vmalloc_buffer(struct snd_pcm_substream *substream)
{
struct snd_pcm_runtime *runtime;
if (PCM_RUNTIME_CHECK(substream))
return -EINVAL;
runtime = substream->runtime;
vfree(runtime->dma_area);
runtime->dma_area = NULL;
return 0;
}
EXPORT_SYMBOL(snd_pcm_lib_free_vmalloc_buffer);
/**
* snd_pcm_lib_get_vmalloc_page - map vmalloc buffer offset to page struct
* @substream: the substream with a buffer allocated by
* snd_pcm_lib_alloc_vmalloc_buffer()
* @offset: offset in the buffer
*
* This function is to be used as the page callback in the PCM ops.
*/
struct page *snd_pcm_lib_get_vmalloc_page(struct snd_pcm_substream *substream,
unsigned long offset)
{
return vmalloc_to_page(substream->runtime->dma_area + offset);
}
EXPORT_SYMBOL(snd_pcm_lib_get_vmalloc_page);