[alsa-devel] [patch 13/18] alsa: nopage

[Takashi Iwai]

At Wed, 05 Dec 2007 18:16:00 +1100,
npiggin at suse.de wrote:
> 
> Convert ALSA from nopage to fault.
> Switch from OOM to SIGBUS if the resource is not available.
> 
> Signed-off-by: Nick Piggin <npiggin at suse.de>
> Cc: perex at perex.cz
> Cc: tiwai at suse.de
> Cc: alsa-devel at alsa-project.org
> Cc: linux-kernel at vger.kernel.org

I applied this to ALSA HG tree.


thanks,

Takashi

> ---
>  sound/core/pcm_native.c |   59 ++++++++++++++++++++----------------------------
>  1 file changed, 25 insertions(+), 34 deletions(-)
> 
> Index: linux-2.6/sound/core/pcm_native.c
> ===================================================================
> --- linux-2.6.orig/sound/core/pcm_native.c
> +++ linux-2.6/sound/core/pcm_native.c
> @@ -3018,26 +3018,23 @@ static unsigned int snd_pcm_capture_poll
>  /*
>   * mmap status record
>   */
> -static struct page * snd_pcm_mmap_status_nopage(struct vm_area_struct *area,
> -						unsigned long address, int *type)
> +static int snd_pcm_mmap_status_fault(struct vm_area_struct *area,
> +						struct vm_fault *vmf)
>  {
>  	struct snd_pcm_substream *substream = area->vm_private_data;
>  	struct snd_pcm_runtime *runtime;
> -	struct page * page;
>  	
>  	if (substream == NULL)
> -		return NOPAGE_SIGBUS;
> +		return VM_FAULT_SIGBUS;
>  	runtime = substream->runtime;
> -	page = virt_to_page(runtime->status);
> -	get_page(page);
> -	if (type)
> -		*type = VM_FAULT_MINOR;
> -	return page;
> +	vmf->page = virt_to_page(runtime->status);
> +	get_page(vmf->page);
> +	return 0;
>  }
>  
>  static struct vm_operations_struct snd_pcm_vm_ops_status =
>  {
> -	.nopage =	snd_pcm_mmap_status_nopage,
> +	.fault =	snd_pcm_mmap_status_fault,
>  };
>  
>  static int snd_pcm_mmap_status(struct snd_pcm_substream *substream, struct file *file,
> @@ -3061,26 +3058,23 @@ static int snd_pcm_mmap_status(struct sn
>  /*
>   * mmap control record
>   */
> -static struct page * snd_pcm_mmap_control_nopage(struct vm_area_struct *area,
> -						 unsigned long address, int *type)
> +static int snd_pcm_mmap_control_fault(struct vm_area_struct *area,
> +						struct vm_fault *vmf)
>  {
>  	struct snd_pcm_substream *substream = area->vm_private_data;
>  	struct snd_pcm_runtime *runtime;
> -	struct page * page;
>  	
>  	if (substream == NULL)
> -		return NOPAGE_SIGBUS;
> +		return VM_FAULT_SIGBUS;
>  	runtime = substream->runtime;
> -	page = virt_to_page(runtime->control);
> -	get_page(page);
> -	if (type)
> -		*type = VM_FAULT_MINOR;
> -	return page;
> +	vmf->page = virt_to_page(runtime->control);
> +	get_page(vmf->page);
> +	return 0;
>  }
>  
>  static struct vm_operations_struct snd_pcm_vm_ops_control =
>  {
> -	.nopage =	snd_pcm_mmap_control_nopage,
> +	.fault =	snd_pcm_mmap_control_fault,
>  };
>  
>  static int snd_pcm_mmap_control(struct snd_pcm_substream *substream, struct file *file,
> @@ -3117,10 +3111,10 @@ static int snd_pcm_mmap_control(struct s
>  #endif /* coherent mmap */
>  
>  /*
> - * nopage callback for mmapping a RAM page
> + * fault callback for mmapping a RAM page
>   */
> -static struct page *snd_pcm_mmap_data_nopage(struct vm_area_struct *area,
> -					     unsigned long address, int *type)
> +static int snd_pcm_mmap_data_fault(struct vm_area_struct *area,
> +						struct vm_fault *vmf)
>  {
>  	struct snd_pcm_substream *substream = area->vm_private_data;
>  	struct snd_pcm_runtime *runtime;
> @@ -3130,33 +3124,30 @@ static struct page *snd_pcm_mmap_data_no
>  	size_t dma_bytes;
>  	
>  	if (substream == NULL)
> -		return NOPAGE_SIGBUS;
> +		return VM_FAULT_SIGBUS;
>  	runtime = substream->runtime;
> -	offset = area->vm_pgoff << PAGE_SHIFT;
> -	offset += address - area->vm_start;
> -	snd_assert((offset % PAGE_SIZE) == 0, return NOPAGE_SIGBUS);
> +	offset = vmf->pgoff << PAGE_SHIFT;
>  	dma_bytes = PAGE_ALIGN(runtime->dma_bytes);
>  	if (offset > dma_bytes - PAGE_SIZE)
> -		return NOPAGE_SIGBUS;
> +		return VM_FAULT_SIGBUS;
>  	if (substream->ops->page) {
>  		page = substream->ops->page(substream, offset);
> -		if (! page)
> -			return NOPAGE_OOM; /* XXX: is this really due to OOM? */
> +		if (!page)
> +			return VM_FAULT_SIGBUS;
>  	} else {
>  		vaddr = runtime->dma_area + offset;
>  		page = virt_to_page(vaddr);
>  	}
>  	get_page(page);
> -	if (type)
> -		*type = VM_FAULT_MINOR;
> -	return page;
> +	vmf->page = page;
> +	return 0;
>  }
>  
>  static struct vm_operations_struct snd_pcm_vm_ops_data =
>  {
>  	.open =		snd_pcm_mmap_data_open,
>  	.close =	snd_pcm_mmap_data_close,
> -	.nopage =	snd_pcm_mmap_data_nopage,
> +	.fault =	snd_pcm_mmap_data_fault,
>  };
>  
>  /*
> 
> -- 
>