[alsa-devel] [PATCH v2 alsa-lib 1/6] pcm: hw: add helper functions to map/unmap status/control data for runtime of PCM substream

[Takashi Iwai]

On Sun, 25 Jun 2017 06:41:19 +0200,
Takashi Sakamoto wrote:
> 
> Handling mapping operation for status/control data includes some
> supplemental operations for fallback mode. It's better to have helper
> functions for this purpose.
> 
> This commit adds the helper functions.
> ---
>  src/pcm/pcm_hw.c | 48 ++++++++++++++++++++++++++++++++++--------------
>  1 file changed, 34 insertions(+), 14 deletions(-)
> 
> diff --git a/src/pcm/pcm_hw.c b/src/pcm/pcm_hw.c
> index a648d12c..abf4afe0 100644
> --- a/src/pcm/pcm_hw.c
> +++ b/src/pcm/pcm_hw.c
> @@ -31,6 +31,7 @@
>  #include <stdlib.h>
>  #include <stddef.h>
>  #include <unistd.h>
> +#include <stdbool.h>
>  #include <signal.h>
>  #include <string.h>
>  #include <fcntl.h>
> @@ -866,7 +867,7 @@ static snd_pcm_sframes_t snd_pcm_hw_readn(snd_pcm_t *pcm, void **bufs, snd_pcm_u
>  	return xfern.result;
>  }
>  
> -static int snd_pcm_hw_mmap_status(snd_pcm_t *pcm)
> +static int map_status_data(snd_pcm_t *pcm)
>  {
>  	snd_pcm_hw_t *hw = pcm->private_data;
>  	struct snd_pcm_sync_ptr sync_ptr;
> @@ -900,7 +901,7 @@ static int snd_pcm_hw_mmap_status(snd_pcm_t *pcm)
>  	return 0;
>  }
>  
> -static int snd_pcm_hw_mmap_control(snd_pcm_t *pcm)
> +static int map_control_data(snd_pcm_t *pcm)
>  {
>  	snd_pcm_hw_t *hw = pcm->private_data;
>  	void *ptr;
> @@ -922,10 +923,28 @@ static int snd_pcm_hw_mmap_control(snd_pcm_t *pcm)
>  	return 0;
>  }
>  
> -static int snd_pcm_hw_munmap_status(snd_pcm_t *pcm)
> +static int map_status_and_control_data(snd_pcm_t *pcm, bool force_fallback)
>  {
>  	snd_pcm_hw_t *hw = pcm->private_data;
>  	int err;
> +
> +	hw->sync_ptr_ioctl = (int)force_fallback;
> +
> +	err = map_status_data(pcm);
> +	if (err < 0)
> +		return err;
> +
> +	err = map_control_data(pcm);
> +	if (err < 0)
> +		return err;

This would leave the status mmap in the error path?


thanks,

Takashi