[PATCH wayland 1/2] shm: Split pool reference counting into external and internal references

[Bryce Harrington]

On Tue, Feb 09, 2016 at 04:03:47PM -0600, Derek Foreman wrote:
> This is a preliminary step towards deferring shm resize operations until
> after the compositor has released all external references on a pool.
> 
> Signed-off-by: Derek Foreman <derekf at osg.samsung.com>

Yep looks good.
Reviewed-by: Bryce Harrington <bryce at osg.samsung.com>
> ---
>  src/wayland-shm.c | 31 +++++++++++++++++++------------
>  1 file changed, 19 insertions(+), 12 deletions(-)
> 
> diff --git a/src/wayland-shm.c b/src/wayland-shm.c
> index a4343a4..6fbf34b 100644
> --- a/src/wayland-shm.c
> +++ b/src/wayland-shm.c
> @@ -52,7 +52,8 @@ static struct sigaction wl_shm_old_sigbus_action;
>  
>  struct wl_shm_pool {
>  	struct wl_resource *resource;
> -	int refcount;
> +	int internal_refcount;
> +	int external_refcount;
>  	char *data;
>  	int32_t size;
>  };
> @@ -73,10 +74,14 @@ struct wl_shm_sigbus_data {
>  };
>  
>  static void
> -shm_pool_unref(struct wl_shm_pool *pool)
> +shm_pool_unref(struct wl_shm_pool *pool, bool external)
>  {
> -	pool->refcount--;
> -	if (pool->refcount)
> +	if (external)
> +		pool->external_refcount--;
> +	else
> +		pool->internal_refcount--;
> +
> +	if (pool->internal_refcount + pool->external_refcount)
>  		return;
>  
>  	munmap(pool->data, pool->size);
> @@ -89,7 +94,7 @@ destroy_buffer(struct wl_resource *resource)
>  	struct wl_shm_buffer *buffer = wl_resource_get_user_data(resource);
>  
>  	if (buffer->pool)
> -		shm_pool_unref(buffer->pool);
> +		shm_pool_unref(buffer->pool, false);
>  	free(buffer);
>  }
>  
> @@ -162,13 +167,13 @@ shm_pool_create_buffer(struct wl_client *client, struct wl_resource *resource,
>  	buffer->stride = stride;
>  	buffer->offset = offset;
>  	buffer->pool = pool;
> -	pool->refcount++;
> +	pool->internal_refcount++;
>  
>  	buffer->resource =
>  		wl_resource_create(client, &wl_buffer_interface, 1, id);
>  	if (buffer->resource == NULL) {
>  		wl_client_post_no_memory(client);
> -		shm_pool_unref(pool);
> +		shm_pool_unref(pool, false);
>  		free(buffer);
>  		return;
>  	}
> @@ -183,7 +188,7 @@ destroy_pool(struct wl_resource *resource)
>  {
>  	struct wl_shm_pool *pool = wl_resource_get_user_data(resource);
>  
> -	shm_pool_unref(pool);
> +	shm_pool_unref(pool, false);
>  }
>  
>  static void
> @@ -243,7 +248,8 @@ shm_create_pool(struct wl_client *client, struct wl_resource *resource,
>  		goto err_free;
>  	}
>  
> -	pool->refcount = 1;
> +	pool->internal_refcount = 1;
> +	pool->external_refcount = 0;
>  	pool->size = size;
>  	pool->data = mmap(NULL, size,
>  			  PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
> @@ -396,9 +402,10 @@ wl_shm_buffer_get_height(struct wl_shm_buffer *buffer)
>  WL_EXPORT struct wl_shm_pool *
>  wl_shm_buffer_ref_pool(struct wl_shm_buffer *buffer)
>  {
> -	assert(buffer->pool->refcount);
> +	assert(buffer->pool->internal_refcount +
> +	       buffer->pool->external_refcount);
>  
> -	buffer->pool->refcount++;
> +	buffer->pool->external_refcount++;
>  	return buffer->pool;
>  }
>  
> @@ -418,7 +425,7 @@ wl_shm_buffer_ref_pool(struct wl_shm_buffer *buffer)
>  WL_EXPORT void
>  wl_shm_pool_unref(struct wl_shm_pool *pool)
>  {
> -	shm_pool_unref(pool);
> +	shm_pool_unref(pool, true);
>  }
>  
>  static void
> -- 
> 2.7.0
> 
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