On Fri, 2019-05-17 at 08:22 -0500, Pierre-Louis Bossart wrote:
On 5/17/19 1:08 AM, Kuninori Morimoto wrote:
From: Kuninori Morimoto kuninori.morimoto.gx@renesas.com
soc_pcm_components_open() try to call try_module_get() based on component->driver->module_get_upon_open. But, it should be always called, not relatead to .open callback. It should be called at (A) istead of (B)
=> (A) if (!component->driver->ops || !component->driver->ops->open) continue; => (B) if (component->driver->module_get_upon_open && !try_module_get(component->dev->driver->owner)) { ... }
ret = component->driver->ops->open(substream);
Signed-off-by: Kuninori Morimoto kuninori.morimoto.gx@renesas.com
Mark, Pierre-Louis, Vinod, Liam
I think this patch is correct, but I'm not sure. I'm happy if someone can confirm it.
The try_module_get()/module_put() mechanism is based on the assumption that the .open and .close callbacks are both mandatory.
Hi Pierre, But is this enforced? We could end up doing a try_module_get() without checking if there is a close callback in which case we'd never do the module_put(), isnt it?
Thanks, Ranjani
open flow: if (!component->driver->ops || !component->driver->ops->open) continue;
if (component->driver->module_get_upon_open && !try_module_get(component->dev->driver->owner)) { ret = -ENODEV; goto module_err; } ret = component->driver->ops->open(substream);close flow: if (!component->driver->ops || !component->driver->ops->close) continue;
component->driver->ops->close(substream); if (component->driver->module_get_upon_open) module_put(component->dev->driver->owner);it'd be odd to allow the refcount to be increased when there is no .open, since if there is no .close either then the refcount never decreases.
sound/soc/soc-pcm.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c index 7737e00..7b4cda6 100644 --- a/sound/soc/soc-pcm.c +++ b/sound/soc/soc-pcm.c @@ -440,10 +440,6 @@ static int soc_pcm_components_open(struct snd_pcm_substream *substream, component = rtdcom->component; *last = component;
if (!component->driver->ops ||!component->driver->ops->open)continue;- if (component->driver->module_get_upon_open && !try_module_get(component->dev->driver->owner)) { dev_err(component->dev,
@@ -452,6 +448,10 @@ static int soc_pcm_components_open(struct snd_pcm_substream *substream, return -ENODEV; }
if (!component->driver->ops ||!component->driver->ops->open)continue;- ret = component->driver->ops->open(substream); if (ret < 0) { dev_err(component->dev,
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