ASoC: pcm: update module refcount if module_get_upon_open is set

Setting the module_get_upon_open field for component driver
prevents the module refcount from being incremented during
component probe(). This could lead to the module being
allowed to be unloaded when a pcm stream is open. So,
if this field is set, the module's refcount should be
incremented during pcm open to prevent module removal
when the component is in use. And, the refcount should
be decremented upon pcm close.

Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Acked-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index 2d5d5cac4ba602f6c9bb53b33124633b448af5ce..d21247546f7f7699e3833035c36a5393aff13d67 100644 (file)
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -15,6 +15,7 @@
 #include <linux/delay.h>
 #include <linux/pinctrl/consumer.h>
 #include <linux/pm_runtime.h>
+#include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/workqueue.h>
 #include <linux/export.h>
@@ -463,6 +464,9 @@ static int soc_pcm_components_close(struct snd_pcm_substream *substream,
                        continue;
 
                component->driver->ops->close(substream);
+
+               if (component->driver->module_get_upon_open)
+                       module_put(component->dev->driver->owner);
        }
 
        return 0;
@@ -513,6 +517,10 @@ static int soc_pcm_open(struct snd_pcm_substream *substream)
                    !component->driver->ops->open)
                        continue;
 
+               if (component->driver->module_get_upon_open &&
+                   !try_module_get(component->dev->driver->owner))
+                       return -ENODEV;
+
                ret = component->driver->ops->open(substream);
                if (ret < 0) {
                        dev_err(component->dev,