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nvmem: use kref

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Use kref for reference counting. Use an approach similar to the one
seen in the common clock subsystem: don't actually destroy the nvmem
device until the last user puts it. This way we can get rid of the
users check from nvmem_unregister().

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Bartosz Golaszewski 2018-09-21 06:40:08 -07:00 committed by Greg Kroah-Hartman
parent fa72d847d6
commit c1de7f43bd
1 changed files with 22 additions and 22 deletions
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44
drivers/nvmem/core.c
View file

@ -19,6 +19,7 @@
#include <linux/fs.h>
#include <linux/idr.h>
#include <linux/init.h>
#include <linux/kref.h>
#include <linux/module.h>
#include <linux/nvmem-consumer.h>
#include <linux/nvmem-provider.h>
@ -31,7 +32,7 @@ struct nvmem_device {
int stride;
int word_size;
int id;
int users;
struct kref refcnt;
size_t size;
bool read_only;
int flags;
@ -463,6 +464,8 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
return ERR_PTR(rval);
}
kref_init(&nvmem->refcnt);
nvmem->id = rval;
nvmem->owner = config->owner;
if (!nvmem->owner && config->dev->driver)
@ -532,6 +535,20 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
}
EXPORT_SYMBOL_GPL(nvmem_register);
static void nvmem_device_release(struct kref *kref)
{
struct nvmem_device *nvmem;
nvmem = container_of(kref, struct nvmem_device, refcnt);
if (nvmem->flags & FLAG_COMPAT)
device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
nvmem_device_remove_all_cells(nvmem);
device_del(&nvmem->dev);
put_device(&nvmem->dev);
}
/**
* nvmem_unregister() - Unregister previously registered nvmem device
*
@ -541,19 +558,7 @@ EXPORT_SYMBOL_GPL(nvmem_register);
*/
int nvmem_unregister(struct nvmem_device *nvmem)
{
mutex_lock(&nvmem_mutex);
if (nvmem->users) {
mutex_unlock(&nvmem_mutex);
return -EBUSY;
}
mutex_unlock(&nvmem_mutex);
if (nvmem->flags & FLAG_COMPAT)
device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
nvmem_device_remove_all_cells(nvmem);
device_del(&nvmem->dev);
put_device(&nvmem->dev);
kref_put(&nvmem->refcnt, nvmem_device_release);
return 0;
}
@ -647,7 +652,6 @@ static struct nvmem_device *__nvmem_device_get(struct device_node *np,
}
}
nvmem->users++;
mutex_unlock(&nvmem_mutex);
if (!try_module_get(nvmem->owner)) {
@ -655,22 +659,18 @@ static struct nvmem_device *__nvmem_device_get(struct device_node *np,
"could not increase module refcount for cell %s\n",
nvmem_dev_name(nvmem));
mutex_lock(&nvmem_mutex);
nvmem->users--;
mutex_unlock(&nvmem_mutex);
return ERR_PTR(-EINVAL);
}
kref_get(&nvmem->refcnt);
return nvmem;
}
static void __nvmem_device_put(struct nvmem_device *nvmem)
{
module_put(nvmem->owner);
mutex_lock(&nvmem_mutex);
nvmem->users--;
mutex_unlock(&nvmem_mutex);
kref_put(&nvmem->refcnt, nvmem_device_release);
}
static struct nvmem_device *nvmem_find(const char *name)