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Commit 6b7a4237 authored by Bartosz Golaszewski's avatar Bartosz Golaszewski Committed by Gerrit - the friendly Code Review server
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nvmem: use kref 



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().

Change-Id: I3b8d40ed78304942e43091bd6916a058c1e3dbc4
Signed-off-by: default avatarBartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: default avatarSrinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Git-commit: c1de7f43bd84271e438a4f2dadc4ba9a353baaea
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: default avatarGaurav Kohli <gkohli@codeaurora.org>
parent 577b57fe

drivers/nvmem/core.c

+22 −22
Original line number Diff line number Diff line
@@ -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>
@@ -32,7 +33,7 @@ struct nvmem_device { 
	int			stride;

	int			word_size;

	int			id;

	int			users;

	struct kref		refcnt;

	size_t			size;

	bool			read_only;

	int			flags;
@@ -464,6 +465,8 @@ 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)
@@ -533,6 +536,20 @@ 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

 *
@@ -542,19 +559,7 @@ 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;

}
@@ -649,7 +654,6 @@ static struct nvmem_device *__nvmem_device_get(struct device_node *np, 
		}

	}



	nvmem->users++;

	mutex_unlock(&nvmem_mutex);



	if (!try_module_get(nvmem->owner)) {
@@ -657,22 +661,18 @@ static struct nvmem_device *__nvmem_device_get(struct device_node *np, 
			"could not increase module refcount for cell %s\n",

			nvmem->name);



		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)