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authorBartosz Golaszewski <bgolaszewski@baylibre.com>2018-09-21 16:40:08 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-09-28 16:14:54 +0300
commitc1de7f43bd84271e438a4f2dadc4ba9a353baaea (patch)
treef08b22fddaa52f2d55f6b2cb34bacc936e8838a9 /drivers/nvmem
parentfa72d847d68d7833b77a4bef944cf2c5baf56f49 (diff)
downloadlinux-c1de7f43bd84271e438a4f2dadc4ba9a353baaea.tar.xz
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(). 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>
Diffstat (limited to 'drivers/nvmem')
-rw-r--r--drivers/nvmem/core.c44
1 files changed, 22 insertions, 22 deletions
diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 0ef84441ebe5..920b56e500cc 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -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 @@ err_put_device:
}
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)