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