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[90.118.185.89]) by smtp.gmail.com with ESMTPSA id l7-v6sm169341wrt.67.2018.09.12.00.51.52 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 12 Sep 2018 00:51:53 -0700 (PDT) From: Bartosz Golaszewski To: Srinivas Kandagatla , "David S . Miller" , Mauro Carvalho Chehab , Greg Kroah-Hartman , Andrew Morton , Arnd Bergmann , Jonathan Corbet , Sekhar Nori , Kevin Hilman , David Lechner , Boris Brezillon , Andrew Lunn , Alban Bedel , Maxime Ripard , Chen-Yu Tsai Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Bartosz Golaszewski Subject: [PATCH v3 06/21] nvmem: use kref Date: Wed, 12 Sep 2018 09:51:14 +0200 Message-Id: <20180912075129.25185-7-brgl@bgdev.pl> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180912075129.25185-1-brgl@bgdev.pl> References: <20180912075129.25185-1-brgl@bgdev.pl> Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org From: Bartosz Golaszewski 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 --- drivers/nvmem/core.c | 44 ++++++++++++++++++++++---------------------- 1 file changed, 22 insertions(+), 22 deletions(-) diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c index ffed8fa16936..552ffedce38e 100644 --- a/drivers/nvmem/core.c +++ b/drivers/nvmem/core.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include #include @@ -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) -- 2.18.0 From mboxrd@z Thu Jan 1 00:00:00 1970 From: brgl@bgdev.pl (Bartosz Golaszewski) Date: Wed, 12 Sep 2018 09:51:14 +0200 Subject: [PATCH v3 06/21] nvmem: use kref In-Reply-To: <20180912075129.25185-1-brgl@bgdev.pl> References: <20180912075129.25185-1-brgl@bgdev.pl> Message-ID: <20180912075129.25185-7-brgl@bgdev.pl> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Bartosz Golaszewski 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 --- drivers/nvmem/core.c | 44 ++++++++++++++++++++++---------------------- 1 file changed, 22 insertions(+), 22 deletions(-) diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c index ffed8fa16936..552ffedce38e 100644 --- a/drivers/nvmem/core.c +++ b/drivers/nvmem/core.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include #include @@ -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) -- 2.18.0