linux-kernel - [PATCH 1/3] nvmem: core: remove member users from struct nvmem

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Date:   Sun, 4 Jun 2017 13:01:43 +0200
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: [PATCH 1/3] nvmem: core: remove member users from struct nvmem_device

Member users is used only to check whether we're allowed to remove
the module. So in case of built-in it's not used at all and in case
that owner is a module we have the module refcount for the same
purpose already. Whenever users is incremented the owner's refcount
is incremented too. Therefore users isn't needed.

Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
---
 drivers/nvmem/core.c | 16 ----------------
 1 file changed, 16 deletions(-)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 8c830a80..4e07f3f8 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -33,7 +33,6 @@ struct nvmem_device {
 	int			word_size;
 	int			ncells;
 	int			id;
-	int			users;
 	size_t			size;
 	bool			read_only;
 	int			flags;
@@ -517,13 +516,6 @@ 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);
 
@@ -562,7 +554,6 @@ static struct nvmem_device *__nvmem_device_get(struct device_node *np,
 		}
 	}
 
-	nvmem->users++;
 	mutex_unlock(&nvmem_mutex);
 
 	if (!try_module_get(nvmem->owner)) {
@@ -570,10 +561,6 @@ 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);
 	}
 
@@ -583,9 +570,6 @@ static struct nvmem_device *__nvmem_device_get(struct device_node *np,
 static void __nvmem_device_put(struct nvmem_device *nvmem)
 {
 	module_put(nvmem->owner);
-	mutex_lock(&nvmem_mutex);
-	nvmem->users--;
-	mutex_unlock(&nvmem_mutex);
 }
 
 static int nvmem_match(struct device *dev, void *data)
-- 
2.13.0