linux-kernel - [PATCH 3/3] nvmem: core: remove nvmem

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Date:   Sun, 4 Jun 2017 13:02:02 +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 3/3] nvmem: core: remove nvmem_mutex

Mutex nvmem_mutex is used in __nvmem_device_get only and isn't needed
due to:

- of_nvmem_find just calls bus_find_device which doesn't need locking
- nvmem_find_cell is protected by nvmem_cells_mutex

Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
---
 drivers/nvmem/core.c | 13 ++-----------
 1 file changed, 2 insertions(+), 11 deletions(-)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 1aa6d25a..783eb431 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -55,7 +55,6 @@ struct nvmem_cell {
 	struct list_head	node;
 };
 
-static DEFINE_MUTEX(nvmem_mutex);
 static DEFINE_IDA(nvmem_ida);
 
 static LIST_HEAD(nvmem_cells);
@@ -538,14 +537,10 @@ static struct nvmem_device *__nvmem_device_get(struct device_node *np,
 {
 	struct nvmem_device *nvmem = NULL;
 
-	mutex_lock(&nvmem_mutex);
-
 	if (np) {
 		nvmem = of_nvmem_find(np);
-		if (!nvmem) {
-			mutex_unlock(&nvmem_mutex);
+		if (!nvmem)
 			return ERR_PTR(-EPROBE_DEFER);
-		}
 	} else {
 		struct nvmem_cell *cell = nvmem_find_cell(cell_id);
 
@@ -554,14 +549,10 @@ static struct nvmem_device *__nvmem_device_get(struct device_node *np,
 			*cellp = cell;
 		}
 
-		if (!nvmem) {
-			mutex_unlock(&nvmem_mutex);
+		if (!nvmem)
 			return ERR_PTR(-ENOENT);
-		}
 	}
 
-	mutex_unlock(&nvmem_mutex);
-
 	if (!try_module_get(nvmem->owner)) {
 		dev_err(&nvmem->dev,
 			"could not increase module refcount for cell %s\n",
-- 
2.13.0