Re: [PATCH 1/3] nvmem: core: remove member users from struct nvmem_device

From: Srinivas Kandagatla
Date: Wed Jun 07 2017 - 11:30:59 EST




On 04/06/17 12:01, Heiner Kallweit wrote:
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

nvmem providers doesn't have to be independent drivers, providers could be part of the other driver which can dynamically register and unregister nvmem providers. For example at24 and at25 drivers.

This patch will break such cases !!



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@xxxxxxxxx>
---
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)