Re: [PATCH 3/3] nvmem: core: use is_bin_visible for permissions

From: Srinivas Kandagatla
Date: Wed Mar 25 2020 - 05:15:46 EST




On 24/03/2020 17:46, Greg KH wrote:
On Tue, Mar 24, 2020 at 05:16:00PM +0000, Srinivas Kandagatla wrote:
By using is_bin_visible callback to set permissions will remove a large list
of attribute groups. These group permissions can be dynamically derived in
the callback.

Suggested-by: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
---
drivers/nvmem/nvmem-sysfs.c | 74 +++++++++----------------------------
1 file changed, 18 insertions(+), 56 deletions(-)

diff --git a/drivers/nvmem/nvmem-sysfs.c b/drivers/nvmem/nvmem-sysfs.c
index 8759c4470012..1ff1801048f6 100644
--- a/drivers/nvmem/nvmem-sysfs.c
+++ b/drivers/nvmem/nvmem-sysfs.c
@@ -103,6 +103,17 @@ static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj,
return count;
}
+static umode_t nvmem_bin_attr_is_visible(struct kobject *kobj,
+ struct bin_attribute *attr, int i)
+{
+ struct device *dev = container_of(kobj, struct device, kobj);
+ struct nvmem_device *nvmem = to_nvmem_device(dev);
+
+ if (nvmem->root_only)
+ return nvmem->read_only ? 0400 : 0600;
+
+ return nvmem->read_only ? 0444 : 0644;
+}

I don't know why this is so hard for me to read, but how about this
instead:

static umode_t nvmem_bin_attr_is_visible(struct kobject *kobj,
struct bin_attribute *attr, int i)
{
struct device *dev = container_of(kobj, struct device, kobj);
struct nvmem_device *nvmem = to_nvmem_device(dev);
umode_t mode = 0400;

if (!nvmem->root_only)
mode |= 0044;

if (!nvmem->read_only)
mode |= 0200;

return mode;
}

Did I get the logic corect?

That looks perfect and matches what is in upstream!
Thanks for suggesting this cleanup!

I will send v2 with this change!

--srini

thanks,

greg k-h