sysfs: add parameter "struct bin_attribute *" in .read/.write methods for sysfs binary attributes

Well, first of all, I don't want to change so many files either.

What I do:
Adding a new parameter "struct bin_attribute *" in the
.read/.write methods for the sysfs binary attributes.

In fact, only the four lines change in fs/sysfs/bin.c and
include/linux/sysfs.h do the real work.
But I have to update all the files that use binary attributes
to make them compatible with the new .read and .write methods.
I'm not sure if I missed any. :(

Why I do this:
For a sysfs attribute, we can get a pointer pointing to the
struct attribute in the .show/.store method,
while we can't do this for the binary attributes.
I don't know why this is different, but this does make it not
so handy to use the binary attributes as the regular ones.
So I think this patch is reasonable. :)

Who benefits from it:
The patch that exposes ACPI tables in sysfs
requires such an improvement.
All the table binary attributes share the same .read method.
Parameter "struct bin_attribute *" is used to get
the table signature and instance number which are used to
distinguish different ACPI table binary attributes.

Without this parameter, we need to offer different .read methods
for different ACPI table binary attributes.
This is impossible as there are various ACPI tables on different
platforms, and we don't know what they are until they are loaded.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/i2c/chips/max6875.c b/drivers/i2c/chips/max6875.c
index 1405ce5b236c..4e238c0a7ca3 100644
--- a/drivers/i2c/chips/max6875.c
+++ b/drivers/i2c/chips/max6875.c
@@ -125,8 +125,9 @@ exit_up:
         mutex_unlock(&data->update_lock);
 }
 
-static ssize_t max6875_read(struct kobject *kobj, char *buf, loff_t off,
-                            size_t count)
+static ssize_t max6875_read(struct kobject *kobj,
+                            struct bin_attribute *bin_attr,
+                            char *buf, loff_t off, size_t count)
 {
         struct i2c_client *client = kobj_to_i2c_client(kobj);
         struct max6875_data *data = i2c_get_clientdata(client);