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, 6 insertions, 4 deletions

diff --git a/drivers/rtc/rtc-ds1742.c b/drivers/rtc/rtc-ds1742.c
index 1638acdbc913..d1778ae8bca5 100644
--- a/drivers/rtc/rtc-ds1742.c
+++ b/drivers/rtc/rtc-ds1742.c
@@ -127,8 +127,9 @@ static const struct rtc_class_ops ds1742_rtc_ops = {
 	.set_time	= ds1742_rtc_set_time,
 };
 
-static ssize_t ds1742_nvram_read(struct kobject *kobj, char *buf,
-				 loff_t pos, size_t size)
+static ssize_t ds1742_nvram_read(struct kobject *kobj,
+				 struct bin_attribute *bin_attr,
+				 char *buf, loff_t pos, size_t size)
 {
 	struct platform_device *pdev =
 		to_platform_device(container_of(kobj, struct device, kobj));
@@ -141,8 +142,9 @@ static ssize_t ds1742_nvram_read(struct kobject *kobj, char *buf,
 	return count;
 }
 
-static ssize_t ds1742_nvram_write(struct kobject *kobj, char *buf,
-				  loff_t pos, size_t size)
+static ssize_t ds1742_nvram_write(struct kobject *kobj,
+				  struct bin_attribute *bin_attr,
+				  char *buf, loff_t pos, size_t size)
 {
 	struct platform_device *pdev =
 		to_platform_device(container_of(kobj, struct device, kobj));