Re: More info about kobj_attribute store and show functions

[Lucas Tanure <tanure@xxxxxxxxx>]

(Forget the last e-mail, please, stupid Gmail)

Hi, 

I'm looking for some information about :

struct kobj_attribute {
        struct attribute attr;
        ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr, char *buf);
        ssize_t (*store)(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count);
};

My function to handle the operation:

static ssize_t my_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) {

char *buffer;

        

        buffer = (char*) kcalloc(count, sizeof(char), GFP_KERNEL);

        copy_from_user(buffer, buf, count);

        .....

        .....

        etc....

}

So, this const char *buf, where ti come from ? Kernel space? 

My copy_from_user it's not working. Should return zero.

There any Macro or function to test if the pointer buf is a kernel pointer ? 

Thanks 

Lucas Tanure

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