Understanding of write file operation in char driver

I am learning char drivers.But i didn't understand write operation of char device driver properly. the below is my write operation static ssize_t dev_write(struct file *fil,const char __user *buff,size_t len,loff_t *off) { pr_info(user input string %s\n,buff); pr_info(user input string

Re: Understanding of write file operation in char driver

On Thu, Jan 1, 2015 at 2:24 AM, me storage me.storage...@gmail.com wrote: I am learning char drivers.But i didn't understand write operation of char device driver properly. the below is my write operation static ssize_t dev_write(struct file *fil,const char __user *buff,size_t len,loff_t

Re: Understanding of write file operation in char driver

Hi All, Thanks Victor Can any one please tell me difference between kernal space user space in code perspective i.e in write function const char *buffer should point to address of *hello* in RAM so how it is changing when i am accessing through some kernel function because it is also accessing