_COPY_FROM_USER(9)                  Memory Management in Linux                 _COPY_FROM_USER(9)



NAME
       _copy_from_user - Copy a block of data from user space.

SYNOPSIS
       unsigned long _copy_from_user(void * to, const void __user * from, unsigned n);

ARGUMENTS
       to
           Destination address, in kernel space.

       from
           Source address, in user space.

       n
           Number of bytes to copy.

CONTEXT
       User context only. This function may sleep if pagefaults are enabled.

DESCRIPTION
       Copy data from user space to kernel space.

       Returns number of bytes that could not be copied. On success, this will be zero.

       If some data could not be copied, this function will pad the copied data to the requested
       size using zero bytes.

COPYRIGHT
Kernel Hackers Manual 4.8.                 January 2017                        _COPY_FROM_USER(9)