centos man page for __copy_to_user_inatomic

__COPY_TO_USER_INATO(9) 				    Memory Management in Linux					   __COPY_TO_USER_INATO(9)

NAME
       __copy_to_user_inatomic - Copy a block of data into user space, with less checking.

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

ARGUMENTS
       to
	   Destination address, in user space.

       from
	   Source address, in kernel space.

       n
	   Number of bytes to copy.

CONTEXT
       User context only.

DESCRIPTION
       Copy data from kernel space to user space. Caller must check the specified block with access_ok before calling this function. The caller
       should also make sure he pins the user space address so that we don't result in page fault and sleep.

       Here we special-case 1, 2 and 4-byte copy_*_user invocations. On a fault we return the initial request size (1, 2 or 4), as copy_*_user
       should do. If a store crosses a page boundary and gets a fault, the x86 will not write anything, so this is accurate.

COPYRIGHT
Kernel Hackers Manual 3.10					     June 2014						   __COPY_TO_USER_INATO(9)