__get_user(9)
NAME
__get_user - Get a simple variable from user space, with less checking.
SYNOPSIS
__get_user(x, ptr);
ARGUMENTS
- x
- Variable to store result.
- ptr
- Source address, in user space.
CONTEXT
User context only. This function may sleep.
DESCRIPTION
This macro copies a single simple variable from user space to kernel
space. It supports simple types like char and int, but not larger data
types like structures or arrays.
ptr must have pointer-to-simple-variable type, and the result of
dereferencing ptr must be assignable to x without a cast.
Caller must check the pointer with access_ok before calling this
function.
Returns zero on success, or -EFAULT on error. On error, the variable x
is set to zero.