- unsigned long __copy_to_user_inatomic(void __user * to, const void * from, unsigned long n);
- Destination address, in user space.
- Source address, in kernel space.
- Number of bytes to copy.
User context only.
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.