250 …rn unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n);
251 extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n…
252 …signed long __must_check __copy_in_user(void __user *to, const void __user *from, unsigned long n);
253 extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n);
255 …nline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)  in copy_from_user()  argument
257 	if (access_ok(VERIFY_READ, from, n))  in copy_from_user()
258 		n = __copy_from_user(to, from, n);  in copy_from_user()
260 		memset(to, 0, n);  in copy_from_user()
261 	return n;  in copy_from_user()
264 … inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n)  in copy_to_user()  argument
266 	if (access_ok(VERIFY_WRITE, to, n))  in copy_to_user()
267 		n = __copy_to_user(to, from, n);  in copy_to_user()
268 	return n;  in copy_to_user()
271 … unsigned long __must_check copy_in_user(void __user *to, const void __user *from, unsigned long n)  in copy_in_user()  argument
273 	if (access_ok(VERIFY_READ, from, n) && access_ok(VERIFY_WRITE, to, n))  in copy_in_user()
274 		n = __copy_in_user(to, from, n);  in copy_in_user()
275 	return n;  in copy_in_user()
281 static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)  in clear_user()  argument
283 	if (access_ok(VERIFY_WRITE, to, n))  in clear_user()
284 		n = __clear_user(to, n);  in clear_user()
285 	return n;  in clear_user()
291 extern __must_check long strnlen_user(const char __user *str, long n);