@@ -50,6 +50,8 @@
  #define mask_user_address(src) (src)
 #endif
 
+#define SMALL_COPY_USER		64
+
 /*
  * Architectures should provide two primitives (raw_copy_{to,from}_user())
  * and get rid of their private instances of copy_{to,from}_user() and

@@ -191,6 +193,9 @@ _inline_copy_from_user(void *to, const void __user *from, unsigned long n)
 	return res;
 }
 
+static __always_inline __must_check unsigned long
+_small_copy_from_user(void *to, const void __user *from, unsigned long n);
+
 extern __must_check unsigned long
 _copy_from_user(void *, const void __user *, unsigned long);
 

@@ -207,6 +212,9 @@ _inline_copy_to_user(void __user *to, const void *from, unsigned long n)
 	return n;
 }
 
+static __always_inline __must_check unsigned long
+_small_copy_to_user(void __user *to, const void *from, unsigned long n);
+
 extern __must_check unsigned long
 _copy_to_user(void __user *, const void *, unsigned long);
 

@@ -215,6 +223,8 @@ copy_from_user_common(void *to, const void __user *from, unsigned long n, bool p
 {
 	if (!check_copy_size(to, n, false))
 		return n;
+	if (!partial && __builtin_constant_p(n) && n <= SMALL_COPY_USER)
+		return _small_copy_from_user(to, from, n);
 	if (IS_ENABLED(ARCH_WANTS_NOINLINE_COPY_USER))
 		return _copy_from_user(to, from, n);
 	else

@@ -239,6 +249,8 @@ copy_to_user_common(void __user *to, const void *from, unsigned long n, bool par
 	if (!check_copy_size(from, n, true))
 		return n;
 
+	if (!partial && __builtin_constant_p(n) && n <= SMALL_COPY_USER)
+		return _small_copy_to_user(to, from, n);
 	if (IS_ENABLED(ARCH_WANTS_NOINLINE_COPY_USER))
 		return _copy_to_user(to, from, n);
 	else

@@ -838,6 +850,41 @@ for (bool done = false; !done; done = true)					\
 #define scoped_user_rw_access(uptr, elbl)				\
 	scoped_user_rw_access_size(uptr, sizeof(*(uptr)), elbl)
 
+static __always_inline __must_check unsigned long
+_small_copy_from_user(void *to, const void __user *from, unsigned long n)
+{
+	might_fault();
+	instrument_copy_from_user_before(to, from, n);
+	scoped_user_read_access_size(from, n, failed) {
+		/*
+		 * Ensure that bad access_ok() speculation will not lead
+		 * to nasty side effects *after* the copy is finished:
+		 */
+		if (!can_do_masked_user_access())
+			barrier_nospec();
+		unsafe_copy_from_user(to, from, n, failed);
+	}
+	instrument_copy_from_user_after(to, from, n, 0);
+	return 0;
+failed:
+	instrument_copy_from_user_after(to, from, n, n);
+	return n;
+}
+
+static __always_inline __must_check unsigned long
+_small_copy_to_user(void __user *to, const void *from, unsigned long n)
+{
+	might_fault();
+	if (should_fail_usercopy())
+		return n;
+	instrument_copy_to_user(to, from, n);
+	scoped_user_write_access_size(to, n, failed)
+		unsafe_copy_to_user(to, from, n, failed);
+	return 0;
+failed:
+	return n;
+}
+
 /**
  * get_user_inline - Read user data inlined
  * @val:	The variable to store the value read from user memory