powerpc/net: Switch csum_and_copy_{to/from}_user to user_access block

Use user_access_begin() instead of the
might_sleep/access_ok/allow_access sequence.

Signed-off-by: Christophe Leroy <[e-mail]>
Signed-off-by: Michael Ellerman <[e-mail]>
Link: https://lore.kernel.org/r/2dee286d[e-mail]

arch/powerpc/lib/checksum_wrappers.c

···
 {
 	__wsum csum;
 
-	might_sleep();
-
-	if (unlikely(!access_ok(src, len)))
+	if (unlikely(!user_read_access_begin(src, len)))
 		return 0;
-
-	allow_read_from_user(src, len);
 
 	csum = csum_partial_copy_generic((void __force *)src, dst, len);
 
-	prevent_read_from_user(src, len);
+	user_read_access_end();
 	return csum;
 }
 EXPORT_SYMBOL(csum_and_copy_from_user);
···
 {
 	__wsum csum;
 
-	might_sleep();
-	if (unlikely(!access_ok(dst, len)))
+	if (unlikely(!user_write_access_begin(dst, len)))
 		return 0;
-
-	allow_write_to_user(dst, len);
 
 	csum = csum_partial_copy_generic(src, (void __force *)dst, len);
 
-	prevent_write_to_user(dst, len);
+	user_write_access_end();
 	return csum;
 }
 EXPORT_SYMBOL(csum_and_copy_to_user);