userfaultfd: uapi: fix UFFDIO_CONTINUE ioctl request definition

This ioctl request reads from uffdio_continue structure written by
userspace which justifies _IOC_WRITE flag.  It also writes back to that
structure which justifies _IOC_READ flag.

See NOTEs in include/uapi/asm-generic/ioctl.h for more information.

Fixes: f619147104c8 ("userfaultfd: add UFFDIO_CONTINUE ioctl")
Signed-off-by: Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org>
Acked-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Axel Rasmussen <axelrasmussen@google.com>
Reviewed-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/uapi/linux/userfaultfd.h b/include/uapi/linux/userfaultfd.h
index bafbeb1..650480f 100644 (file)
--- a/include/uapi/linux/userfaultfd.h
+++ b/include/uapi/linux/userfaultfd.h
@@ -80,8 +80,8 @@
                                      struct uffdio_zeropage)
 #define UFFDIO_WRITEPROTECT    _IOWR(UFFDIO, _UFFDIO_WRITEPROTECT, \
                                      struct uffdio_writeprotect)
-#define UFFDIO_CONTINUE                _IOR(UFFDIO, _UFFDIO_CONTINUE,  \
-                                    struct uffdio_continue)
+#define UFFDIO_CONTINUE                _IOWR(UFFDIO, _UFFDIO_CONTINUE, \
+                                     struct uffdio_continue)
 
 /* read() structure */
 struct uffd_msg {