s390/vdso: don't clear PG_reserved

The VDSO is part of the kernel image and therefore the struct pages are
marked as reserved during boot.

As we install a special mapping, the actual struct pages will never be
exposed to MM via the page tables.  We can therefore leave the pages
marked as reserved.

Link: http://lkml.kernel.org/r/20190114125903.24845-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Suggested-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c
index 4ff354887db412a504bb432956c28b2ba6b8a936..e7920a68a12ecf977e73a237a446bf65a5dfbecc 100644 (file)
--- a/arch/s390/kernel/vdso.c
+++ b/arch/s390/kernel/vdso.c
@@ -291,7 +291,6 @@ static int __init vdso_init(void)
        BUG_ON(vdso32_pagelist == NULL);
        for (i = 0; i < vdso32_pages - 1; i++) {
                struct page *pg = virt_to_page(vdso32_kbase + i*PAGE_SIZE);
-               ClearPageReserved(pg);
                get_page(pg);
                vdso32_pagelist[i] = pg;
        }
@@ -309,7 +308,6 @@ static int __init vdso_init(void)
        BUG_ON(vdso64_pagelist == NULL);
        for (i = 0; i < vdso64_pages - 1; i++) {
                struct page *pg = virt_to_page(vdso64_kbase + i*PAGE_SIZE);
-               ClearPageReserved(pg);
                get_page(pg);
                vdso64_pagelist[i] = pg;
        }