riscv/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/[email protected]
Signed-off-by: David Hildenbrand <[email protected]>
Acked-by: Palmer Dabbelt <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Tobias Klauser <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

arch/riscv/kernel/vdso.c

@@ -54,7 +54,6 @@ static int __init vdso_init(void)
 		struct page *pg;
 
 		pg = virt_to_page(vdso_start + (i << PAGE_SHIFT));
-		ClearPageReserved(pg);
 		vdso_pagelist[i] = pg;
 	}
 	vdso_pagelist[i] = virt_to_page(vdso_data);