Commit eb0bf929 authored Oct 08, 2013 by Heiko Carstens Committed by Martin Schwidefsky Oct 24, 2013

s390/gup: handle zero nr_pages case correctly



If [__]get_user_pages_fast() gets called with nr_pages == 0, the current
code would walk the page tables and pin as many pages until the first
invalid pte (or the kernel crashed while writing struct page pointers to
the pages array).
So let's handle at least the nr_pages == 0 case correctly and exit early.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

parent 01997bbc

arch/s390/mm/gup.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -180,7 +180,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
		addr = start;
		len = (unsigned long) nr_pages << PAGE_SHIFT;
		end = start + len;
		if ((end < start) \|\| (end > TASK_SIZE))
		if ((end <= start) \|\| (end > TASK_SIZE))
		return 0;
		/*
		* local_irq_save() doesn't prevent pagetable teardown, but does

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