Commit 7561e8ca authored Mar 25, 2010 by David Howells Committed by Linus Torvalds Mar 25, 2010

NOMMU: Revert 'nommu: get_user_pages(): pin last page on non-page-aligned start'



Revert the following patch:

	commit c08c6e1f
	Author: Steven J. Magnani <steve@digidescorp.com>
	Date:   Fri Mar 5 13:42:24 2010 -0800

	nommu: get_user_pages(): pin last page on non-page-aligned start

As it assumes that the mappings begin at the start of pages - something that
isn't necessarily true on NOMMU systems.  On NOMMU systems, it is possible for
a mapping to only occupy part of the page, and not necessarily touch either end
of it; in fact it's also possible for multiple non-overlapping mappings to
coexist on one page (consider direct mappings of ROMFS files, for example).

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steven J. Magnani <steve@digidescorp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 39f1cd63

mm/nommu.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -146,7 +146,7 @@ int __get_user_pages(struct task_struct tsk, struct mm_struct mm,
		(VM_MAYREAD \| VM_MAYWRITE) : (VM_READ \| VM_WRITE);

		for (i = 0; i < nr_pages; i++) {
		vma = find_extend_vma(mm, start);
		vma = find_vma(mm, start);
		if (!vma)
		goto finish_or_fault;

		@@ -764,7 +764,7 @@ EXPORT_SYMBOL(find_vma);
		*/
		struct vm_area_struct find_extend_vma(struct mm_struct mm, unsigned long addr)
		{
		return find_vma(mm, addr & PAGE_MASK);
		return find_vma(mm, addr);
		}

		/*

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