Commit 57250a5b authored Aug 09, 2010 by Jeremy Fitzhardinge Committed by Linus Torvalds Aug 09, 2010

mmu-notifiers: remove mmu notifier calls in apply_to_page_range()



It is not appropriate for apply_to_page_range() to directly call any mmu
notifiers, because it is a general purpose function whose effect depends
on what context it is called in and what the callback function does.

In particular, if it is being used as part of an mmu notifier
implementation, the recursive calls can be particularly problematic.

It is up to apply_to_page_range's caller to do any notifier calls if
necessary.  It does not affect any in-tree users because they all operate
on init_mm, and mmu notifiers only pertain to usermode mappings.

[stefano.stabellini@eu.citrix.com: remove unused local `start']
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Avi Kivity <avi@qumranet.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 58c37f6e

mm/memory.c

+2 −3

Original line number	Diff line number	Diff line
		@@ -2006,11 +2006,10 @@ int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
		{
		pgd_t *pgd;
		unsigned long next;
		unsigned long start = addr, end = addr + size;
		unsigned long end = addr + size;
		int err;

		BUG_ON(addr >= end);
		mmu_notifier_invalidate_range_start(mm, start, end);
		pgd = pgd_offset(mm, addr);
		do {
		next = pgd_addr_end(addr, end);
		@@ -2018,7 +2017,7 @@ int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
		if (err)
		break;
		} while (pgd++, addr = next, addr != end);
		mmu_notifier_invalidate_range_end(mm, start, end);

		return err;
		}
		EXPORT_SYMBOL_GPL(apply_to_page_range);

Admin message