Commit 9c312058 authored Mar 28, 2008 by Andrew Morton Committed by Linus Torvalds Mar 28, 2008

Avoid false positive warnings in kmap_atomic_prot() with DEBUG_HIGHMEM

I believe http://bugzilla.kernel.org/show_bug.cgi?id=10318

 is a false
positive.  There's no way in which networking will be using highmem pages
here, so it won't be taking the KM_USER0 kmap slot, so there's no point in
performing these checks.

Cc: Pawel Staszewski <pstaszewski@artcom.pl>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: Christoph Lameter <clameter@sgi.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 [ Really sad.  We lose almost all real-life coverage of the debug tests
   with this patch. Now it will only report problems for the cases where
   people actually end up using a HIGHMEM page, not when they just _might_
   use one.    - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 1f71f503

arch/x86/mm/highmem_32.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -73,15 +73,15 @@ void kmap_atomic_prot(struct page page, enum km_type type, pgprot_t prot)
		{
		enum fixed_addresses idx;
		unsigned long vaddr;
		/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */

		debug_kmap_atomic_prot(type);

		/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
		pagefault_disable();

		if (!PageHighMem(page))
		return page_address(page);

		debug_kmap_atomic_prot(type);

		idx = type + KM_TYPE_NR*smp_processor_id();
		vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
		BUG_ON(!pte_none(*(kmap_pte-idx)));

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