Commit d2dc1f4a authored Aug 05, 2008 by Jan Beulich Committed by Linus Torvalds Aug 05, 2008

dma: fix order calculation in dma_mark_declared_memory_occupied()



get_order() takes byte-sized input, not a page-granular one.

Irrespective of this fix I'm inclined to believe that this doesn't work
right anyway - bitmap_allocate_region() has an implicit assumption of
'pos' being suitable for 'order', which this function doesn't seem to
enforce (and since it's being called with a byte-granular value there's no
reason to believe that the callers would make sure device_addr is passed
accordingly - it's also not documented that way).

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Dmitry Baryshkov <dbaryshkov@gmail.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 978cc90c

kernel/dma-coherent.c

+2 −3

Original line number	Diff line number	Diff line
		@@ -77,15 +77,14 @@ void dma_mark_declared_memory_occupied(struct device dev,
		{
		struct dma_coherent_mem *mem = dev->dma_mem;
		int pos, err;
		int pages = (size + (device_addr & ~PAGE_MASK) + PAGE_SIZE - 1);

		pages >>= PAGE_SHIFT;
		size += device_addr & ~PAGE_MASK;

		if (!mem)
		return ERR_PTR(-EINVAL);

		pos = (device_addr - mem->device_base) >> PAGE_SHIFT;
		err = bitmap_allocate_region(mem->bitmap, pos, get_order(pages));
		err = bitmap_allocate_region(mem->bitmap, pos, get_order(size));
		if (err != 0)
		return ERR_PTR(err);
		return mem->virt_base + (pos << PAGE_SHIFT);

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