dma: fix order calculation in dma_mark_declared_memory_occupied()
Jan Beulich [Tue, 5 Aug 2008 20:01:31 +0000 (13:01 -0700)]
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>

kernel/dma-coherent.c

index 7517115..91e9695 100644 (file)
@@ -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);