dma_declare_coherent_memory wrong allocation

dma_declare_coherent_memory() allocates a bitmap 1 bit per page, it
calculates the bitmap size based on size of long, but allocates bytes...
Thanks to James Bottomley for clarifications and corrections.

Signed-off-by: G. Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: James Bottomley <James.Bottomley@SteelEye.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/i386/kernel/pci-dma.c b/arch/i386/kernel/pci-dma.c
index 3ebcea0..30b754f 100644
--- a/arch/i386/kernel/pci-dma.c
+++ b/arch/i386/kernel/pci-dma.c
@@ -77,7 +77,7 @@
 {
 	void __iomem *mem_base = NULL;
 	int pages = size >> PAGE_SHIFT;
-	int bitmap_size = (pages + 31)/32;
+	int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
 
 	if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0)
 		goto out;