On Sat, 21 Apr 2007, Andrew Morton wrote:
> On Fri, 13 Apr 2007 20:08:28 +0200 (CEST) Guennadi Liakhovetski <[email protected]> wrote:
>
> > Hi
> >
> > Either I've finally gone blind on this Friday 13th or... Looks like this
> > almost 3 year old function has a bug. Patch below compile-tested... in a
> > way.
[patch skipped]
> Looks that way to me, too.
Then I'll dare suggest arch/cris - the second and last arch implementing
this API - has the same problem. Maintainer added to cc:, patch below.
> It also hopes like hell that `size' was a multiple of PAGE_SIZE.
Well, this API seems to have a bigger problem: it is difficult to get to
SoC/bus-local memory from several child devices. Even if I do implement
that DMA_MEMORY_INCLUDES_CHILDREN flag, 1) you do not always have the
desired device as your immediate parent, 2) you have to ref-count it. For
example, I was trying to use SoC-local SRAM on PXA270 from the
framebuffer, but fb-devices on PXA are either platform devices, or
sometimes get other parents. So, looks like another way to get to the SoC
node is needed...
Thanks
Guennadi
---
Guennadi Liakhovetski
Fix dma_declare_coherent_memory wrong allocation for cris/arch-v32
arch/cris/arch-v32 seems to have copy-pasted the bug from arch/i386 fixed
with an earlier patch - allocate bitmap in bytes, not words.
Signed-off-by: G. Liakhovetski <[email protected]>
diff --git a/arch/cris/arch-v32/drivers/pci/dma.c b/arch/cris/arch-v32/drivers/pci/dma.c
index 70d3bf0..d634347 100644
--- a/arch/cris/arch-v32/drivers/pci/dma.c
+++ b/arch/cris/arch-v32/drivers/pci/dma.c
@@ -76,7 +76,7 @@ int dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,
{
void __iomem *mem_base;
int pages = size >> PAGE_SHIFT;
- int bitmap_size = (pages + 31)/32;
+ int bitmap_size = DIV_ROUND_UP(pages, 8);
if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0)
goto out;
-
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