Subject: Re: [PATCH 05/10] x86: add check code for map/unmap_single code

From: Joerg Roedel <[email-masked]>
Date: Sat, 22 Nov 2008 10:39:08 +0100

On Sat, Nov 22, 2008 at 12:27:41PM +0900, FUJITA Tomonori wrote:
> On Fri, 21 Nov 2008 17:26:05 +0100
> Joerg Roedel <[email-masked]> wrote:
> 
> > Impact: detect bugs in map/unmap_single usage
> > 
> > Signed-off-by: Joerg Roedel <[email-masked]>
> > ---
> >  arch/x86/include/asm/dma-mapping.h |    9 +++++-
> >  arch/x86/include/asm/dma_debug.h   |   20 +++++++++++++
> >  arch/x86/kernel/pci-dma-debug.c    |   55 ++++++++++++++++++++++++++++++++++++
> >  3 files changed, 83 insertions(+), 1 deletions(-)
> > 
> > diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
> > index 83d7b7d..c9bead2 100644
> > --- a/arch/x86/include/asm/dma-mapping.h
> > +++ b/arch/x86/include/asm/dma-mapping.h
> > @@ -98,9 +98,14 @@ dma_map_single(struct device *hwdev, void *ptr, size_t size,
> >  	       int direction)
> >  {
> >  	struct dma_mapping_ops *ops = get_dma_ops(hwdev);
> > +	dma_addr_t addr;
> >  
> >  	BUG_ON(!valid_dma_direction(direction));
> > -	return ops->map_single(hwdev, virt_to_phys(ptr), size, direction);
> > +	addr = ops->map_single(hwdev, virt_to_phys(ptr), size, direction);
> > +
> > +	debug_map_single(hwdev, ptr, size, direction, addr);
> 
> debug_map_single could fail due to OOM. Then debug_unmap_single in
> dma_unmap_single gives a false warning because it can't find the
> dma_debug_entry?

True. I will add a check to disable checking when a map operation has
failed.

Joerg