| Message ID | 1271076835-3182-1-git-send-email-stefan.bader@canonical.com |
|---|---|
| State | Accepted |
| Delegated to: | Andy Whitcroft |
| Headers | show |
On Mon, Apr 12, 2010 at 02:53:55PM +0200, Stefan Bader wrote: > This is really just hiding the warning about incompatible driver > code (for other archs). But its part of what is done for hot- > plugging in KVM (supposedly cloud) and its in the x86 only code > only, so it might be a way to prevent scared reports about nothing. > > Stefan > > From 72e6b51aa333435b9492011a4842ab0c462503de Mon Sep 17 00:00:00 2001 > From: Stefan Bader <stefan.bader@canonical.com> > Date: Mon, 29 Mar 2010 19:12:36 +0200 > Subject: [PATCH] dma-mapping: Remove WARN_ON in dma_free_coherent > > BugLink: http://bugs.launchpad.net/ubuntu/bugs/458201 > > Triggered by the following backtrace: > > WARNING: at > /build/buildd/linux-2.6.32/arch/x86/include/asm/dma-mapping.h:154 > ___free_dma_mem_cluster+0x102/0x110() > > [<ffffffff81064f9b>] warn_slowpath_common+0x7b/0xc0 > [<ffffffff81064ff4>] warn_slowpath_null+0x14/0x20 > [<ffffffff8139a2a2>] ___free_dma_mem_cluster+0x102/0x110 > [<ffffffff8139a072>] __sym_mfree+0xd2/0x100 > [<ffffffff8139a109>] __sym_mfree_dma+0x69/0x100 > [<ffffffff8139245f>] sym_hcb_free+0x8f/0x1f0 > > This patch never will be accepted upstream because the WARN_ON > is supposed to perevent driver development which is only > compatible with x86 on x86 (ARM can sleep in that function). > The right way to fix it would be to make the offending function > use locks in the right way but that requires careful implementation. > > Signed-off-by: Stefan Bader <stefan.bader@canonical.com> > --- > arch/x86/include/asm/dma-mapping.h | 2 -- > 1 files changed, 0 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h > index 6a25d5d..2d6097f 100644 > --- a/arch/x86/include/asm/dma-mapping.h > +++ b/arch/x86/include/asm/dma-mapping.h > @@ -151,8 +151,6 @@ static inline void dma_free_coherent(struct device *dev, size_t size, > { > struct dma_map_ops *ops = get_dma_ops(dev); > > - WARN_ON(irqs_disabled()); /* for portability */ > - > if (dma_release_from_coherent(dev, get_order(size), vaddr)) > return; This only removes a WARN_ON, ie no functionality should be changed. As the warning is bogus in a number of places which will trigger bug reports it is probabally best to remove it for now. Acked-by: Andy Whitcroft <apw@canonical.com> -apw
Applied to Lucid. -apw
diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h index 6a25d5d..2d6097f 100644 --- a/arch/x86/include/asm/dma-mapping.h +++ b/arch/x86/include/asm/dma-mapping.h @@ -151,8 +151,6 @@ static inline void dma_free_coherent(struct device *dev, size_t size, { struct dma_map_ops *ops = get_dma_ops(dev); - WARN_ON(irqs_disabled()); /* for portability */ - if (dma_release_from_coherent(dev, get_order(size), vaddr)) return;