Re: [PATCH] x86: Fix CONFIG_PCI=n compile failure

[Ingo Molnar <mingo@elte.hu>]

* James Bottomley <James.Bottomley@HansenPartnership.com> wrote:

> This:
> 
> commit fae9a0d8ca68a14da8d2351ad3e0bf42f3b29899
> Author: Glauber Costa <gcosta@redhat.com>
> Date:   Tue Apr 8 13:20:56 2008 -0300
> 
>     x86: merge iommu initialization parameters
> 
> Moved the forbid_dac parameter into pci-dma.c but forgot that it's a 
> PCI only symbol thus causing a compile failure if CONFIG_PCI=N.  Fix 
> by surrounding the set clause in iommu_setup with #ifdef CONFIG_PCI

uhm, that's wrong James, the above commit you refer to is half a year 
old and has been released in v2.6.26 and v2.6.27 ;-)

The patch that broke the !CONFIG_PCI build in this cycle is this one:

| From 5b6985ce8ec7127b4d60ad450b64ca8b82748a3b Mon Sep 17 00:00:00 2001
| From: Fenghua Yu <fenghua.yu@intel.com>
| Date: Thu, 16 Oct 2008 18:02:32 -0700
| Subject: [PATCH] intel-iommu: IA64 support
|
| The current Intel IOMMU code assumes that both host page size and 
| Intel IOMMU page size are 4KiB. The first patch supports variable 
| page size. This provides support for IA64 which has multiple page 
| sizes.
|
| This patch also adds some other code hooks for IA64 platform 
| including DMAR_OPERATION_TIMEOUT definition.
|
| [dwmw2: some cleanup]
| Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
| Signed-off-by: Tony Luck <tony.luck@intel.com>
| Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>


> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
> 
> ---
> 
> diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
> index 1972266..47c5a7a 100644
> --- a/arch/x86/kernel/pci-dma.c
> +++ b/arch/x86/kernel/pci-dma.c
> @@ -202,6 +202,7 @@ static __init int iommu_setup(char *p)
>  			iommu_merge = 0;
>  		if (!strncmp(p, "forcesac", 8))
>  			iommu_sac_force = 1;
> +#ifdef CONFIG_PCI
>  		if (!strncmp(p, "allowdac", 8))
>  			forbid_dac = 0;
>  		if (!strncmp(p, "nodac", 5))
> @@ -210,6 +211,7 @@ static __init int iommu_setup(char *p)
>  			forbid_dac = -1;
>  			return 1;
>  		}
> +#endif

that's the wrong fix, the right fix from Fenghua Yu (from about a week 
ago) is at:

  http://marc.info/?l=linux-kernel&m=122480590627590&w=2

and it is in the PCI tree already.

	Ingo