Messages in this thread Patch in this message |  | | Date | Sun, 4 Jan 2009 11:05:11 +0100 | From | Ingo Molnar <> | Subject | Re: [GIT PULL] various IOMMU updates for 2.6.29 |
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* Joerg Roedel <joerg.roedel@amd.com> wrote:
> @@ -491,7 +491,7 @@ int alloc_iommu(struct dmar_drhd_unit *drhd) > int map_size; > u32 ver; > static int iommu_allocated = 0; > - int agaw; > + int agaw = 0; > > iommu = kzalloc(sizeof(*iommu), GFP_KERNEL); > if (!iommu) > @@ -507,6 +507,7 @@ int alloc_iommu(struct dmar_drhd_unit *drhd) > iommu->cap = dmar_readq(iommu->reg + DMAR_CAP_REG); > iommu->ecap = dmar_readq(iommu->reg + DMAR_ECAP_REG); > > +#ifdef CONFIG_DMAR > agaw = iommu_calculate_agaw(iommu); > if (agaw < 0) { > printk(KERN_ERR
yeah, setting it to zero should be safe in this case - agaw == 0 is a potentially bogus value as far as the hw is concerned, but the only user of it is intel-iommu.c which is only built if CONFIG_DMAR is set - and this is the non-DMA-remap case so it should not matter. David, do you agree?
but, that #ifdef in your patch is inacceptably ugly. The right approach is for iommu_calculate_agaw() to be an inline function in the !CONFIG_DMAR case, which returns 0. That makes the above code sequence work out of box, without any ugly #ifdefs.
See the patch below - i have queued it up in tip/core/urgent.
Ingo
-----------------------------> From c66b9906f863696159e05890bb7123269bb9a9de Mon Sep 17 00:00:00 2001 From: Ingo Molnar <mingo@elte.hu> Date: Sun, 4 Jan 2009 10:55:02 +0100 Subject: [PATCH] intel-iommu: fix build error with INTR_REMAP=y and DMAR=n
dmar.o can be built in the CONFIG_INTR_REMAP=y case but iommu_calculate_agaw() is only available if VT-d is built as well.
So create an inline version of iommu_calculate_agaw() for the !CONFIG_DMAR case. The iommu->agaw value wont be used in this case, but the code is cleaner (has less #ifdefs) if we have it around unconditionally.
Signed-off-by: Ingo Molnar <mingo@elte.hu> --- include/linux/dma_remapping.h | 8 ++++++++ 1 files changed, 8 insertions(+), 0 deletions(-)
diff --git a/include/linux/dma_remapping.h b/include/linux/dma_remapping.h index 136f170..af1dab4 100644 --- a/include/linux/dma_remapping.h +++ b/include/linux/dma_remapping.h @@ -17,7 +17,15 @@ struct dmar_domain; struct root_entry; extern void free_dmar_iommu(struct intel_iommu *iommu); + +#ifdef CONFIG_DMAR extern int iommu_calculate_agaw(struct intel_iommu *iommu); +#else +static inline int iommu_calculate_agaw(struct intel_iommu *iommu) +{ + return 0; +} +#endif extern int dmar_disabled;
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