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    SubjectRe: [GIT PULL] various IOMMU updates for 2.6.29

    * 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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