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    SubjectRe: [PATCH v9 5/8] perf/amd/iommu: Modify functions to query max banks and counters
    On Tue, Feb 07, 2017 at 02:40:33AM -0600, Suravee Suthikulpanit wrote:
    > Currently, amd_iommu_pc_get_max_[banks|counters]() use end-point
    > device ID to locate an IOMMU and check the reported max banks/counters.
    > The logic assumes that the IOMMU_BASE_DEVID belongs to the first IOMMU,
    > and uses it to acquire a reference to the first IOMMU, which does not work
    > on certain systems. Instead, modify the function to take an IOMMU index,
    > and use it to query the corresponding AMD IOMMU instance.
    >
    > Currently, hardcodes the IOMMU index to 0 since the current AMD IOMMU
    > perf implementation only supports a single IOMMU. A subsequent
    > patch will add support for multiple IOMMUs, and will use a proper IOMMU index.
    >
    > Cc: Peter Zijlstra <peterz@infradead.org>
    > Cc: Borislav Petkov <bp@alien8.de>
    > Cc: Joerg Roedel <joro@8bytes.org>
    > Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
    > ---

    ...

    > diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
    > index 1b5adb4..eb654e7 100644
    > --- a/drivers/iommu/amd_iommu_init.c
    > +++ b/drivers/iommu/amd_iommu_init.c
    > @@ -2715,6 +2715,21 @@ bool amd_iommu_v2_supported(void)
    > }
    > EXPORT_SYMBOL(amd_iommu_v2_supported);
    >
    > +struct amd_iommu *get_amd_iommu(unsigned int idx)
    > +{
    > + unsigned int i = 0;
    > + struct amd_iommu *iommu, *ret = NULL;
    > +
    > + for_each_iommu(iommu) {
    > + if (i++ == idx) {
    > + ret = iommu;
    > + break;

    return iommu;

    no need for the assignment and the break.

    > + }
    > + }
    > + return ret;
    > +}
    > +EXPORT_SYMBOL(get_amd_iommu);

    --
    Regards/Gruss,
    Boris.

    Good mailing practices for 400: avoid top-posting and trim the reply.

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