In commit <8bf478163e69> ("iommu/vt-d: Split up iommu->domains array"), it
it splits iommu->domains in two levels. Each first level contains 256
entries of second level. In case of the ndomains is exact a multiple of
256, it would have one more extra first level entry for current
implementation.This patch refines this calculation to reduce the extra first level entry when ndomains is exact a multiple of 256. Signed-off-by: Wei Yang <[email protected]> --- drivers/iommu/intel-iommu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index d7fa268..1c8b587 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -1634,7 +1634,7 @@ static int iommu_init_domains(struct intel_iommu *iommu) return -ENOMEM; } - size = ((ndomains >> 8) + 1) * sizeof(struct dmar_domain **); + size = DIV_ROUND_UP(ndomains, 256) * sizeof(struct dmar_domain **); iommu->domains = kzalloc(size, GFP_KERNEL); if (iommu->domains) { @@ -1699,7 +1699,7 @@ static void disable_dmar_iommu(struct intel_iommu *iommu) static void free_dmar_iommu(struct intel_iommu *iommu) { if ((iommu->domains) && (iommu->domain_ids)) { - int elems = (cap_ndoms(iommu->cap) >> 8) + 1; + int elems = DIV_ROUND_UP(cap_ndoms(iommu->cap), 256); int i; for (i = 0; i < elems; i++) -- 2.5.0
