iommu/vt-d: Reduce extra first level entry in iommu->domains

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.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index a644d0c..748e5e4 100644 (file)
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -1672,7 +1672,7 @@ static int iommu_init_domains(struct intel_iommu *iommu)
                return -ENOMEM;
        }
 
-       size = ((ndomains >> 8) + 1) * sizeof(struct dmar_domain **);
+       size = (ALIGN(ndomains, 256) >> 8) * sizeof(struct dmar_domain **);
        iommu->domains = kzalloc(size, GFP_KERNEL);
 
        if (iommu->domains) {
@@ -1737,7 +1737,7 @@ 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 = ALIGN(cap_ndoms(iommu->cap), 256) >> 8;
                int i;
 
                for (i = 0; i < elems; i++)