iommu/tegra-smmu: Use __GFP_ZERO to allocate zeroed pages

Rather than explicitly zeroing pages allocated via alloc_page(), add
__GFP_ZERO to the gfp mask to ask the allocator for zeroed pages.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Thierry Reding <treding@nvidia.com>

diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index eb9f6068fe2e0fad5ff69d2e79448bf1fdd852bd..27d31f62a822ecb1586c74f72912af2c24f406f3 100644 (file)
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -258,8 +258,6 @@ static bool tegra_smmu_capable(enum iommu_cap cap)
 static struct iommu_domain *tegra_smmu_domain_alloc(unsigned type)
 {
        struct tegra_smmu_as *as;
-       unsigned int i;
-       uint32_t *pd;
 
        if (type != IOMMU_DOMAIN_UNMANAGED)
                return NULL;
@@ -270,7 +268,7 @@ static struct iommu_domain *tegra_smmu_domain_alloc(unsigned type)
 
        as->attr = SMMU_PD_READABLE | SMMU_PD_WRITABLE | SMMU_PD_NONSECURE;
 
-       as->pd = alloc_page(GFP_KERNEL | __GFP_DMA);
+       as->pd = alloc_page(GFP_KERNEL | __GFP_DMA | __GFP_ZERO);
        if (!as->pd) {
                kfree(as);
                return NULL;
@@ -291,12 +289,6 @@ static struct iommu_domain *tegra_smmu_domain_alloc(unsigned type)
                return NULL;
        }
 
-       /* clear PDEs */
-       pd = page_address(as->pd);
-
-       for (i = 0; i < SMMU_NUM_PDE; i++)
-               pd[i] = 0;
-
        /* setup aperture */
        as->domain.geometry.aperture_start = 0;
        as->domain.geometry.aperture_end = 0xffffffff;
@@ -533,21 +525,15 @@ static u32 *as_get_pte(struct tegra_smmu_as *as, dma_addr_t iova,
        u32 *pd = page_address(as->pd), *pt;
        unsigned int pde = iova_pd_index(iova);
        struct tegra_smmu *smmu = as->smmu;
-       unsigned int i;
 
        if (!as->pts[pde]) {
                struct page *page;
                dma_addr_t dma;
 
-               page = alloc_page(GFP_KERNEL | __GFP_DMA);
+               page = alloc_page(GFP_KERNEL | __GFP_DMA | __GFP_ZERO);
                if (!page)
                        return NULL;
 
-               pt = page_address(page);
-
-               for (i = 0; i < SMMU_NUM_PTE; i++)
-                       pt[i] = 0;
-
                dma = dma_map_page(smmu->dev, page, 0, SMMU_SIZE_PT,
                                   DMA_TO_DEVICE);
                if (dma_mapping_error(smmu->dev, dma)) {