iommu/tegra-smmu: Use kcalloc() to allocate counter array

Use kcalloc() to allocate the use-counter array for the page directory
entries/page tables.  Using kcalloc() allows us to be provided with
zero-initialised memory from the allocators, rather than initialising
it ourselves.

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

1 files changed, 6 insertions, 15 deletions

diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index 8ec5ac45caab..d649b06cc4ca 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -40,7 +40,7 @@ struct tegra_smmu_as {
         struct iommu_domain domain;
         struct tegra_smmu *smmu;
         unsigned int use_count;
-        struct page *count;
+        u32 *count;
         struct page **pts;
         struct page *pd;
         unsigned id;
@@ -265,7 +265,7 @@ static struct iommu_domain *tegra_smmu_domain_alloc(unsigned type)
                 return NULL;
         }
 
-        as->count = alloc_page(GFP_KERNEL);
+        as->count = kcalloc(SMMU_NUM_PDE, sizeof(u32), GFP_KERNEL);
         if (!as->count) {
                 __free_page(as->pd);
                 kfree(as);
@@ -274,7 +274,7 @@ static struct iommu_domain *tegra_smmu_domain_alloc(unsigned type)
 
         as->pts = kcalloc(SMMU_NUM_PDE, sizeof(*as->pts), GFP_KERNEL);
         if (!as->pts) {
-                __free_page(as->count);
+                kfree(as->count);
                 __free_page(as->pd);
                 kfree(as);
                 return NULL;
@@ -287,13 +287,6 @@ static struct iommu_domain *tegra_smmu_domain_alloc(unsigned type)
         for (i = 0; i < SMMU_NUM_PDE; i++)
                 pd[i] = 0;
 
-        /* clear PDE usage counters */
-        pd = page_address(as->count);
-        SetPageReserved(as->count);
-
-        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;
@@ -509,7 +502,7 @@ static u32 *tegra_smmu_pte_lookup(struct tegra_smmu_as *as, unsigned long iova,
 static u32 *as_get_pte(struct tegra_smmu_as *as, dma_addr_t iova,
                        struct page **pagep)
 {
-        u32 *pd = page_address(as->pd), *pt, *count;
+        u32 *pd = page_address(as->pd), *pt;
         unsigned int pde = iova_pd_index(iova);
         struct tegra_smmu *smmu = as->smmu;
         struct page *page;
@@ -545,9 +538,8 @@ static u32 *as_get_pte(struct tegra_smmu_as *as, dma_addr_t iova,
         pt = page_address(page);
 
         /* Keep track of entries in this page table. */
-        count = page_address(as->count);
         if (pt[iova_pt_index(iova)] == 0)
-                count[pde]++;
+                as->count[pde]++;
 
         return tegra_smmu_pte_offset(page, iova);
 }
@@ -556,7 +548,6 @@ static void tegra_smmu_pte_put_use(struct tegra_smmu_as *as, unsigned long iova)
 {
         struct tegra_smmu *smmu = as->smmu;
         unsigned int pde = iova_pd_index(iova);
-        u32 *count = page_address(as->count);
         u32 *pd = page_address(as->pd);
         struct page *page = as->pts[pde];
 
@@ -564,7 +555,7 @@ static void tegra_smmu_pte_put_use(struct tegra_smmu_as *as, unsigned long iova)
          * When no entries in this page table are used anymore, return the
          * memory page to the system.
          */
-        if (--count[pde] == 0) {
+        if (--as->count[pde] == 0) {
                 unsigned int offset = pde * sizeof(*pd);
 
                 /* Clear the page directory entry first */