[PATCH v3 06/12] iommu/exynos: allocate lv2 page table from own slab

[Cho KyongHo]

Since kmalloc() does not guarantee the alignment of 1KB when it
allocates 1KB, it is required to allocate lv2 page table from
own slab that guarantees alignment of 1KB.

Change-Id: Ia25642c7c0143d2c50a8ed5a3d0dd9067f324c4e
Signed-off-by: KyongHo Cho <pullip.cho at samsung.com>
---
 drivers/iommu/exynos-iommu.c | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index 4061b17..0bb194e 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -104,6 +104,8 @@
 #define REG_PB1_SADDR		0x054
 #define REG_PB1_EADDR		0x058
 
+static struct kmem_cache *lv2table_kmem_cache;
+
 static unsigned long *section_entry(unsigned long *pgtable, unsigned long iova)
 {
 	return pgtable + lv1ent_offset(iova);
@@ -865,7 +867,8 @@ static void exynos_iommu_domain_destroy(struct iommu_domain *domain)
 
 	for (i = 0; i < NUM_LV1ENTRIES; i++)
 		if (lv1ent_page(priv->pgtable + i))
-			kfree(__va(lv2table_base(priv->pgtable + i)));
+			kmem_cache_free(lv2table_kmem_cache,
+					__va(lv2table_base(priv->pgtable + i)));
 
 	free_pages((unsigned long)priv->pgtable, 2);
 	free_pages((unsigned long)priv->lv2entcnt, 1);
@@ -959,7 +962,7 @@ static unsigned long *alloc_lv2entry(unsigned long *sent, unsigned long iova,
 	if (lv1ent_fault(sent)) {
 		unsigned long *pent;
 
-		pent = kzalloc(LV2TABLE_SIZE, GFP_ATOMIC);
+		pent = kmem_cache_zalloc(lv2table_kmem_cache, GFP_ATOMIC);
 		BUG_ON((unsigned long)pent & (LV2TABLE_SIZE - 1));
 		if (!pent)
 			return NULL;
@@ -982,7 +985,7 @@ static int lv1set_section(unsigned long *sent, phys_addr_t paddr, short *pgcnt)
 		if (*pgcnt != NUM_LV2ENTRIES)
 			return -EADDRINUSE;
 
-		kfree(page_entry(sent, 0));
+		kmem_cache_free(lv2table_kmem_cache, page_entry(sent, 0));
 
 		*pgcnt = 0;
 	}
@@ -1168,10 +1171,23 @@ static int __init exynos_iommu_init(void)
 {
 	int ret;
 
+	lv2table_kmem_cache = kmem_cache_create("exynos-iommu-lv2table",
+		LV2TABLE_SIZE, LV2TABLE_SIZE, 0, NULL);
+	if (!lv2table_kmem_cache) {
+		pr_err("%s: failed to create kmem cache\n", __func__);
+		return -ENOMEM;
+	}
+
 	ret = platform_driver_register(&exynos_sysmmu_driver);
 
 	if (ret == 0)
-		bus_set_iommu(&platform_bus_type, &exynos_iommu_ops);
+		ret = bus_set_iommu(&platform_bus_type, &exynos_iommu_ops);
+
+	if (ret) {
+		pr_err("%s: Failed to register exynos-iommu driver.\n",
+								__func__);
+		kmem_cache_destroy(lv2table_kmem_cache);
+	}
 
 	return ret;
 }
-- 
1.8.0