iommu/omap: Check for NULL in iopte_free()

The iopte_free() function should check for NULL because
kmem_cache_free() will panic on NULL argument.

Signed-off-by: Zhouyi Zhou <yizhouzhou@ict.ac.cn>
Signed-off-by: Joerg Roedel <joro@8bytes.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
index 8acea87cbc0e..7fcbfc498fa9 100644
--- a/drivers/iommu/omap-iommu.c
+++ b/drivers/iommu/omap-iommu.c
@@ -520,7 +520,8 @@ static void flush_iopte_range(u32 *first, u32 *last)
 static void iopte_free(u32 *iopte)
 {
         /* Note: freed iopte's must be clean ready for re-use */
-        kmem_cache_free(iopte_cachep, iopte);
+        if (iopte)
+                kmem_cache_free(iopte_cachep, iopte);
 }
 
 static u32 *iopte_alloc(struct omap_iommu *obj, u32 *iopgd, u32 da)