AMD IOMMU: add stats counter for map_single requests

Impact: see number of map_single requests in debugfs
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

arch/x86/kernel/amd_iommu.c

@@ -65,6 +65,7 @@ static struct dma_ops_domain *find_protection_domain(u16 devid);
  */
 
 DECLARE_STATS_COUNTER(compl_wait);
+DECLARE_STATS_COUNTER(cnt_map_single);
 
 static struct dentry *stats_dir;
 static struct dentry *de_isolate;
@@ -92,6 +93,7 @@ static void amd_iommu_stats_init(void)
 					 (u32 *)&amd_iommu_unmap_flush);
 
 	amd_iommu_stats_add(&compl_wait);
+	amd_iommu_stats_add(&cnt_map_single);
 }
 
 #endif
@@ -1278,6 +1280,8 @@ static dma_addr_t map_single(struct device *dev, phys_addr_t paddr,
 	dma_addr_t addr;
 	u64 dma_mask;
 
+	INC_STATS_COUNTER(cnt_map_single);
+
 	if (!check_device(dev))
 		return bad_dma_address;