AMD IOMMU: add stats counter for cross-page request

Impact: see number of requests for more than one page in debugfs
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

arch/x86/kernel/amd_iommu.c

@@ -71,6 +71,7 @@ DECLARE_STATS_COUNTER(cnt_map_sg);
 DECLARE_STATS_COUNTER(cnt_unmap_sg);
 DECLARE_STATS_COUNTER(cnt_alloc_coherent);
 DECLARE_STATS_COUNTER(cnt_free_coherent);
+DECLARE_STATS_COUNTER(cross_page);
 
 static struct dentry *stats_dir;
 static struct dentry *de_isolate;
@@ -104,6 +105,7 @@ static void amd_iommu_stats_init(void)
 	amd_iommu_stats_add(&cnt_unmap_sg);
 	amd_iommu_stats_add(&cnt_alloc_coherent);
 	amd_iommu_stats_add(&cnt_free_coherent);
+	amd_iommu_stats_add(&cross_page);
 }
 
 #endif
@@ -1217,6 +1219,9 @@ static dma_addr_t __map_single(struct device *dev,
 	pages = iommu_num_pages(paddr, size, PAGE_SIZE);
 	paddr &= PAGE_MASK;
 
+	if (pages > 1)
+		INC_STATS_COUNTER(cross_page);
+
 	if (align)
 		align_mask = (1UL << get_order(size)) - 1;