powerpc/iommu: Use bitmap library

- Caluculate the bitmap size with BITS_TO_LONGS()
 - Use bitmap_empty() to verify that all bits are cleared

This also includes a printk to pr_warn() conversion.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/kernel/iommu.c

@@ -656,7 +656,7 @@ struct iommu_table *iommu_init_table(struct iommu_table *tbl, int nid)
 	struct iommu_pool *p;
 
 	/* number of bytes needed for the bitmap */
-	sz = (tbl->it_size + 7) >> 3;
+	sz = BITS_TO_LONGS(tbl->it_size) * sizeof(unsigned long);
 
 	page = alloc_pages_node(nid, GFP_ATOMIC, get_order(sz));
 	if (!page)
@@ -708,7 +708,7 @@ struct iommu_table *iommu_init_table(struct iommu_table *tbl, int nid)
 
 void iommu_free_table(struct iommu_table *tbl, const char *node_name)
 {
-	unsigned long bitmap_sz, i;
+	unsigned long bitmap_sz;
 	unsigned int order;
 
 	if (!tbl || !tbl->it_map) {
@@ -718,17 +718,11 @@ void iommu_free_table(struct iommu_table *tbl, const char *node_name)
 	}
 
 	/* verify that table contains no entries */
-	/* it_size is in entries, and we're examining 64 at a time */
-	for (i = 0; i < (tbl->it_size/64); i++) {
-		if (tbl->it_map[i] != 0) {
-			printk(KERN_WARNING "%s: Unexpected TCEs for %s\n",
-				__func__, node_name);
-			break;
-		}
-	}
+	if (!bitmap_empty(tbl->it_map, tbl->it_size))
+		pr_warn("%s: Unexpected TCEs for %s\n", __func__, node_name);
 
 	/* calculate bitmap size in bytes */
-	bitmap_sz = (tbl->it_size + 7) / 8;
+	bitmap_sz = BITS_TO_LONGS(tbl->it_size) * sizeof(unsigned long);
 
 	/* free bitmap */
 	order = get_order(bitmap_sz);