powerpc/iommu: Put IOMMU group explicitly

So far an iommu_table lifetime was the same as PE. Dynamic DMA windows
will change this and iommu_free_table() will not always require
the group to be released.

This moves iommu_group_put() out of iommu_free_table().

This adds a iommu_pseries_free_table() helper which does
iommu_group_put() and iommu_free_table(). Later it will be
changed to receive a table_group and we will have to change less
lines then.

This should cause no behavioural change.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/iommu.c

@@ -726,13 +726,6 @@ void iommu_free_table(struct iommu_table *tbl, const char *node_name)
 	if (tbl->it_offset == 0)
 		clear_bit(0, tbl->it_map);
 
-#ifdef CONFIG_IOMMU_API
-	if (tbl->it_group) {
-		iommu_group_put(tbl->it_group);
-		BUG_ON(tbl->it_group);
-	}
-#endif
-
 	/* verify that table contains no entries */
 	if (!bitmap_empty(tbl->it_map, tbl->it_size))
 		pr_warn("%s: Unexpected TCEs for %s\n", __func__, node_name);

arch/powerpc/platforms/powernv/pci-ioda.c

@@ -23,6 +23,7 @@
 #include <linux/io.h>
 #include <linux/msi.h>
 #include <linux/memblock.h>
+#include <linux/iommu.h>
 
 #include <asm/sections.h>
 #include <asm/io.h>
@@ -1310,6 +1311,10 @@ static void pnv_pci_ioda2_release_dma_pe(struct pci_dev *dev, struct pnv_ioda_pe
 	if (rc)
 		pe_warn(pe, "OPAL error %ld release DMA window\n", rc);
 
+	if (tbl->it_group) {
+		iommu_group_put(tbl->it_group);
+		BUG_ON(tbl->it_group);
+	}
 	iommu_free_table(tbl, of_node_full_name(dev->dev.of_node));
 	free_pages(addr, get_order(TCE32_TABLE_SIZE));
 	pe->tce32_table = NULL;

arch/powerpc/platforms/pseries/iommu.c

@@ -36,6 +36,7 @@
 #include <linux/crash_dump.h>
 #include <linux/memory.h>
 #include <linux/of.h>
+#include <linux/iommu.h>
 #include <asm/io.h>
 #include <asm/prom.h>
 #include <asm/rtas.h>
@@ -51,6 +52,18 @@
 
 #include "pseries.h"
 
+static void iommu_pseries_free_table(struct iommu_table *tbl,
+		const char *node_name)
+{
+#ifdef CONFIG_IOMMU_API
+	if (tbl->it_group) {
+		iommu_group_put(tbl->it_group);
+		BUG_ON(tbl->it_group);
+	}
+#endif
+	iommu_free_table(tbl, node_name);
+}
+
 static void tce_invalidate_pSeries_sw(struct iommu_table *tbl,
 				      __be64 *startp, __be64 *endp)
 {
@@ -1271,7 +1284,8 @@ static int iommu_reconfig_notifier(struct notifier_block *nb, unsigned long acti
 		 */
 		remove_ddw(np, false);
 		if (pci && pci->iommu_table)
-			iommu_free_table(pci->iommu_table, np->full_name);
+			iommu_pseries_free_table(pci->iommu_table,
+					np->full_name);
 
 		spin_lock(&direct_window_list_lock);
 		list_for_each_entry(window, &direct_window_list, list) {