[PATCH kernel v4 11/19] powerpc/powernv: Reference iommu_table while it is linked to a group

[Alexey Kardashevskiy]

The iommu_table pointer stored in iommu_table_group may get stale
by accident, this adds referencing and removes a redundant comment
about this.

Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
Reviewed-by: David Gibson <da...@gibson.dropbear.id.au>
---
 arch/powerpc/platforms/powernv/pci-ioda-tce.c | 3 ++-
 arch/powerpc/platforms/powernv/pci-ioda.c     | 4 ----
 2 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/pci-ioda-tce.c 
b/arch/powerpc/platforms/powernv/pci-ioda-tce.c
index 7639b21..697449a 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda-tce.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda-tce.c
@@ -368,6 +368,7 @@ void pnv_pci_unlink_table_and_group(struct iommu_table *tbl,
        found = false;
        for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
                if (table_group->tables[i] == tbl) {
+                       iommu_tce_table_put(tbl);
                        table_group->tables[i] = NULL;
                        found = true;
                        break;
@@ -393,7 +394,7 @@ long pnv_pci_link_table_and_group(int node, int num,
        tgl->table_group = table_group;
        list_add_rcu(&tgl->next, &tbl->it_group_list);
 
-       table_group->tables[num] = tbl;
+       table_group->tables[num] = iommu_tce_table_get(tbl);
 
        return 0;
 }
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c 
b/arch/powerpc/platforms/powernv/pci-ioda.c
index c894c38..6193f1d 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -2716,10 +2716,6 @@ static long pnv_pci_ioda2_npu_unset_window(
 
 static void pnv_ioda2_npu_take_ownership(struct iommu_table_group *table_group)
 {
-       /*
-        * Detach NPU first as pnv_ioda2_take_ownership() will destroy
-        * the iommu_table if 32bit DMA is enabled.
-        */
        pnv_npu_take_ownership(gpe_table_group_to_npe(table_group));
        pnv_ioda2_take_ownership(table_group);
 }
-- 
2.17.1