powerpc/pseries/iommu: Add iommu_pseries_alloc_table() helper

Creates a helper to allow allocating a new iommu_table without the need
to reallocate the iommu_group.

This will be helpful for replacing the iommu_table for the new DMA window,
after we remove the old one with iommu_tce_table_put().

Signed-off-by: Leonardo Bras <leobras.c@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Frederic Barrat <fbarrat@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210817063929.38701-4-leobras.c@gmail.com

diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index b1b8d12..33d8286 100644 (file)
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -53,28 +53,31 @@ enum {
        DDW_EXT_QUERY_OUT_SIZE = 2
 };
 
-static struct iommu_table_group *iommu_pseries_alloc_group(int node)
+static struct iommu_table *iommu_pseries_alloc_table(int node)
 {
-       struct iommu_table_group *table_group;
        struct iommu_table *tbl;
 
-       table_group = kzalloc_node(sizeof(struct iommu_table_group), GFP_KERNEL,
-                          node);
-       if (!table_group)
-               return NULL;
-
        tbl = kzalloc_node(sizeof(struct iommu_table), GFP_KERNEL, node);
        if (!tbl)
-               goto free_group;
+               return NULL;
 
        INIT_LIST_HEAD_RCU(&tbl->it_group_list);
        kref_init(&tbl->it_kref);
+       return tbl;
+}
 
-       table_group->tables[0] = tbl;
+static struct iommu_table_group *iommu_pseries_alloc_group(int node)
+{
+       struct iommu_table_group *table_group;
+
+       table_group = kzalloc_node(sizeof(*table_group), GFP_KERNEL, node);
+       if (!table_group)
+               return NULL;
 
-       return table_group;
+       table_group->tables[0] = iommu_pseries_alloc_table(node);
+       if (table_group->tables[0])
+               return table_group;
 
-free_group:
        kfree(table_group);
        return NULL;
 }