1 files changed, 60 insertions, 3 deletions

diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index 373adf69b01c..6e765bf00670 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -678,8 +678,6 @@ void page_table_free(struct mm_struct *mm, unsigned long *table)
         }
 }
 
-#ifdef CONFIG_HAVE_RCU_TABLE_FREE
-
 static void __page_table_free_rcu(void *table, unsigned bit)
 {
         struct page *page;
@@ -733,7 +731,66 @@ void __tlb_remove_table(void *_table)
                 free_pages((unsigned long) table, ALLOC_ORDER);
 }
 
-#endif
+static void tlb_remove_table_smp_sync(void *arg)
+{
+        /* Simply deliver the interrupt */
+}
+
+static void tlb_remove_table_one(void *table)
+{
+        /*
+         * This isn't an RCU grace period and hence the page-tables cannot be
+         * assumed to be actually RCU-freed.
+         *
+         * It is however sufficient for software page-table walkers that rely
+         * on IRQ disabling. See the comment near struct mmu_table_batch.
+         */
+        smp_call_function(tlb_remove_table_smp_sync, NULL, 1);
+        __tlb_remove_table(table);
+}
+
+static void tlb_remove_table_rcu(struct rcu_head *head)
+{
+        struct mmu_table_batch *batch;
+        int i;
+
+        batch = container_of(head, struct mmu_table_batch, rcu);
+
+        for (i = 0; i < batch->nr; i++)
+                __tlb_remove_table(batch->tables[i]);
+
+        free_page((unsigned long)batch);
+}
+
+void tlb_table_flush(struct mmu_gather *tlb)
+{
+        struct mmu_table_batch **batch = &tlb->batch;
+
+        if (*batch) {
+                __tlb_flush_mm(tlb->mm);
+                call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu);
+                *batch = NULL;
+        }
+}
+
+void tlb_remove_table(struct mmu_gather *tlb, void *table)
+{
+        struct mmu_table_batch **batch = &tlb->batch;
+
+        if (*batch == NULL) {
+                *batch = (struct mmu_table_batch *)
+                        __get_free_page(GFP_NOWAIT | __GFP_NOWARN);
+                if (*batch == NULL) {
+                        __tlb_flush_mm(tlb->mm);
+                        tlb_remove_table_one(table);
+                        return;
+                }
+                (*batch)->nr = 0;
+        }
+        (*batch)->tables[(*batch)->nr++] = table;
+        if ((*batch)->nr == MAX_TABLE_BATCH)
+                tlb_table_flush(tlb);
+}
 
 /*
  * switch on pgstes for its userspace process (for kvm)