2 files changed, 16 insertions, 1 deletions
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 716255f88bbd..8848fec51ce9 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -1868,5 +1868,4 @@ static int __init hash64_debugfs(void)
 	return 0;
 }
 machine_device_initcall(pseries, hash64_debugfs);
-
 #endif /* CONFIG_DEBUG_FS */
diff --git a/arch/powerpc/mm/mmu_context_book3s64.c b/arch/powerpc/mm/mmu_context_book3s64.c
index fd0bc6db2dcd..7bc5b63034db 100644
--- a/arch/powerpc/mm/mmu_context_book3s64.c
+++ b/arch/powerpc/mm/mmu_context_book3s64.c
@@ -57,6 +57,22 @@ again:
 	return index;
 }
 
+void hash__reserve_context_id(int id)
+{
+	int rc, result = 0;
+
+	do {
+		if (!ida_pre_get(&mmu_context_ida, GFP_KERNEL))
+			break;
+
+		spin_lock(&mmu_context_lock);
+		rc = ida_get_new_above(&mmu_context_ida, id, &result);
+		spin_unlock(&mmu_context_lock);
+	} while (rc == -EAGAIN);
+
+	WARN(result != id, "mmu: Failed to reserve context id %d (rc %d)\n", id, result);
+}
+
 int hash__alloc_context_id(void)
 {
 	unsigned long max;