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Subject: [PATCH 5/8] user: Use generic ns_common::count
From:   Kirill Tkhai <ktkhai@virtuozzo.com>
To:     christian.brauner@ubuntu.com, akpm@linux-foundation.org,
        ebiederm@xmission.com, viro@zeniv.linux.org.uk,
        adobriyan@gmail.com, davem@davemloft.net,
        linux-kernel@vger.kernel.org, ktkhai@virtuozzo.com
Date:   Mon, 03 Aug 2020 13:16:37 +0300
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Convert user namespace to use generic counter.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
---
 include/linux/user_namespace.h |    5 ++---
 kernel/user.c                  |    2 +-
 kernel/user_namespace.c        |    4 ++--
 3 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index 6ef1c7109fc4..64cf8ebdc4ec 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -57,7 +57,6 @@ struct user_namespace {
 	struct uid_gid_map	uid_map;
 	struct uid_gid_map	gid_map;
 	struct uid_gid_map	projid_map;
-	atomic_t		count;
 	struct user_namespace	*parent;
 	int			level;
 	kuid_t			owner;
@@ -109,7 +108,7 @@ void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
 {
 	if (ns)
-		atomic_inc(&ns->count);
+		refcount_inc(&ns->ns.count);
 	return ns;
 }
 
@@ -119,7 +118,7 @@ extern void __put_user_ns(struct user_namespace *ns);
 
 static inline void put_user_ns(struct user_namespace *ns)
 {
-	if (ns && atomic_dec_and_test(&ns->count))
+	if (ns && refcount_dec_and_test(&ns->ns.count))
 		__put_user_ns(ns);
 }
 
diff --git a/kernel/user.c b/kernel/user.c
index b1635d94a1f2..a2478cddf536 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -55,7 +55,7 @@ struct user_namespace init_user_ns = {
 			},
 		},
 	},
-	.count = ATOMIC_INIT(3),
+	.ns.count = REFCOUNT_INIT(3),
 	.owner = GLOBAL_ROOT_UID,
 	.group = GLOBAL_ROOT_GID,
 	.ns.inum = PROC_USER_INIT_INO,
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 87804e0371fe..7c2bbe8f3e45 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -111,7 +111,7 @@ int create_user_ns(struct cred *new)
 		goto fail_free;
 	ns->ns.ops = &userns_operations;
 
-	atomic_set(&ns->count, 1);
+	refcount_set(&ns->ns.count, 1);
 	/* Leave the new->user_ns reference with the new user namespace. */
 	ns->parent = parent_ns;
 	ns->level = parent_ns->level + 1;
@@ -197,7 +197,7 @@ static void free_user_ns(struct work_struct *work)
 		kmem_cache_free(user_ns_cachep, ns);
 		dec_user_namespaces(ucounts);
 		ns = parent;
-	} while (atomic_dec_and_test(&parent->count));
+	} while (refcount_dec_and_test(&parent->ns.count));
 }
 
 void __put_user_ns(struct user_namespace *ns)