1 files changed, 33 insertions, 8 deletions

diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index 45f09bec02c4..9c3be157397e 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -5,8 +5,10 @@
 #include <linux/kref.h>
 #include <linux/nsproxy.h>
 #include <linux/ns_common.h>
+#include <linux/rculist_nulls.h>
 #include <linux/sched.h>
 #include <linux/workqueue.h>
+#include <linux/rcuref.h>
 #include <linux/rwsem.h>
 #include <linux/sysctl.h>
 #include <linux/err.h>
@@ -21,9 +23,11 @@ struct uid_gid_extent {
 };
 
 struct uid_gid_map { /* 64 bytes -- 1 cache line */
-	u32 nr_extents;
 	union {
-		struct uid_gid_extent extent[UID_GID_MAP_MAX_BASE_EXTENTS];
+		struct {
+			struct uid_gid_extent extent[UID_GID_MAP_MAX_BASE_EXTENTS];
+			u32 nr_extents;
+		};
 		struct {
 			struct uid_gid_extent *forward;
 			struct uid_gid_extent *reverse;
@@ -65,6 +69,10 @@ enum rlimit_type {
 	UCOUNT_RLIMIT_COUNTS,
 };
 
+#if IS_ENABLED(CONFIG_BINFMT_MISC)
+struct binfmt_misc;
+#endif
+
 struct user_namespace {
 	struct uid_gid_map	uid_map;
 	struct uid_gid_map	gid_map;
@@ -102,13 +110,18 @@ struct user_namespace {
 	struct ucounts		*ucounts;
 	long ucount_max[UCOUNT_COUNTS];
 	long rlimit_max[UCOUNT_RLIMIT_COUNTS];
+
+#if IS_ENABLED(CONFIG_BINFMT_MISC)
+	struct binfmt_misc *binfmt_misc;
+#endif
 } __randomize_layout;
 
 struct ucounts {
-	struct hlist_node node;
+	struct hlist_nulls_node node;
 	struct user_namespace *ns;
 	kuid_t uid;
-	atomic_t count;
+	struct rcu_head rcu;
+	rcuref_t count;
 	atomic_long_t ucount[UCOUNT_COUNTS];
 	atomic_long_t rlimit[UCOUNT_RLIMIT_COUNTS];
 };
@@ -121,9 +134,15 @@ void retire_userns_sysctls(struct user_namespace *ns);
 struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, enum ucount_type type);
 void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
 struct ucounts *alloc_ucounts(struct user_namespace *ns, kuid_t uid);
-struct ucounts * __must_check get_ucounts(struct ucounts *ucounts);
 void put_ucounts(struct ucounts *ucounts);
 
+static inline struct ucounts * __must_check get_ucounts(struct ucounts *ucounts)
+{
+	if (rcuref_get(&ucounts->count))
+		return ucounts;
+	return NULL;
+}
+
 static inline long get_rlimit_value(struct ucounts *ucounts, enum rlimit_type type)
 {
 	return atomic_long_read(&ucounts->rlimit[type]);
@@ -131,7 +150,8 @@ static inline long get_rlimit_value(struct ucounts *ucounts, enum rlimit_type ty
 
 long inc_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v);
 bool dec_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v);
-long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum rlimit_type type);
+long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum rlimit_type type,
+			    bool override_rlimit);
 void dec_rlimit_put_ucounts(struct ucounts *ucounts, enum rlimit_type type);
 bool is_rlimit_overlimit(struct ucounts *ucounts, enum rlimit_type type, unsigned long max);
 
@@ -146,12 +166,17 @@ static inline void set_userns_rlimit_max(struct user_namespace *ns,
 	ns->rlimit_max[type] = max <= LONG_MAX ? max : LONG_MAX;
 }
 
+static inline struct user_namespace *to_user_ns(struct ns_common *ns)
+{
+	return container_of(ns, struct user_namespace, ns);
+}
+
 #ifdef CONFIG_USER_NS
 
 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
 {
 	if (ns)
-		refcount_inc(&ns->ns.count);
+		ns_ref_inc(ns);
 	return ns;
 }
 
@@ -161,7 +186,7 @@ extern void __put_user_ns(struct user_namespace *ns);
 
 static inline void put_user_ns(struct user_namespace *ns)
 {
-	if (ns && refcount_dec_and_test(&ns->ns.count))
+	if (ns && ns_ref_put(ns))
 		__put_user_ns(ns);
 }