1 files changed, 51 insertions, 215 deletions

diff --git a/include/linux/ns_common.h b/include/linux/ns_common.h
index 66ea09b48377..136f6a322e53 100644
--- a/include/linux/ns_common.h
+++ b/include/linux/ns_common.h
@@ -2,139 +2,18 @@
 #ifndef _LINUX_NS_COMMON_H
 #define _LINUX_NS_COMMON_H
 
+#include <linux/ns/ns_common_types.h>
 #include <linux/refcount.h>
-#include <linux/rbtree.h>
 #include <linux/vfsdebug.h>
 #include <uapi/linux/sched.h>
 #include <uapi/linux/nsfs.h>
 
-struct proc_ns_operations;
-
-struct cgroup_namespace;
-struct ipc_namespace;
-struct mnt_namespace;
-struct net;
-struct pid_namespace;
-struct time_namespace;
-struct user_namespace;
-struct uts_namespace;
-
-extern struct cgroup_namespace init_cgroup_ns;
-extern struct ipc_namespace init_ipc_ns;
-extern struct mnt_namespace init_mnt_ns;
-extern struct net init_net;
-extern struct pid_namespace init_pid_ns;
-extern struct time_namespace init_time_ns;
-extern struct user_namespace init_user_ns;
-extern struct uts_namespace init_uts_ns;
-
-extern const struct proc_ns_operations netns_operations;
-extern const struct proc_ns_operations utsns_operations;
-extern const struct proc_ns_operations ipcns_operations;
-extern const struct proc_ns_operations pidns_operations;
-extern const struct proc_ns_operations pidns_for_children_operations;
-extern const struct proc_ns_operations userns_operations;
-extern const struct proc_ns_operations mntns_operations;
-extern const struct proc_ns_operations cgroupns_operations;
-extern const struct proc_ns_operations timens_operations;
-extern const struct proc_ns_operations timens_for_children_operations;
-
-/*
- * Namespace lifetimes are managed via a two-tier reference counting model:
- *
- * (1) __ns_ref (refcount_t): Main reference count tracking memory
- *     lifetime. Controls when the namespace structure itself is freed.
- *     It also pins the namespace on the namespace trees whereas (2)
- *     only regulates their visibility to userspace.
- *
- * (2) __ns_ref_active (atomic_t): Reference count tracking active users.
- *     Controls visibility of the namespace in the namespace trees.
- *     Any live task that uses the namespace (via nsproxy or cred) holds
- *     an active reference. Any open file descriptor or bind-mount of
- *     the namespace holds an active reference. Once all tasks have
- *     called exited their namespaces and all file descriptors and
- *     bind-mounts have been released the active reference count drops
- *     to zero and the namespace becomes inactive. IOW, the namespace
- *     cannot be listed or opened via file handles anymore.
- *
- *     Note that it is valid to transition from active to inactive and
- *     back from inactive to active e.g., when resurrecting an inactive
- *     namespace tree via the SIOCGSKNS ioctl().
- *
- * Relationship and lifecycle states:
- *
- * - Active (__ns_ref_active > 0):
- *   Namespace is actively used and visible to userspace. The namespace
- *   can be reopened via /proc/<pid>/ns/<ns_type>, via namespace file
- *   handles, or discovered via listns().
- *
- * - Inactive (__ns_ref_active == 0, __ns_ref > 0):
- *   No tasks are actively using the namespace and it isn't pinned by
- *   any bind-mounts or open file descriptors anymore. But the namespace
- *   is still kept alive by internal references. For example, the user
- *   namespace could be pinned by an open file through file->f_cred
- *   references when one of the now defunct tasks had opened a file and
- *   handed the file descriptor off to another process via a UNIX
- *   sockets. Such references keep the namespace structure alive through
- *   __ns_ref but will not hold an active reference.
- *
- * - Destroyed (__ns_ref == 0):
- *   No references remain. The namespace is removed from the tree and freed.
- *
- * State transitions:
- *
- * Active -> Inactive:
- *   When the last task using the namespace exits it drops its active
- *   references to all namespaces. However, user and pid namespaces
- *   remain accessible until the task has been reaped.
- *
- * Inactive -> Active:
- *   An inactive namespace tree might be resurrected due to e.g., the
- *   SIOCGSKNS ioctl() on a socket.
- *
- * Inactive -> Destroyed:
- *   When __ns_ref drops to zero the namespace is removed from the
- *   namespaces trees and the memory is freed (after RCU grace period).
- *
- * Initial namespaces:
- *   Boot-time namespaces (init_net, init_pid_ns, etc.) start with
- *   __ns_ref_active = 1 and remain active forever.
- */
-struct ns_common {
-	u32 ns_type;
-	struct dentry *stashed;
-	const struct proc_ns_operations *ops;
-	unsigned int inum;
-	refcount_t __ns_ref; /* do not use directly */
-	union {
-		struct {
-			u64 ns_id;
-			struct /* global namespace rbtree and list */ {
-				struct rb_node ns_unified_tree_node;
-				struct list_head ns_unified_list_node;
-			};
-			struct /* per type rbtree and list */ {
-				struct rb_node ns_tree_node;
-				struct list_head ns_list_node;
-			};
-			struct /* namespace ownership rbtree and list */ {
-				struct rb_root ns_owner_tree; /* rbtree of namespaces owned by this namespace */
-				struct list_head ns_owner; /* list of namespaces owned by this namespace */
-				struct rb_node ns_owner_tree_node; /* node in the owner namespace's rbtree */
-				struct list_head ns_owner_entry; /* node in the owner namespace's ns_owned list */
-			};
-			atomic_t __ns_ref_active; /* do not use directly */
-		};
-		struct rcu_head ns_rcu;
-	};
-};
-
 bool is_current_namespace(struct ns_common *ns);
 int __ns_common_init(struct ns_common *ns, u32 ns_type, const struct proc_ns_operations *ops, int inum);
 void __ns_common_free(struct ns_common *ns);
 struct ns_common *__must_check ns_owner(struct ns_common *ns);
 
-static __always_inline bool is_initial_namespace(struct ns_common *ns)
+static __always_inline bool is_ns_init_inum(const struct ns_common *ns)
 {
 	VFS_WARN_ON_ONCE(ns->inum == 0);
 	return unlikely(in_range(ns->inum, MNT_NS_INIT_INO,
@@ -147,93 +26,19 @@ static __always_inline bool is_ns_init_id(const struct ns_common *ns)
 	return ns->ns_id <= NS_LAST_INIT_ID;
 }
 
-#define to_ns_common(__ns)                                    \
-	_Generic((__ns),                                      \
-		struct cgroup_namespace *:       &(__ns)->ns, \
-		const struct cgroup_namespace *: &(__ns)->ns, \
-		struct ipc_namespace *:          &(__ns)->ns, \
-		const struct ipc_namespace *:    &(__ns)->ns, \
-		struct mnt_namespace *:          &(__ns)->ns, \
-		const struct mnt_namespace *:    &(__ns)->ns, \
-		struct net *:                    &(__ns)->ns, \
-		const struct net *:              &(__ns)->ns, \
-		struct pid_namespace *:          &(__ns)->ns, \
-		const struct pid_namespace *:    &(__ns)->ns, \
-		struct time_namespace *:         &(__ns)->ns, \
-		const struct time_namespace *:   &(__ns)->ns, \
-		struct user_namespace *:         &(__ns)->ns, \
-		const struct user_namespace *:   &(__ns)->ns, \
-		struct uts_namespace *:          &(__ns)->ns, \
-		const struct uts_namespace *:    &(__ns)->ns)
-
-#define ns_init_inum(__ns)                                     \
-	_Generic((__ns),                                       \
-		struct cgroup_namespace *: CGROUP_NS_INIT_INO, \
-		struct ipc_namespace *:    IPC_NS_INIT_INO,    \
-		struct mnt_namespace *:    MNT_NS_INIT_INO,    \
-		struct net *:              NET_NS_INIT_INO,    \
-		struct pid_namespace *:    PID_NS_INIT_INO,    \
-		struct time_namespace *:   TIME_NS_INIT_INO,   \
-		struct user_namespace *:   USER_NS_INIT_INO,   \
-		struct uts_namespace *:    UTS_NS_INIT_INO)
-
-#define ns_init_ns(__ns)                                    \
-	_Generic((__ns),                                    \
-		struct cgroup_namespace *: &init_cgroup_ns, \
-		struct ipc_namespace *:    &init_ipc_ns,    \
-		struct mnt_namespace *:    &init_mnt_ns,     \
-		struct net *:              &init_net,       \
-		struct pid_namespace *:    &init_pid_ns,    \
-		struct time_namespace *:   &init_time_ns,   \
-		struct user_namespace *:   &init_user_ns,   \
-		struct uts_namespace *:    &init_uts_ns)
-
-#define ns_init_id(__ns)						\
-	_Generic((__ns),						\
-		struct cgroup_namespace *:	CGROUP_NS_INIT_ID,	\
-		struct ipc_namespace *:		IPC_NS_INIT_ID,		\
-		struct mnt_namespace *:		MNT_NS_INIT_ID,		\
-		struct net *:			NET_NS_INIT_ID,		\
-		struct pid_namespace *:		PID_NS_INIT_ID,		\
-		struct time_namespace *:	TIME_NS_INIT_ID,	\
-		struct user_namespace *:	USER_NS_INIT_ID,	\
-		struct uts_namespace *:		UTS_NS_INIT_ID)
-
-#define to_ns_operations(__ns)                                                                         \
-	_Generic((__ns),                                                                               \
-		struct cgroup_namespace *: (IS_ENABLED(CONFIG_CGROUPS) ? &cgroupns_operations : NULL), \
-		struct ipc_namespace *:    (IS_ENABLED(CONFIG_IPC_NS)  ? &ipcns_operations    : NULL), \
-		struct mnt_namespace *:    &mntns_operations,                                          \
-		struct net *:              (IS_ENABLED(CONFIG_NET_NS)  ? &netns_operations    : NULL), \
-		struct pid_namespace *:    (IS_ENABLED(CONFIG_PID_NS)  ? &pidns_operations    : NULL), \
-		struct time_namespace *:   (IS_ENABLED(CONFIG_TIME_NS) ? &timens_operations   : NULL), \
-		struct user_namespace *:   (IS_ENABLED(CONFIG_USER_NS) ? &userns_operations   : NULL), \
-		struct uts_namespace *:    (IS_ENABLED(CONFIG_UTS_NS)  ? &utsns_operations    : NULL))
-
-#define ns_common_type(__ns)                                \
-	_Generic((__ns),                                    \
-		struct cgroup_namespace *: CLONE_NEWCGROUP, \
-		struct ipc_namespace *:    CLONE_NEWIPC,    \
-		struct mnt_namespace *:    CLONE_NEWNS,     \
-		struct net *:              CLONE_NEWNET,    \
-		struct pid_namespace *:    CLONE_NEWPID,    \
-		struct time_namespace *:   CLONE_NEWTIME,   \
-		struct user_namespace *:   CLONE_NEWUSER,   \
-		struct uts_namespace *:    CLONE_NEWUTS)
-
-#define NS_COMMON_INIT(nsname, refs)							\
-{											\
-	.ns_type		= ns_common_type(&nsname),				\
-	.ns_id			= ns_init_id(&nsname),					\
-	.inum			= ns_init_inum(&nsname),				\
-	.ops			= to_ns_operations(&nsname),				\
-	.stashed		= NULL,							\
-	.__ns_ref		= REFCOUNT_INIT(refs),					\
-	.__ns_ref_active	= ATOMIC_INIT(1),					\
-	.ns_list_node		= LIST_HEAD_INIT(nsname.ns.ns_list_node),		\
-	.ns_owner_entry		= LIST_HEAD_INIT(nsname.ns.ns_owner_entry),		\
-	.ns_owner		= LIST_HEAD_INIT(nsname.ns.ns_owner),			\
-	.ns_unified_list_node	= LIST_HEAD_INIT(nsname.ns.ns_unified_list_node),	\
+#define NS_COMMON_INIT(nsname)										\
+{													\
+	.ns_type			= ns_common_type(&nsname),					\
+	.ns_id				= ns_init_id(&nsname),						\
+	.inum				= ns_init_inum(&nsname),					\
+	.ops				= to_ns_operations(&nsname),					\
+	.stashed			= NULL,								\
+	.__ns_ref			= REFCOUNT_INIT(1),						\
+	.__ns_ref_active		= ATOMIC_INIT(1),						\
+	.ns_unified_node.ns_list_entry	= LIST_HEAD_INIT(nsname.ns.ns_unified_node.ns_list_entry),	\
+	.ns_tree_node.ns_list_entry	= LIST_HEAD_INIT(nsname.ns.ns_tree_node.ns_list_entry),		\
+	.ns_owner_node.ns_list_entry	= LIST_HEAD_INIT(nsname.ns.ns_owner_node.ns_list_entry),	\
+	.ns_owner_root.ns_list_head	= LIST_HEAD_INIT(nsname.ns.ns_owner_root.ns_list_head),		\
 }
 
 #define ns_common_init(__ns)                     \
@@ -255,8 +60,18 @@ static __always_inline __must_check int __ns_ref_active_read(const struct ns_com
 	return atomic_read(&ns->__ns_ref_active);
 }
 
+static __always_inline __must_check int __ns_ref_read(const struct ns_common *ns)
+{
+	return refcount_read(&ns->__ns_ref);
+}
+
 static __always_inline __must_check bool __ns_ref_put(struct ns_common *ns)
 {
+	if (is_ns_init_id(ns)) {
+		VFS_WARN_ON_ONCE(__ns_ref_read(ns) != 1);
+		VFS_WARN_ON_ONCE(__ns_ref_active_read(ns) != 1);
+		return false;
+	}
 	if (refcount_dec_and_test(&ns->__ns_ref)) {
 		VFS_WARN_ON_ONCE(__ns_ref_active_read(ns));
 		return true;
@@ -266,23 +81,44 @@ static __always_inline __must_check bool __ns_ref_put(struct ns_common *ns)
 
 static __always_inline __must_check bool __ns_ref_get(struct ns_common *ns)
 {
+	if (is_ns_init_id(ns)) {
+		VFS_WARN_ON_ONCE(__ns_ref_read(ns) != 1);
+		VFS_WARN_ON_ONCE(__ns_ref_active_read(ns) != 1);
+		return true;
+	}
 	if (refcount_inc_not_zero(&ns->__ns_ref))
 		return true;
 	VFS_WARN_ON_ONCE(__ns_ref_active_read(ns));
 	return false;
 }
 
-static __always_inline __must_check int __ns_ref_read(const struct ns_common *ns)
+static __always_inline void __ns_ref_inc(struct ns_common *ns)
 {
-	return refcount_read(&ns->__ns_ref);
+	if (is_ns_init_id(ns)) {
+		VFS_WARN_ON_ONCE(__ns_ref_read(ns) != 1);
+		VFS_WARN_ON_ONCE(__ns_ref_active_read(ns) != 1);
+		return;
+	}
+	refcount_inc(&ns->__ns_ref);
+}
+
+static __always_inline __must_check bool __ns_ref_dec_and_lock(struct ns_common *ns,
+							       spinlock_t *ns_lock)
+{
+	if (is_ns_init_id(ns)) {
+		VFS_WARN_ON_ONCE(__ns_ref_read(ns) != 1);
+		VFS_WARN_ON_ONCE(__ns_ref_active_read(ns) != 1);
+		return false;
+	}
+	return refcount_dec_and_lock(&ns->__ns_ref, ns_lock);
 }
 
 #define ns_ref_read(__ns) __ns_ref_read(to_ns_common((__ns)))
-#define ns_ref_inc(__ns) refcount_inc(&to_ns_common((__ns))->__ns_ref)
+#define ns_ref_inc(__ns) __ns_ref_inc(to_ns_common((__ns)))
 #define ns_ref_get(__ns) __ns_ref_get(to_ns_common((__ns)))
 #define ns_ref_put(__ns) __ns_ref_put(to_ns_common((__ns)))
-#define ns_ref_put_and_lock(__ns, __lock) \
-	refcount_dec_and_lock(&to_ns_common((__ns))->__ns_ref, (__lock))
+#define ns_ref_put_and_lock(__ns, __ns_lock) \
+	__ns_ref_dec_and_lock(to_ns_common((__ns)), __ns_lock)
 
 #define ns_ref_active_read(__ns) \
 	((__ns) ? __ns_ref_active_read(to_ns_common(__ns)) : 0)