namespaces: mqueue ns: move mqueue_mnt into struct ipc_namespace

Move mqueue vfsmount plus a few tunables into the ipc_namespace struct.
The CONFIG_IPC_NS boolean and the ipc_namespace struct will serve both the
posix message queue namespaces and the SYSV ipc namespaces.

The sysctl code will be fixed separately in patch 3.  After just this
patch, making a change to posix mqueue tunables always changes the values
in the initial ipc namespace.
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/ipc_namespace.h

@@ -44,24 +44,55 @@ struct ipc_namespace {
 	int		shm_tot;
 
 	struct notifier_block ipcns_nb;
+
+	/* The kern_mount of the mqueuefs sb.  We take a ref on it */
+	struct vfsmount	*mq_mnt;
+
+	/* # queues in this ns, protected by mq_lock */
+	unsigned int    mq_queues_count;
+
+	/* next fields are set through sysctl */
+	unsigned int    mq_queues_max;   /* initialized to DFLT_QUEUESMAX */
+	unsigned int    mq_msg_max;      /* initialized to DFLT_MSGMAX */
+	unsigned int    mq_msgsize_max;  /* initialized to DFLT_MSGSIZEMAX */
+
 };
 
 extern struct ipc_namespace init_ipc_ns;
 extern atomic_t nr_ipc_ns;
 
-#ifdef CONFIG_SYSVIPC
+#if defined(CONFIG_POSIX_MQUEUE) || defined(CONFIG_SYSVIPC)
 #define INIT_IPC_NS(ns)		.ns		= &init_ipc_ns,
+#else
+#define INIT_IPC_NS(ns)
+#endif
 
+#ifdef CONFIG_SYSVIPC
 extern int register_ipcns_notifier(struct ipc_namespace *);
 extern int cond_register_ipcns_notifier(struct ipc_namespace *);
 extern void unregister_ipcns_notifier(struct ipc_namespace *);
 extern int ipcns_notify(unsigned long);
-
 #else /* CONFIG_SYSVIPC */
-#define INIT_IPC_NS(ns)
+static inline int register_ipcns_notifier(struct ipc_namespace *ns)
+{ return 0; }
+static inline int cond_register_ipcns_notifier(struct ipc_namespace *ns)
+{ return 0; }
+static inline void unregister_ipcns_notifier(struct ipc_namespace *ns) { }
+static inline int ipcns_notify(unsigned long l) { return 0; }
 #endif /* CONFIG_SYSVIPC */
 
-#if defined(CONFIG_SYSVIPC) && defined(CONFIG_IPC_NS)
+#ifdef CONFIG_POSIX_MQUEUE
+extern void mq_init_ns(struct ipc_namespace *ns);
+/* default values */
+#define DFLT_QUEUESMAX 256     /* max number of message queues */
+#define DFLT_MSGMAX    10      /* max number of messages in each queue */
+#define HARD_MSGMAX    (131072/sizeof(void *))
+#define DFLT_MSGSIZEMAX 8192   /* max message size */
+#else
+#define mq_init_ns(ns) ((void) 0)
+#endif
+
+#if defined(CONFIG_IPC_NS)
 extern void free_ipc_ns(struct kref *kref);
 extern struct ipc_namespace *copy_ipcs(unsigned long flags,
 				       struct ipc_namespace *ns);

init/Kconfig

@@ -670,10 +670,10 @@ config UTS_NS
 
 config IPC_NS
 	bool "IPC namespace"
-	depends on NAMESPACES && SYSVIPC
+	depends on NAMESPACES && (SYSVIPC || POSIX_MQUEUE)
 	help
 	  In this namespace tasks work with IPC ids which correspond to
-	  different IPC objects in different namespaces
+	  different IPC objects in different namespaces.
 
 config USER_NS
 	bool "User namespace (EXPERIMENTAL)"

ipc/msgutil.c

@@ -13,10 +13,32 @@
 #include <linux/security.h>
 #include <linux/slab.h>
 #include <linux/ipc.h>
+#include <linux/ipc_namespace.h>
 #include <asm/uaccess.h>
 
 #include "util.h"
 
+/*
+ * The next 2 defines are here bc this is the only file
+ * compiled when either CONFIG_SYSVIPC and CONFIG_POSIX_MQUEUE
+ * and not CONFIG_IPC_NS.
+ */
+struct ipc_namespace init_ipc_ns = {
+	.kref = {
+		/* It's not for this patch to change, but should this be 1? */
+		.refcount	= ATOMIC_INIT(2),
+	},
+#ifdef CONFIG_POSIX_MQUEUE
+	.mq_mnt          = NULL,
+	.mq_queues_count = 0,
+	.mq_queues_max   = DFLT_QUEUESMAX,
+	.mq_msg_max      = DFLT_MSGMAX,
+	.mq_msgsize_max  = DFLT_MSGSIZEMAX,
+#endif
+};
+
+atomic_t nr_ipc_ns = ATOMIC_INIT(1);
+
 struct msg_msgseg {
 	struct msg_msgseg* next;
 	/* the next part of the message follows immediately */

ipc/namespace.c

@@ -25,6 +25,7 @@ static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns)
 	sem_init_ns(ns);
 	msg_init_ns(ns);
 	shm_init_ns(ns);
+	mq_init_ns(ns);
 
 	/*
 	 * msgmni has already been computed for the new ipc ns.
@@ -101,6 +102,7 @@ void free_ipc_ns(struct kref *kref)
 	sem_exit_ns(ns);
 	msg_exit_ns(ns);
 	shm_exit_ns(ns);
+	mq_exit_ns(ns);
 	kfree(ns);
 	atomic_dec(&nr_ipc_ns);
 

ipc/util.c

@@ -47,15 +47,6 @@ struct ipc_proc_iface {
 	int (*show)(struct seq_file *, void *);
 };
 
-struct ipc_namespace init_ipc_ns = {
-	.kref = {
-		.refcount	= ATOMIC_INIT(2),
-	},
-};
-
-atomic_t nr_ipc_ns = ATOMIC_INIT(1);
-
-
 #ifdef CONFIG_MEMORY_HOTPLUG
 
 static void ipc_memory_notifier(struct work_struct *work)

ipc/util.h

@@ -20,6 +20,13 @@ void shm_init (void);
 
 struct ipc_namespace;
 
+#ifdef CONFIG_POSIX_MQUEUE
+void mq_exit_ns(struct ipc_namespace *ns);
+#else
+static inline void mq_exit_ns(struct ipc_namespace *ns) { }
+#endif
+
+#ifdef CONFIG_SYSVIPC
 void sem_init_ns(struct ipc_namespace *ns);
 void msg_init_ns(struct ipc_namespace *ns);
 void shm_init_ns(struct ipc_namespace *ns);
@@ -27,6 +34,15 @@ void shm_init_ns(struct ipc_namespace *ns);
 void sem_exit_ns(struct ipc_namespace *ns);
 void msg_exit_ns(struct ipc_namespace *ns);
 void shm_exit_ns(struct ipc_namespace *ns);
+#else
+static inline void sem_init_ns(struct ipc_namespace *ns) { }
+static inline void msg_init_ns(struct ipc_namespace *ns) { }
+static inline void shm_init_ns(struct ipc_namespace *ns) { }
+
+static inline void sem_exit_ns(struct ipc_namespace *ns) { }
+static inline void msg_exit_ns(struct ipc_namespace *ns) { }
+static inline void shm_exit_ns(struct ipc_namespace *ns) { }
+#endif
 
 /*
  * Structure that holds the parameters needed by the ipc operations