IPC: make struct ipc_ids static in ipc_namespace

Each ipc_namespace contains a table of 3 pointers to struct ipc_ids (3 for
msg, sem and shm, structure used to store all ipcs) These 'struct ipc_ids'
are dynamically allocated for each icp_namespace as the ipc_namespace
itself (for the init namespace, they are initialized with pointers to
static variables instead)

It is so for historical reason: in fact, before the use of idr to store the
ipcs, the ipcs were stored in tables of variable length, depending of the
maximum number of ipc allowed.  Now, these 'struct ipc_ids' have a fixed
size.  As they are allocated in any cases for each new ipc_namespace, there
is no gain of memory in having them allocated separately of the struct
ipc_namespace.

This patch proposes to make this table static in the struct ipc_namespace.
Thus, we can allocate all in once and get rid of all the code needed to
allocate and free these ipc_ids separately.

Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net>
Acked-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 22 deletions

diff --git a/ipc/msg.c b/ipc/msg.c
index 5879bfeb79ca..ab0c38b29533 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -67,9 +67,7 @@ struct msg_sender {
 #define SEARCH_NOTEQUAL         3
 #define SEARCH_LESSEQUAL        4
 
-static struct ipc_ids init_msg_ids;
-
-#define msg_ids(ns)     (*((ns)->ids[IPC_MSG_IDS]))
+#define msg_ids(ns)     ((ns)->ids[IPC_MSG_IDS])
 
 #define msg_unlock(msq)         ipc_unlock(&(msq)->q_perm)
 #define msg_buildid(id, seq)    ipc_buildid(id, seq)
@@ -80,30 +78,17 @@ static int newque(struct ipc_namespace *, struct ipc_params *);
 static int sysvipc_msg_proc_show(struct seq_file *s, void *it);
 #endif
 
-static void __msg_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids)
+void msg_init_ns(struct ipc_namespace *ns)
 {
-        ns->ids[IPC_MSG_IDS] = ids;
         ns->msg_ctlmax = MSGMAX;
         ns->msg_ctlmnb = MSGMNB;
         ns->msg_ctlmni = MSGMNI;
         atomic_set(&ns->msg_bytes, 0);
         atomic_set(&ns->msg_hdrs, 0);
-        ipc_init_ids(ids);
+        ipc_init_ids(&ns->ids[IPC_MSG_IDS]);
 }
 
 #ifdef CONFIG_IPC_NS
-int msg_init_ns(struct ipc_namespace *ns)
-{
-        struct ipc_ids *ids;
-
-        ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL);
-        if (ids == NULL)
-                return -ENOMEM;
-
-        __msg_init_ns(ns, ids);
-        return 0;
-}
-
 void msg_exit_ns(struct ipc_namespace *ns)
 {
         struct msg_queue *msq;
@@ -126,15 +111,12 @@ void msg_exit_ns(struct ipc_namespace *ns)
         }
 
         up_write(&msg_ids(ns).rw_mutex);
-
-        kfree(ns->ids[IPC_MSG_IDS]);
-        ns->ids[IPC_MSG_IDS] = NULL;
 }
 #endif
 
 void __init msg_init(void)
 {
-        __msg_init_ns(&init_ipc_ns, &init_msg_ids);
+        msg_init_ns(&init_ipc_ns);
         ipc_init_proc_interface("sysvipc/msg",
                                 "       key      msqid perms      cbytes       qnum lspid lrpid   uid   gid  cuid  cgid      stime      rtime      ctime\n",
                                 IPC_MSG_IDS, sysvipc_msg_proc_show);