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, 21 deletions

diff --git a/ipc/namespace.c b/ipc/namespace.c
index cef1139e6c9..1fed8922d47 100644
--- a/ipc/namespace.c
+++ b/ipc/namespace.c
@@ -14,35 +14,18 @@
 
 static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns)
 {
-	int err;
 	struct ipc_namespace *ns;
 
-	err = -ENOMEM;
 	ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
 	if (ns == NULL)
-		goto err_mem;
+		return ERR_PTR(-ENOMEM);
 
-	err = sem_init_ns(ns);
-	if (err)
-		goto err_sem;
-	err = msg_init_ns(ns);
-	if (err)
-		goto err_msg;
-	err = shm_init_ns(ns);
-	if (err)
-		goto err_shm;
+	sem_init_ns(ns);
+	msg_init_ns(ns);
+	shm_init_ns(ns);
 
 	kref_init(&ns->kref);
 	return ns;
-
-err_shm:
-	msg_exit_ns(ns);
-err_msg:
-	sem_exit_ns(ns);
-err_sem:
-	kfree(ns);
-err_mem:
-	return ERR_PTR(err);
 }
 
 struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns)