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/sem.c b/ipc/sem.c
index 7836edb..1f7e28d 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -87,14 +87,12 @@
 #include <asm/uaccess.h>
 #include "util.h"
 
-#define sem_ids(ns)	(*((ns)->ids[IPC_SEM_IDS]))
+#define sem_ids(ns)	((ns)->ids[IPC_SEM_IDS])
 
 #define sem_unlock(sma)		ipc_unlock(&(sma)->sem_perm)
 #define sem_checkid(sma, semid)	ipc_checkid(&sma->sem_perm, semid)
 #define sem_buildid(id, seq)	ipc_buildid(id, seq)
 
-static struct ipc_ids init_sem_ids;
-
 static int newary(struct ipc_namespace *, struct ipc_params *);
 static void freeary(struct ipc_namespace *, struct sem_array *);
 #ifdef CONFIG_PROC_FS
@@ -118,30 +116,17 @@ static int sysvipc_sem_proc_show(struct seq_file *s, void *it);
 #define sc_semopm	sem_ctls[2]
 #define sc_semmni	sem_ctls[3]
 
-static void __sem_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids)
+void sem_init_ns(struct ipc_namespace *ns)
 {
-	ns->ids[IPC_SEM_IDS] = ids;
 	ns->sc_semmsl = SEMMSL;
 	ns->sc_semmns = SEMMNS;
 	ns->sc_semopm = SEMOPM;
 	ns->sc_semmni = SEMMNI;
 	ns->used_sems = 0;
-	ipc_init_ids(ids);
+	ipc_init_ids(&ns->ids[IPC_SEM_IDS]);
 }
 
 #ifdef CONFIG_IPC_NS
-int sem_init_ns(struct ipc_namespace *ns)
-{
-	struct ipc_ids *ids;
-
-	ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL);
-	if (ids == NULL)
-		return -ENOMEM;
-
-	__sem_init_ns(ns, ids);
-	return 0;
-}
-
 void sem_exit_ns(struct ipc_namespace *ns)
 {
 	struct sem_array *sma;
@@ -163,15 +148,12 @@ void sem_exit_ns(struct ipc_namespace *ns)
 		total++;
 	}
 	up_write(&sem_ids(ns).rw_mutex);
-
-	kfree(ns->ids[IPC_SEM_IDS]);
-	ns->ids[IPC_SEM_IDS] = NULL;
 }
 #endif
 
 void __init sem_init (void)
 {
-	__sem_init_ns(&init_ipc_ns, &init_sem_ids);
+	sem_init_ns(&init_ipc_ns);
 	ipc_init_proc_interface("sysvipc/sem",
 				"       key      semid perms      nsems   uid   gid  cuid  cgid      otime      ctime\n",
 				IPC_SEM_IDS, sysvipc_sem_proc_show);