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, 3 insertions, 3 deletions

diff --git a/ipc/util.c b/ipc/util.c
index 910db7748199..fd1b50da9db8 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -833,7 +833,7 @@ static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos)
         if (ipc && ipc != SEQ_START_TOKEN)
                 ipc_unlock(ipc);
 
-        return sysvipc_find_ipc(iter->ns->ids[iface->ids], *pos, pos);
+        return sysvipc_find_ipc(&iter->ns->ids[iface->ids], *pos, pos);
 }
 
 /*
@@ -846,7 +846,7 @@ static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos)
         struct ipc_proc_iface *iface = iter->iface;
         struct ipc_ids *ids;
 
-        ids = iter->ns->ids[iface->ids];
+        ids = &iter->ns->ids[iface->ids];
 
         /*
          * Take the lock - this will be released by the corresponding
@@ -877,7 +877,7 @@ static void sysvipc_proc_stop(struct seq_file *s, void *it)
         if (ipc && ipc != SEQ_START_TOKEN)
                 ipc_unlock(ipc);
 
-        ids = iter->ns->ids[iface->ids];
+        ids = &iter->ns->ids[iface->ids];
         /* Release the lock we took in start() */
         up_read(&ids->rw_mutex);
 }