Commit a5001a0d authored by Davidlohr Bueso's avatar Davidlohr Bueso Committed by Linus Torvalds

ipc,msg: introduce lockless functions to obtain the ipc object

Add msq_obtain_object() and msq_obtain_object_check(), which will allow
us to get the ipc object without acquiring the lock.  Just as with
semaphores, these functions are basically wrappers around
ipc_obtain_object*().
Signed-off-by: 's avatarDavidlohr Bueso <davidlohr.bueso@hp.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: 's avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2cafed30
......@@ -166,6 +166,27 @@ static inline struct msg_queue *msg_lock_check(struct ipc_namespace *ns,
return container_of(ipcp, struct msg_queue, q_perm);
}
static inline struct msg_queue *msq_obtain_object(struct ipc_namespace *ns, int id)
{
struct kern_ipc_perm *ipcp = ipc_obtain_object(&msg_ids(ns), id);
if (IS_ERR(ipcp))
return ERR_CAST(ipcp);
return container_of(ipcp, struct msg_queue, q_perm);
}
static inline struct msg_queue *msq_obtain_object_check(struct ipc_namespace *ns,
int id)
{
struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&msg_ids(ns), id);
if (IS_ERR(ipcp))
return ERR_CAST(ipcp);
return container_of(ipcp, struct msg_queue, q_perm);
}
static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
{
ipc_rmid(&msg_ids(ns), &s->q_perm);
......
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