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authorDavidlohr Bueso <davidlohr.bueso@hp.com>2013-07-08 16:01:15 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-10-18 07:45:46 -0700
commit15d49ab4814e9b3e6b340ec073a3ce95862643a9 (patch)
treec8829ba3bb8d7fc71929db896f6fdd705e0b7573 /ipc
parentf1f7913980afb02f8dee9ee190b29230e69cf7a4 (diff)
downloadlinaro-lsk-15d49ab4814e9b3e6b340ec073a3ce95862643a9.tar.gz
ipc,msg: introduce lockless functions to obtain the ipc object
commit a5001a0d9768568de5d613c3b3a5b9c7721299da upstream. 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: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'ipc')
-rw-r--r--ipc/msg.c21
1 files changed, 21 insertions, 0 deletions
diff --git a/ipc/msg.c b/ipc/msg.c
index 94a1c4b1fb7..4e8cf7b9434 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -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);