Add shm_obtain_object() and shm_obtain_object_check(), which will allow us
to get the ipc object without acquiring the lock. Just as with other forms
of ipc, these functions are basically wrappers around ipc_obtain_object*().
Signed-off-by: Davidlohr Bueso <davidlohr.bueso@xxxxxx>
---
ipc/shm.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/ipc/shm.c b/ipc/shm.c
index c6b4ad5..216ae72 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -124,6 +124,26 @@ void __init shm_init (void)
IPC_SHM_IDS, sysvipc_shm_proc_show);
}
+static inline struct shmid_kernel *shm_obtain_object(struct ipc_namespace *ns, int id)
+{
+ struct kern_ipc_perm *ipcp = ipc_obtain_object(&shm_ids(ns), id);
+
+ if (IS_ERR(ipcp))
+ return ERR_CAST(ipcp);
+
+ return container_of(ipcp, struct shmid_kernel, shm_perm);
+}
+
+static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace *ns, int id)
+{
+ struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&shm_ids(ns), id);
+
+ if (IS_ERR(ipcp))
+ return ERR_CAST(ipcp);
+
+ return container_of(ipcp, struct shmid_kernel, shm_perm);
+}
+
/*
* shm_lock_(check_) routines are called in the paths where the rw_mutex
* is not necessarily held.
--
1.7.11.7
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