Doug / smarc-fsl-linux-kernel

Download as
Browse Code ยป

Commit a5001a0d9768568de5d613c3b3a5b9c7721299da

Authored by Davidlohr Bueso
Committed by Linus Torvalds
1 parent 2cafed30f1
Exists in smarc-imx_3.14.28_1.0.0_ga and in 1 other branch imx_3.14.28_1.0.0_ga

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: 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>

Showing 1 changed file with 21 additions and 0 deletions Side-by-side Diff

... ... @@ -166,6 +166,27 @@
166 166 return container_of(ipcp, struct msg_queue, q_perm);
167 167 }
168 168  
  169 +static inline struct msg_queue *msq_obtain_object(struct ipc_namespace *ns, int id)
  170 +{
  171 + struct kern_ipc_perm *ipcp = ipc_obtain_object(&msg_ids(ns), id);
  172 +
  173 + if (IS_ERR(ipcp))
  174 + return ERR_CAST(ipcp);
  175 +
  176 + return container_of(ipcp, struct msg_queue, q_perm);
  177 +}
  178 +
  179 +static inline struct msg_queue *msq_obtain_object_check(struct ipc_namespace *ns,
  180 + int id)
  181 +{
  182 + struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&msg_ids(ns), id);
  183 +
  184 + if (IS_ERR(ipcp))
  185 + return ERR_CAST(ipcp);
  186 +
  187 + return container_of(ipcp, struct msg_queue, q_perm);
  188 +}
  189 +
169 190 static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
170 191 {
171 192 ipc_rmid(&msg_ids(ns), &s->q_perm);