ipc: get rid of ipc_lock_down()

Remove the ipc_lock_down() routines: they used to call idr_find() locklessly
(given that the ipc ids lock was already held), so they are not needed
anymore.

Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Acked-by: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Jim Houston <jim.houston@comcast.net>
Cc: Pierre Peiffer <peifferp@gmail.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 18 deletions

diff --git a/ipc/shm.c b/ipc/shm.c
index a726aebce7d7..e77ec698cf40 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -112,23 +112,8 @@ void __init shm_init (void)
 }
 
 /*
- * shm_lock_(check_)down routines are called in the paths where the rw_mutex
- * is held to protect access to the idr tree.
- */
-static inline struct shmid_kernel *shm_lock_down(struct ipc_namespace *ns,
-                                                int id)
-{
-        struct kern_ipc_perm *ipcp = ipc_lock_down(&shm_ids(ns), id);
-
-        if (IS_ERR(ipcp))
-                return (struct shmid_kernel *)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 held.
+ * is not necessarily held.
  */
 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
 {
@@ -211,7 +196,7 @@ static void shm_close(struct vm_area_struct *vma)
 
         down_write(&shm_ids(ns).rw_mutex);
         /* remove from the list of attaches of the shm segment */
-        shp = shm_lock_down(ns, sfd->id);
+        shp = shm_lock(ns, sfd->id);
         BUG_ON(IS_ERR(shp));
         shp->shm_lprid = task_tgid_vnr(current);
         shp->shm_dtim = get_seconds();
@@ -932,7 +917,7 @@ invalid:
 
 out_nattch:
         down_write(&shm_ids(ns).rw_mutex);
-        shp = shm_lock_down(ns, shmid);
+        shp = shm_lock(ns, shmid);
         BUG_ON(IS_ERR(shp));
         shp->shm_nattch--;
         if(shp->shm_nattch == 0 &&