ipc: remove the ipc_get() routine

[safe/jmp/linux-2.6] / ipc / shm.c

diff --git a/ipc/shm.c b/ipc/shm.c
index d20cc25..8cf1cf3 100644 (file)
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -63,8 +63,6 @@ static struct ipc_ids init_shm_ids;
        ((struct shmid_kernel*)ipc_lock(&shm_ids(ns),id))
 #define shm_unlock(shp)                        \
        ipc_unlock(&(shp)->shm_perm)
-#define shm_get(ns, id)                        \
-       ((struct shmid_kernel*)ipc_get(&shm_ids(ns),id))
 #define shm_buildid(ns, id, seq)       \
        ipc_buildid(&shm_ids(ns), id, seq)
 
@@ -563,7 +561,19 @@ static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
                struct shmid_kernel *shp;
                struct inode *inode;
 
-               shp = shm_get(ns, next_id);
+               /*
+                * idr_find() is called via shm_get(), so with shm_ids.mutex
+                * locked. Since ipc_addid() is also called with
+                * shm_ids.mutex down, there is no need to add read barriers
+                * here to gurantee the writes in ipc_addid() are seen in
+                * order here (for Alpha).
+                * However idr_find() itself does not necessary require
+                * ipc_ids.mutex down. So if idr_find() is used by other
+                * places without ipc_ids.mutex down, then it needs read
+                * read memory barriers as ipc_lock() does.
+                */
+
+               shp = idr_find(&shm_ids(ns).ipcs_idr, next_id);
                if (shp == NULL)
                        continue;