Storing ipcs into IDRs

This patch converts casts of struct kern_ipc_perm to
   . struct msg_queue
   . struct sem_array
   . struct shmid_kernel
into the equivalent container_of() macro. It improves code maintenance
because the code need not change if kern_ipc_perm is no longer at the
beginning of the containing struct.

Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 6 deletions

diff --git a/ipc/sem.c b/ipc/sem.c
index 673d63da52c6..446c8f518045 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -176,13 +176,17 @@ void __init sem_init (void)
 
 static inline struct sem_array *sem_lock(struct ipc_namespace *ns, int id)
 {
-        return (struct sem_array *) ipc_lock(&sem_ids(ns), id);
+        struct kern_ipc_perm *ipcp = ipc_lock(&sem_ids(ns), id);
+
+        return container_of(ipcp, struct sem_array, sem_perm);
 }
 
 static inline struct sem_array *sem_lock_check(struct ipc_namespace *ns,
                                                 int id)
 {
-        return (struct sem_array *) ipc_lock_check(&sem_ids(ns), id);
+        struct kern_ipc_perm *ipcp = ipc_lock_check(&sem_ids(ns), id);
+
+        return container_of(ipcp, struct sem_array, sem_perm);
 }
 
 static inline void sem_rmid(struct ipc_namespace *ns, struct sem_array *s)
@@ -277,14 +281,21 @@ static int newary(struct ipc_namespace *ns, struct ipc_params *params)
 }
 
 
-static inline int sem_security(void *sma, int semflg)
+static inline int sem_security(struct kern_ipc_perm *ipcp, int semflg)
 {
-        return security_sem_associate((struct sem_array *) sma, semflg);
+        struct sem_array *sma;
+
+        sma = container_of(ipcp, struct sem_array, sem_perm);
+        return security_sem_associate(sma, semflg);
 }
 
-static inline int sem_more_checks(void *sma, struct ipc_params *params)
+static inline int sem_more_checks(struct kern_ipc_perm *ipcp,
+                                struct ipc_params *params)
 {
-        if (params->u.nsems > ((struct sem_array *)sma)->sem_nsems)
+        struct sem_array *sma;
+
+        sma = container_of(ipcp, struct sem_array, sem_perm);
+        if (params->u.nsems > sma->sem_nsems)
                 return -EINVAL;
 
         return 0;