ipc: integrate ipc_checkid() into ipc_lock()

This patch introduces a new ipc_lock_check() routine interface:
   . each time ipc_checkid() is called, this is done after calling ipc_lock().
     ipc_checkid() is now called from inside ipc_lock_check().

[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: fix RCU locking]
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, 2 insertions, 21 deletions

diff --git a/ipc/util.c b/ipc/util.c
index e72865f677a7..9b0c4e7753af 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -678,7 +678,7 @@ struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id)
         out = idr_find(&ids->ipcs_idr, lid);
         if (out == NULL) {
                 rcu_read_unlock();
-                return NULL;
+                return ERR_PTR(-EINVAL);
         }
 
         spin_lock(&out->lock);
@@ -689,36 +689,17 @@ struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id)
         if (out->deleted) {
                 spin_unlock(&out->lock);
                 rcu_read_unlock();
-                return NULL;
+                return ERR_PTR(-EINVAL);
         }
 
         return out;
 }
 
-void ipc_lock_by_ptr(struct kern_ipc_perm *perm)
-{
-        rcu_read_lock();
-        spin_lock(&perm->lock);
-}
-
-void ipc_unlock(struct kern_ipc_perm* perm)
-{
-        spin_unlock(&perm->lock);
-        rcu_read_unlock();
-}
-
 int ipc_buildid(struct ipc_ids* ids, int id, int seq)
 {
         return SEQ_MULTIPLIER*seq + id;
 }
 
-int ipc_checkid(struct ipc_ids* ids, struct kern_ipc_perm* ipcp, int uid)
-{
-        if(uid/SEQ_MULTIPLIER != ipcp->seq)
-                return 1;
-        return 0;
-}
-
 #ifdef __ARCH_WANT_IPC_PARSE_VERSION