ipc/sem.c: store which operation blocks in perform_atomic_semop()

Preparation for the next patch: In the slow-path of perform_atomic_semop(), store a pointer to the operation that caused the operation to block. Signed-off-by: Manfred Spraul <[email protected]> Cc: Davidlohr Bueso <[email protected]> Cc: Michael Kerrisk <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
dtwlin · Jun 6, 2014 · ed247b7 · ed247b7
1 parent d198cd6
commit ed247b7
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/ipc/sem.c b/ipc/sem.c
@@ -109,6 +109,7 @@ struct sem_queue {
 	int			pid;	 /* process id of requesting process */
 	int			status;	 /* completion status of operation */
 	struct sembuf		*sops;	 /* array of pending operations */
+	struct sembuf		*blocking; /* the operation that blocked */
 	int			nsops;	 /* number of operations */
 	int			alter;	 /* does *sops alter the array? */
 };
@@ -642,6 +643,8 @@ static int perform_atomic_semop(struct sem_array *sma, struct sem_queue *q)
 	goto undo;
 
 would_block:
+	q->blocking = sop;
+
 	if (sop->sem_flg & IPC_NOWAIT)
 		result = -EAGAIN;
 	else