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 <manfred@colorfullife.com>
Cc: Davidlohr Bueso <davidlohr.bueso@hp.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/ipc/sem.c b/ipc/sem.c
index b93b561..d61362b 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -109,6 +109,7 @@
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 @@
goto undo;
would_block:
+ q->blocking = sop;
+
if (sop->sem_flg & IPC_NOWAIT)
result = -EAGAIN;
else