From ed247b7ca0d20b4528eec362f8435594818d7601 Mon Sep 17 00:00:00 2001
From: Manfred Spraul <manfred@colorfullife.com>
Date: Fri, 6 Jun 2014 14:37:49 -0700
Subject: [PATCH] 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>
---
ipc/sem.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/ipc/sem.c b/ipc/sem.c
index b93b561842cdf..d61362b31f1eb 100644
--- 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
--
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