[PATCH 5/6] ipc/sem.c: Store which operation blocks in perform_atomic_semop()

Manfred Spraul
2014-05-18T07:59:46Z

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>
---
ipc/sem.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/ipc/sem.c b/ipc/sem.c
index 7b1585d..8b5e976 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 @@ out_of_range:
goto undo;

would_block:
+ q->blocking = sop;
+
if (sop->sem_flg & IPC_NOWAIT)
result = -EAGAIN;
else
--
1.9.0