[openib-general] [PATCH 1/1] IWCM cm_work_handler improvements

[Tom Tucker]

Move the removal of the work queue element to the 
end of the processing loop. This avoids the race with 
the cm_event_handler and obviates the need for the local
copy of the work structure.

I'll be testing this concurrently, but here's the patch for review...

Signed-off-by: Tom Tucker <tom at opengridcomputing.com>

---

 drivers/infiniband/core/iwcm.c |   12 ++++--------
 1 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/drivers/infiniband/core/iwcm.c b/drivers/infiniband/core/iwcm.c
index c3fb304..3a14355 100644
--- a/drivers/infiniband/core/iwcm.c
+++ b/drivers/infiniband/core/iwcm.c
@@ -830,21 +830,15 @@ static int process_event(struct iwcm_id_
  */
 static void cm_work_handler(void *arg)
 {
-	struct iwcm_work *work = arg, lwork;
+	struct iwcm_work *work = arg;
 	struct iwcm_id_private *cm_id_priv = work->cm_id;
 	unsigned long flags;
-	int empty;
 	int ret = 0;
 
 	spin_lock_irqsave(&cm_id_priv->lock, flags);
-	empty = list_empty(&cm_id_priv->work_list);
-	while (!empty) {
+	while (!list_empty(&cm_id_priv->work_list)) {
 		work = list_entry(cm_id_priv->work_list.next,
 				  struct iwcm_work, list);
-		list_del_init(&work->list);
-		empty = list_empty(&cm_id_priv->work_list);
-		lwork = *work;
-		put_work(work);
 		spin_unlock_irqrestore(&cm_id_priv->lock, flags);
 
 		ret = process_event(cm_id_priv, &work->event);
@@ -863,6 +857,8 @@ static void cm_work_handler(void *arg)
 			return;
 		}
 		spin_lock_irqsave(&cm_id_priv->lock, flags);
+		list_del_init(&work->list);
+		put_work(work);
 	}
 	spin_unlock_irqrestore(&cm_id_priv->lock, flags);
 }