Re: [PATCH 1/2] iWARP Connection Manager.

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Steve Wise wrote:
+int iw_cm_disconnect(struct iw_cm_id *cm_id, int abrupt)
+{
+	struct iwcm_id_private *cm_id_priv;
+	unsigned long flags;
+	int ret = 0;
+
+	cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
+	/* Wait if we're currently in a connect or accept downcall */
+ wait_event(cm_id_priv->connect_wait, + !test_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags));

Am I understanding this check correctly? You're checking to see if the user has called iw_cm_disconnect() at the same time that they called iw_cm_connect() or iw_cm_accept(). Are connect / accept blocking, or are you just waiting for an event?


The CM must wait for the low level provider to finish a connect() or
accept() operation before telling the low level provider to disconnect
via modifying the iwarp QP.  Regardless of whether they block, this
disconnect can happen concurrently with the connect/accept so we need to
hold the disconnect until the connect/accept completes.


+EXPORT_SYMBOL(iw_cm_disconnect);
+static void destroy_cm_id(struct iw_cm_id *cm_id)
+{
+	struct iwcm_id_private *cm_id_priv;
+	unsigned long flags;
+	int ret;
+
+	cm_id_priv = container_of(cm_id, struct iwcm_id_private, id);
+	/* Wait if we're currently in a connect or accept downcall. A
+	 * listening endpoint should never block here. */
+ wait_event(cm_id_priv->connect_wait, + !test_bit(IWCM_F_CONNECT_WAIT, &cm_id_priv->flags));

Same question/comment as above.



Same answer.

There's a difference between trying to handle the user calling disconnect/destroy at the same time a call to accept/connect is active, versus the user calling disconnect/destroy after accept/connect have returned. In the latter case, I think you're fine. In the first case, this is allowing a user to call destroy at the same time that they're calling accept/connect. Additionally, there's no guarantee that the F_CONNECT_WAIT flag has been set by accept/connect by the time disconnect/destroy tests it.

- Sean
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