rbd: define common queue_con_delay() (802c6d96) · Commits · 戴 / test

This patch defines a single function, queue_con_delay() to call queue_delayed_work() for a connection. It basically generalizes what was previously queue_con() by adding the delay argument. queue_con() is now a simple helper that passes 0 for its delay. queue_con_delay() returns 0 if it queued work or an errno if it did not for some reason. If con_work() finds the BACKOFF flag set for a connection, it now calls queue_con_delay() to handle arranging to start again after a delay. Note about connection reference counts: con_work() only ever gets called as a work item function. At the time that work is scheduled, a reference to the connection is acquired, and the corresponding con_work() call is then responsible for dropping that reference before it returns. Previously, the backoff handling inside con_work() silently handed off its reference to delayed work it scheduled. Now that queue_con_delay() is used, a new reference is acquired for the newly-scheduled work, and the original reference is dropped by the con->ops->put() call at the end of the function. Signed-off-by:

Alex Elder <elder@inktank.com> Reviewed-by:

Sage Weil <sage@inktank.com>

net/ceph/messenger.c

+23 −15

Original line number	Diff line number	Diff line
		@@ -2244,22 +2244,33 @@ bad_tag:


		/*
		* Atomically queue work on a connection. Bump @con reference to
		* avoid races with connection teardown.
		* Atomically queue work on a connection after the specified delay.
		* Bump @con reference to avoid races with connection teardown.
		* Returns 0 if work was queued, or an error code otherwise.
		*/
		static void queue_con(struct ceph_connection *con)
		static int queue_con_delay(struct ceph_connection *con, unsigned long delay)
		{
		if (!con->ops->get(con)) {
		dout("queue_con %p ref count 0\n", con);
		return;
		dout("%s %p ref count 0\n", __func__, con);

		return -ENOENT;
		}

		if (!queue_delayed_work(ceph_msgr_wq, &con->work, 0)) {
		dout("queue_con %p - already queued\n", con);
		if (!queue_delayed_work(ceph_msgr_wq, &con->work, delay)) {
		dout("%s %p - already queued\n", __func__, con);
		con->ops->put(con);
		} else {
		dout("queue_con %p\n", con);

		return -EBUSY;
		}

		dout("%s %p %lu\n", __func__, con, delay);

		return 0;
		}

		static void queue_con(struct ceph_connection *con)
		{
		(void) queue_con_delay(con, 0);
		}

		/*
		@@ -2294,14 +2305,11 @@ restart:

		if (test_and_clear_bit(CON_FLAG_BACKOFF, &con->flags)) {
		dout("con_work %p backing off\n", con);
		if (queue_delayed_work(ceph_msgr_wq, &con->work,
		round_jiffies_relative(con->delay))) {
		dout("con_work %p backoff %lu\n", con, con->delay);
		mutex_unlock(&con->mutex);
		return;
		} else {
		ret = queue_con_delay(con, round_jiffies_relative(con->delay));
		if (ret) {
		dout("con_work %p FAILED to back off %lu\n", con,
		con->delay);
		BUG_ON(ret == -ENOENT);
		set_bit(CON_FLAG_BACKOFF, &con->flags);
		}
		goto done;

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