2013-10-05 16:14:10

by Stanislaw Gruszka

[permalink] [raw]
Subject: [PATCH] rt2x00: do not pause queue on flush

Pausing queue on flush make no sense since txdone procedure un-pause
queue. Before flush procedure we have to assure queue is stopped,
i.e. on receive path h/w RX is disabled, on transmit path queue is
disabled in mac80211. That conditions are true except one function:
rt2x00usb_watchdog_tx_dma(), so add stop/start queue there.

Note stop/start queue can be racy if we do this from multiple paths,
but currently we stop TX queues only on rt2x00lib_disable_radio(),
which also stop/sync watchdog, hance we have no race condition.

Signed-off-by: Stanislaw Gruszka <[email protected]>
---
drivers/net/wireless/rt2x00/rt2x00queue.c | 37 ++++------------------------
drivers/net/wireless/rt2x00/rt2x00usb.c | 2 +
2 files changed, 8 insertions(+), 31 deletions(-)

diff --git a/drivers/net/wireless/rt2x00/rt2x00queue.c b/drivers/net/wireless/rt2x00/rt2x00queue.c
index 6c8a33b..218e320 100644
--- a/drivers/net/wireless/rt2x00/rt2x00queue.c
+++ b/drivers/net/wireless/rt2x00/rt2x00queue.c
@@ -1033,38 +1033,21 @@ EXPORT_SYMBOL_GPL(rt2x00queue_stop_queue);

void rt2x00queue_flush_queue(struct data_queue *queue, bool drop)
{
- bool started;
bool tx_queue =
(queue->qid == QID_AC_VO) ||
(queue->qid == QID_AC_VI) ||
(queue->qid == QID_AC_BE) ||
(queue->qid == QID_AC_BK);

- mutex_lock(&queue->status_lock);

/*
- * If the queue has been started, we must stop it temporarily
- * to prevent any new frames to be queued on the device. If
- * we are not dropping the pending frames, the queue must
- * only be stopped in the software and not the hardware,
- * otherwise the queue will never become empty on its own.
+ * If we are not supposed to drop any pending
+ * frames, this means we must force a start (=kick)
+ * to the queue to make sure the hardware will
+ * start transmitting.
*/
- started = test_bit(QUEUE_STARTED, &queue->flags);
- if (started) {
- /*
- * Pause the queue
- */
- rt2x00queue_pause_queue(queue);
-
- /*
- * If we are not supposed to drop any pending
- * frames, this means we must force a start (=kick)
- * to the queue to make sure the hardware will
- * start transmitting.
- */
- if (!drop && tx_queue)
- queue->rt2x00dev->ops->lib->kick_queue(queue);
- }
+ if (!drop && tx_queue)
+ queue->rt2x00dev->ops->lib->kick_queue(queue);

/*
* Check if driver supports flushing, if that is the case we can
@@ -1080,14 +1063,6 @@ void rt2x00queue_flush_queue(struct data_queue *queue, bool drop)
if (unlikely(!rt2x00queue_empty(queue)))
rt2x00_warn(queue->rt2x00dev, "Queue %d failed to flush\n",
queue->qid);
-
- /*
- * Restore the queue to the previous status
- */
- if (started)
- rt2x00queue_unpause_queue(queue);
-
- mutex_unlock(&queue->status_lock);
}
EXPORT_SYMBOL_GPL(rt2x00queue_flush_queue);

diff --git a/drivers/net/wireless/rt2x00/rt2x00usb.c b/drivers/net/wireless/rt2x00/rt2x00usb.c
index 8828987..4e12162 100644
--- a/drivers/net/wireless/rt2x00/rt2x00usb.c
+++ b/drivers/net/wireless/rt2x00/rt2x00usb.c
@@ -523,7 +523,9 @@ static void rt2x00usb_watchdog_tx_dma(struct data_queue *queue)
rt2x00_warn(queue->rt2x00dev, "TX queue %d DMA timed out, invoke forced forced reset\n",
queue->qid);

+ rt2x00queue_stop_queue(queue);
rt2x00queue_flush_queue(queue, true);
+ rt2x00queue_start_queue(queue);
}

static int rt2x00usb_dma_timeout(struct data_queue *queue)
--
1.7.4.4