60 lines
1.9 KiB
Diff
60 lines
1.9 KiB
Diff
From: Sujith Manoharan <c_manoha@qca.qualcomm.com>
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Date: Fri, 17 Oct 2014 07:40:30 +0530
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Subject: [PATCH] ath9k: Do not start BA when scanning
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mac80211 currently has a race which can be hit
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with this sequence:
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* Start a scan operation.
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* TX BA is initiated by ieee80211_start_tx_ba_session().
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* Driver sets up internal state and calls
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ieee80211_start_tx_ba_cb_irqsafe().
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* mac80211 adds a packet to sdata->skb_queue with
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type IEEE80211_SDATA_QUEUE_AGG_START.
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* ieee80211_iface_work() doesn't process the
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packet because scan is in progress.
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* ADDBA response timer expires and the sta/tid is
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torn down.
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* Driver receives BA stop notification and calls
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ieee80211_stop_tx_ba_cb_irqsafe().
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* This is also added to the queue by mac80211.
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* Now, scan finishes.
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At this point, the queued up packets might be processed
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if some other operation schedules the sdata work. Since
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the tids have been cleaned up already, warnings are hit.
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If this doesn't happen, the packets are left in the queue
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until the interface is torn down.
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Since initiating a BA session when scan is in progress
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leads to flaky connections, especially in MCC mode, we
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can drop the TX BA request. This improves connectivity
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with legacy clients in MCC mode.
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Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
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---
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--- a/drivers/net/wireless/ath/ath9k/main.c
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+++ b/drivers/net/wireless/ath/ath9k/main.c
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@@ -1885,6 +1885,7 @@ static int ath9k_ampdu_action(struct iee
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u16 tid, u16 *ssn, u8 buf_size)
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{
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struct ath_softc *sc = hw->priv;
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+ struct ath_common *common = ath9k_hw_common(sc->sc_ah);
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bool flush = false;
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int ret = 0;
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@@ -1896,6 +1897,12 @@ static int ath9k_ampdu_action(struct iee
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case IEEE80211_AMPDU_RX_STOP:
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break;
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case IEEE80211_AMPDU_TX_START:
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+ if (ath9k_is_chanctx_enabled()) {
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+ if (test_bit(ATH_OP_SCANNING, &common->op_flags)) {
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+ ret = -EBUSY;
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+ break;
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+ }
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+ }
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ath9k_ps_wakeup(sc);
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ret = ath_tx_aggr_start(sc, sta, tid, ssn);
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if (!ret)
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