[PATCH 5.4 07/61] ath9k: Postpone key cache entry deletion for TXQ frames reference it

Sasha Levin
2021-08-24T17:14:39Z

From: Jouni Malinen <jouni@codeaurora.org>

commit ca2848022c12789685d3fab3227df02b863f9696 upstream.

Do not delete a key cache entry that is still being referenced by
pending frames in TXQs. This avoids reuse of the key cache entry while a
frame might still be transmitted using it.

To avoid having to do any additional operations during the main TX path
operations, track pending key cache entries in a new bitmap and check
whether any pending entries can be deleted before every new key
add/remove operation. Also clear any remaining entries when stopping the
interface.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20201214172118.18100-6-jouni@codeaurora.org
Cc: Pali Rohár <pali@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/wireless/ath/ath9k/hw.h | 1 +
drivers/net/wireless/ath/ath9k/main.c | 87 ++++++++++++++++++++++++++-
2 files changed, 87 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ath/ath9k/hw.h b/drivers/net/wireless/ath/ath9k/hw.h
index 2e4489700a85..2842ca205a0a 100644
--- a/drivers/net/wireless/ath/ath9k/hw.h
+++ b/drivers/net/wireless/ath/ath9k/hw.h
@@ -819,6 +819,7 @@ struct ath_hw {
struct ath9k_pacal_info pacal_info;
struct ar5416Stats stats;
struct ath9k_tx_queue_info txq[ATH9K_NUM_TX_QUEUES];
+ DECLARE_BITMAP(pending_del_keymap, ATH_KEYMAX);

enum ath9k_int imask;
u32 imrs2_reg;
diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c
index c08a7202dca2..28ccdcb197de 100644
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -823,12 +823,80 @@ exit:
ieee80211_free_txskb(hw, skb);
}

+static bool ath9k_txq_list_has_key(struct list_head *txq_list, u32 keyix)
+{
+ struct ath_buf *bf;
+ struct ieee80211_tx_info *txinfo;
+ struct ath_frame_info *fi;
+
+ list_for_each_entry(bf, txq_list, list) {
+ if (bf->bf_state.stale || !bf->bf_mpdu)
+ continue;
+
+ txinfo = IEEE80211_SKB_CB(bf->bf_mpdu);
+ fi = (struct ath_frame_info *)&txinfo->rate_driver_data[0];
+ if (fi->keyix == keyix)
+ return true;
+ }
+
+ return false;
+}
+
+static bool ath9k_txq_has_key(struct ath_softc *sc, u32 keyix)
+{
+ struct ath_hw *ah = sc->sc_ah;
+ int i;
+ struct ath_txq *txq;
+ bool key_in_use = false;
+
+ for (i = 0; !key_in_use && i < ATH9K_NUM_TX_QUEUES; i++) {
+ if (!ATH_TXQ_SETUP(sc, i))
+ continue;
+ txq = &sc->tx.txq[i];
+ if (!txq->axq_depth)
+ continue;
+ if (!ath9k_hw_numtxpending(ah, txq->axq_qnum))
+ continue;
+
+ ath_txq_lock(sc, txq);
+ key_in_use = ath9k_txq_list_has_key(&txq->axq_q, keyix);
+ if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA) {
+ int idx = txq->txq_tailidx;
+
+ while (!key_in_use &&
+ !list_empty(&txq->txq_fifo[idx])) {
+ key_in_use = ath9k_txq_list_has_key(
+ &txq->txq_fifo[idx], keyix);
+ INCR(idx, ATH_TXFIFO_DEPTH);
+ }
+ }
+ ath_txq_unlock(sc, txq);
+ }
+
+ return key_in_use;
+}
+
+static void ath9k_pending_key_del(struct ath_softc *sc, u8 keyix)
+{
+ struct ath_hw *ah = sc->sc_ah;
+ struct ath_common *common = ath9k_hw_common(ah);
+
+ if (!test_bit(keyix, ah->pending_del_keymap) ||
+ ath9k_txq_has_key(sc, keyix))
+ return;
+
+ /* No more TXQ frames point to this key cache entry, so delete it. */
+ clear_bit(keyix, ah->pending_del_keymap);
+ ath_key_delete(common, keyix);
+}
+
static void ath9k_stop(struct ieee80211_hw *hw)
{
struct ath_softc *sc = hw->priv;
struct ath_hw *ah = sc->sc_ah;
struct ath_common *common = ath9k_hw_common(ah);
bool prev_idle;
+ int i;

ath9k_deinit_channel_context(sc);

@@ -896,6 +964,9 @@ static void ath9k_stop(struct ieee80211_hw *hw)

spin_unlock_bh(&sc->sc_pcu_lock);

+ for (i = 0; i < ATH_KEYMAX; i++)
+ ath9k_pending_key_del(sc, i);
+
/* Clear key cache entries explicitly to get rid of any potentially
* remaining keys.
*/
@@ -1712,6 +1783,12 @@ static int ath9k_set_key(struct ieee80211_hw *hw,
if (sta)
an = (struct ath_node *)sta->drv_priv;

+ /* Delete pending key cache entries if no more frames are pointing to
+ * them in TXQs.
+ */
+ for (i = 0; i < ATH_KEYMAX; i++)
+ ath9k_pending_key_del(sc, i);
+
switch (cmd) {
case SET_KEY:
if (sta)
@@ -1741,7 +1818,15 @@ static int ath9k_set_key(struct ieee80211_hw *hw,
}
break;
case DISABLE_KEY:
- ath_key_delete(common, key->hw_key_idx);
+ if (ath9k_txq_has_key(sc, key->hw_key_idx)) {
+ /* Delay key cache entry deletion until there are no
+ * remaining TXQ frames pointing to this entry.
+ */
+ set_bit(key->hw_key_idx, sc->sc_ah->pending_del_keymap);
+ ath_hw_keysetmac(common, key->hw_key_idx, NULL);
+ } else {
+ ath_key_delete(common, key->hw_key_idx);
+ }
if (an) {
for (i = 0; i < ARRAY_SIZE(an->key_idx); i++) {
if (an->key_idx[i] != key->hw_key_idx)
--
2.30.2