ath9k: implement buffer holding handling for EDMA FIFO
Inside one FIFO slot queue, EDMA chipsets have the same link pointer
re-read race condition as older chipsets, so the same buffer holding
logic needs to be used in order to avoid use-after-free bugs.
Unlike on older chips, it can be skipped for the end of the queue.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
index 94b2ee1..5bc5802 100644
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -516,8 +516,7 @@
* not a holding desc.
*/
INIT_LIST_HEAD(&bf_head);
- if ((sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA) ||
- bf_next != NULL || !bf_last->bf_stale)
+ if (bf_next != NULL || !bf_last->bf_stale)
list_move_tail(&bf->list, &bf_head);
if (!txpending || (tid->state & AGGR_CLEANUP)) {
@@ -537,8 +536,7 @@
!txfail);
} else {
/* retry the un-acked ones */
- if (!(sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA) &&
- bf->bf_next == NULL && bf_last->bf_stale) {
+ if (bf->bf_next == NULL && bf_last->bf_stale) {
struct ath_buf *tbf;
tbf = ath_clone_txbuf(sc, bf_last);
@@ -2264,6 +2262,7 @@
struct ath_txq *txq;
struct ath_buf *bf, *lastbf;
struct list_head bf_head;
+ struct list_head *fifo_list;
int status;
for (;;) {
@@ -2291,20 +2290,24 @@
TX_STAT_INC(txq->axq_qnum, txprocdesc);
- if (list_empty(&txq->txq_fifo[txq->txq_tailidx])) {
+ fifo_list = &txq->txq_fifo[txq->txq_tailidx];
+ if (list_empty(fifo_list)) {
ath_txq_unlock(sc, txq);
return;
}
- bf = list_first_entry(&txq->txq_fifo[txq->txq_tailidx],
- struct ath_buf, list);
+ bf = list_first_entry(fifo_list, struct ath_buf, list);
+ if (bf->bf_stale) {
+ list_del(&bf->list);
+ ath_tx_return_buffer(sc, bf);
+ bf = list_first_entry(fifo_list, struct ath_buf, list);
+ }
+
lastbf = bf->bf_lastbf;
INIT_LIST_HEAD(&bf_head);
- list_cut_position(&bf_head, &txq->txq_fifo[txq->txq_tailidx],
- &lastbf->list);
-
- if (list_empty(&txq->txq_fifo[txq->txq_tailidx])) {
+ if (list_is_last(&lastbf->list, fifo_list)) {
+ list_splice_tail_init(fifo_list, &bf_head);
INCR(txq->txq_tailidx, ATH_TXFIFO_DEPTH);
if (!list_empty(&txq->axq_q)) {
@@ -2315,6 +2318,11 @@
list_splice_tail_init(&txq->axq_q, &bf_q);
ath_tx_txqaddbuf(sc, txq, &bf_q, true);
}
+ } else {
+ lastbf->bf_stale = true;
+ if (bf != lastbf)
+ list_cut_position(&bf_head, fifo_list,
+ lastbf->list.prev);
}
ath_tx_process_buffer(sc, txq, &ts, bf, &bf_head);