bnxt_en: improve TX timestamping FIFO configuration

JIRA: https://issues.redhat.com/browse/RHEL-76565

commit 8f7ae5a
Author: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Date:   Thu Apr 24 05:55:47 2025 -0700

    bnxt_en: improve TX timestamping FIFO configuration

    Reconfiguration of netdev may trigger close/open procedure which can
    break FIFO status by adjusting the amount of empty slots for TX
    timestamps. But it is not really needed because timestamps for the
    packets sent over the wire still can be retrieved. On the other side,
    during netdev close procedure any skbs waiting for TX timestamps can be
    leaked because there is no cleaning procedure called. Free skbs waiting
    for TX timestamps when closing netdev.

    Fixes: 8aa2a79 ("bnxt_en: Increase the max total outstanding PTP TX packets to 4")
    Reviewed-by: Michael Chan <michael.chan@broadcom.com>
    Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
    Signed-off-by: Vadim Fedorenko <vadfed@meta.com>
    Link: https://patch.msgid.link/20250424125547.460632-1-vadfed@meta.com
    Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Signed-off-by: Shruti Parab <shruti.parab@broadcom.com>

Author: Shruti Parab

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -3401,6 +3401,9 @@ static void bnxt_free_tx_skbs(struct bnxt *bp)
 
 		bnxt_free_one_tx_ring_skbs(bp, txr, i);
 	}
+
+	if (bp->ptp_cfg && !(bp->fw_cap & BNXT_FW_CAP_TX_TS_CMP))
+		bnxt_ptp_free_txts_skbs(bp->ptp_cfg);
 }
 
 static void bnxt_free_one_rx_ring(struct bnxt *bp, struct bnxt_rx_ring_info *rxr)
@@ -12664,8 +12667,6 @@ static int __bnxt_open_nic(struct bnxt *bp, bool irq_re_init, bool link_re_init)
 	/* VF-reps may need to be re-opened after the PF is re-opened */
 	if (BNXT_PF(bp))
 		bnxt_vf_reps_open(bp);
-	if (bp->ptp_cfg && !(bp->fw_cap & BNXT_FW_CAP_TX_TS_CMP))
-		WRITE_ONCE(bp->ptp_cfg->tx_avail, BNXT_MAX_TX_TS);
 	bnxt_ptp_init_rtc(bp, true);
 	bnxt_ptp_cfg_tstamp_filters(bp);
 	if (BNXT_SUPPORTS_MULTI_RSS_CTX(bp))

drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c

@@ -794,6 +794,27 @@ static long bnxt_ptp_ts_aux_work(struct ptp_clock_info *ptp_info)
 	return HZ;
 }
 
+void bnxt_ptp_free_txts_skbs(struct bnxt_ptp_cfg *ptp)
+{
+	struct bnxt_ptp_tx_req *txts_req;
+	u16 cons = ptp->txts_cons;
+
+	/* make sure ptp aux worker finished with
+	 * possible BNXT_STATE_OPEN set
+	 */
+	ptp_cancel_worker_sync(ptp->ptp_clock);
+
+	ptp->tx_avail = BNXT_MAX_TX_TS;
+	while (cons != ptp->txts_prod) {
+		txts_req = &ptp->txts_req[cons];
+		if (!IS_ERR_OR_NULL(txts_req->tx_skb))
+			dev_kfree_skb_any(txts_req->tx_skb);
+		cons = NEXT_TXTS(cons);
+	}
+	ptp->txts_cons = cons;
+	ptp_schedule_worker(ptp->ptp_clock, 0);
+}
+
 int bnxt_ptp_get_txts_prod(struct bnxt_ptp_cfg *ptp, u16 *prod)
 {
 	spin_lock_bh(&ptp->ptp_tx_lock);
@@ -1105,7 +1126,6 @@ int bnxt_ptp_init(struct bnxt *bp)
 void bnxt_ptp_clear(struct bnxt *bp)
 {
 	struct bnxt_ptp_cfg *ptp = bp->ptp_cfg;
-	int i;
 
 	if (!ptp)
 		return;
@@ -1117,12 +1137,5 @@ void bnxt_ptp_clear(struct bnxt *bp)
 	kfree(ptp->ptp_info.pin_config);
 	ptp->ptp_info.pin_config = NULL;
 
-	for (i = 0; i < BNXT_MAX_TX_TS; i++) {
-		if (ptp->txts_req[i].tx_skb) {
-			dev_kfree_skb_any(ptp->txts_req[i].tx_skb);
-			ptp->txts_req[i].tx_skb = NULL;
-		}
-	}
-
 	bnxt_unmap_ptp_regs(bp);
 }

drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.h

@@ -162,6 +162,7 @@ int bnxt_ptp_cfg_tstamp_filters(struct bnxt *bp);
 void bnxt_ptp_reapply_pps(struct bnxt *bp);
 int bnxt_hwtstamp_set(struct net_device *dev, struct ifreq *ifr);
 int bnxt_hwtstamp_get(struct net_device *dev, struct ifreq *ifr);
+void bnxt_ptp_free_txts_skbs(struct bnxt_ptp_cfg *ptp);
 int bnxt_ptp_get_txts_prod(struct bnxt_ptp_cfg *ptp, u16 *prod);
 void bnxt_get_tx_ts_p5(struct bnxt *bp, struct sk_buff *skb, u16 prod);
 int bnxt_get_rx_ts_p5(struct bnxt *bp, u64 *ts, u32 pkt_ts);