qede: Fix concurrency issue in PTP Tx path processing.

PTP Tx timestamping data structures are not protected against the
concurrent access in the Tx paths. Protecting the same using atomic
bit locks.
Signed-off-by: Sudarsana Reddy Kalluru <Sudarsana.Kalluru@cavium.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/qlogic/qede/qede.h

@@ -167,10 +167,11 @@ struct qede_dev {
 	u32				dp_module;
 	u8				dp_level;
 
-	u32 flags;
+	unsigned long flags;
 #define QEDE_FLAG_IS_VF			BIT(0)
 #define IS_VF(edev)	(!!((edev)->flags & QEDE_FLAG_IS_VF))
 #define QEDE_TX_TIMESTAMPING_EN		BIT(1)
+#define QEDE_FLAGS_PTP_TX_IN_PRORGESS	BIT(2)
 
 	const struct qed_eth_ops	*ops;
 	struct qede_ptp			*ptp;

drivers/net/ethernet/qlogic/qede/qede_ptp.c

@@ -181,6 +181,7 @@ static void qede_ptp_task(struct work_struct *work)
 	skb_tstamp_tx(ptp->tx_skb, &shhwtstamps);
 	dev_kfree_skb_any(ptp->tx_skb);
 	ptp->tx_skb = NULL;
+	clear_bit_unlock(QEDE_FLAGS_PTP_TX_IN_PRORGESS, &edev->flags);
 
 	DP_VERBOSE(edev, QED_MSG_DEBUG,
 		   "Tx timestamp, timestamp cycles = %llu, ns = %llu\n",
@@ -485,6 +486,9 @@ void qede_ptp_tx_ts(struct qede_dev *edev, struct sk_buff *skb)
 	if (!ptp)
 		return;
 
+	if (test_and_set_bit_lock(QEDE_FLAGS_PTP_TX_IN_PRORGESS, &edev->flags))
+		return;
+
 	if (unlikely(!(edev->flags & QEDE_TX_TIMESTAMPING_EN))) {
 		DP_NOTICE(edev,
 			  "Tx timestamping was not enabled, this packet will not be timestamped\n");