ixgbe: clean up Rx time stamping code

Time stamping resources are per-interface so there is no need
to keep separate last_rx_timestamp for each Rx ring, move
last_rx_timestamp to the adapter structure.

With last_rx_timestamp inside adapter, ixgbe_ptp_rx_hwtstamp()
inline function is reduced to a single if statement so it is
no longer necessary. If statement is placed directly in
ixgbe_process_skb_fields() fixing likely/unlikely marking.

Checks for q_vector or adapter to be NULL are superfluous.

Comment about taking I/O hit is a leftover from previous design.

Signed-off-by: Jakub Kicinski <kubakici@wp.pl>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbe/ixgbe.h

@@ -256,7 +256,6 @@ struct ixgbe_ring {
 		struct ixgbe_tx_buffer *tx_buffer_info;
 		struct ixgbe_rx_buffer *rx_buffer_info;
 	};
-	unsigned long last_rx_timestamp;
 	unsigned long state;
 	u8 __iomem *tail;
 	dma_addr_t dma;			/* phys. address of descriptor ring */
@@ -770,6 +769,7 @@ struct ixgbe_adapter {
 	unsigned long ptp_tx_start;
 	unsigned long last_overflow_check;
 	unsigned long last_rx_ptp_check;
+	unsigned long last_rx_timestamp;
 	spinlock_t tmreg_lock;
 	struct cyclecounter cc;
 	struct timecounter tc;
@@ -944,24 +944,7 @@ void ixgbe_ptp_init(struct ixgbe_adapter *adapter);
 void ixgbe_ptp_stop(struct ixgbe_adapter *adapter);
 void ixgbe_ptp_overflow_check(struct ixgbe_adapter *adapter);
 void ixgbe_ptp_rx_hang(struct ixgbe_adapter *adapter);
-void __ixgbe_ptp_rx_hwtstamp(struct ixgbe_q_vector *q_vector,
-			     struct sk_buff *skb);
-static inline void ixgbe_ptp_rx_hwtstamp(struct ixgbe_ring *rx_ring,
-					 union ixgbe_adv_rx_desc *rx_desc,
-					 struct sk_buff *skb)
-{
-	if (unlikely(!ixgbe_test_staterr(rx_desc, IXGBE_RXDADV_STAT_TS)))
-		return;
-
-	__ixgbe_ptp_rx_hwtstamp(rx_ring->q_vector, skb);
-
-	/*
-	 * Update the last_rx_timestamp timer in order to enable watchdog check
-	 * for error case of latched timestamp on a dropped packet.
-	 */
-	rx_ring->last_rx_timestamp = jiffies;
-}
-
+void ixgbe_ptp_rx_hwtstamp(struct ixgbe_adapter *adapter, struct sk_buff *skb);
 int ixgbe_ptp_set_ts_config(struct ixgbe_adapter *adapter, struct ifreq *ifr);
 int ixgbe_ptp_get_ts_config(struct ixgbe_adapter *adapter, struct ifreq *ifr);
 void ixgbe_ptp_start_cyclecounter(struct ixgbe_adapter *adapter);

drivers/net/ethernet/intel/ixgbe/ixgbe_main.c

@@ -1664,7 +1664,8 @@ static void ixgbe_process_skb_fields(struct ixgbe_ring *rx_ring,
 
 	ixgbe_rx_checksum(rx_ring, rx_desc, skb);
 
-	ixgbe_ptp_rx_hwtstamp(rx_ring, rx_desc, skb);
+	if (unlikely(ixgbe_test_staterr(rx_desc, IXGBE_RXDADV_STAT_TS)))
+		ixgbe_ptp_rx_hwtstamp(rx_ring->q_vector->adapter, skb);
 
 	if ((dev->features & NETIF_F_HW_VLAN_CTAG_RX) &&
 	    ixgbe_test_staterr(rx_desc, IXGBE_RXD_STAT_VP)) {

drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c

@@ -435,10 +435,8 @@ void ixgbe_ptp_overflow_check(struct ixgbe_adapter *adapter)
 void ixgbe_ptp_rx_hang(struct ixgbe_adapter *adapter)
 {
 	struct ixgbe_hw *hw = &adapter->hw;
-	struct ixgbe_ring *rx_ring;
 	u32 tsyncrxctl = IXGBE_READ_REG(hw, IXGBE_TSYNCRXCTL);
 	unsigned long rx_event;
-	int n;
 
 	/* if we don't have a valid timestamp in the registers, just update the
 	 * timeout counter and exit
@@ -450,11 +448,8 @@ void ixgbe_ptp_rx_hang(struct ixgbe_adapter *adapter)
 
 	/* determine the most recent watchdog or rx_timestamp event */
 	rx_event = adapter->last_rx_ptp_check;
-	for (n = 0; n < adapter->num_rx_queues; n++) {
-		rx_ring = adapter->rx_ring[n];
-		if (time_after(rx_ring->last_rx_timestamp, rx_event))
-			rx_event = rx_ring->last_rx_timestamp;
-	}
+	if (time_after(adapter->last_rx_timestamp, rx_event))
+		rx_event = adapter->last_rx_timestamp;
 
 	/* only need to read the high RXSTMP register to clear the lock */
 	if (time_is_before_jiffies(rx_event + 5*HZ)) {
@@ -530,49 +525,40 @@ static void ixgbe_ptp_tx_hwtstamp_work(struct work_struct *work)
 }
 
 /**
- * __ixgbe_ptp_rx_hwtstamp - utility function which checks for RX time stamp
- * @q_vector: structure containing interrupt and ring information
+ * ixgbe_ptp_rx_hwtstamp - utility function which checks for RX time stamp
+ * @adapter: pointer to adapter struct
  * @skb: particular skb to send timestamp with
  *
  * if the timestamp is valid, we convert it into the timecounter ns
  * value, then store that result into the shhwtstamps structure which
  * is passed up the network stack
  */
-void __ixgbe_ptp_rx_hwtstamp(struct ixgbe_q_vector *q_vector,
-			     struct sk_buff *skb)
+void ixgbe_ptp_rx_hwtstamp(struct ixgbe_adapter *adapter, struct sk_buff *skb)
 {
-	struct ixgbe_adapter *adapter;
-	struct ixgbe_hw *hw;
+	struct ixgbe_hw *hw = &adapter->hw;
 	struct skb_shared_hwtstamps *shhwtstamps;
 	u64 regval = 0, ns;
 	u32 tsyncrxctl;
 	unsigned long flags;
 
-	/* we cannot process timestamps on a ring without a q_vector */
-	if (!q_vector || !q_vector->adapter)
-		return;
-
-	adapter = q_vector->adapter;
-	hw = &adapter->hw;
-
-	/*
-	 * Read the tsyncrxctl register afterwards in order to prevent taking an
-	 * I/O hit on every packet.
-	 */
 	tsyncrxctl = IXGBE_READ_REG(hw, IXGBE_TSYNCRXCTL);
 	if (!(tsyncrxctl & IXGBE_TSYNCRXCTL_VALID))
 		return;
 
 	regval |= (u64)IXGBE_READ_REG(hw, IXGBE_RXSTMPL);
 	regval |= (u64)IXGBE_READ_REG(hw, IXGBE_RXSTMPH) << 32;
 
-
 	spin_lock_irqsave(&adapter->tmreg_lock, flags);
 	ns = timecounter_cyc2time(&adapter->tc, regval);
 	spin_unlock_irqrestore(&adapter->tmreg_lock, flags);
 
 	shhwtstamps = skb_hwtstamps(skb);
 	shhwtstamps->hwtstamp = ns_to_ktime(ns);
+
+	/* Update the last_rx_timestamp timer in order to enable watchdog check
+	 * for error case of latched timestamp on a dropped packet.
+	 */
+	adapter->last_rx_timestamp = jiffies;
 }
 
 int ixgbe_ptp_get_ts_config(struct ixgbe_adapter *adapter, struct ifreq *ifr)