Merge branch 'r8169-use-new-macros-from-netdev_queues-h'

Heiner Kallweit says:

====================
r8169: use new macros from netdev_queues.h

Add one missing subqueue version of the macros, and use the new macros
in r8169 to simplify the code.
====================

Link: https://lore.kernel.org/r/7147a001-3d9c-a48d-d398-a94c666aa65b@gmail.comSigned-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/ethernet/realtek/r8169_main.c

@@ -30,6 +30,7 @@
 #include <linux/ipv6.h>
 #include <asm/unaligned.h>
 #include <net/ip6_checksum.h>
+#include <net/netdev_queues.h>
 
 #include "r8169.h"
 #include "r8169_firmware.h"
@@ -68,6 +69,8 @@
 #define NUM_RX_DESC	256	/* Number of Rx descriptor registers */
 #define R8169_TX_RING_BYTES	(NUM_TX_DESC * sizeof(struct TxDesc))
 #define R8169_RX_RING_BYTES	(NUM_RX_DESC * sizeof(struct RxDesc))
+#define R8169_TX_STOP_THRS	(MAX_SKB_FRAGS + 1)
+#define R8169_TX_START_THRS	(2 * R8169_TX_STOP_THRS)
 
 #define OCP_STD_PHY_BASE	0xa400
 
@@ -4162,13 +4165,9 @@ static bool rtl8169_tso_csum_v2(struct rtl8169_private *tp,
 	return true;
 }
 
-static bool rtl_tx_slots_avail(struct rtl8169_private *tp)
+static unsigned int rtl_tx_slots_avail(struct rtl8169_private *tp)
 {
-	unsigned int slots_avail = READ_ONCE(tp->dirty_tx) + NUM_TX_DESC
-					- READ_ONCE(tp->cur_tx);
-
-	/* A skbuff with nr_frags needs nr_frags+1 entries in the tx queue */
-	return slots_avail > MAX_SKB_FRAGS;
+	return READ_ONCE(tp->dirty_tx) + NUM_TX_DESC - READ_ONCE(tp->cur_tx);
 }
 
 /* Versions RTL8102e and from RTL8168c onwards support csum_v2 */
@@ -4245,27 +4244,10 @@ static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb,
 
 	WRITE_ONCE(tp->cur_tx, tp->cur_tx + frags + 1);
 
-	stop_queue = !rtl_tx_slots_avail(tp);
-	if (unlikely(stop_queue)) {
-		/* Avoid wrongly optimistic queue wake-up: rtl_tx thread must
-		 * not miss a ring update when it notices a stopped queue.
-		 */
-		smp_wmb();
-		netif_stop_queue(dev);
-		/* Sync with rtl_tx:
-		 * - publish queue status and cur_tx ring index (write barrier)
-		 * - refresh dirty_tx ring index (read barrier).
-		 * May the current thread have a pessimistic view of the ring
-		 * status and forget to wake up queue, a racing rtl_tx thread
-		 * can't.
-		 */
-		smp_mb__after_atomic();
-		if (rtl_tx_slots_avail(tp))
-			netif_start_queue(dev);
-		door_bell = true;
-	}
-
-	if (door_bell)
+	stop_queue = !netif_subqueue_maybe_stop(dev, 0, rtl_tx_slots_avail(tp),
+						R8169_TX_STOP_THRS,
+						R8169_TX_START_THRS);
+	if (door_bell || stop_queue)
 		rtl8169_doorbell(tp);
 
 	return NETDEV_TX_OK;
@@ -4389,19 +4371,12 @@ static void rtl_tx(struct net_device *dev, struct rtl8169_private *tp,
 	}
 
 	if (tp->dirty_tx != dirty_tx) {
-		netdev_completed_queue(dev, pkts_compl, bytes_compl);
 		dev_sw_netstats_tx_add(dev, pkts_compl, bytes_compl);
+		WRITE_ONCE(tp->dirty_tx, dirty_tx);
 
-		/* Sync with rtl8169_start_xmit:
-		 * - publish dirty_tx ring index (write barrier)
-		 * - refresh cur_tx ring index and queue status (read barrier)
-		 * May the current thread miss the stopped queue condition,
-		 * a racing xmit thread can only have a right view of the
-		 * ring status.
-		 */
-		smp_store_mb(tp->dirty_tx, dirty_tx);
-		if (netif_queue_stopped(dev) && rtl_tx_slots_avail(tp))
-			netif_wake_queue(dev);
+		netif_subqueue_completed_wake(dev, 0, pkts_compl, bytes_compl,
+					      rtl_tx_slots_avail(tp),
+					      R8169_TX_START_THRS);
 		/*
 		 * 8168 hack: TxPoll requests are lost when the Tx packets are
 		 * too close. Let's kick an extra TxPoll request when a burst

include/net/netdev_queues.h

@@ -160,4 +160,14 @@ netdev_txq_completed_mb(struct netdev_queue *dev_queue,
 		netif_txq_maybe_stop(txq, get_desc, stop_thrs, start_thrs); \
 	})
 
+#define netif_subqueue_completed_wake(dev, idx, pkts, bytes,		\
+				      get_desc, start_thrs)		\
+	({								\
+		struct netdev_queue *txq;				\
+									\
+		txq = netdev_get_tx_queue(dev, idx);			\
+		netif_txq_completed_wake(txq, pkts, bytes,		\
+					 get_desc, start_thrs);		\
+	})
+
 #endif