Commit 8624e9bb authored by Heiner Kallweit's avatar Heiner Kallweit Committed by Paolo Abeni
Browse files

r8169: use new macro netif_subqueue_maybe_stop in rtl8169_start_xmit 



Use new net core macro netif_subqueue_maybe_stop in the start_xmit path
to simplify the code. Whilst at it, set the tx queue start threshold to
twice the stop threshold. Before values were the same, resulting in
stopping/starting the queue more often than needed.

Signed-off-by: default avatarHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent cb18e559

drivers/net/ethernet/realtek/r8169_main.c

+11 −28
Original line number Diff line number Diff line
@@ -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;
@@ -4400,7 +4382,8 @@ static void rtl_tx(struct net_device *dev, struct rtl8169_private *tp, 
		 * ring status.

		 */

		smp_store_mb(tp->dirty_tx, dirty_tx);

		if (netif_queue_stopped(dev) && rtl_tx_slots_avail(tp))

		if (netif_queue_stopped(dev) &&

		    rtl_tx_slots_avail(tp) >= R8169_TX_START_THRS)

			netif_wake_queue(dev);

		/*

		 * 8168 hack: TxPoll requests are lost when the Tx packets are