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r8169: use new macro netif_subqueue_maybe_stop in rtl8169_start_xmit

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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: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Heiner Kallweit 2023-04-17 11:37:20 +02:00 committed by Paolo Abeni
parent cb18e5595d
commit 8624e9bbef
1 changed files with 11 additions and 28 deletions
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39
drivers/net/ethernet/realtek/r8169_main.c
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@ -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