From 477206a018f902895bfcd069dd820bfe94c187b1 Mon Sep 17 00:00:00 2001 From: Julien Ducourthial Date: Wed, 9 May 2012 00:00:06 +0200 Subject: [PATCH] r8169: fix unsigned int wraparound with TSO The r8169 may get stuck or show bad behaviour after activating TSO : the net_device is not stopped when it has no more TX descriptors. This problem comes from TX_BUFS_AVAIL which may reach -1 when all transmit descriptors are in use. The patch simply tries to keep positive values. Tested with 8111d(onboard) on a D510MO, and with 8111e(onboard) on a Zotac 890GXITX. Signed-off-by: Julien Ducourthial Acked-by: Francois Romieu Signed-off-by: David S. Miller --- drivers/net/ethernet/realtek/r8169.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/drivers/net/ethernet/realtek/r8169.c b/drivers/net/ethernet/realtek/r8169.c index f54509377efa..ce6b44d1f252 100644 --- a/drivers/net/ethernet/realtek/r8169.c +++ b/drivers/net/ethernet/realtek/r8169.c @@ -61,8 +61,12 @@ #define R8169_MSG_DEFAULT \ (NETIF_MSG_DRV | NETIF_MSG_PROBE | NETIF_MSG_IFUP | NETIF_MSG_IFDOWN) -#define TX_BUFFS_AVAIL(tp) \ - (tp->dirty_tx + NUM_TX_DESC - tp->cur_tx - 1) +#define TX_SLOTS_AVAIL(tp) \ + (tp->dirty_tx + NUM_TX_DESC - tp->cur_tx) + +/* A skbuff with nr_frags needs nr_frags+1 entries in the tx queue */ +#define TX_FRAGS_READY_FOR(tp,nr_frags) \ + (TX_SLOTS_AVAIL(tp) >= (nr_frags + 1)) /* Maximum number of multicast addresses to filter (vs. Rx-all-multicast). The RTL chips use a 64 element hash table based on the Ethernet CRC. */ @@ -5115,7 +5119,7 @@ static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb, u32 opts[2]; int frags; - if (unlikely(TX_BUFFS_AVAIL(tp) < skb_shinfo(skb)->nr_frags)) { + if (unlikely(!TX_FRAGS_READY_FOR(tp, skb_shinfo(skb)->nr_frags))) { netif_err(tp, drv, dev, "BUG! Tx Ring full when queue awake!\n"); goto err_stop_0; } @@ -5169,7 +5173,7 @@ static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb, mmiowb(); - if (TX_BUFFS_AVAIL(tp) < MAX_SKB_FRAGS) { + if (!TX_FRAGS_READY_FOR(tp, MAX_SKB_FRAGS)) { /* Avoid wrongly optimistic queue wake-up: rtl_tx thread must * not miss a ring update when it notices a stopped queue. */ @@ -5183,7 +5187,7 @@ static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb, * can't. */ smp_mb(); - if (TX_BUFFS_AVAIL(tp) >= MAX_SKB_FRAGS) + if (TX_FRAGS_READY_FOR(tp, MAX_SKB_FRAGS)) netif_wake_queue(dev); } @@ -5306,7 +5310,7 @@ static void rtl_tx(struct net_device *dev, struct rtl8169_private *tp) */ smp_mb(); if (netif_queue_stopped(dev) && - (TX_BUFFS_AVAIL(tp) >= MAX_SKB_FRAGS)) { + TX_FRAGS_READY_FOR(tp, MAX_SKB_FRAGS)) { netif_wake_queue(dev); } /* -- 2.20.1