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Commit 477206a0 authored by Julien Ducourthial's avatar Julien Ducourthial Committed by David S. Miller
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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: default avatarJulien Ducourthial <jducourt@free.fr>
Acked-by: default avatarFrancois Romieu <romieu@fr.zoreil.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c5baa80a

drivers/net/ethernet/realtek/r8169.c

+10 −6
Original line number Diff line number Diff line
@@ -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);

		}

		/*