arc_emac_tx_clean() is called by the the napi poll handler, which is scheduled only when a rx interrupt is raised. In absence of received packets the reclaim of used buffers is not executed, blocking further transmissions.
This can be easily reproduced starting the transmission of a UDP flow with iperf, which blocks almost immediately because skbs are not freed and the socket send buffer becomes full: iperf S c037a308 0 87 82 0x00000000 [<c037a308>] (__schedule) from [<c0379da4>] (schedule_timeout+0x124/0x178) [<c0379da4>] (schedule_timeout) from [<c02c253c>] (sock_alloc_send_pskb+0x2a8/0x3a4) [<c02c253c>] (sock_alloc_send_pskb) from [<c02c265c>] (sock_alloc_send_skb+0x24/0x2c) [<c02c265c>] (sock_alloc_send_skb) from [<c02fd0e4>] (__ip_append_data+0x670/0x9b0) [<c02fd0e4>] (__ip_append_data) from [<c02ffd1c>] (ip_make_skb+0xb0/0xe4) [<c02ffd1c>] (ip_make_skb) from [<c0322c78>] (udp_sendmsg+0x210/0x7d4) [<c0322c78>] (udp_sendmsg) from [<c032c798>] (inet_sendmsg+0x7c/0xb4) [<c032c798>] (inet_sendmsg) from [<c02bf734>] (sock_aio_write+0xcc/0xec) [<c02bf734>] (sock_aio_write) from [<c00e0bfc>] (do_sync_write+0x84/0xac) [<c00e0bfc>] (do_sync_write) from [<c00e174c>] (vfs_write+0x108/0x1ac) [<c00e174c>] (vfs_write) from [<c00e1af8>] (SyS_write+0x40/0x8c) [<c00e1af8>] (SyS_write) from [<c000e620>] (ret_fast_syscall+0x0/0x30) The patch schedules a napi poll after tx interrupts to allow the tx reclaim to run in the described situation. Signed-off-by: Beniamino Galvani <[email protected]> --- drivers/net/ethernet/arc/emac_main.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/net/ethernet/arc/emac_main.c b/drivers/net/ethernet/arc/emac_main.c index 18e2fac..4adc01f 100644 --- a/drivers/net/ethernet/arc/emac_main.c +++ b/drivers/net/ethernet/arc/emac_main.c @@ -298,7 +298,7 @@ static int arc_emac_poll(struct napi_struct *napi, int budget) work_done = arc_emac_rx(ndev, budget); if (work_done < budget) { napi_complete(napi); - arc_reg_or(priv, R_ENABLE, RXINT_MASK); + arc_reg_or(priv, R_ENABLE, RXINT_MASK | TXINT_MASK); } return work_done; @@ -327,9 +327,9 @@ static irqreturn_t arc_emac_intr(int irq, void *dev_instance) /* Reset all flags except "MDIO complete" */ arc_reg_set(priv, R_STATUS, status); - if (status & RXINT_MASK) { + if (status & (RXINT_MASK | TXINT_MASK)) { if (likely(napi_schedule_prep(&priv->napi))) { - arc_reg_clr(priv, R_ENABLE, RXINT_MASK); + arc_reg_clr(priv, R_ENABLE, RXINT_MASK | TXINT_MASK); __napi_schedule(&priv->napi); } } @@ -440,7 +440,7 @@ static int arc_emac_open(struct net_device *ndev) arc_reg_set(priv, R_TX_RING, (unsigned int)priv->txbd_dma); /* Enable interrupts */ - arc_reg_set(priv, R_ENABLE, RXINT_MASK | ERR_MASK); + arc_reg_set(priv, R_ENABLE, RXINT_MASK | TXINT_MASK | ERR_MASK); /* Set CONTROL */ arc_reg_set(priv, R_CTRL, @@ -511,7 +511,7 @@ static int arc_emac_stop(struct net_device *ndev) netif_stop_queue(ndev); /* Disable interrupts */ - arc_reg_clr(priv, R_ENABLE, RXINT_MASK | ERR_MASK); + arc_reg_clr(priv, R_ENABLE, RXINT_MASK | TXINT_MASK | ERR_MASK); /* Disable EMAC */ arc_reg_clr(priv, R_CTRL, EN_MASK); -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
