From: Ben Hutchings Date: Thu, 22 Jan 2015 12:40:25 +0000 (+0000) Subject: sh_eth: Detach net device when stopping queue to resize DMA rings X-Git-Tag: firefly_0821_release~176^2~2456^2~14^2~2 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=bd8889163a7f392f89de5bb01ad00f5772c7ea25;p=firefly-linux-kernel-4.4.55.git sh_eth: Detach net device when stopping queue to resize DMA rings We must only ever stop TX queues when they are full or the net device is not 'ready' so far as the net core, and specifically the watchdog, is concerned. Otherwise, the watchdog may fire *immediately* if no packets have been added to the queue in the last 5 seconds. What's more, sh_eth_tx_timeout() will likely crash if called while we're resizing the TX ring. I could easily trigger this by running the loop: while ethtool -G eth0 rx 128 && ethtool -G eth0 rx 64; do echo -n .; done Signed-off-by: Ben Hutchings Signed-off-by: David S. Miller --- diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c index 4ae22fc05918..fa8a7b775b4a 100644 --- a/drivers/net/ethernet/renesas/sh_eth.c +++ b/drivers/net/ethernet/renesas/sh_eth.c @@ -1968,6 +1968,7 @@ static int sh_eth_set_ringparam(struct net_device *ndev, return -EINVAL; if (netif_running(ndev)) { + netif_device_detach(ndev); netif_tx_disable(ndev); /* Disable interrupts by clearing the interrupt mask. */ sh_eth_write(ndev, 0x0000, EESIPR); @@ -2001,7 +2002,7 @@ static int sh_eth_set_ringparam(struct net_device *ndev, sh_eth_write(ndev, mdp->cd->eesipr_value, EESIPR); /* Setting the Rx mode will start the Rx process. */ sh_eth_write(ndev, EDRRR_R, EDRRR); - netif_wake_queue(ndev); + netif_device_attach(ndev); } return 0;