From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756189AbcL0Dkm (ORCPT ); Mon, 26 Dec 2016 22:40:42 -0500 Received: from mga01.intel.com ([192.55.52.88]:40978 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755592AbcL0Dkk (ORCPT ); Mon, 26 Dec 2016 22:40:40 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.33,414,1477983600"; d="scan'208";a="23078433" From: "Kweh, Hock Leong" To: "David S. Miller" , Joao Pinto , Giuseppe CAVALLARO , seraphin.bonnaffe@st.com Cc: Alexandre TORGUE , Joachim Eastwood , Niklas Cassel , Johan Hovold , pavel@ucw.cz, "Kweh, Hock Leong" , Ong Boon Leong , netdev , LKML , weifeng.voon@intel.com, Lars Persson Subject: [PATCH] net: stmmac: synchronize stmmac_open and stmmac_dvr_probe Date: Tue, 27 Dec 2016 19:44:59 +0800 Message-Id: <1482839100-20612-1-git-send-email-hock.leong.kweh@intel.com> X-Mailer: git-send-email 1.7.9.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Kweh, Hock Leong" If kernel module stmmac driver being loaded after OS booted, there is a race condition between stmmac_open() and stmmac_mdio_register(), which is invoked inside stmmac_dvr_probe(), and the error is showed in dmesg log as PHY not found and stmmac_open() failed: [ 473.919358] stmmaceth 0000:01:00.0 (unnamed net_device) (uninitialized): stmmac_dvr_probe: warning: cannot get CSR clock [ 473.919382] stmmaceth 0000:01:00.0: no reset control found [ 473.919412] stmmac - user ID: 0x10, Synopsys ID: 0x42 [ 473.919429] stmmaceth 0000:01:00.0: DMA HW capability register supported [ 473.919436] stmmaceth 0000:01:00.0: RX Checksum Offload Engine supported [ 473.919443] stmmaceth 0000:01:00.0: TX Checksum insertion supported [ 473.919451] stmmaceth 0000:01:00.0 (unnamed net_device) (uninitialized): Enable RX Mitigation via HW Watchdog Timer [ 473.921395] libphy: PHY stmmac-1:00 not found [ 473.921417] stmmaceth 0000:01:00.0 eth0: Could not attach to PHY [ 473.921427] stmmaceth 0000:01:00.0 eth0: stmmac_open: Cannot attach to PHY (error: -19) [ 473.959710] libphy: stmmac: probed [ 473.959724] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 0 IRQ POLL (stmmac-1:00) active [ 473.959728] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 1 IRQ POLL (stmmac-1:01) [ 473.959731] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 2 IRQ POLL (stmmac-1:02) [ 473.959734] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 3 IRQ POLL (stmmac-1:03) The resolution used wait_for_completion_interruptible() to synchronize stmmac_open() and stmmac_dvr_probe() to prevent the race condition happening. Signed-off-by: Kweh, Hock Leong --- drivers/net/ethernet/stmicro/stmmac/stmmac.h | 1 + drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 10 ++++++++++ 2 files changed, 11 insertions(+) diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h index eab04ae..5daf8a5 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h @@ -131,6 +131,7 @@ struct stmmac_priv { u32 rx_tail_addr; u32 tx_tail_addr; u32 mss; + struct completion probe_done; #ifdef CONFIG_DEBUG_FS struct dentry *dbgfs_dir; diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index bb40382..28e85f6 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -1770,6 +1770,14 @@ static int stmmac_open(struct net_device *dev) struct stmmac_priv *priv = netdev_priv(dev); int ret; + ret = wait_for_completion_interruptible(&priv->probe_done); + if (ret) { + netdev_err(priv->dev, + "%s: Interrupted while waiting probe completion\n", + __func__); + return ret; + } + stmmac_check_ether_addr(priv); if (priv->hw->pcs != STMMAC_PCS_RGMII && @@ -3226,6 +3234,7 @@ int stmmac_dvr_probe(struct device *device, priv = netdev_priv(ndev); priv->device = device; priv->dev = ndev; + init_completion(&priv->probe_done); stmmac_set_ethtool_ops(ndev); priv->pause = pause; @@ -3372,6 +3381,7 @@ int stmmac_dvr_probe(struct device *device, } } + complete_all(&priv->probe_done); return 0; error_mdio_register: -- 1.7.9.5