From: Gabor Juhos Date: Fri, 8 Nov 2013 08:17:54 +0000 (+0000) Subject: ar71xx: ag71xx: fix a race involving netdev registration X-Git-Tag: reboot~8726 X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=7bd3a7bc7b21a98a6ba3198a3ecb94a6a16716f6;p=oweals%2Fopenwrt.git ar71xx: ag71xx: fix a race involving netdev registration In particular, phy_connect before register_netdev. This is because register_netdev runs the netdev notifiers, which can race with the rest of the initialization in ag71xx_probe. In my case this manifested in two ways: 1) If ag71xx is compiled as a module and inserted after netifd has started, netifd is notified by register_netdev before the call to ag71xx_phy_connect. netifd tries to bring the interface up, which calls ag71xx_open, which in turn enters ag71xx_phy_start. This keys off ag->phy_dev (which is still NULL) and thinks this is a fixed-link board, and enters ag71xx_link_adjust. This looks at ag->speed which is not yet initialized and hits the BUG() in the switch (ag->speed) in ag71xx_link_adjust. This is the wrong code path for ag71xx_phy_start - my board has PHYs that need to be brought up with phy_start. Doing ag71xx_phy_connect before register_netdev ensures that ag->phy_dev is non-NULL before ag71xx_phy_start is ever called. 2) When ag71xx is built into the kernel, and netconsole is enabled, there is a gap in the initial burst of replayed printks right after the netdev comes up. My assumption is that netconsole is also triggered by a netdev notifier, and part of this printk burst happens before the call into ag71xx_phy_connect, so part of the burst is lost while the PHY comes up. This patch fixes the gap - all the printks before eth0 comes up are bursted in full when netconsole initializes. ag71xx_phy_connect_xxx no longer runs with a registered netdev, so the logging has been adjusted accordingly to avoid "unregistered net_device" or "eth%d" messages in dmesg. Signed-off-by: Catalin Patulea Signed-off-by: Gabor Juhos SVN-Revision: 38689 --- diff --git a/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c b/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c index fc6be0e001..f4d6735349 100644 --- a/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c +++ b/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c @@ -1178,16 +1178,6 @@ static int ag71xx_probe(struct platform_device *pdev) netif_napi_add(dev, &ag->napi, ag71xx_poll, AG71XX_NAPI_WEIGHT); - err = register_netdev(dev); - if (err) { - dev_err(&pdev->dev, "unable to register net device\n"); - goto err_free_desc; - } - - pr_info("%s: Atheros AG71xx at 0x%08lx, irq %d, mode:%s\n", - dev->name, dev->base_addr, dev->irq, - ag71xx_get_phy_if_mode_name(pdata->phy_if_mode)); - ag71xx_dump_regs(ag); ag71xx_hw_init(ag); @@ -1196,7 +1186,7 @@ static int ag71xx_probe(struct platform_device *pdev) err = ag71xx_phy_connect(ag); if (err) - goto err_unregister_netdev; + goto err_free_desc; err = ag71xx_debugfs_init(ag); if (err) @@ -1204,12 +1194,20 @@ static int ag71xx_probe(struct platform_device *pdev) platform_set_drvdata(pdev, dev); + err = register_netdev(dev); + if (err) { + dev_err(&pdev->dev, "unable to register net device\n"); + goto err_phy_disconnect; + } + + pr_info("%s: Atheros AG71xx at 0x%08lx, irq %d, mode:%s\n", + dev->name, dev->base_addr, dev->irq, + ag71xx_get_phy_if_mode_name(pdata->phy_if_mode)); + return 0; err_phy_disconnect: ag71xx_phy_disconnect(ag); -err_unregister_netdev: - unregister_netdev(dev); err_free_desc: dma_free_coherent(NULL, sizeof(struct ag71xx_desc), ag->stop_desc, ag->stop_desc_dma); diff --git a/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_phy.c b/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_phy.c index f3791e28b2..9de77e924b 100644 --- a/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_phy.c +++ b/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_phy.c @@ -76,7 +76,7 @@ void ag71xx_phy_stop(struct ag71xx *ag) static int ag71xx_phy_connect_fixed(struct ag71xx *ag) { - struct net_device *dev = ag->dev; + struct device *dev = &ag->pdev->dev; struct ag71xx_platform_data *pdata = ag71xx_get_pdata(ag); int ret = 0; @@ -87,12 +87,12 @@ static int ag71xx_phy_connect_fixed(struct ag71xx *ag) case SPEED_1000: break; default: - netdev_err(dev, "invalid speed specified\n"); + dev_err(dev, "invalid speed specified\n"); ret = -EINVAL; break; } - netdev_dbg(dev, "using fixed link parameters\n"); + dev_dbg(dev, "using fixed link parameters\n"); ag->duplex = pdata->duplex; ag->speed = pdata->speed; @@ -102,7 +102,7 @@ static int ag71xx_phy_connect_fixed(struct ag71xx *ag) static int ag71xx_phy_connect_multi(struct ag71xx *ag) { - struct net_device *dev = ag->dev; + struct device *dev = &ag->pdev->dev; struct ag71xx_platform_data *pdata = ag71xx_get_pdata(ag); struct phy_device *phydev = NULL; int phy_addr; @@ -116,7 +116,7 @@ static int ag71xx_phy_connect_multi(struct ag71xx *ag) continue; DBG("%s: PHY found at %s, uid=%08x\n", - dev->name, + dev_name(dev), dev_name(&ag->mii_bus->phy_map[phy_addr]->dev), ag->mii_bus->phy_map[phy_addr]->phy_id); @@ -125,17 +125,17 @@ static int ag71xx_phy_connect_multi(struct ag71xx *ag) } if (!phydev) { - netdev_err(dev, "no PHY found with phy_mask=%08x\n", + dev_err(dev, "no PHY found with phy_mask=%08x\n", pdata->phy_mask); return -ENODEV; } - ag->phy_dev = phy_connect(dev, dev_name(&phydev->dev), + ag->phy_dev = phy_connect(ag->dev, dev_name(&phydev->dev), &ag71xx_phy_link_adjust, pdata->phy_if_mode); if (IS_ERR(ag->phy_dev)) { - netdev_err(dev, "could not connect to PHY at %s\n", + dev_err(dev, "could not connect to PHY at %s\n", dev_name(&phydev->dev)); return PTR_ERR(ag->phy_dev); } @@ -148,7 +148,7 @@ static int ag71xx_phy_connect_multi(struct ag71xx *ag) phydev->advertising = phydev->supported; - netdev_info(dev, "connected to PHY at %s [uid=%08x, driver=%s]\n", + dev_info(dev, "connected to PHY at %s [uid=%08x, driver=%s]\n", dev_name(&phydev->dev), phydev->phy_id, phydev->drv->name); ag->link = 0; @@ -203,7 +203,7 @@ int ag71xx_phy_connect(struct ag71xx *ag) ag->mii_bus = dev_to_mii_bus(pdata->mii_bus_dev); if (ag->mii_bus == NULL) { - netdev_err(ag->dev, "unable to find MII bus on device '%s'\n", + dev_err(&ag->pdev->dev, "unable to find MII bus on device '%s'\n", dev_name(pdata->mii_bus_dev)); return -ENODEV; }