FAILED: patch "[PATCH] net: bcmgenet: synchronize EXT_RGMII_OOB_CTRL access" failed to apply to 4.19-stable tree

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y
git checkout FETCH_HEAD
git cherry-pick -x d85cf67a339685beae1d0aee27b7f61da95455be
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2024051358-starter-disposal-9d42@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^..

Possible dependencies:

d85cf67a3396 ("net: bcmgenet: synchronize EXT_RGMII_OOB_CTRL access") 696450c05181 ("net: bcmgenet: Clear RGMII_LINK upon link down") fc13d8c03773 ("net: bcmgenet: pull mac_config from adjust_link") fcb5dfe7dc40 ("net: bcmgenet: remove old link state values") 50e356686fa9 ("net: bcmgenet: remove netif_carrier_off from adjust_link") b972b54a68b2 ("net: bcmgenet: Patch PHY interface for dedicated PHY driver") 28e303da55b3 ("net: broadcom: share header defining UniMAC registers") 12cf8e75727a ("bgmac: add bgmac_umac_*() helpers for accessing UniMAC registers") ccaab4d3df98 ("MAINTAINERS: GENET: Add UniMAC MDIO controller files") f69ccc563df0 ("MAINTAINERS: GENET: Add DT binding file")
d0cac91817c8 ("MAINTAINERS: GENET: Add missing platform data file") 8c7da63978f1 ("bgmac: configure MTU and add support for frames beyond 8192 byte size") 9fb16955fb66 ("Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From d85cf67a339685beae1d0aee27b7f61da95455be Mon Sep 17 00:00:00 2001
From: Doug Berger <[email protected]>
Date: Thu, 25 Apr 2024 15:27:19 -0700
Subject: [PATCH] net: bcmgenet: synchronize EXT_RGMII_OOB_CTRL access

The EXT_RGMII_OOB_CTRL register can be written from different contexts. It is predominantly written from the adjust_link handler which is synchronized by the phydev->lock, but can also be written from a different context when configuring the mii in bcmgenet_mii_config().

The chances of contention are quite low, but it is conceivable that adjust_link could occur during resume when WoL is enabled so use the phydev->lock synchronizer in bcmgenet_mii_config() to be sure.

index 9ada89355747..86a4aa72b3d4 100644
@@ -2,7 +2,7 @@
 /*
  * Broadcom GENET MDIO routines
  *
- * Copyright (c) 2014-2017 Broadcom
+ * Copyright (c) 2014-2024 Broadcom
  */
 
 #include <linux/acpi.h>

@@ -275,6 +275,7 @@ int bcmgenet_mii_config(struct net_device *dev, bool init)
 	 * block for the interface to work, unconditionally clear the
 	 * Out-of-band disable since we do not need it.
 	 */
+	mutex_lock(&phydev->lock);
 	reg = bcmgenet_ext_readl(priv, EXT_RGMII_OOB_CTRL);
 	reg &= ~OOB_DISABLE;
 	if (priv->ext_phy) {

@@ -286,6 +287,7 @@ int bcmgenet_mii_config(struct net_device *dev, bool init)
 			reg |= RGMII_MODE_EN;
 	}
 	bcmgenet_ext_writel(priv, reg, EXT_RGMII_OOB_CTRL);
+	mutex_unlock(&phydev->lock);
 
 	if (init)
 		dev_info(kdev, "configuring instance for %s\n", phy_name);