From 3d5f3636715e51bb58d8fabe2a1804db3f120c2b Mon Sep 17 00:00:00 2001
From: Dom Cobley <popcornmix@gmail.com>
Date: Mon, 5 Sep 2022 12:45:09 +0100
Subject: [PATCH] Revert "Revert "usbnet: smsc95xx: Fix deadlock on runtime
 resume""

This reverts commit 2f82838ec69a86ffe786e57a37d4bcf746760017.
---
 drivers/net/usb/smsc95xx.c | 26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c
index 4fd95c8..cedd187 100644
--- a/drivers/net/usb/smsc95xx.c
+++ b/drivers/net/usb/smsc95xx.c
@@ -70,6 +70,7 @@ struct smsc95xx_priv {
 	struct fwnode_handle *irqfwnode;
 	struct mii_bus *mdiobus;
 	struct phy_device *phydev;
+	struct task_struct *pm_task;
 };
 
 static bool turbo_mode = true;
@@ -91,13 +92,14 @@ MODULE_PARM_DESC(macaddr, "MAC address");
 static int __must_check __smsc95xx_read_reg(struct usbnet *dev, u32 index,
 					    u32 *data, int in_pm)
 {
+	struct smsc95xx_priv *pdata = dev->driver_priv;
 	u32 buf;
 	int ret;
 	int (*fn)(struct usbnet *, u8, u8, u16, u16, void *, u16);
 
 	BUG_ON(!dev);
 
-	if (!in_pm)
+	if (current != pdata->pm_task)
 		fn = usbnet_read_cmd;
 	else
 		fn = usbnet_read_cmd_nopm;
@@ -121,13 +123,14 @@ static int __must_check __smsc95xx_read_reg(struct usbnet *dev, u32 index,
 static int __must_check __smsc95xx_write_reg(struct usbnet *dev, u32 index,
 					     u32 data, int in_pm)
 {
+	struct smsc95xx_priv *pdata = dev->driver_priv;
 	u32 buf;
 	int ret;
 	int (*fn)(struct usbnet *, u8, u8, u16, u16, const void *, u16);
 
 	BUG_ON(!dev);
 
-	if (!in_pm)
+	if (current != pdata->pm_task)
 		fn = usbnet_write_cmd;
 	else
 		fn = usbnet_write_cmd_nopm;
@@ -1546,9 +1549,12 @@ static int smsc95xx_suspend(struct usb_interface *intf, pm_message_t message)
 	u32 val, link_up;
 	int ret;
 
+	pdata->pm_task = current;
+
 	ret = usbnet_suspend(intf, message);
 	if (ret < 0) {
 		netdev_warn(dev->net, "usbnet_suspend error\n");
+		pdata->pm_task = NULL;
 		return ret;
 	}
 
@@ -1788,6 +1794,7 @@ done:
 	if (ret && PMSG_IS_AUTO(message))
 		usbnet_resume(intf);
 
+	pdata->pm_task = NULL;
 	return ret;
 }
 
@@ -1808,29 +1815,31 @@ static int smsc95xx_resume(struct usb_interface *intf)
 	/* do this first to ensure it's cleared even in error case */
 	pdata->suspend_flags = 0;
 
+	pdata->pm_task = current;
+
 	if (suspend_flags & SUSPEND_ALLMODES) {
 		/* clear wake-up sources */
 		ret = smsc95xx_read_reg_nopm(dev, WUCSR, &val);
 		if (ret < 0)
-			return ret;
+			goto done;
 
 		val &= ~(WUCSR_WAKE_EN_ | WUCSR_MPEN_);
 
 		ret = smsc95xx_write_reg_nopm(dev, WUCSR, val);
 		if (ret < 0)
-			return ret;
+			goto done;
 
 		/* clear wake-up status */
 		ret = smsc95xx_read_reg_nopm(dev, PM_CTRL, &val);
 		if (ret < 0)
-			return ret;
+			goto done;
 
 		val &= ~PM_CTL_WOL_EN_;
 		val |= PM_CTL_WUPS_;
 
 		ret = smsc95xx_write_reg_nopm(dev, PM_CTRL, val);
 		if (ret < 0)
-			return ret;
+			goto done;
 	}
 
 	phy_init_hw(pdata->phydev);
@@ -1839,15 +1848,20 @@ static int smsc95xx_resume(struct usb_interface *intf)
 	if (ret < 0)
 		netdev_warn(dev->net, "usbnet_resume error\n");
 
+done:
+	pdata->pm_task = NULL;
 	return ret;
 }
 
 static int smsc95xx_reset_resume(struct usb_interface *intf)
 {
 	struct usbnet *dev = usb_get_intfdata(intf);
+	struct smsc95xx_priv *pdata = dev->driver_priv;
 	int ret;
 
+	pdata->pm_task = current;
 	ret = smsc95xx_reset(dev);
+	pdata->pm_task = NULL;
 	if (ret < 0)
 		return ret;
 
-- 
2.7.4