FAILED: patch "[PATCH] USB: gadget: core: adjust uevent timing on gadget unbind" failed to apply to 5.10-stable tree

The patch below does not apply to the 5.10-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-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 73ea73affe8622bdf292de898da869d441da6a9d
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2023121132-these-deviation-5ab6@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

73ea73affe86 ("USB: gadget: core: adjust uevent timing on gadget unbind") 50966da807c8 ("usb: gadget: udc: core: Offload usb_udc_vbus_handler processing") 1016fc0c096c ("USB: gadget: Fix obscure lockdep violation for udc_mutex") f9d76d15072c ("USB: gadget: Add ID numbers to gadget names")
fc274c1e9973 ("USB: gadget: Add a new bus for gadgets")
6ebb449f9f25 ("USB: gadget: Register udc before gadget")
af1969a2d734 ("USB: gadget: Rename usb_gadget_probe_driver()")
710f5d627a98 ("Merge tag 'usb-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb")

thanks,

greg k-h

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

From 73ea73affe8622bdf292de898da869d441da6a9d Mon Sep 17 00:00:00 2001
From: Roy Luo <[email protected]>
Date: Tue, 28 Nov 2023 22:17:56 +0000
Subject: [PATCH] USB: gadget: core: adjust uevent timing on gadget unbind

The KOBJ_CHANGE uevent is sent before gadget unbind is actually executed, resulting in inaccurate uevent emitted at incorrect timing (the uevent would have USB_UDC_DRIVER variable set while it would soon be removed).
Move the KOBJ_CHANGE uevent to the end of the unbind function so that uevent is sent only after the change has been made.

index ded9531f141b..d59f94464b87 100644
@@ -1646,8 +1646,6 @@ static void gadget_unbind_driver(struct device *dev)
 
 	dev_dbg(&udc->dev, "unbinding gadget driver [%s]\n", driver->function);
 
-	kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
-
 	udc->allow_connect = false;
 	cancel_work_sync(&udc->vbus_work);
 	mutex_lock(&udc->connect_lock);

@@ -1667,6 +1665,8 @@ static void gadget_unbind_driver(struct device *dev)
 	driver->is_bound = false;
 	udc->driver = NULL;
 	mutex_unlock(&udc_lock);
+
+	kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
 }
 
 /* ------------------------------------------------------------------------- */

The KOBJ_CHANGE uevent is sent before gadget unbind is actually executed, resulting in inaccurate uevent emitted at incorrect timing (the uevent would have USB_UDC_DRIVER variable set while it would soon be removed).
Move the KOBJ_CHANGE uevent to the end of the unbind function so that uevent is sent only after the change has been made.

---
 drivers/usb/gadget/udc/core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

index 14d9d1ee16fc..7b3c0787d5a4 100644
@@ -1353,8 +1353,6 @@ static void usb_gadget_remove_driver(struct usb_udc *udc)
 	dev_dbg(&udc->dev, "unregistering UDC driver [%s]\n",
 			udc->driver->function);
 
-	kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
-
 	usb_gadget_disconnect(udc->gadget);
 	if (udc->gadget->irq)
 		synchronize_irq(udc->gadget->irq);

@@ -1363,6 +1361,8 @@ static void usb_gadget_remove_driver(struct usb_udc *udc)
 
 	udc->driver = NULL;
 	udc->gadget->dev.driver = NULL;
+
+	kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
 }
 
 /**

2.43.0.472.g3155946c3a-goog

Why just a 5.10.y backport? What about 5.15.y as well? You can't upgrade kernels and have a regression :(

thanks,

greg k-h

I was waiting for the 5.10 backport to be accepted before sending the 5.15 as this was my first time sending something to the stable tree and I wasn't sure whether I got everything right. Maybe I was being too conservative.
I saw you've applied the patch to 5.15 as well, thanks for that!

Happy holiday!
Roy Luo