[PATCH AUTOSEL 6.18-6.1] usb: gadget: udc: skip pullup() if already connected

[Sasha Levin <sashal@kernel.org>]

From: Xu Yang <xu.yang_2@nxp.com>

[ Upstream commit 62911bc82b0332aee7546156800d3516500fa1e1 ]

The device controller may update vbus status via usb_udc_vbus_handler(),
which tries to connect the gadget even though gadget_bind_driver() has
already called usb_udc_connect_control_locked(). This causes pullup() to
be called twice. Avoid this by checking if gadget->connected is true.

This also set gadget->connected as false in usb_gadget_activate() if it
became connected while it was being deactivated. Otherwise,
usb_gadget_connect_locked will return early and pullup() won't be called.

Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://patch.msgid.link/20260423095355.2673035-1-xu.yang_2@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

LLM Generated explanations, may be completely bogus:

The background `git log -S` search finished. In this **v6.18.43**
checkout the history is flattened, so pickaxe only points at
`19eef1d98eeda` for `vbus_work` in `core.c` — it doesn’t show when that
logic was really introduced. That matches what we already inferred from
mainline: the dual connect path dates to the 2023 `usb_udc_vbus_handler`
workqueue offload.

That doesn’t change the backport call: the buggy code is present in this
tree, the fix is small and applies cleanly, and the verdict remains
**YES**.

 drivers/usb/gadget/udc/core.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c
index ab1bcc5512b2c..fa49746d54036 100644
--- a/drivers/usb/gadget/udc/core.c
+++ b/drivers/usb/gadget/udc/core.c
@@ -714,6 +714,9 @@ static int usb_gadget_connect_locked(struct usb_gadget *gadget)
 		goto out;
 	}
 
+	if (gadget->connected)
+		goto out;
+
 	if (gadget->deactivated || !gadget->udc->allow_connect || !gadget->udc->started) {
 		/*
 		 * If the gadget isn't usable (because it is deactivated,
@@ -887,8 +890,10 @@ int usb_gadget_activate(struct usb_gadget *gadget)
 	 * If gadget has been connected before deactivation, or became connected
 	 * while it was being deactivated, we call usb_gadget_connect().
 	 */
-	if (gadget->connected)
+	if (gadget->connected) {
+		gadget->connected = false;
 		ret = usb_gadget_connect_locked(gadget);
+	}
 
 unlock:
 	mutex_unlock(&gadget->udc->connect_lock);
-- 
2.53.0