linux-kernel - [PATCH v2 7/8] USB: cdc-acm: always claim data interface

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Date:   Mon, 22 Mar 2021 16:53:17 +0100
From:   Johan Hovold <johan@...nel.org>
To:     Oliver Neukum <oneukum@...e.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        Johan Hovold <johan@...nel.org>
Subject: [PATCH v2 7/8] USB: cdc-acm: always claim data interface

Make sure to always claim the data interface and bail out if binding
fails.

Note that the driver had a check to verify that the data interface was
not already bound to a driver but would not detect other failures (e.g.
if the interface was not authorised).

Signed-off-by: Johan Hovold <johan@...nel.org>
---
 drivers/usb/class/cdc-acm.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 6991ffd66c5d..914486d0f68c 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1296,13 +1296,6 @@ static int acm_probe(struct usb_interface *intf,
 	if (!combined_interfaces && intf != control_interface)
 		return -ENODEV;
 
-	if (!combined_interfaces && usb_interface_claimed(data_interface)) {
-		/* valid in this context */
-		dev_dbg(&intf->dev, "The data interface isn't available\n");
-		return -EBUSY;
-	}
-
-
 	if (data_interface->cur_altsetting->desc.bNumEndpoints < 2 ||
 	    control_interface->cur_altsetting->desc.bNumEndpoints == 0)
 		return -EINVAL;
@@ -1486,7 +1479,11 @@ static int acm_probe(struct usb_interface *intf,
 	acm->line.bDataBits = 8;
 	acm_set_line(acm, &acm->line);
 
-	usb_driver_claim_interface(&acm_driver, data_interface, acm);
+	if (!acm->combined_interfaces) {
+		rv = usb_driver_claim_interface(&acm_driver, data_interface, acm);
+		if (rv)
+			goto err_remove_files;
+	}
 
 	tty_dev = tty_port_register_device(&acm->port, acm_tty_driver, minor,
 			&control_interface->dev);
@@ -1508,6 +1505,7 @@ static int acm_probe(struct usb_interface *intf,
 		usb_set_intfdata(data_interface, NULL);
 		usb_driver_release_interface(&acm_driver, data_interface);
 	}
+err_remove_files:
 	if (acm->country_codes) {
 		device_remove_file(&acm->control->dev,
 				&dev_attr_wCountryCodes);
-- 
2.26.3