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authorJohan Hovold <jhovold@gmail.com>2014-05-26 19:23:33 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-05-27 15:04:08 -0700
commitc14829fad88dbeda57253590695b85ba51270621 (patch)
tree911ee5af3c0c0df403ae5346bf6e442a2c32406c /drivers/usb/serial
parentb0a9aa6da8088b722326a858ab572a13b5b6f9cb (diff)
downloadlinux-stericsson-c14829fad88dbeda57253590695b85ba51270621.tar.gz
USB: serial: fix potential runtime pm imbalance at device remove
Only call usb_autopm_put_interface() if the corresponding usb_autopm_get_interface() was successful. This prevents a potential runtime PM counter imbalance should usb_autopm_get_interface() fail. Note that the USB PM usage counter is reset when the interface is unbound, but that the runtime PM counter may be left unbalanced. Also add comment on why we don't need to worry about racing resume/suspend on autopm_get failures. Fixes: d5fd650cfc7f ("usb: serial: prevent suspend/resume from racing against probe/remove") Signed-off-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/serial')
-rw-r--r--drivers/usb/serial/bus.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/drivers/usb/serial/bus.c b/drivers/usb/serial/bus.c
index 35a2373cde67..9374bd2aba20 100644
--- a/drivers/usb/serial/bus.c
+++ b/drivers/usb/serial/bus.c
@@ -97,13 +97,19 @@ static int usb_serial_device_remove(struct device *dev)
struct usb_serial_port *port;
int retval = 0;
int minor;
+ int autopm_err;
port = to_usb_serial_port(dev);
if (!port)
return -ENODEV;
- /* make sure suspend/resume doesn't race against port_remove */
- usb_autopm_get_interface(port->serial->interface);
+ /*
+ * Make sure suspend/resume doesn't race against port_remove.
+ *
+ * Note that no further runtime PM callbacks will be made if
+ * autopm_get fails.
+ */
+ autopm_err = usb_autopm_get_interface(port->serial->interface);
minor = port->minor;
tty_unregister_device(usb_serial_tty_driver, minor);
@@ -117,7 +123,9 @@ static int usb_serial_device_remove(struct device *dev)
dev_info(dev, "%s converter now disconnected from ttyUSB%d\n",
driver->description, minor);
- usb_autopm_put_interface(port->serial->interface);
+ if (!autopm_err)
+ usb_autopm_put_interface(port->serial->interface);
+
return retval;
}