From: Oliver Neukum <oliver@neukum.org>
Date: Thu, 2 Jul 2009 15:01:06 +0000 (+0200)
Subject: USB: ldusb should signal an error in poll if the device is disconnected
X-Git-Tag: firefly_0821_release~12454^2~95
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=d12b85e7de1abce4db940ebb169f064583b5796e;p=firefly-linux-kernel-4.4.55.git

USB: ldusb should signal an error in poll if the device is disconnected

poll() should test for a disconnection of the device.

Signed-off-by: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/drivers/usb/misc/ldusb.c b/drivers/usb/misc/ldusb.c
index ad4fb15b5dcb..90f130126c10 100644
--- a/drivers/usb/misc/ldusb.c
+++ b/drivers/usb/misc/ldusb.c
@@ -412,6 +412,9 @@ static unsigned int ld_usb_poll(struct file *file, poll_table *wait)
 
 	dev = file->private_data;
 
+	if (!dev->intf)
+		return POLLERR | POLLHUP;
+
 	poll_wait(file, &dev->read_wait, wait);
 	poll_wait(file, &dev->write_wait, wait);
 
@@ -767,6 +770,9 @@ static void ld_usb_disconnect(struct usb_interface *intf)
 		ld_usb_delete(dev);
 	} else {
 		dev->intf = NULL;
+		/* wake up pollers */
+		wake_up_interruptible_all(&dev->read_wait);
+		wake_up_interruptible_all(&dev->write_wait);
 		mutex_unlock(&dev->mutex);
 	}