usbhid: prevent deadlock during timeout
On some HCDs usb_unlink_urb() can directly call the
completion handler. That limits the spinlocks that can
be taken in the handler to locks not held while calling
usb_unlink_urb()
To prevent a race with resubmission, this patch exposes
usbcore's infrastructure for blocking submission, uses it
and so drops the lock without causing a race in usbhid.
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/usb.h b/include/linux/usb.h
index 8fa9a93..5483cd7 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -1369,6 +1369,7 @@
extern void usb_kill_urb(struct urb *urb);
extern void usb_poison_urb(struct urb *urb);
extern void usb_unpoison_urb(struct urb *urb);
+extern void usb_block_urb(struct urb *urb);
extern void usb_kill_anchored_urbs(struct usb_anchor *anchor);
extern void usb_poison_anchored_urbs(struct usb_anchor *anchor);
extern void usb_unpoison_anchored_urbs(struct usb_anchor *anchor);
@@ -1381,6 +1382,8 @@
extern void usb_scuttle_anchored_urbs(struct usb_anchor *anchor);
extern int usb_anchor_empty(struct usb_anchor *anchor);
+#define usb_unblock_urb usb_unpoison_urb
+
/**
* usb_urb_dir_in - check if an URB describes an IN transfer
* @urb: URB to be checked