UHCI: Add some WARN_ON()s

This patch (as872) adds some WARN_ON()s to various error checks which
are never supposed to fail.  Unsettlingly, one of them has shown up in
a user's log!  Maybe making the warning more visible and having the
call-stack information available will help pinpoint the source of the
problem.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/host/uhci-q.c b/drivers/usb/host/uhci-q.c
index 19a0cc0..4aed305 100644 (file)
--- a/drivers/usb/host/uhci-q.c
+++ b/drivers/usb/host/uhci-q.c
@@ -123,10 +123,14 @@ static struct uhci_td *uhci_alloc_td(struct uhci_hcd *uhci)
 
 static void uhci_free_td(struct uhci_hcd *uhci, struct uhci_td *td)
 {
-       if (!list_empty(&td->list))
+       if (!list_empty(&td->list)) {
                dev_warn(uhci_dev(uhci), "td %p still in list!\n", td);
-       if (!list_empty(&td->fl_list))
+               WARN_ON(1);
+       }
+       if (!list_empty(&td->fl_list)) {
                dev_warn(uhci_dev(uhci), "td %p still in fl_list!\n", td);
+               WARN_ON(1);
+       }
 
        dma_pool_free(uhci->td_pool, td, td->dma_handle);
 }
@@ -291,8 +295,10 @@ static struct uhci_qh *uhci_alloc_qh(struct uhci_hcd *uhci,
 static void uhci_free_qh(struct uhci_hcd *uhci, struct uhci_qh *qh)
 {
        WARN_ON(qh->state != QH_STATE_IDLE && qh->udev);
-       if (!list_empty(&qh->queue))
+       if (!list_empty(&qh->queue)) {
                dev_warn(uhci_dev(uhci), "qh %p list not empty!\n", qh);
+               WARN_ON(1);
+       }
 
        list_del(&qh->node);
        if (qh->udev) {
@@ -740,9 +746,11 @@ static void uhci_free_urb_priv(struct uhci_hcd *uhci,
 {
        struct uhci_td *td, *tmp;
 
-       if (!list_empty(&urbp->node))
+       if (!list_empty(&urbp->node)) {
                dev_warn(uhci_dev(uhci), "urb %p still on QH's list!\n",
                                urbp->urb);
+               WARN_ON(1);
+       }
 
        list_for_each_entry_safe(td, tmp, &urbp->td_list, list) {
                uhci_remove_td_from_urbp(td);