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[PATCH] USB: UHCI: fix obscure bug in enqueue()

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This patch (as676) fixes a small bug in uhci-hcd's enqueue routine.  When
an URB is unlinked or gets an error and the completion handler queues
another URB for the same endpoint, the queue shouldn't be allowed to start
up again until the handler returns.  Not even if the new URB is the only
one on its queue.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Alan Stern 2006-05-05 16:32:02 -04:00 committed by Greg Kroah-Hartman
parent 4de7d2c231
commit 2775562ad2
1 changed files with 15 additions and 9 deletions
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24
drivers/usb/host/uhci-q.c
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@ -1148,8 +1148,9 @@ static int uhci_urb_enqueue(struct usb_hcd *hcd,
/* If the new URB is the first and only one on this QH then either /* If the new URB is the first and only one on this QH then either
* the QH is new and idle or else it's unlinked and waiting to * the QH is new and idle or else it's unlinked and waiting to
* become idle, so we can activate it right away. */ * become idle, so we can activate it right away. But only if the
if (qh->queue.next == &urbp->node) * queue isn't stopped. */
if (qh->queue.next == &urbp->node && !qh->is_stopped)
uhci_activate_qh(uhci, qh); uhci_activate_qh(uhci, qh);
goto done; goto done;
@ -1293,27 +1294,32 @@ static void uhci_scan_qh(struct uhci_hcd *uhci, struct uhci_qh *qh,
if (urb->status == -EINPROGRESS) /* Not dequeued */ if (urb->status == -EINPROGRESS) /* Not dequeued */
urb->status = status; urb->status = status;
else else
status = -ECONNRESET; status = ECONNRESET; /* Not -ECONNRESET */
spin_unlock(&urb->lock); spin_unlock(&urb->lock);
/* Dequeued but completed URBs can't be given back unless /* Dequeued but completed URBs can't be given back unless
* the QH is stopped or has finished unlinking. */ * the QH is stopped or has finished unlinking. */
if (status == -ECONNRESET && if (status == ECONNRESET) {
!(qh->is_stopped || QH_FINISHED_UNLINKING(qh))) if (QH_FINISHED_UNLINKING(qh))
return; qh->is_stopped = 1;
else if (!qh->is_stopped)
return;
}
uhci_giveback_urb(uhci, qh, urb, regs); uhci_giveback_urb(uhci, qh, urb, regs);
if (qh->is_stopped) if (status < 0)
break; break;
} }
/* If the QH is neither stopped nor finished unlinking (normal case), /* If the QH is neither stopped nor finished unlinking (normal case),
* our work here is done. */ * our work here is done. */
restart: if (QH_FINISHED_UNLINKING(qh))
if (!(qh->is_stopped || QH_FINISHED_UNLINKING(qh))) qh->is_stopped = 1;
else if (!qh->is_stopped)
return; return;
/* Otherwise give back each of the dequeued URBs */ /* Otherwise give back each of the dequeued URBs */
restart:
list_for_each_entry(urbp, &qh->queue, node) { list_for_each_entry(urbp, &qh->queue, node) {
urb = urbp->urb; urb = urbp->urb;
if (urb->status != -EINPROGRESS) { if (urb->status != -EINPROGRESS) {