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-rw-r--r--drivers/usb/wusbcore/wa-xfer.c25
1 files changed, 15 insertions, 10 deletions
diff --git a/drivers/usb/wusbcore/wa-xfer.c b/drivers/usb/wusbcore/wa-xfer.c
index 16968c89949..f5c81afc6e9 100644
--- a/drivers/usb/wusbcore/wa-xfer.c
+++ b/drivers/usb/wusbcore/wa-xfer.c
@@ -928,7 +928,7 @@ static void wa_xfer_delayed_run(struct wa_rpipe *rpipe)
spin_lock_irqsave(&rpipe->seg_lock, flags);
while (atomic_read(&rpipe->segs_available) > 0
&& !list_empty(&rpipe->seg_list)) {
- seg = list_entry(rpipe->seg_list.next, struct wa_seg,
+ seg = list_first_entry(&(rpipe->seg_list), struct wa_seg,
list_node);
list_del(&seg->list_node);
xfer = seg->xfer;
@@ -1093,30 +1093,35 @@ error_xfer_submit:
*
* We need to be careful here, as dequeue() could be called in the
* middle. That's why we do the whole thing under the
- * wa->xfer_list_lock. If dequeue() jumps in, it first locks urb->lock
+ * wa->xfer_list_lock. If dequeue() jumps in, it first locks xfer->lock
* and then checks the list -- so as we would be acquiring in inverse
- * order, we just drop the lock once we have the xfer and reacquire it
- * later.
+ * order, we move the delayed list to a separate list while locked and then
+ * submit them without the list lock held.
*/
void wa_urb_enqueue_run(struct work_struct *ws)
{
struct wahc *wa = container_of(ws, struct wahc, xfer_work);
struct wa_xfer *xfer, *next;
struct urb *urb;
+ LIST_HEAD(tmp_list);
+ /* Create a copy of the wa->xfer_delayed_list while holding the lock */
spin_lock_irq(&wa->xfer_list_lock);
- list_for_each_entry_safe(xfer, next, &wa->xfer_delayed_list,
- list_node) {
+ list_cut_position(&tmp_list, &wa->xfer_delayed_list,
+ wa->xfer_delayed_list.prev);
+ spin_unlock_irq(&wa->xfer_list_lock);
+
+ /*
+ * enqueue from temp list without list lock held since wa_urb_enqueue_b
+ * can take xfer->lock as well as lock mutexes.
+ */
+ list_for_each_entry_safe(xfer, next, &tmp_list, list_node) {
list_del_init(&xfer->list_node);
- spin_unlock_irq(&wa->xfer_list_lock);
urb = xfer->urb;
wa_urb_enqueue_b(xfer);
usb_put_urb(urb); /* taken when queuing */
-
- spin_lock_irq(&wa->xfer_list_lock);
}
- spin_unlock_irq(&wa->xfer_list_lock);
}
EXPORT_SYMBOL_GPL(wa_urb_enqueue_run);