USB: whci-hcd: make endpoint_reset method async

usb_hcd_endpoint_reset() may be called in atomic context and must not
sleep.  So make whci-hcd's endpoint_reset() asynchronous.  URBs
submitted while the reset is in progress will be queued (on the std
list) and transfers will resume once the reset is complete.

Signed-off-by: David Vrabel <david.vrabel@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

5 files changed, 31 insertions, 6 deletions

diff --git a/drivers/usb/host/whci/asl.c b/drivers/usb/host/whci/asl.c
index c2050785a819..c632437c7649 100644
--- a/drivers/usb/host/whci/asl.c
+++ b/drivers/usb/host/whci/asl.c
@@ -227,11 +227,21 @@ void scan_async_work(struct work_struct *work)
         /*
          * Now that the ASL is updated, complete the removal of any
          * removed qsets.
+         *
+         * If the qset was to be reset, do so and reinsert it into the
+         * ASL if it has pending transfers.
          */
         spin_lock_irq(&whc->lock);
 
         list_for_each_entry_safe(qset, t, &whc->async_removed_list, list_node) {
                 qset_remove_complete(whc, qset);
+                if (qset->reset) {
+                        qset_reset(whc, qset);
+                        if (!list_empty(&qset->stds)) {
+                                asl_qset_insert_begin(whc, qset);
+                                queue_work(whc->workqueue, &whc->async_work);
+                        }
+                }
         }
 
         spin_unlock_irq(&whc->lock);
@@ -267,7 +277,7 @@ int asl_urb_enqueue(struct whc *whc, struct urb *urb, gfp_t mem_flags)
         else
                 err = qset_add_urb(whc, qset, urb, GFP_ATOMIC);
         if (!err) {
-                if (!qset->in_sw_list)
+                if (!qset->in_sw_list && !qset->remove)
                         asl_qset_insert_begin(whc, qset);
         } else
                 usb_hcd_unlink_urb_from_ep(&whc->wusbhc.usb_hcd, urb);
diff --git a/drivers/usb/host/whci/hcd.c b/drivers/usb/host/whci/hcd.c
index e019a5058ab8..687b622a1612 100644
--- a/drivers/usb/host/whci/hcd.c
+++ b/drivers/usb/host/whci/hcd.c
@@ -192,19 +192,23 @@ static void whc_endpoint_reset(struct usb_hcd *usb_hcd,
         struct wusbhc *wusbhc = usb_hcd_to_wusbhc(usb_hcd);
         struct whc *whc = wusbhc_to_whc(wusbhc);
         struct whc_qset *qset;
+        unsigned long flags;
+
+        spin_lock_irqsave(&whc->lock, flags);
 
         qset = ep->hcpriv;
         if (qset) {
                 qset->remove = 1;
+                qset->reset = 1;
 
                 if (usb_endpoint_xfer_bulk(&ep->desc)
                     || usb_endpoint_xfer_control(&ep->desc))
                         queue_work(whc->workqueue, &whc->async_work);
                 else
                         queue_work(whc->workqueue, &whc->periodic_work);
-
-                qset_reset(whc, qset);
         }
+
+        spin_unlock_irqrestore(&whc->lock, flags);
 }
 
 
diff --git a/drivers/usb/host/whci/pzl.c b/drivers/usb/host/whci/pzl.c
index ff4ef9e910d9..a9e05bac6646 100644
--- a/drivers/usb/host/whci/pzl.c
+++ b/drivers/usb/host/whci/pzl.c
@@ -255,11 +255,21 @@ void scan_periodic_work(struct work_struct *work)
         /*
          * Now that the PZL is updated, complete the removal of any
          * removed qsets.
+         *
+         * If the qset was to be reset, do so and reinsert it into the
+         * PZL if it has pending transfers.
          */
         spin_lock_irq(&whc->lock);
 
         list_for_each_entry_safe(qset, t, &whc->periodic_removed_list, list_node) {
                 qset_remove_complete(whc, qset);
+                if (qset->reset) {
+                        qset_reset(whc, qset);
+                        if (!list_empty(&qset->stds)) {
+                                qset_insert_in_sw_list(whc, qset);
+                                queue_work(whc->workqueue, &whc->periodic_work);
+                        }
+                }
         }
 
         spin_unlock_irq(&whc->lock);
@@ -295,7 +305,7 @@ int pzl_urb_enqueue(struct whc *whc, struct urb *urb, gfp_t mem_flags)
         else
                 err = qset_add_urb(whc, qset, urb, GFP_ATOMIC);
         if (!err) {
-                if (!qset->in_sw_list)
+                if (!qset->in_sw_list && !qset->remove)
                         qset_insert_in_sw_list(whc, qset);
         } else
                 usb_hcd_unlink_urb_from_ep(&whc->wusbhc.usb_hcd, urb);
diff --git a/drivers/usb/host/whci/qset.c b/drivers/usb/host/whci/qset.c
index 640b38fbd051..1b9dc1571570 100644
--- a/drivers/usb/host/whci/qset.c
+++ b/drivers/usb/host/whci/qset.c
@@ -103,7 +103,6 @@ static void qset_fill_qh(struct whc_qset *qset, struct urb *urb)
 void qset_clear(struct whc *whc, struct whc_qset *qset)
 {
         qset->td_start = qset->td_end = qset->ntds = 0;
-        qset->remove = 0;
 
         qset->qh.link = cpu_to_le32(QH_LINK_NTDS(8) | QH_LINK_T);
         qset->qh.status = qset->qh.status & QH_STATUS_SEQ_MASK;
@@ -125,7 +124,7 @@ void qset_clear(struct whc *whc, struct whc_qset *qset)
  */
 void qset_reset(struct whc *whc, struct whc_qset *qset)
 {
-        wait_for_completion(&qset->remove_complete);
+        qset->reset = 0;
 
         qset->qh.status &= ~QH_STATUS_SEQ_MASK;
         qset->qh.cur_window = cpu_to_le32((1 << qset->max_burst) - 1);
@@ -156,6 +155,7 @@ struct whc_qset *get_qset(struct whc *whc, struct urb *urb,
 
 void qset_remove_complete(struct whc *whc, struct whc_qset *qset)
 {
+        qset->remove = 0;
         list_del_init(&qset->list_node);
         complete(&qset->remove_complete);
 }
diff --git a/drivers/usb/host/whci/whci-hc.h b/drivers/usb/host/whci/whci-hc.h
index 794dba0d0f0a..e8d0001605be 100644
--- a/drivers/usb/host/whci/whci-hc.h
+++ b/drivers/usb/host/whci/whci-hc.h
@@ -264,6 +264,7 @@ struct whc_qset {
         unsigned in_sw_list:1;
         unsigned in_hw_list:1;
         unsigned remove:1;
+        unsigned reset:1;
         struct urb *pause_after_urb;
         struct completion remove_complete;
         int max_burst;