USB: EHCI: split needs_rescan into two flags

[mirror_ubuntu-zesty-kernel.git] / drivers / usb / host / ehci-q.c

diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index c95f60d43b1a9d3603978ae0d1c21c69b0598dcb..fca741dbf9dff4e361f51a7018382dca7c2bf786 100644 (file)
--- a/drivers/usb/host/ehci-q.c
+++ b/drivers/usb/host/ehci-q.c
@@ -322,7 +322,7 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
  rescan:
        last = NULL;
        last_status = -EINPROGRESS;
-       qh->needs_rescan = 0;
+       qh->dequeue_during_giveback = 0;
 
        /* remove de-activated QTDs from front of queue.
         * after faults (including short reads), cleanup this urb
@@ -518,18 +518,12 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
        }
 
        /* Do we need to rescan for URBs dequeued during a giveback? */
-       if (unlikely(qh->needs_rescan)) {
+       if (unlikely(qh->dequeue_during_giveback)) {
                /* If the QH is already unlinked, do the rescan now. */
                if (state == QH_STATE_IDLE)
                        goto rescan;
 
-               /* Otherwise we have to wait until the QH is fully unlinked.
-                * Our caller will start an unlink if qh->needs_rescan is
-                * set.  But if an unlink has already started, nothing needs
-                * to be done.
-                */
-               if (state != QH_STATE_LINKED)
-                       qh->needs_rescan = 0;
+               /* Otherwise the caller must unlink the QH. */
        }
 
        /* restore original state; caller must unlink or relink */
@@ -538,29 +532,23 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
        /* be sure the hardware's done with the qh before refreshing
         * it after fault cleanup, or recovering from silicon wrongly
         * overlaying the dummy qtd (which reduces DMA chatter).
+        *
+        * We won't refresh a QH that's linked (after the HC
+        * stopped the queue).  That avoids a race:
+        *  - HC reads first part of QH;
+        *  - CPU updates that first part and the token;
+        *  - HC reads rest of that QH, including token
+        * Result:  HC gets an inconsistent image, and then
+        * DMAs to/from the wrong memory (corrupting it).
+        *
+        * That should be rare for interrupt transfers,
+        * except maybe high bandwidth ...
         */
-       if (stopped != 0 || hw->hw_qtd_next == EHCI_LIST_END(ehci)) {
-               if (state == QH_STATE_LINKED) {
-                       /*
-                        * We won't refresh a QH that's linked (after the HC
-                        * stopped the queue).  That avoids a race:
-                        *  - HC reads first part of QH;
-                        *  - CPU updates that first part and the token;
-                        *  - HC reads rest of that QH, including token
-                        * Result:  HC gets an inconsistent image, and then
-                        * DMAs to/from the wrong memory (corrupting it).
-                        *
-                        * That should be rare for interrupt transfers,
-                        * except maybe high bandwidth ...
-                        *
-                        * Therefore tell the caller to start an unlink.
-                        */
-                       qh->needs_rescan = 1;
-               }
-               /* otherwise, unlink already started */
-       }
+       if (stopped != 0 || hw->hw_qtd_next == EHCI_LIST_END(ehci))
+               qh->exception = 1;
 
-       return qh->needs_rescan;
+       /* Let the caller know if the QH needs to be unlinked. */
+       return qh->exception;
 }
 
 /*-------------------------------------------------------------------------*/
@@ -1002,8 +990,9 @@ static void qh_link_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
        head->qh_next.qh = qh;
        head->hw->hw_next = dma;
 
-       qh->xacterrs = 0;
        qh->qh_state = QH_STATE_LINKED;
+       qh->xacterrs = 0;
+       qh->exception = 0;
        /* qtd completions reported later by interrupt */
 
        enable_async(ehci);
@@ -1317,16 +1306,9 @@ static void unlink_empty_async_suspended(struct ehci_hcd *ehci)
 
 static void start_unlink_async(struct ehci_hcd *ehci, struct ehci_qh *qh)
 {
-       /*
-        * If the QH isn't linked then there's nothing we can do
-        * unless we were called during a giveback, in which case
-        * qh_completions() has to deal with it.
-        */
-       if (qh->qh_state != QH_STATE_LINKED) {
-               if (qh->qh_state == QH_STATE_COMPLETING)
-                       qh->needs_rescan = 1;
+       /* If the QH isn't linked then there's nothing we can do. */
+       if (qh->qh_state != QH_STATE_LINKED)
                return;
-       }
 
        single_unlink_async(ehci, qh);
        start_iaa_cycle(ehci, false);