1 files changed, 63 insertions, 27 deletions

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 7113d16e2d3a..54139a2f06ce 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -514,8 +514,12 @@ void xhci_find_new_dequeue_state(struct xhci_hcd *xhci,
                         (unsigned long long) addr);
 }
 
+/* flip_cycle means flip the cycle bit of all but the first and last TRB.
+ * (The last TRB actually points to the ring enqueue pointer, which is not part
+ * of this TD.)  This is used to remove partially enqueued isoc TDs from a ring.
+ */
 static void td_to_noop(struct xhci_hcd *xhci, struct xhci_ring *ep_ring,
-                struct xhci_td *cur_td)
+                struct xhci_td *cur_td, bool flip_cycle)
 {
         struct xhci_segment *cur_seg;
         union xhci_trb *cur_trb;
@@ -528,6 +532,12 @@ static void td_to_noop(struct xhci_hcd *xhci, struct xhci_ring *ep_ring,
                          * leave the pointers intact.
                          */
                         cur_trb->generic.field[3] &= cpu_to_le32(~TRB_CHAIN);
+                        /* Flip the cycle bit (link TRBs can't be the first
+                         * or last TRB).
+                         */
+                        if (flip_cycle)
+                                cur_trb->generic.field[3] ^=
+                                        cpu_to_le32(TRB_CYCLE);
                         xhci_dbg(xhci, "Cancel (unchain) link TRB\n");
                         xhci_dbg(xhci, "Address = %p (0x%llx dma); "
                                         "in seg %p (0x%llx dma)\n",
@@ -541,6 +551,11 @@ static void td_to_noop(struct xhci_hcd *xhci, struct xhci_ring *ep_ring,
                         cur_trb->generic.field[2] = 0;
                         /* Preserve only the cycle bit of this TRB */
                         cur_trb->generic.field[3] &= cpu_to_le32(TRB_CYCLE);
+                        /* Flip the cycle bit except on the first or last TRB */
+                        if (flip_cycle && cur_trb != cur_td->first_trb &&
+                                        cur_trb != cur_td->last_trb)
+                                cur_trb->generic.field[3] ^=
+                                        cpu_to_le32(TRB_CYCLE);
                         cur_trb->generic.field[3] |= cpu_to_le32(
                                 TRB_TYPE(TRB_TR_NOOP));
                         xhci_dbg(xhci, "Cancel TRB %p (0x%llx dma) "
@@ -719,14 +734,14 @@ static void handle_stopped_endpoint(struct xhci_hcd *xhci,
                                         cur_td->urb->stream_id,
                                         cur_td, &deq_state);
                 else
-                        td_to_noop(xhci, ep_ring, cur_td);
+                        td_to_noop(xhci, ep_ring, cur_td, false);
 remove_finished_td:
                 /*
                  * The event handler won't see a completion for this TD anymore,
                  * so remove it from the endpoint ring's TD list.  Keep it in
                  * the cancelled TD list for URB completion later.
                  */
-                list_del(&cur_td->td_list);
+                list_del_init(&cur_td->td_list);
         }
         last_unlinked_td = cur_td;
         xhci_stop_watchdog_timer_in_irq(xhci, ep);
@@ -754,7 +769,7 @@ remove_finished_td:
         do {
                 cur_td = list_entry(ep->cancelled_td_list.next,
                                 struct xhci_td, cancelled_td_list);
-                list_del(&cur_td->cancelled_td_list);
+                list_del_init(&cur_td->cancelled_td_list);
 
                 /* Clean up the cancelled URB */
                 /* Doesn't matter what we pass for status, since the core will
@@ -862,9 +877,9 @@ void xhci_stop_endpoint_command_watchdog(unsigned long arg)
                                 cur_td = list_first_entry(&ring->td_list,
                                                 struct xhci_td,
                                                 td_list);
-                                list_del(&cur_td->td_list);
+                                list_del_init(&cur_td->td_list);
                                 if (!list_empty(&cur_td->cancelled_td_list))
-                                        list_del(&cur_td->cancelled_td_list);
+                                        list_del_init(&cur_td->cancelled_td_list);
                                 xhci_giveback_urb_in_irq(xhci, cur_td,
                                                 -ESHUTDOWN, "killed");
                         }
@@ -873,7 +888,7 @@ void xhci_stop_endpoint_command_watchdog(unsigned long arg)
                                                 &temp_ep->cancelled_td_list,
                                                 struct xhci_td,
                                                 cancelled_td_list);
-                                list_del(&cur_td->cancelled_td_list);
+                                list_del_init(&cur_td->cancelled_td_list);
                                 xhci_giveback_urb_in_irq(xhci, cur_td,
                                                 -ESHUTDOWN, "killed");
                         }
@@ -1565,10 +1580,10 @@ td_cleanup:
                         else
                                 *status = 0;
                 }
-                list_del(&td->td_list);
+                list_del_init(&td->td_list);
                 /* Was this TD slated to be cancelled but completed anyway? */
                 if (!list_empty(&td->cancelled_td_list))
-                        list_del(&td->cancelled_td_list);
+                        list_del_init(&td->cancelled_td_list);
 
                 urb_priv->td_cnt++;
                 /* Giveback the urb when all the tds are completed */
@@ -2500,11 +2515,8 @@ static int prepare_transfer(struct xhci_hcd *xhci,
 
         if (td_index == 0) {
                 ret = usb_hcd_link_urb_to_ep(bus_to_hcd(urb->dev->bus), urb);
-                if (unlikely(ret)) {
-                        xhci_urb_free_priv(xhci, urb_priv);
-                        urb->hcpriv = NULL;
+                if (unlikely(ret))
                         return ret;
-                }
         }
 
         td->urb = urb;
@@ -2672,6 +2684,10 @@ static u32 xhci_v1_0_td_remainder(int running_total, int trb_buff_len,
 {
         int packets_transferred;
 
+        /* One TRB with a zero-length data packet. */
+        if (running_total == 0 && trb_buff_len == 0)
+                return 0;
+
         /* All the TRB queueing functions don't count the current TRB in
          * running_total.
          */
@@ -3113,20 +3129,15 @@ static int count_isoc_trbs_needed(struct xhci_hcd *xhci,
                 struct urb *urb, int i)
 {
         int num_trbs = 0;
-        u64 addr, td_len, running_total;
+        u64 addr, td_len;
 
         addr = (u64) (urb->transfer_dma + urb->iso_frame_desc[i].offset);
         td_len = urb->iso_frame_desc[i].length;
 
-        running_total = TRB_MAX_BUFF_SIZE - (addr & (TRB_MAX_BUFF_SIZE - 1));
-        running_total &= TRB_MAX_BUFF_SIZE - 1;
-        if (running_total != 0)
-                num_trbs++;
-
-        while (running_total < td_len) {
+        num_trbs = DIV_ROUND_UP(td_len + (addr & (TRB_MAX_BUFF_SIZE - 1)),
+                        TRB_MAX_BUFF_SIZE);
+        if (num_trbs == 0)
                 num_trbs++;
-                running_total += TRB_MAX_BUFF_SIZE;
-        }
 
         return num_trbs;
 }
@@ -3226,6 +3237,7 @@ static int xhci_queue_isoc_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
         start_trb = &ep_ring->enqueue->generic;
         start_cycle = ep_ring->cycle_state;
 
+        urb_priv = urb->hcpriv;
         /* Queue the first TRB, even if it's zero-length */
         for (i = 0; i < num_tds; i++) {
                 unsigned int total_packet_count;
@@ -3237,9 +3249,11 @@ static int xhci_queue_isoc_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
                 addr = start_addr + urb->iso_frame_desc[i].offset;
                 td_len = urb->iso_frame_desc[i].length;
                 td_remain_len = td_len;
-                /* FIXME: Ignoring zero-length packets, can those happen? */
                 total_packet_count = roundup(td_len,
                                 le16_to_cpu(urb->ep->desc.wMaxPacketSize));
+                /* A zero-length transfer still involves at least one packet. */
+                if (total_packet_count == 0)
+                        total_packet_count++;
                 burst_count = xhci_get_burst_count(xhci, urb->dev, urb,
                                 total_packet_count);
                 residue = xhci_get_last_burst_packet_count(xhci,
@@ -3249,12 +3263,13 @@ static int xhci_queue_isoc_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 
                 ret = prepare_transfer(xhci, xhci->devs[slot_id], ep_index,
                                 urb->stream_id, trbs_per_td, urb, i, mem_flags);
-                if (ret < 0)
-                        return ret;
+                if (ret < 0) {
+                        if (i == 0)
+                                return ret;
+                        goto cleanup;
+                }
 
-                urb_priv = urb->hcpriv;
                 td = urb_priv->td[i];
-
                 for (j = 0; j < trbs_per_td; j++) {
                         u32 remainder = 0;
                         field = TRB_TBC(burst_count) | TRB_TLBPC(residue);
@@ -3344,6 +3359,27 @@ static int xhci_queue_isoc_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
         giveback_first_trb(xhci, slot_id, ep_index, urb->stream_id,
                         start_cycle, start_trb);
         return 0;
+cleanup:
+        /* Clean up a partially enqueued isoc transfer. */
+
+        for (i--; i >= 0; i--)
+                list_del_init(&urb_priv->td[i]->td_list);
+
+        /* Use the first TD as a temporary variable to turn the TDs we've queued
+         * into No-ops with a software-owned cycle bit. That way the hardware
+         * won't accidentally start executing bogus TDs when we partially
+         * overwrite them.  td->first_trb and td->start_seg are already set.
+         */
+        urb_priv->td[0]->last_trb = ep_ring->enqueue;
+        /* Every TRB except the first & last will have its cycle bit flipped. */
+        td_to_noop(xhci, ep_ring, urb_priv->td[0], true);
+
+        /* Reset the ring enqueue back to the first TRB and its cycle bit. */
+        ep_ring->enqueue = urb_priv->td[0]->first_trb;
+        ep_ring->enq_seg = urb_priv->td[0]->start_seg;
+        ep_ring->cycle_state = start_cycle;
+        usb_hcd_unlink_urb_from_ep(bus_to_hcd(urb->dev->bus), urb);
+        return ret;
 }
 
 /*