usb: host: xhci: handle COMP_STOP from SETUP phase too

Stop Endpoint command can come at any point and we
have no control of that. We should make sure to
handle COMP_STOP on SETUP phase as well, otherwise
urb->actual_length might be set to negative values
in some occasions such as below:

 urb->length = 4;
 build_control_transfer_td_for(urb, ep);

 					stop_endpoint(ep);

COMP_STOP:
	[...]
	urb->actual_length = urb->length - trb->length;

trb->length is 8 for SETUP stage (8 control request
bytes), so actual_length would be set to -4 in this
case.

While doing that, also make sure to use TRB_TYPE
field of the actual TRB instead of matching pointers
to figure out in which stage of the control transfer
we got our completion event.

Cc: <stable@vger.kernel.org>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 7a14e9ad664d8e806dc1035d6207eb11fb40e477..25f522b09dd9746938168e6f675464db9f2e6740 100644 (file)
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1971,8 +1971,9 @@ static int process_ctrl_td(struct xhci_hcd *xhci, struct xhci_td *td,
        struct xhci_ep_ctx *ep_ctx;
        u32 trb_comp_code;
        u32 remaining, requested;
-       bool on_data_stage;
+       u32 trb_type;
 
+       trb_type = TRB_FIELD_TO_TYPE(le32_to_cpu(ep_trb->generic.field[3]));
        slot_id = TRB_TO_SLOT_ID(le32_to_cpu(event->flags));
        xdev = xhci->devs[slot_id];
        ep_index = TRB_TO_EP_ID(le32_to_cpu(event->flags)) - 1;
@@ -1982,14 +1983,11 @@ static int process_ctrl_td(struct xhci_hcd *xhci, struct xhci_td *td,
        requested = td->urb->transfer_buffer_length;
        remaining = EVENT_TRB_LEN(le32_to_cpu(event->transfer_len));
 
-       /* not setup (dequeue), or status stage means we are at data stage */
-       on_data_stage = (ep_trb != ep_ring->dequeue && ep_trb != td->last_trb);
-
        switch (trb_comp_code) {
        case COMP_SUCCESS:
-               if (ep_trb != td->last_trb) {
+               if (trb_type != TRB_STATUS) {
                        xhci_warn(xhci, "WARN: Success on ctrl %s TRB without IOC set?\n",
-                                 on_data_stage ? "data" : "setup");
+                                 (trb_type == TRB_DATA) ? "data" : "setup");
                        *status = -ESHUTDOWN;
                        break;
                }
@@ -1999,15 +1997,25 @@ static int process_ctrl_td(struct xhci_hcd *xhci, struct xhci_td *td,
                *status = 0;
                break;
        case COMP_STOP_SHORT:
-               if (on_data_stage)
+               if (trb_type == TRB_DATA || trb_type == TRB_NORMAL)
                        td->urb->actual_length = remaining;
                else
                        xhci_warn(xhci, "WARN: Stopped Short Packet on ctrl setup or status TRB\n");
                goto finish_td;
        case COMP_STOP:
-               if (on_data_stage)
+               switch (trb_type) {
+               case TRB_SETUP:
+                       td->urb->actual_length = 0;
+                       goto finish_td;
+               case TRB_DATA:
+               case TRB_NORMAL:
                        td->urb->actual_length = requested - remaining;
-               goto finish_td;
+                       goto finish_td;
+               default:
+                       xhci_warn(xhci, "WARN: unexpected TRB Type %d\n",
+                                 trb_type);
+                       goto finish_td;
+               }
        case COMP_STOP_INVAL:
                goto finish_td;
        default:
@@ -2019,7 +2027,7 @@ static int process_ctrl_td(struct xhci_hcd *xhci, struct xhci_td *td,
                /* else fall through */
        case COMP_STALL:
                /* Did we transfer part of the data (middle) phase? */
-               if (on_data_stage)
+               if (trb_type == TRB_DATA || trb_type == TRB_NORMAL)
                        td->urb->actual_length = requested - remaining;
                else if (!td->urb_length_set)
                        td->urb->actual_length = 0;
@@ -2027,14 +2035,15 @@ static int process_ctrl_td(struct xhci_hcd *xhci, struct xhci_td *td,
        }
 
        /* stopped at setup stage, no data transferred */
-       if (ep_trb == ep_ring->dequeue)
+       if (trb_type == TRB_SETUP)
                goto finish_td;
 
        /*
         * if on data stage then update the actual_length of the URB and flag it
         * as set, so it won't be overwritten in the event for the last TRB.
         */
-       if (on_data_stage) {
+       if (trb_type == TRB_DATA ||
+               trb_type == TRB_NORMAL) {
                td->urb_length_set = true;
                td->urb->actual_length = requested - remaining;
                xhci_dbg(xhci, "Waiting for status stage event\n");