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>

1 files changed, 21 insertions, 12 deletions

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 7a14e9ad664d..25f522b09dd9 100644
--- 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");