patch "xhci: don't finish a TD if we get a short transfer event mid TD" added to usb-linus

patch "xhci: don't finish a TD if we get a short transfer event mid TD" added to usb-linus

[gregkh]

This is a note to let you know that I've just added the patch titled

    xhci: don't finish a TD if we get a short transfer event mid TD

to my usb git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


>From e210c422b6fdd2dc123bedc588f399aefd8bf9de Mon Sep 17 00:00:00 2001
From: Mathias Nyman <mathias.nyman@linux.intel.com>
Date: Mon, 12 Oct 2015 11:30:11 +0300
Subject: xhci: don't finish a TD if we get a short transfer event mid TD

If the difference is big enough between the bytes asked and received
in a bulk transfer we can get a short transfer event pointing to a TRB in
the middle of the TD. We don't want to handle the TD yet as we will anyway
receive a new event for the last TRB in the TD.

Hold off from finishing the TD and removing it from the list until we
receive an event for the last TRB in the TD

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/host/xhci-ring.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 43291f93afeb..79e89e6aef73 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -2191,6 +2191,10 @@ static int process_bulk_intr_td(struct xhci_hcd *xhci, struct xhci_td *td,
 		}
 	/* Fast path - was this the last TRB in the TD for this URB? */
 	} else if (event_trb == td->last_trb) {
+		if (td->urb_length_set && trb_comp_code == COMP_SHORT_TX)
+			return finish_td(xhci, td, event_trb, event, ep,
+					 status, false);
+
 		if (EVENT_TRB_LEN(le32_to_cpu(event->transfer_len)) != 0) {
 			td->urb->actual_length =
 				td->urb->transfer_buffer_length -
@@ -2242,6 +2246,12 @@ static int process_bulk_intr_td(struct xhci_hcd *xhci, struct xhci_td *td,
 			td->urb->actual_length +=
 				TRB_LEN(le32_to_cpu(cur_trb->generic.field[2])) -
 				EVENT_TRB_LEN(le32_to_cpu(event->transfer_len));
+
+		if (trb_comp_code == COMP_SHORT_TX) {
+			xhci_dbg(xhci, "mid bulk/intr SP, wait for last TRB event\n");
+			td->urb_length_set = true;
+			return 0;
+		}
 	}
 
 	return finish_td(xhci, td, event_trb, event, ep, status, false);
-- 
2.6.1