If there is a receive timeout without any active
requests, we can tell the connection was idle and
ignore the timeout.
If there are active requests for which we expect
to receive a reply we close the connection.
This makes it possible to set an upper bound on
the time a usbip device may be unresponsive.
This is a workaround for the lack of heart-beat
messages in the USBIP protocol.
Extending the protocol would break compatibility
with all previous stub versions, so this seems like
the lesser evil.
Signed-off-by: Max Vozeler <max@xxxxxxxxxxx>
Tested-by: Mark Wehby <MWehby@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/usbip/vhci_rx.c | 21 ++++++++++++++++++++-
1 files changed, 20 insertions(+), 1 deletions(-)
diff --git a/drivers/staging/usbip/vhci_rx.c b/drivers/staging/usbip/vhci_rx.c
index ac15cea..bf69914 100644
--- a/drivers/staging/usbip/vhci_rx.c
+++ b/drivers/staging/usbip/vhci_rx.c
@@ -193,6 +193,19 @@ static void vhci_recv_ret_unlink(struct vhci_device *vdev,
return;
}
+static int vhci_priv_tx_empty(struct vhci_device *vdev)
+{
+ int empty = 0;
+
+ spin_lock(&vdev->priv_lock);
+
+ empty = list_empty(&vdev->priv_rx);
+
+ spin_unlock(&vdev->priv_lock);
+
+ return empty;
+}
+
/* recv a pdu */
static void vhci_rx_pdu(struct usbip_device *ud)
{
@@ -210,8 +223,14 @@ static void vhci_rx_pdu(struct usbip_device *ud)
if (ret < 0) {
if (ret == -ECONNRESET)
usbip_uinfo("connection reset by peer\n");
- else if (ret != -ERESTARTSYS)
+ else if (ret == -EAGAIN) {
+ /* ignore if connection was idle */
+ if (vhci_priv_tx_empty(vdev))
+ return;
+ usbip_uinfo("connection timed out with pending urbs\n");
+ } else if (ret != -ERESTARTSYS)
usbip_uinfo("xmit failed %d\n", ret);
+
usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
return;
}
--
1.7.2.3
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