xhci: dbc: Flush queued requests before stopping dbc

JIRA: https://issues.redhat.com/browse/RHEL-116007

commit efe3e3a
Author: Mathias Nyman <mathias.nyman@linux.intel.com>
Date: Fri, 27 Jun 2025 17:41:22 +0300

  Flush dbc requests when dbc is stopped and transfer rings are freed.
  Failure to flush them lead to leaking memory and dbc completing odd
  requests after resuming from suspend, leading to error messages such as:

  [   95.344392] xhci_hcd 0000:00:0d.0: no matched request

  Cc: stable <stable@kernel.org>
  Fixes: dfba217 ("usb: xhci: Add DbC support in xHCI driver")
  Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
  Link: https://lore.kernel.org/r/20250627144127.3889714-5-mathias.nyman@linux.intel.com
  Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Desnes Nunes <desnesn@redhat.com>

Author: Desnes Nunes

drivers/usb/host/xhci-dbgcap.c

@@ -652,6 +652,10 @@ static void xhci_dbc_stop(struct xhci_dbc *dbc)
 	case DS_DISABLED:
 		return;
 	case DS_CONFIGURED:
+		spin_lock(&dbc->lock);
+		xhci_dbc_flush_requests(dbc);
+		spin_unlock(&dbc->lock);
+
 		if (dbc->driver->disconnect)
 			dbc->driver->disconnect(dbc);
 		break;