When the address of a request was not aligned with an 8-byte boundary, the
USB DMA was unable to process it, necessitating the use of an internal
bounce buffer.
In these cases, the request->buf had to be copied to/from this bounce
buffer. However, if this unaligned address scenario arises, it is
unnecessary to perform heavy cache maintenance operations like
usb_gadget_map(unmap)_request_by_dev() on the request->buf, as the DMA
does not utilize it at all. it can be skipped at this case.
iperf3 tests on the rndis case:
Transmit speed (TX): Improved from 299Mbps to 440Mbps
Receive speed (RX): Improved from 290Mbps to 500Mbps
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20230518204947.3770236-1-Frank.Li@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
if (request->status == -EINPROGRESS)
request->status = status;
- usb_gadget_unmap_request_by_dev(priv_dev->sysdev, request,
+ if (likely(!(priv_req->flags & REQUEST_UNALIGNED)))
+ usb_gadget_unmap_request_by_dev(priv_dev->sysdev, request,
priv_ep->dir);
if ((priv_req->flags & REQUEST_UNALIGNED) &&
if (ret < 0)
return ret;
- ret = usb_gadget_map_request_by_dev(priv_dev->sysdev, request,
+ if (likely(!(priv_req->flags & REQUEST_UNALIGNED))) {
+ ret = usb_gadget_map_request_by_dev(priv_dev->sysdev, request,
usb_endpoint_dir_in(ep->desc));
- if (ret)
- return ret;
+ if (ret)
+ return ret;
+ }
list_add_tail(&request->list, &priv_ep->deferred_req_list);