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Commit 04a378f3 authored by Thomas Pugliese's avatar Thomas Pugliese Committed by Greg Kroah-Hartman
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usb: wusbcore: combine iso transfer result frame reads when possible 



When reading the transfer result data for an isochronous in request, if
the current frame actual_length is contiguous with the next frame and
actual_length is a multiple of the DTI endpoint max packet size, combine
the current frame with the next frame in a single URB.  This reduces the
number of URBs that must be submitted in that case which increases
performance and reduces CPU interrupt overhead.

Signed-off-by: default avatarThomas Pugliese <thomas.pugliese@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7338a065

drivers/usb/wusbcore/wa-xfer.c

+76 −30
Original line number Diff line number Diff line
@@ -2160,22 +2160,59 @@ static void wa_complete_remaining_xfer_segs(struct wa_xfer *xfer, 
}



/* Populate the wa->buf_in_urb based on the current isoc transfer state. */

static void __wa_populate_buf_in_urb_isoc(struct wahc *wa, struct wa_xfer *xfer,

	struct wa_seg *seg, int curr_iso_frame)

static int __wa_populate_buf_in_urb_isoc(struct wahc *wa, struct wa_xfer *xfer,

	struct wa_seg *seg)

{

	int urb_start_frame = seg->isoc_frame_index + seg->isoc_frame_offset;

	int seg_index, total_len = 0, urb_frame_index = urb_start_frame;

	struct usb_iso_packet_descriptor *iso_frame_desc =

						xfer->urb->iso_frame_desc;

	const int dti_packet_size = usb_endpoint_maxp(wa->dti_epd);

	int next_frame_contiguous;

	struct usb_iso_packet_descriptor *iso_frame;



	BUG_ON(wa->buf_in_urb->status == -EINPROGRESS);



	/*

	 * If the current frame actual_length is contiguous with the next frame

	 * and actual_length is a multiple of the DTI endpoint max packet size,

	 * combine the current frame with the next frame in a single URB.  This

	 * reduces the number of URBs that must be submitted in that case.

	 */

	seg_index = seg->isoc_frame_index;

	do {

		next_frame_contiguous = 0;



		iso_frame = &iso_frame_desc[urb_frame_index];

		total_len += iso_frame->actual_length;

		++urb_frame_index;

		++seg_index;



		if (seg_index < seg->isoc_frame_count) {

			struct usb_iso_packet_descriptor *next_iso_frame;



			next_iso_frame = &iso_frame_desc[urb_frame_index];



			if ((iso_frame->offset + iso_frame->actual_length) ==

				next_iso_frame->offset)

				next_frame_contiguous = 1;

		}

	} while (next_frame_contiguous

			&& ((iso_frame->actual_length % dti_packet_size) == 0));



	/* this should always be 0 before a resubmit. */

	wa->buf_in_urb->num_mapped_sgs	= 0;

	wa->buf_in_urb->transfer_dma = xfer->urb->transfer_dma +

		xfer->urb->iso_frame_desc[curr_iso_frame].offset;

	wa->buf_in_urb->transfer_buffer_length =

		xfer->urb->iso_frame_desc[curr_iso_frame].actual_length;

		iso_frame_desc[urb_start_frame].offset;

	wa->buf_in_urb->transfer_buffer_length = total_len;

	wa->buf_in_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;

	wa->buf_in_urb->transfer_buffer = NULL;

	wa->buf_in_urb->sg = NULL;

	wa->buf_in_urb->num_sgs = 0;

	wa->buf_in_urb->context = seg;



	/* return the number of frames included in this URB. */

	return seg_index - seg->isoc_frame_index;

}



/* Populate the wa->buf_in_urb based on the current transfer state. */
@@ -2458,19 +2495,20 @@ static int wa_process_iso_packet_status(struct wahc *wa, struct urb *urb) 
	}



	if (xfer->is_inbound && data_frame_count) {

		int result;

		int result, urb_frame_count;



		seg->isoc_frame_index = first_frame_index;

		/* submit a read URB for the first frame with data. */

		__wa_populate_buf_in_urb_isoc(wa, xfer, seg,

			seg->isoc_frame_index + seg->isoc_frame_offset);

		urb_frame_count = __wa_populate_buf_in_urb_isoc(wa, xfer, seg);

		/* advance index to start of next read URB. */

		seg->isoc_frame_index += urb_frame_count;



		result = usb_submit_urb(wa->buf_in_urb, GFP_ATOMIC);

		if (result < 0) {

			dev_err(dev, "DTI Error: Could not submit buf in URB (%d)",

				result);

			wa_reset_all(wa);

		} else if (data_frame_count > 1)

		} else if (data_frame_count > urb_frame_count)

			/* If we need to read multiple frames, set DTI busy. */

			dti_busy = 1;

	} else {
@@ -2511,8 +2549,9 @@ static void wa_buf_in_cb(struct urb *urb) 
	struct wahc *wa;

	struct device *dev;

	struct wa_rpipe *rpipe;

	unsigned rpipe_ready = 0, seg_index, isoc_data_frame_count = 0;

	unsigned rpipe_ready = 0, isoc_data_frame_count = 0;

	unsigned long flags;

	int resubmit_dti = 0;

	u8 done = 0;



	/* free the sg if it was used. */
@@ -2524,17 +2563,16 @@ static void wa_buf_in_cb(struct urb *urb) 
	dev = &wa->usb_iface->dev;



	if (usb_pipeisoc(xfer->urb->pipe)) {

		/*

		 * Find the next isoc frame with data.  Bail out after

		 * isoc_data_frame_count > 1 since there is no need to walk

		 * the entire frame array.  We just need to know if

		 * isoc_data_frame_count is 0, 1, or >1.

		 */

		seg_index = seg->isoc_frame_index + 1;

		while ((seg_index < seg->isoc_frame_count)

			&& (isoc_data_frame_count <= 1)) {

		struct usb_iso_packet_descriptor *iso_frame_desc =

			xfer->urb->iso_frame_desc;

		int	seg_index;



		/*

		 * Find the next isoc frame with data and count how many

		 * frames with data remain.

		 */

		seg_index = seg->isoc_frame_index;

		while (seg_index < seg->isoc_frame_count) {

			const int urb_frame_index =

				seg->isoc_frame_offset + seg_index;
@@ -2555,16 +2593,28 @@ static void wa_buf_in_cb(struct urb *urb) 


		seg->result += urb->actual_length;

		if (isoc_data_frame_count > 0) {

			int result;

			/* submit a read URB for the first frame with data. */

			__wa_populate_buf_in_urb_isoc(wa, xfer, seg,

				seg->isoc_frame_index + seg->isoc_frame_offset);

			int result, urb_frame_count;



			/* submit a read URB for the next frame with data. */

			urb_frame_count = __wa_populate_buf_in_urb_isoc(wa,

				 xfer, seg);

			/* advance index to start of next read URB. */

			seg->isoc_frame_index += urb_frame_count;

			result = usb_submit_urb(wa->buf_in_urb, GFP_ATOMIC);

			if (result < 0) {

				dev_err(dev, "DTI Error: Could not submit buf in URB (%d)",

					result);

				wa_reset_all(wa);

			}

			/*

			 * If we are in this callback and

			 * isoc_data_frame_count > 0, it means that the dti_urb

			 * submission was delayed in wa_dti_cb.  Once

			 * we submit the last buf_in_urb, we can submit the

			 * delayed dti_urb.

			 */

			  resubmit_dti = (isoc_data_frame_count ==

							urb_frame_count);

		} else {

			rpipe = xfer->ep->hcpriv;

			dev_dbg(dev,
@@ -2585,6 +2635,7 @@ static void wa_buf_in_cb(struct urb *urb) 
	case -ENOENT:		/* as it was done by the who unlinked us */

		break;

	default:		/* Other errors ... */

		resubmit_dti = 1;

		spin_lock_irqsave(&xfer->lock, flags);

		rpipe = xfer->ep->hcpriv;

		if (printk_ratelimit())
@@ -2607,13 +2658,8 @@ static void wa_buf_in_cb(struct urb *urb) 
		if (rpipe_ready)

			wa_xfer_delayed_run(rpipe);

	}

	/*

	 * If we are in this callback and isoc_data_frame_count > 0, it means

	 * that the dti_urb submission was delayed in wa_dti_cb.  Once

	 * isoc_data_frame_count gets to 1, we can submit the deferred URB

	 * since the last buf_in_urb was just submitted.

	 */

	if (isoc_data_frame_count == 1) {



	if (resubmit_dti) {

		int result = usb_submit_urb(wa->dti_urb, GFP_ATOMIC);

		if (result < 0) {

			dev_err(dev, "DTI Error: Could not submit DTI URB (%d)\n",