int usb_submit_urb()

in core/urb.c [367:595]


int usb_submit_urb(struct urb *urb, gfp_t mem_flags)
{
	int				xfertype, max;
	struct usb_device		*dev;
	struct usb_host_endpoint	*ep;
	int				is_out;
	unsigned int			allowed;

	if (!urb || !urb->complete)
		return -EINVAL;
	if (urb->hcpriv) {
		WARN_ONCE(1, "URB %pK submitted while active\n", urb);
		return -EBUSY;
	}

	dev = urb->dev;
	if ((!dev) || (dev->state < USB_STATE_UNAUTHENTICATED))
		return -ENODEV;

	/* For now, get the endpoint from the pipe.  Eventually drivers
	 * will be required to set urb->ep directly and we will eliminate
	 * urb->pipe.
	 */
	ep = usb_pipe_endpoint(dev, urb->pipe);
	if (!ep)
		return -ENOENT;

	urb->ep = ep;
	urb->status = -EINPROGRESS;
	urb->actual_length = 0;

	/* Lots of sanity checks, so HCDs can rely on clean data
	 * and don't need to duplicate tests
	 */
	xfertype = usb_endpoint_type(&ep->desc);
	if (xfertype == USB_ENDPOINT_XFER_CONTROL) {
		struct usb_ctrlrequest *setup =
				(struct usb_ctrlrequest *) urb->setup_packet;

		if (!setup)
			return -ENOEXEC;
		is_out = !(setup->bRequestType & USB_DIR_IN) ||
				!setup->wLength;
		dev_WARN_ONCE(&dev->dev, (usb_pipeout(urb->pipe) != is_out),
				"BOGUS control dir, pipe %x doesn't match bRequestType %x\n",
				urb->pipe, setup->bRequestType);
		if (le16_to_cpu(setup->wLength) != urb->transfer_buffer_length) {
			dev_dbg(&dev->dev, "BOGUS control len %d doesn't match transfer length %d\n",
					le16_to_cpu(setup->wLength),
					urb->transfer_buffer_length);
			return -EBADR;
		}
	} else {
		is_out = usb_endpoint_dir_out(&ep->desc);
	}

	/* Clear the internal flags and cache the direction for later use */
	urb->transfer_flags &= ~(URB_DIR_MASK | URB_DMA_MAP_SINGLE |
			URB_DMA_MAP_PAGE | URB_DMA_MAP_SG | URB_MAP_LOCAL |
			URB_SETUP_MAP_SINGLE | URB_SETUP_MAP_LOCAL |
			URB_DMA_SG_COMBINED);
	urb->transfer_flags |= (is_out ? URB_DIR_OUT : URB_DIR_IN);

	if (xfertype != USB_ENDPOINT_XFER_CONTROL &&
			dev->state < USB_STATE_CONFIGURED)
		return -ENODEV;

	max = usb_endpoint_maxp(&ep->desc);
	if (max <= 0) {
		dev_dbg(&dev->dev,
			"bogus endpoint ep%d%s in %s (bad maxpacket %d)\n",
			usb_endpoint_num(&ep->desc), is_out ? "out" : "in",
			__func__, max);
		return -EMSGSIZE;
	}

	/* periodic transfers limit size per frame/uframe,
	 * but drivers only control those sizes for ISO.
	 * while we're checking, initialize return status.
	 */
	if (xfertype == USB_ENDPOINT_XFER_ISOC) {
		int	n, len;

		/* SuperSpeed isoc endpoints have up to 16 bursts of up to
		 * 3 packets each
		 */
		if (dev->speed >= USB_SPEED_SUPER) {
			int     burst = 1 + ep->ss_ep_comp.bMaxBurst;
			int     mult = USB_SS_MULT(ep->ss_ep_comp.bmAttributes);
			max *= burst;
			max *= mult;
		}

		if (dev->speed == USB_SPEED_SUPER_PLUS &&
		    USB_SS_SSP_ISOC_COMP(ep->ss_ep_comp.bmAttributes)) {
			struct usb_ssp_isoc_ep_comp_descriptor *isoc_ep_comp;

			isoc_ep_comp = &ep->ssp_isoc_ep_comp;
			max = le32_to_cpu(isoc_ep_comp->dwBytesPerInterval);
		}

		/* "high bandwidth" mode, 1-3 packets/uframe? */
		if (dev->speed == USB_SPEED_HIGH)
			max *= usb_endpoint_maxp_mult(&ep->desc);

		if (urb->number_of_packets <= 0)
			return -EINVAL;
		for (n = 0; n < urb->number_of_packets; n++) {
			len = urb->iso_frame_desc[n].length;
			if (len < 0 || len > max)
				return -EMSGSIZE;
			urb->iso_frame_desc[n].status = -EXDEV;
			urb->iso_frame_desc[n].actual_length = 0;
		}
	} else if (urb->num_sgs && !urb->dev->bus->no_sg_constraint &&
			dev->speed != USB_SPEED_WIRELESS) {
		struct scatterlist *sg;
		int i;

		for_each_sg(urb->sg, sg, urb->num_sgs - 1, i)
			if (sg->length % max)
				return -EINVAL;
	}

	/* the I/O buffer must be mapped/unmapped, except when length=0 */
	if (urb->transfer_buffer_length > INT_MAX)
		return -EMSGSIZE;

	/*
	 * stuff that drivers shouldn't do, but which shouldn't
	 * cause problems in HCDs if they get it wrong.
	 */

	/* Check that the pipe's type matches the endpoint's type */
	if (usb_pipe_type_check(urb->dev, urb->pipe))
		dev_WARN(&dev->dev, "BOGUS urb xfer, pipe %x != type %x\n",
			usb_pipetype(urb->pipe), pipetypes[xfertype]);

	/* Check against a simple/standard policy */
	allowed = (URB_NO_TRANSFER_DMA_MAP | URB_NO_INTERRUPT | URB_DIR_MASK |
			URB_FREE_BUFFER);
	switch (xfertype) {
	case USB_ENDPOINT_XFER_BULK:
	case USB_ENDPOINT_XFER_INT:
		if (is_out)
			allowed |= URB_ZERO_PACKET;
		fallthrough;
	default:			/* all non-iso endpoints */
		if (!is_out)
			allowed |= URB_SHORT_NOT_OK;
		break;
	case USB_ENDPOINT_XFER_ISOC:
		allowed |= URB_ISO_ASAP;
		break;
	}
	allowed &= urb->transfer_flags;

	/* warn if submitter gave bogus flags */
	if (allowed != urb->transfer_flags)
		dev_WARN(&dev->dev, "BOGUS urb flags, %x --> %x\n",
			urb->transfer_flags, allowed);

	/*
	 * Force periodic transfer intervals to be legal values that are
	 * a power of two (so HCDs don't need to).
	 *
	 * FIXME want bus->{intr,iso}_sched_horizon values here.  Each HC
	 * supports different values... this uses EHCI/UHCI defaults (and
	 * EHCI can use smaller non-default values).
	 */
	switch (xfertype) {
	case USB_ENDPOINT_XFER_ISOC:
	case USB_ENDPOINT_XFER_INT:
		/* too small? */
		switch (dev->speed) {
		case USB_SPEED_WIRELESS:
			if ((urb->interval < 6)
				&& (xfertype == USB_ENDPOINT_XFER_INT))
				return -EINVAL;
			fallthrough;
		default:
			if (urb->interval <= 0)
				return -EINVAL;
			break;
		}
		/* too big? */
		switch (dev->speed) {
		case USB_SPEED_SUPER_PLUS:
		case USB_SPEED_SUPER:	/* units are 125us */
			/* Handle up to 2^(16-1) microframes */
			if (urb->interval > (1 << 15))
				return -EINVAL;
			max = 1 << 15;
			break;
		case USB_SPEED_WIRELESS:
			if (urb->interval > 16)
				return -EINVAL;
			break;
		case USB_SPEED_HIGH:	/* units are microframes */
			/* NOTE usb handles 2^15 */
			if (urb->interval > (1024 * 8))
				urb->interval = 1024 * 8;
			max = 1024 * 8;
			break;
		case USB_SPEED_FULL:	/* units are frames/msec */
		case USB_SPEED_LOW:
			if (xfertype == USB_ENDPOINT_XFER_INT) {
				if (urb->interval > 255)
					return -EINVAL;
				/* NOTE ohci only handles up to 32 */
				max = 128;
			} else {
				if (urb->interval > 1024)
					urb->interval = 1024;
				/* NOTE usb and ohci handle up to 2^15 */
				max = 1024;
			}
			break;
		default:
			return -EINVAL;
		}
		if (dev->speed != USB_SPEED_WIRELESS) {
			/* Round down to a power of 2, no more than max */
			urb->interval = min(max, 1 << ilog2(urb->interval));
		}
	}

	return usb_hcd_submit_urb(urb, mem_flags);
}