File-copy from v4.4.100

This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Please refer to that tree for all history prior to this point.

Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/drivers/usb/usbip/stub_rx.c b/drivers/usb/usbip/stub_rx.c
new file mode 100644
index 0000000..00e475c
--- /dev/null
+++ b/drivers/usb/usbip/stub_rx.c
@@ -0,0 +1,594 @@
+/*
+ * Copyright (C) 2003-2008 Takahiro Hirofuchi
+ *
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
+ * USA.
+ */
+
+#include <asm/byteorder.h>
+#include <linux/kthread.h>
+#include <linux/usb.h>
+#include <linux/usb/hcd.h>
+
+#include "usbip_common.h"
+#include "stub.h"
+
+static int is_clear_halt_cmd(struct urb *urb)
+{
+	struct usb_ctrlrequest *req;
+
+	req = (struct usb_ctrlrequest *) urb->setup_packet;
+
+	 return (req->bRequest == USB_REQ_CLEAR_FEATURE) &&
+		 (req->bRequestType == USB_RECIP_ENDPOINT) &&
+		 (req->wValue == USB_ENDPOINT_HALT);
+}
+
+static int is_set_interface_cmd(struct urb *urb)
+{
+	struct usb_ctrlrequest *req;
+
+	req = (struct usb_ctrlrequest *) urb->setup_packet;
+
+	return (req->bRequest == USB_REQ_SET_INTERFACE) &&
+		(req->bRequestType == USB_RECIP_INTERFACE);
+}
+
+static int is_set_configuration_cmd(struct urb *urb)
+{
+	struct usb_ctrlrequest *req;
+
+	req = (struct usb_ctrlrequest *) urb->setup_packet;
+
+	return (req->bRequest == USB_REQ_SET_CONFIGURATION) &&
+		(req->bRequestType == USB_RECIP_DEVICE);
+}
+
+static int is_reset_device_cmd(struct urb *urb)
+{
+	struct usb_ctrlrequest *req;
+	__u16 value;
+	__u16 index;
+
+	req = (struct usb_ctrlrequest *) urb->setup_packet;
+	value = le16_to_cpu(req->wValue);
+	index = le16_to_cpu(req->wIndex);
+
+	if ((req->bRequest == USB_REQ_SET_FEATURE) &&
+	    (req->bRequestType == USB_RT_PORT) &&
+	    (value == USB_PORT_FEAT_RESET)) {
+		usbip_dbg_stub_rx("reset_device_cmd, port %u\n", index);
+		return 1;
+	} else
+		return 0;
+}
+
+static int tweak_clear_halt_cmd(struct urb *urb)
+{
+	struct usb_ctrlrequest *req;
+	int target_endp;
+	int target_dir;
+	int target_pipe;
+	int ret;
+
+	req = (struct usb_ctrlrequest *) urb->setup_packet;
+
+	/*
+	 * The stalled endpoint is specified in the wIndex value. The endpoint
+	 * of the urb is the target of this clear_halt request (i.e., control
+	 * endpoint).
+	 */
+	target_endp = le16_to_cpu(req->wIndex) & 0x000f;
+
+	/* the stalled endpoint direction is IN or OUT?. USB_DIR_IN is 0x80.  */
+	target_dir = le16_to_cpu(req->wIndex) & 0x0080;
+
+	if (target_dir)
+		target_pipe = usb_rcvctrlpipe(urb->dev, target_endp);
+	else
+		target_pipe = usb_sndctrlpipe(urb->dev, target_endp);
+
+	ret = usb_clear_halt(urb->dev, target_pipe);
+	if (ret < 0)
+		dev_err(&urb->dev->dev,
+			"usb_clear_halt error: devnum %d endp %d ret %d\n",
+			urb->dev->devnum, target_endp, ret);
+	else
+		dev_info(&urb->dev->dev,
+			 "usb_clear_halt done: devnum %d endp %d\n",
+			 urb->dev->devnum, target_endp);
+
+	return ret;
+}
+
+static int tweak_set_interface_cmd(struct urb *urb)
+{
+	struct usb_ctrlrequest *req;
+	__u16 alternate;
+	__u16 interface;
+	int ret;
+
+	req = (struct usb_ctrlrequest *) urb->setup_packet;
+	alternate = le16_to_cpu(req->wValue);
+	interface = le16_to_cpu(req->wIndex);
+
+	usbip_dbg_stub_rx("set_interface: inf %u alt %u\n",
+			  interface, alternate);
+
+	ret = usb_set_interface(urb->dev, interface, alternate);
+	if (ret < 0)
+		dev_err(&urb->dev->dev,
+			"usb_set_interface error: inf %u alt %u ret %d\n",
+			interface, alternate, ret);
+	else
+		dev_info(&urb->dev->dev,
+			"usb_set_interface done: inf %u alt %u\n",
+			interface, alternate);
+
+	return ret;
+}
+
+static int tweak_set_configuration_cmd(struct urb *urb)
+{
+	struct stub_priv *priv = (struct stub_priv *) urb->context;
+	struct stub_device *sdev = priv->sdev;
+	struct usb_ctrlrequest *req;
+	__u16 config;
+	int err;
+
+	req = (struct usb_ctrlrequest *) urb->setup_packet;
+	config = le16_to_cpu(req->wValue);
+
+	err = usb_set_configuration(sdev->udev, config);
+	if (err && err != -ENODEV)
+		dev_err(&sdev->udev->dev, "can't set config #%d, error %d\n",
+			config, err);
+	return 0;
+}
+
+static int tweak_reset_device_cmd(struct urb *urb)
+{
+	struct stub_priv *priv = (struct stub_priv *) urb->context;
+	struct stub_device *sdev = priv->sdev;
+
+	dev_info(&urb->dev->dev, "usb_queue_reset_device\n");
+
+	/*
+	 * With the implementation of pre_reset and post_reset the driver no
+	 * longer unbinds. This allows the use of synchronous reset.
+	 */
+
+	if (usb_lock_device_for_reset(sdev->udev, sdev->interface) < 0) {
+		dev_err(&urb->dev->dev, "could not obtain lock to reset device\n");
+		return 0;
+	}
+	usb_reset_device(sdev->udev);
+	usb_unlock_device(sdev->udev);
+
+	return 0;
+}
+
+/*
+ * clear_halt, set_interface, and set_configuration require special tricks.
+ */
+static void tweak_special_requests(struct urb *urb)
+{
+	if (!urb || !urb->setup_packet)
+		return;
+
+	if (usb_pipetype(urb->pipe) != PIPE_CONTROL)
+		return;
+
+	if (is_clear_halt_cmd(urb))
+		/* tweak clear_halt */
+		 tweak_clear_halt_cmd(urb);
+
+	else if (is_set_interface_cmd(urb))
+		/* tweak set_interface */
+		tweak_set_interface_cmd(urb);
+
+	else if (is_set_configuration_cmd(urb))
+		/* tweak set_configuration */
+		tweak_set_configuration_cmd(urb);
+
+	else if (is_reset_device_cmd(urb))
+		tweak_reset_device_cmd(urb);
+	else
+		usbip_dbg_stub_rx("no need to tweak\n");
+}
+
+/*
+ * stub_recv_unlink() unlinks the URB by a call to usb_unlink_urb().
+ * By unlinking the urb asynchronously, stub_rx can continuously
+ * process coming urbs.  Even if the urb is unlinked, its completion
+ * handler will be called and stub_tx will send a return pdu.
+ *
+ * See also comments about unlinking strategy in vhci_hcd.c.
+ */
+static int stub_recv_cmd_unlink(struct stub_device *sdev,
+				struct usbip_header *pdu)
+{
+	int ret;
+	unsigned long flags;
+	struct stub_priv *priv;
+
+	spin_lock_irqsave(&sdev->priv_lock, flags);
+
+	list_for_each_entry(priv, &sdev->priv_init, list) {
+		if (priv->seqnum != pdu->u.cmd_unlink.seqnum)
+			continue;
+
+		dev_info(&priv->urb->dev->dev, "unlink urb %p\n",
+			 priv->urb);
+
+		/*
+		 * This matched urb is not completed yet (i.e., be in
+		 * flight in usb hcd hardware/driver). Now we are
+		 * cancelling it. The unlinking flag means that we are
+		 * now not going to return the normal result pdu of a
+		 * submission request, but going to return a result pdu
+		 * of the unlink request.
+		 */
+		priv->unlinking = 1;
+
+		/*
+		 * In the case that unlinking flag is on, prev->seqnum
+		 * is changed from the seqnum of the cancelling urb to
+		 * the seqnum of the unlink request. This will be used
+		 * to make the result pdu of the unlink request.
+		 */
+		priv->seqnum = pdu->base.seqnum;
+
+		spin_unlock_irqrestore(&sdev->priv_lock, flags);
+
+		/*
+		 * usb_unlink_urb() is now out of spinlocking to avoid
+		 * spinlock recursion since stub_complete() is
+		 * sometimes called in this context but not in the
+		 * interrupt context.  If stub_complete() is executed
+		 * before we call usb_unlink_urb(), usb_unlink_urb()
+		 * will return an error value. In this case, stub_tx
+		 * will return the result pdu of this unlink request
+		 * though submission is completed and actual unlinking
+		 * is not executed. OK?
+		 */
+		/* In the above case, urb->status is not -ECONNRESET,
+		 * so a driver in a client host will know the failure
+		 * of the unlink request ?
+		 */
+		ret = usb_unlink_urb(priv->urb);
+		if (ret != -EINPROGRESS)
+			dev_err(&priv->urb->dev->dev,
+				"failed to unlink a urb %p, ret %d\n",
+				priv->urb, ret);
+
+		return 0;
+	}
+
+	usbip_dbg_stub_rx("seqnum %d is not pending\n",
+			  pdu->u.cmd_unlink.seqnum);
+
+	/*
+	 * The urb of the unlink target is not found in priv_init queue. It was
+	 * already completed and its results is/was going to be sent by a
+	 * CMD_RET pdu. In this case, usb_unlink_urb() is not needed. We only
+	 * return the completeness of this unlink request to vhci_hcd.
+	 */
+	stub_enqueue_ret_unlink(sdev, pdu->base.seqnum, 0);
+
+	spin_unlock_irqrestore(&sdev->priv_lock, flags);
+
+	return 0;
+}
+
+static int valid_request(struct stub_device *sdev, struct usbip_header *pdu)
+{
+	struct usbip_device *ud = &sdev->ud;
+	int valid = 0;
+
+	if (pdu->base.devid == sdev->devid) {
+		spin_lock_irq(&ud->lock);
+		if (ud->status == SDEV_ST_USED) {
+			/* A request is valid. */
+			valid = 1;
+		}
+		spin_unlock_irq(&ud->lock);
+	}
+
+	return valid;
+}
+
+static struct stub_priv *stub_priv_alloc(struct stub_device *sdev,
+					 struct usbip_header *pdu)
+{
+	struct stub_priv *priv;
+	struct usbip_device *ud = &sdev->ud;
+	unsigned long flags;
+
+	spin_lock_irqsave(&sdev->priv_lock, flags);
+
+	priv = kmem_cache_zalloc(stub_priv_cache, GFP_ATOMIC);
+	if (!priv) {
+		dev_err(&sdev->interface->dev, "alloc stub_priv\n");
+		spin_unlock_irqrestore(&sdev->priv_lock, flags);
+		usbip_event_add(ud, SDEV_EVENT_ERROR_MALLOC);
+		return NULL;
+	}
+
+	priv->seqnum = pdu->base.seqnum;
+	priv->sdev = sdev;
+
+	/*
+	 * After a stub_priv is linked to a list_head,
+	 * our error handler can free allocated data.
+	 */
+	list_add_tail(&priv->list, &sdev->priv_init);
+
+	spin_unlock_irqrestore(&sdev->priv_lock, flags);
+
+	return priv;
+}
+
+static int get_pipe(struct stub_device *sdev, int epnum, int dir)
+{
+	struct usb_device *udev = sdev->udev;
+	struct usb_host_endpoint *ep;
+	struct usb_endpoint_descriptor *epd = NULL;
+
+	if (dir == USBIP_DIR_IN)
+		ep = udev->ep_in[epnum & 0x7f];
+	else
+		ep = udev->ep_out[epnum & 0x7f];
+	if (!ep) {
+		dev_err(&sdev->interface->dev, "no such endpoint?, %d\n",
+			epnum);
+		BUG();
+	}
+
+	epd = &ep->desc;
+	if (usb_endpoint_xfer_control(epd)) {
+		if (dir == USBIP_DIR_OUT)
+			return usb_sndctrlpipe(udev, epnum);
+		else
+			return usb_rcvctrlpipe(udev, epnum);
+	}
+
+	if (usb_endpoint_xfer_bulk(epd)) {
+		if (dir == USBIP_DIR_OUT)
+			return usb_sndbulkpipe(udev, epnum);
+		else
+			return usb_rcvbulkpipe(udev, epnum);
+	}
+
+	if (usb_endpoint_xfer_int(epd)) {
+		if (dir == USBIP_DIR_OUT)
+			return usb_sndintpipe(udev, epnum);
+		else
+			return usb_rcvintpipe(udev, epnum);
+	}
+
+	if (usb_endpoint_xfer_isoc(epd)) {
+		if (dir == USBIP_DIR_OUT)
+			return usb_sndisocpipe(udev, epnum);
+		else
+			return usb_rcvisocpipe(udev, epnum);
+	}
+
+	/* NOT REACHED */
+	dev_err(&sdev->interface->dev, "get pipe, epnum %d\n", epnum);
+	return 0;
+}
+
+static void masking_bogus_flags(struct urb *urb)
+{
+	int				xfertype;
+	struct usb_device		*dev;
+	struct usb_host_endpoint	*ep;
+	int				is_out;
+	unsigned int	allowed;
+
+	if (!urb || urb->hcpriv || !urb->complete)
+		return;
+	dev = urb->dev;
+	if ((!dev) || (dev->state < USB_STATE_UNAUTHENTICATED))
+		return;
+
+	ep = (usb_pipein(urb->pipe) ? dev->ep_in : dev->ep_out)
+		[usb_pipeendpoint(urb->pipe)];
+	if (!ep)
+		return;
+
+	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;
+		is_out = !(setup->bRequestType & USB_DIR_IN) ||
+			!setup->wLength;
+	} else {
+		is_out = usb_endpoint_dir_out(&ep->desc);
+	}
+
+	/* enforce 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:
+		if (is_out)
+			allowed |= URB_ZERO_PACKET;
+		/* FALLTHROUGH */
+	case USB_ENDPOINT_XFER_CONTROL:
+		allowed |= URB_NO_FSBR;	/* only affects UHCI */
+		/* 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;
+	}
+	urb->transfer_flags &= allowed;
+}
+
+static void stub_recv_cmd_submit(struct stub_device *sdev,
+				 struct usbip_header *pdu)
+{
+	int ret;
+	struct stub_priv *priv;
+	struct usbip_device *ud = &sdev->ud;
+	struct usb_device *udev = sdev->udev;
+	int pipe = get_pipe(sdev, pdu->base.ep, pdu->base.direction);
+
+	priv = stub_priv_alloc(sdev, pdu);
+	if (!priv)
+		return;
+
+	/* setup a urb */
+	if (usb_pipeisoc(pipe))
+		priv->urb = usb_alloc_urb(pdu->u.cmd_submit.number_of_packets,
+					  GFP_KERNEL);
+	else
+		priv->urb = usb_alloc_urb(0, GFP_KERNEL);
+
+	if (!priv->urb) {
+		dev_err(&sdev->interface->dev, "malloc urb\n");
+		usbip_event_add(ud, SDEV_EVENT_ERROR_MALLOC);
+		return;
+	}
+
+	/* allocate urb transfer buffer, if needed */
+	if (pdu->u.cmd_submit.transfer_buffer_length > 0) {
+		priv->urb->transfer_buffer =
+			kzalloc(pdu->u.cmd_submit.transfer_buffer_length,
+				GFP_KERNEL);
+		if (!priv->urb->transfer_buffer) {
+			usbip_event_add(ud, SDEV_EVENT_ERROR_MALLOC);
+			return;
+		}
+	}
+
+	/* copy urb setup packet */
+	priv->urb->setup_packet = kmemdup(&pdu->u.cmd_submit.setup, 8,
+					  GFP_KERNEL);
+	if (!priv->urb->setup_packet) {
+		dev_err(&sdev->interface->dev, "allocate setup_packet\n");
+		usbip_event_add(ud, SDEV_EVENT_ERROR_MALLOC);
+		return;
+	}
+
+	/* set other members from the base header of pdu */
+	priv->urb->context                = (void *) priv;
+	priv->urb->dev                    = udev;
+	priv->urb->pipe                   = pipe;
+	priv->urb->complete               = stub_complete;
+
+	usbip_pack_pdu(pdu, priv->urb, USBIP_CMD_SUBMIT, 0);
+
+
+	if (usbip_recv_xbuff(ud, priv->urb) < 0)
+		return;
+
+	if (usbip_recv_iso(ud, priv->urb) < 0)
+		return;
+
+	/* no need to submit an intercepted request, but harmless? */
+	tweak_special_requests(priv->urb);
+
+	masking_bogus_flags(priv->urb);
+	/* urb is now ready to submit */
+	ret = usb_submit_urb(priv->urb, GFP_KERNEL);
+
+	if (ret == 0)
+		usbip_dbg_stub_rx("submit urb ok, seqnum %u\n",
+				  pdu->base.seqnum);
+	else {
+		dev_err(&sdev->interface->dev, "submit_urb error, %d\n", ret);
+		usbip_dump_header(pdu);
+		usbip_dump_urb(priv->urb);
+
+		/*
+		 * Pessimistic.
+		 * This connection will be discarded.
+		 */
+		usbip_event_add(ud, SDEV_EVENT_ERROR_SUBMIT);
+	}
+
+	usbip_dbg_stub_rx("Leave\n");
+}
+
+/* recv a pdu */
+static void stub_rx_pdu(struct usbip_device *ud)
+{
+	int ret;
+	struct usbip_header pdu;
+	struct stub_device *sdev = container_of(ud, struct stub_device, ud);
+	struct device *dev = &sdev->udev->dev;
+
+	usbip_dbg_stub_rx("Enter\n");
+
+	memset(&pdu, 0, sizeof(pdu));
+
+	/* receive a pdu header */
+	ret = usbip_recv(ud->tcp_socket, &pdu, sizeof(pdu));
+	if (ret != sizeof(pdu)) {
+		dev_err(dev, "recv a header, %d\n", ret);
+		usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
+		return;
+	}
+
+	usbip_header_correct_endian(&pdu, 0);
+
+	if (usbip_dbg_flag_stub_rx)
+		usbip_dump_header(&pdu);
+
+	if (!valid_request(sdev, &pdu)) {
+		dev_err(dev, "recv invalid request\n");
+		usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
+		return;
+	}
+
+	switch (pdu.base.command) {
+	case USBIP_CMD_UNLINK:
+		stub_recv_cmd_unlink(sdev, &pdu);
+		break;
+
+	case USBIP_CMD_SUBMIT:
+		stub_recv_cmd_submit(sdev, &pdu);
+		break;
+
+	default:
+		/* NOTREACHED */
+		dev_err(dev, "unknown pdu\n");
+		usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
+		break;
+	}
+}
+
+int stub_rx_loop(void *data)
+{
+	struct usbip_device *ud = data;
+
+	while (!kthread_should_stop()) {
+		if (usbip_event_happened(ud))
+			break;
+
+		stub_rx_pdu(ud);
+	}
+
+	return 0;
+}