9 files changed, 409 insertions, 130 deletions

diff --git a/drivers/usb/usbip/Kconfig b/drivers/usb/usbip/Kconfig
index 2f86b28fa3da..7bbae7a08642 100644
--- a/drivers/usb/usbip/Kconfig
+++ b/drivers/usb/usbip/Kconfig
@@ -4,6 +4,7 @@ config USBIP_CORE
 	tristate "USB/IP support"
 	depends on NET
 	select USB_COMMON
+	select SGL_ALLOC
 	---help---
 	  This enables pushing USB packets over IP to allow remote
 	  machines direct access to USB devices. It provides the
diff --git a/drivers/usb/usbip/stub.h b/drivers/usb/usbip/stub.h
index 35618ceb2791..d11270560c24 100644
--- a/drivers/usb/usbip/stub.h
+++ b/drivers/usb/usbip/stub.h
@@ -52,7 +52,11 @@ struct stub_priv {
 	unsigned long seqnum;
 	struct list_head list;
 	struct stub_device *sdev;
-	struct urb *urb;
+	struct urb **urbs;
+	struct scatterlist *sgl;
+	int num_urbs;
+	int completed_urbs;
+	int urb_status;
 
 	int unlinking;
 };
@@ -86,6 +90,7 @@ extern struct usb_device_driver stub_driver;
 struct bus_id_priv *get_busid_priv(const char *busid);
 void put_busid_priv(struct bus_id_priv *bid);
 int del_match_busid(char *busid);
+void stub_free_priv_and_urb(struct stub_priv *priv);
 void stub_device_cleanup_urbs(struct stub_device *sdev);
 
 /* stub_rx.c */
diff --git a/drivers/usb/usbip/stub_main.c b/drivers/usb/usbip/stub_main.c
index bf8a5feb0ee9..a20bb2d04f4d 100644
--- a/drivers/usb/usbip/stub_main.c
+++ b/drivers/usb/usbip/stub_main.c
@@ -6,6 +6,7 @@
 #include <linux/string.h>
 #include <linux/module.h>
 #include <linux/device.h>
+#include <linux/scatterlist.h>
 
 #include "usbip_common.h"
 #include "stub.h"
@@ -283,13 +284,49 @@ static struct stub_priv *stub_priv_pop_from_listhead(struct list_head *listhead)
 	struct stub_priv *priv, *tmp;
 
 	list_for_each_entry_safe(priv, tmp, listhead, list) {
-		list_del(&priv->list);
+		list_del_init(&priv->list);
 		return priv;
 	}
 
 	return NULL;
 }
 
+void stub_free_priv_and_urb(struct stub_priv *priv)
+{
+	struct urb *urb;
+	int i;
+
+	for (i = 0; i < priv->num_urbs; i++) {
+		urb = priv->urbs[i];
+
+		if (!urb)
+			return;
+
+		kfree(urb->setup_packet);
+		urb->setup_packet = NULL;
+
+
+		if (urb->transfer_buffer && !priv->sgl) {
+			kfree(urb->transfer_buffer);
+			urb->transfer_buffer = NULL;
+		}
+
+		if (urb->num_sgs) {
+			sgl_free(urb->sg);
+			urb->sg = NULL;
+			urb->num_sgs = 0;
+		}
+
+		usb_free_urb(urb);
+	}
+	if (!list_empty(&priv->list))
+		list_del(&priv->list);
+	if (priv->sgl)
+		sgl_free(priv->sgl);
+	kfree(priv->urbs);
+	kmem_cache_free(stub_priv_cache, priv);
+}
+
 static struct stub_priv *stub_priv_pop(struct stub_device *sdev)
 {
 	unsigned long flags;
@@ -316,25 +353,15 @@ done:
 void stub_device_cleanup_urbs(struct stub_device *sdev)
 {
 	struct stub_priv *priv;
-	struct urb *urb;
+	int i;
 
 	dev_dbg(&sdev->udev->dev, "Stub device cleaning up urbs\n");
 
 	while ((priv = stub_priv_pop(sdev))) {
-		urb = priv->urb;
-		dev_dbg(&sdev->udev->dev, "free urb seqnum %lu\n",
-			priv->seqnum);
-		usb_kill_urb(urb);
-
-		kmem_cache_free(stub_priv_cache, priv);
+		for (i = 0; i < priv->num_urbs; i++)
+			usb_kill_urb(priv->urbs[i]);
 
-		kfree(urb->transfer_buffer);
-		urb->transfer_buffer = NULL;
-
-		kfree(urb->setup_packet);
-		urb->setup_packet = NULL;
-
-		usb_free_urb(urb);
+		stub_free_priv_and_urb(priv);
 	}
 }
 
diff --git a/drivers/usb/usbip/stub_rx.c b/drivers/usb/usbip/stub_rx.c
index b0a855acafa3..e2b019532234 100644
--- a/drivers/usb/usbip/stub_rx.c
+++ b/drivers/usb/usbip/stub_rx.c
@@ -7,6 +7,7 @@
 #include <linux/kthread.h>
 #include <linux/usb.h>
 #include <linux/usb/hcd.h>
+#include <linux/scatterlist.h>
 
 #include "usbip_common.h"
 #include "stub.h"
@@ -201,7 +202,7 @@ static void tweak_special_requests(struct urb *urb)
 static int stub_recv_cmd_unlink(struct stub_device *sdev,
 				struct usbip_header *pdu)
 {
-	int ret;
+	int ret, i;
 	unsigned long flags;
 	struct stub_priv *priv;
 
@@ -246,12 +247,14 @@ static int stub_recv_cmd_unlink(struct stub_device *sdev,
 		 * 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 # %lu, ret %d\n",
-				priv->seqnum, ret);
-
+		for (i = priv->completed_urbs; i < priv->num_urbs; i++) {
+			ret = usb_unlink_urb(priv->urbs[i]);
+			if (ret != -EINPROGRESS)
+				dev_err(&priv->urbs[i]->dev->dev,
+					"failed to unlink %d/%d urb of seqnum %lu, ret %d\n",
+					i + 1, priv->num_urbs,
+					priv->seqnum, ret);
+		}
 		return 0;
 	}
 
@@ -433,92 +436,191 @@ static void masking_bogus_flags(struct urb *urb)
 	urb->transfer_flags &= allowed;
 }
 
+static int stub_recv_xbuff(struct usbip_device *ud, struct stub_priv *priv)
+{
+	int ret;
+	int i;
+
+	for (i = 0; i < priv->num_urbs; i++) {
+		ret = usbip_recv_xbuff(ud, priv->urbs[i]);
+		if (ret < 0)
+			break;
+	}
+
+	return ret;
+}
+
 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;
+	struct scatterlist *sgl = NULL, *sg;
+	void *buffer = NULL;
+	unsigned long long buf_len;
+	int nents;
+	int num_urbs = 1;
 	int pipe = get_pipe(sdev, pdu);
+	int use_sg = pdu->u.cmd_submit.transfer_flags & URB_DMA_MAP_SG;
+	int support_sg = 1;
+	int np = 0;
+	int ret, i;
 
 	if (pipe == -1)
 		return;
 
+	/*
+	 * Smatch reported the error case where use_sg is true and buf_len is 0.
+	 * In this case, It adds SDEV_EVENT_ERROR_MALLOC and stub_priv will be
+	 * released by stub event handler and connection will be shut down.
+	 */
 	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);
+	buf_len = (unsigned long long)pdu->u.cmd_submit.transfer_buffer_length;
 
-	if (!priv->urb) {
-		usbip_event_add(ud, SDEV_EVENT_ERROR_MALLOC);
-		return;
+	if (use_sg && !buf_len) {
+		dev_err(&udev->dev, "sg buffer with zero length\n");
+		goto err_malloc;
 	}
 
 	/* 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) {
+	if (buf_len) {
+		if (use_sg) {
+			sgl = sgl_alloc(buf_len, GFP_KERNEL, &nents);
+			if (!sgl)
+				goto err_malloc;
+
+			/* Check if the server's HCD supports SG */
+			if (!udev->bus->sg_tablesize) {
+				/*
+				 * If the server's HCD doesn't support SG, break
+				 * a single SG request into several URBs and map
+				 * each SG list entry to corresponding URB
+				 * buffer. The previously allocated SG list is
+				 * stored in priv->sgl (If the server's HCD
+				 * support SG, SG list is stored only in
+				 * urb->sg) and it is used as an indicator that
+				 * the server split single SG request into
+				 * several URBs. Later, priv->sgl is used by
+				 * stub_complete() and stub_send_ret_submit() to
+				 * reassemble the divied URBs.
+				 */
+				support_sg = 0;
+				num_urbs = nents;
+				priv->completed_urbs = 0;
+				pdu->u.cmd_submit.transfer_flags &=
+								~URB_DMA_MAP_SG;
+			}
+		} else {
+			buffer = kzalloc(buf_len, GFP_KERNEL);
+			if (!buffer)
+				goto err_malloc;
+		}
+	}
+
+	/* allocate urb array */
+	priv->num_urbs = num_urbs;
+	priv->urbs = kmalloc_array(num_urbs, sizeof(*priv->urbs), GFP_KERNEL);
+	if (!priv->urbs)
+		goto err_urbs;
+
+	/* setup a urb */
+	if (support_sg) {
+		if (usb_pipeisoc(pipe))
+			np = pdu->u.cmd_submit.number_of_packets;
+
+		priv->urbs[0] = usb_alloc_urb(np, GFP_KERNEL);
+		if (!priv->urbs[0])
+			goto err_urb;
+
+		if (buf_len) {
+			if (use_sg) {
+				priv->urbs[0]->sg = sgl;
+				priv->urbs[0]->num_sgs = nents;
+				priv->urbs[0]->transfer_buffer = NULL;
+			} else {
+				priv->urbs[0]->transfer_buffer = buffer;
+			}
+		}
+
+		/* copy urb setup packet */
+		priv->urbs[0]->setup_packet = kmemdup(&pdu->u.cmd_submit.setup,
+					8, GFP_KERNEL);
+		if (!priv->urbs[0]->setup_packet) {
 			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(&udev->dev, "allocate setup_packet\n");
-		usbip_event_add(ud, SDEV_EVENT_ERROR_MALLOC);
-		return;
+		usbip_pack_pdu(pdu, priv->urbs[0], USBIP_CMD_SUBMIT, 0);
+	} else {
+		for_each_sg(sgl, sg, nents, i) {
+			priv->urbs[i] = usb_alloc_urb(0, GFP_KERNEL);
+			/* The URBs which is previously allocated will be freed
+			 * in stub_device_cleanup_urbs() if error occurs.
+			 */
+			if (!priv->urbs[i])
+				goto err_urb;
+
+			usbip_pack_pdu(pdu, priv->urbs[i], USBIP_CMD_SUBMIT, 0);
+			priv->urbs[i]->transfer_buffer = sg_virt(sg);
+			priv->urbs[i]->transfer_buffer_length = sg->length;
+		}
+		priv->sgl = sgl;
 	}
 
-	/* 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;
+	for (i = 0; i < num_urbs; i++) {
+		/* set other members from the base header of pdu */
+		priv->urbs[i]->context = (void *) priv;
+		priv->urbs[i]->dev = udev;
+		priv->urbs[i]->pipe = pipe;
+		priv->urbs[i]->complete = stub_complete;
 
-	usbip_pack_pdu(pdu, priv->urb, USBIP_CMD_SUBMIT, 0);
+		/* no need to submit an intercepted request, but harmless? */
+		tweak_special_requests(priv->urbs[i]);
 
+		masking_bogus_flags(priv->urbs[i]);
+	}
 
-	if (usbip_recv_xbuff(ud, priv->urb) < 0)
+	if (stub_recv_xbuff(ud, priv) < 0)
 		return;
 
-	if (usbip_recv_iso(ud, priv->urb) < 0)
+	if (usbip_recv_iso(ud, priv->urbs[0]) < 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(&udev->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);
+	for (i = 0; i < priv->num_urbs; i++) {
+		ret = usb_submit_urb(priv->urbs[i], GFP_KERNEL);
+
+		if (ret == 0)
+			usbip_dbg_stub_rx("submit urb ok, seqnum %u\n",
+					pdu->base.seqnum);
+		else {
+			dev_err(&udev->dev, "submit_urb error, %d\n", ret);
+			usbip_dump_header(pdu);
+			usbip_dump_urb(priv->urbs[i]);
+
+			/*
+			 * Pessimistic.
+			 * This connection will be discarded.
+			 */
+			usbip_event_add(ud, SDEV_EVENT_ERROR_SUBMIT);
+			break;
+		}
 	}
 
 	usbip_dbg_stub_rx("Leave\n");
+	return;
+
+err_urb:
+	kfree(priv->urbs);
+err_urbs:
+	kfree(buffer);
+	sgl_free(sgl);
+err_malloc:
+	usbip_event_add(ud, SDEV_EVENT_ERROR_MALLOC);
 }
 
 /* recv a pdu */
diff --git a/drivers/usb/usbip/stub_tx.c b/drivers/usb/usbip/stub_tx.c
index f0ec41a50cbc..36010a82b359 100644
--- a/drivers/usb/usbip/stub_tx.c
+++ b/drivers/usb/usbip/stub_tx.c
@@ -5,25 +5,11 @@
 
 #include <linux/kthread.h>
 #include <linux/socket.h>
+#include <linux/scatterlist.h>
 
 #include "usbip_common.h"
 #include "stub.h"
 
-static void stub_free_priv_and_urb(struct stub_priv *priv)
-{
-	struct urb *urb = priv->urb;
-
-	kfree(urb->setup_packet);
-	urb->setup_packet = NULL;
-
-	kfree(urb->transfer_buffer);
-	urb->transfer_buffer = NULL;
-
-	list_del(&priv->list);
-	kmem_cache_free(stub_priv_cache, priv);
-	usb_free_urb(urb);
-}
-
 /* be in spin_lock_irqsave(&sdev->priv_lock, flags) */
 void stub_enqueue_ret_unlink(struct stub_device *sdev, __u32 seqnum,
 			     __u32 status)
@@ -85,6 +71,22 @@ void stub_complete(struct urb *urb)
 		break;
 	}
 
+	/*
+	 * If the server breaks single SG request into the several URBs, the
+	 * URBs must be reassembled before sending completed URB to the vhci.
+	 * Don't wake up the tx thread until all the URBs are completed.
+	 */
+	if (priv->sgl) {
+		priv->completed_urbs++;
+
+		/* Only save the first error status */
+		if (urb->status && !priv->urb_status)
+			priv->urb_status = urb->status;
+
+		if (priv->completed_urbs < priv->num_urbs)
+			return;
+	}
+
 	/* link a urb to the queue of tx. */
 	spin_lock_irqsave(&sdev->priv_lock, flags);
 	if (sdev->ud.tcp_socket == NULL) {
@@ -156,18 +158,22 @@ static int stub_send_ret_submit(struct stub_device *sdev)
 	size_t total_size = 0;
 
 	while ((priv = dequeue_from_priv_tx(sdev)) != NULL) {
-		int ret;
-		struct urb *urb = priv->urb;
+		struct urb *urb = priv->urbs[0];
 		struct usbip_header pdu_header;
 		struct usbip_iso_packet_descriptor *iso_buffer = NULL;
 		struct kvec *iov = NULL;
+		struct scatterlist *sg;
+		u32 actual_length = 0;
 		int iovnum = 0;
+		int ret;
+		int i;
 
 		txsize = 0;
 		memset(&pdu_header, 0, sizeof(pdu_header));
 		memset(&msg, 0, sizeof(msg));
 
-		if (urb->actual_length > 0 && !urb->transfer_buffer) {
+		if (urb->actual_length > 0 && !urb->transfer_buffer &&
+		   !urb->num_sgs) {
 			dev_err(&sdev->udev->dev,
 				"urb: actual_length %d transfer_buffer null\n",
 				urb->actual_length);
@@ -176,6 +182,11 @@ static int stub_send_ret_submit(struct stub_device *sdev)
 
 		if (usb_pipetype(urb->pipe) == PIPE_ISOCHRONOUS)
 			iovnum = 2 + urb->number_of_packets;
+		else if (usb_pipein(urb->pipe) && urb->actual_length > 0 &&
+			urb->num_sgs)
+			iovnum = 1 + urb->num_sgs;
+		else if (usb_pipein(urb->pipe) && priv->sgl)
+			iovnum = 1 + priv->num_urbs;
 		else
 			iovnum = 2;
 
@@ -192,6 +203,15 @@ static int stub_send_ret_submit(struct stub_device *sdev)
 		setup_ret_submit_pdu(&pdu_header, urb);
 		usbip_dbg_stub_tx("setup txdata seqnum: %d\n",
 				  pdu_header.base.seqnum);
+
+		if (priv->sgl) {
+			for (i = 0; i < priv->num_urbs; i++)
+				actual_length += priv->urbs[i]->actual_length;
+
+			pdu_header.u.ret_submit.status = priv->urb_status;
+			pdu_header.u.ret_submit.actual_length = actual_length;
+		}
+
 		usbip_header_correct_endian(&pdu_header, 1);
 
 		iov[iovnum].iov_base = &pdu_header;
@@ -200,12 +220,47 @@ static int stub_send_ret_submit(struct stub_device *sdev)
 		txsize += sizeof(pdu_header);
 
 		/* 2. setup transfer buffer */
-		if (usb_pipein(urb->pipe) &&
+		if (usb_pipein(urb->pipe) && priv->sgl) {
+			/* If the server split a single SG request into several
+			 * URBs because the server's HCD doesn't support SG,
+			 * reassemble the split URB buffers into a single
+			 * return command.
+			 */
+			for (i = 0; i < priv->num_urbs; i++) {
+				iov[iovnum].iov_base =
+					priv->urbs[i]->transfer_buffer;
+				iov[iovnum].iov_len =
+					priv->urbs[i]->actual_length;
+				iovnum++;
+			}
+			txsize += actual_length;
+		} else if (usb_pipein(urb->pipe) &&
 		    usb_pipetype(urb->pipe) != PIPE_ISOCHRONOUS &&
 		    urb->actual_length > 0) {
-			iov[iovnum].iov_base = urb->transfer_buffer;
-			iov[iovnum].iov_len  = urb->actual_length;
-			iovnum++;
+			if (urb->num_sgs) {
+				unsigned int copy = urb->actual_length;
+				int size;
+
+				for_each_sg(urb->sg, sg, urb->num_sgs, i) {
+					if (copy == 0)
+						break;
+
+					if (copy < sg->length)
+						size = copy;
+					else
+						size = sg->length;
+
+					iov[iovnum].iov_base = sg_virt(sg);
+					iov[iovnum].iov_len = size;
+
+					iovnum++;
+					copy -= size;
+				}
+			} else {
+				iov[iovnum].iov_base = urb->transfer_buffer;
+				iov[iovnum].iov_len  = urb->actual_length;
+				iovnum++;
+			}
 			txsize += urb->actual_length;
 		} else if (usb_pipein(urb->pipe) &&
 			   usb_pipetype(urb->pipe) == PIPE_ISOCHRONOUS) {
diff --git a/drivers/usb/usbip/usbip_common.c b/drivers/usb/usbip/usbip_common.c
index 45da3e01c7b0..e4b96674c405 100644
--- a/drivers/usb/usbip/usbip_common.c
+++ b/drivers/usb/usbip/usbip_common.c
@@ -680,8 +680,12 @@ EXPORT_SYMBOL_GPL(usbip_pad_iso);
 /* some members of urb must be substituted before. */
 int usbip_recv_xbuff(struct usbip_device *ud, struct urb *urb)
 {
-	int ret;
+	struct scatterlist *sg;
+	int ret = 0;
+	int recv;
 	int size;
+	int copy;
+	int i;
 
 	if (ud->side == USBIP_STUB || ud->side == USBIP_VUDC) {
 		/* the direction of urb must be OUT. */
@@ -701,29 +705,51 @@ int usbip_recv_xbuff(struct usbip_device *ud, struct urb *urb)
 	if (!(size > 0))
 		return 0;
 
-	if (size > urb->transfer_buffer_length) {
+	if (size > urb->transfer_buffer_length)
 		/* should not happen, probably malicious packet */
-		if (ud->side == USBIP_STUB) {
-			usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
-			return 0;
-		} else {
-			usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
-			return -EPIPE;
-		}
-	}
+		goto error;
 
-	ret = usbip_recv(ud->tcp_socket, urb->transfer_buffer, size);
-	if (ret != size) {
-		dev_err(&urb->dev->dev, "recv xbuf, %d\n", ret);
-		if (ud->side == USBIP_STUB || ud->side == USBIP_VUDC) {
-			usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
-		} else {
-			usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
-			return -EPIPE;
+	if (urb->num_sgs) {
+		copy = size;
+		for_each_sg(urb->sg, sg, urb->num_sgs, i) {
+			int recv_size;
+
+			if (copy < sg->length)
+				recv_size = copy;
+			else
+				recv_size = sg->length;
+
+			recv = usbip_recv(ud->tcp_socket, sg_virt(sg),
+						recv_size);
+
+			if (recv != recv_size)
+				goto error;
+
+			copy -= recv;
+			ret += recv;
+
+			if (!copy)
+				break;
 		}
+
+		if (ret != size)
+			goto error;
+	} else {
+		ret = usbip_recv(ud->tcp_socket, urb->transfer_buffer, size);
+		if (ret != size)
+			goto error;
 	}
 
 	return ret;
+
+error:
+	dev_err(&urb->dev->dev, "recv xbuf, %d\n", ret);
+	if (ud->side == USBIP_STUB || ud->side == USBIP_VUDC)
+		usbip_event_add(ud, SDEV_EVENT_ERROR_TCP);
+	else
+		usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
+
+	return -EPIPE;
 }
 EXPORT_SYMBOL_GPL(usbip_recv_xbuff);
 
diff --git a/drivers/usb/usbip/vhci_hcd.c b/drivers/usb/usbip/vhci_hcd.c
index 000ab7225717..585a84d319bd 100644
--- a/drivers/usb/usbip/vhci_hcd.c
+++ b/drivers/usb/usbip/vhci_hcd.c
@@ -697,7 +697,8 @@ static int vhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb, gfp_t mem_flag
 	}
 	vdev = &vhci_hcd->vdev[portnum-1];
 
-	if (!urb->transfer_buffer && urb->transfer_buffer_length) {
+	if (!urb->transfer_buffer && !urb->num_sgs &&
+	     urb->transfer_buffer_length) {
 		dev_dbg(dev, "Null URB transfer buffer\n");
 		return -EINVAL;
 	}
@@ -1143,6 +1144,15 @@ static int vhci_setup(struct usb_hcd *hcd)
 		hcd->speed = HCD_USB3;
 		hcd->self.root_hub->speed = USB_SPEED_SUPER;
 	}
+
+	/*
+	 * Support SG.
+	 * sg_tablesize is an arbitrary value to alleviate memory pressure
+	 * on the host.
+	 */
+	hcd->self.sg_tablesize = 32;
+	hcd->self.no_sg_constraint = 1;
+
 	return 0;
 }
 
diff --git a/drivers/usb/usbip/vhci_rx.c b/drivers/usb/usbip/vhci_rx.c
index 44cd64518925..00fc98741c5d 100644
--- a/drivers/usb/usbip/vhci_rx.c
+++ b/drivers/usb/usbip/vhci_rx.c
@@ -77,19 +77,27 @@ static void vhci_recv_ret_submit(struct vhci_device *vdev,
 	usbip_pack_pdu(pdu, urb, USBIP_RET_SUBMIT, 0);
 
 	/* recv transfer buffer */
-	if (usbip_recv_xbuff(ud, urb) < 0)
-		return;
+	if (usbip_recv_xbuff(ud, urb) < 0) {
+		urb->status = -EPROTO;
+		goto error;
+	}
 
 	/* recv iso_packet_descriptor */
-	if (usbip_recv_iso(ud, urb) < 0)
-		return;
+	if (usbip_recv_iso(ud, urb) < 0) {
+		urb->status = -EPROTO;
+		goto error;
+	}
 
 	/* restore the padding in iso packets */
 	usbip_pad_iso(ud, urb);
 
+error:
 	if (usbip_dbg_flag_vhci_rx)
 		usbip_dump_urb(urb);
 
+	if (urb->num_sgs)
+		urb->transfer_flags &= ~URB_DMA_MAP_SG;
+
 	usbip_dbg_vhci_rx("now giveback urb %u\n", pdu->base.seqnum);
 
 	spin_lock_irqsave(&vhci->lock, flags);
diff --git a/drivers/usb/usbip/vhci_tx.c b/drivers/usb/usbip/vhci_tx.c
index 9aed15a358b7..acac49402c2b 100644
--- a/drivers/usb/usbip/vhci_tx.c
+++ b/drivers/usb/usbip/vhci_tx.c
@@ -5,6 +5,7 @@
 
 #include <linux/kthread.h>
 #include <linux/slab.h>
+#include <linux/scatterlist.h>
 
 #include "usbip_common.h"
 #include "vhci.h"
@@ -50,19 +51,23 @@ static struct vhci_priv *dequeue_from_priv_tx(struct vhci_device *vdev)
 
 static int vhci_send_cmd_submit(struct vhci_device *vdev)
 {
+	struct usbip_iso_packet_descriptor *iso_buffer = NULL;
 	struct vhci_priv *priv = NULL;
+	struct scatterlist *sg;
 
 	struct msghdr msg;
-	struct kvec iov[3];
+	struct kvec *iov;
 	size_t txsize;
 
 	size_t total_size = 0;
+	int iovnum;
+	int err = -ENOMEM;
+	int i;
 
 	while ((priv = dequeue_from_priv_tx(vdev)) != NULL) {
 		int ret;
 		struct urb *urb = priv->urb;
 		struct usbip_header pdu_header;
-		struct usbip_iso_packet_descriptor *iso_buffer = NULL;
 
 		txsize = 0;
 		memset(&pdu_header, 0, sizeof(pdu_header));
@@ -72,18 +77,45 @@ static int vhci_send_cmd_submit(struct vhci_device *vdev)
 		usbip_dbg_vhci_tx("setup txdata urb seqnum %lu\n",
 				  priv->seqnum);
 
+		if (urb->num_sgs && usb_pipeout(urb->pipe))
+			iovnum = 2 + urb->num_sgs;
+		else
+			iovnum = 3;
+
+		iov = kcalloc(iovnum, sizeof(*iov), GFP_KERNEL);
+		if (!iov) {
+			usbip_event_add(&vdev->ud, SDEV_EVENT_ERROR_MALLOC);
+			return -ENOMEM;
+		}
+
+		if (urb->num_sgs)
+			urb->transfer_flags |= URB_DMA_MAP_SG;
+
 		/* 1. setup usbip_header */
 		setup_cmd_submit_pdu(&pdu_header, urb);
 		usbip_header_correct_endian(&pdu_header, 1);
+		iovnum = 0;
 
-		iov[0].iov_base = &pdu_header;
-		iov[0].iov_len  = sizeof(pdu_header);
+		iov[iovnum].iov_base = &pdu_header;
+		iov[iovnum].iov_len  = sizeof(pdu_header);
 		txsize += sizeof(pdu_header);
+		iovnum++;
 
 		/* 2. setup transfer buffer */
 		if (!usb_pipein(urb->pipe) && urb->transfer_buffer_length > 0) {
-			iov[1].iov_base = urb->transfer_buffer;
-			iov[1].iov_len  = urb->transfer_buffer_length;
+			if (urb->num_sgs &&
+				      !usb_endpoint_xfer_isoc(&urb->ep->desc)) {
+				for_each_sg(urb->sg, sg, urb->num_sgs, i) {
+					iov[iovnum].iov_base = sg_virt(sg);
+					iov[iovnum].iov_len = sg->length;
+					iovnum++;
+				}
+			} else {
+				iov[iovnum].iov_base = urb->transfer_buffer;
+				iov[iovnum].iov_len  =
+						urb->transfer_buffer_length;
+				iovnum++;
+			}
 			txsize += urb->transfer_buffer_length;
 		}
 
@@ -95,30 +127,43 @@ static int vhci_send_cmd_submit(struct vhci_device *vdev)
 			if (!iso_buffer) {
 				usbip_event_add(&vdev->ud,
 						SDEV_EVENT_ERROR_MALLOC);
-				return -1;
+				goto err_iso_buffer;
 			}
 
-			iov[2].iov_base = iso_buffer;
-			iov[2].iov_len  = len;
+			iov[iovnum].iov_base = iso_buffer;
+			iov[iovnum].iov_len  = len;
+			iovnum++;
 			txsize += len;
 		}
 
-		ret = kernel_sendmsg(vdev->ud.tcp_socket, &msg, iov, 3, txsize);
+		ret = kernel_sendmsg(vdev->ud.tcp_socket, &msg, iov, iovnum,
+				     txsize);
 		if (ret != txsize) {
 			pr_err("sendmsg failed!, ret=%d for %zd\n", ret,
 			       txsize);
-			kfree(iso_buffer);
 			usbip_event_add(&vdev->ud, VDEV_EVENT_ERROR_TCP);
-			return -1;
+			err = -EPIPE;
+			goto err_tx;
 		}
 
+		kfree(iov);
+		/* This is only for isochronous case */
 		kfree(iso_buffer);
+		iso_buffer = NULL;
+
 		usbip_dbg_vhci_tx("send txdata\n");
 
 		total_size += txsize;
 	}
 
 	return total_size;
+
+err_tx:
+	kfree(iso_buffer);
+err_iso_buffer:
+	kfree(iov);
+
+	return err;
 }
 
 static struct vhci_unlink *dequeue_from_unlink_tx(struct vhci_device *vdev)