stub_tx.c

  1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * Copyright (C) 2003-2008 Takahiro Hirofuchi
  4 */
  5
  6#include <linux/kthread.h>
  7#include <linux/minmax.h>
  8#include <linux/socket.h>
  9#include <linux/scatterlist.h>
 10
 11#include "usbip_common.h"
 12#include "stub.h"
 13
 14/* be in spin_lock_irqsave(&sdev->priv_lock, flags) */
 15void stub_enqueue_ret_unlink(struct stub_device *sdev, __u32 seqnum,
 16			     __u32 status)
 17{
 18	struct stub_unlink *unlink;
 19
 20	unlink = kzalloc(sizeof(struct stub_unlink), GFP_ATOMIC);
 21	if (!unlink) {
 22		usbip_event_add(&sdev->ud, VDEV_EVENT_ERROR_MALLOC);
 23		return;
 24	}
 25
 26	unlink->seqnum = seqnum;
 27	unlink->status = status;
 28
 29	list_add_tail(&unlink->list, &sdev->unlink_tx);
 30}
 31
 32/**
 33 * stub_complete - completion handler of a usbip urb
 34 * @urb: pointer to the urb completed
 35 *
 36 * When a urb has completed, the USB core driver calls this function mostly in
 37 * the interrupt context. To return the result of a urb, the completed urb is
 38 * linked to the pending list of returning.
 39 *
 40 */
 41void stub_complete(struct urb *urb)
 42{
 43	struct stub_priv *priv = (struct stub_priv *) urb->context;
 44	struct stub_device *sdev = priv->sdev;
 45	unsigned long flags;
 46
 47	usbip_dbg_stub_tx("complete! status %d\n", urb->status);
 48
 49	switch (urb->status) {
 50	case 0:
 51		/* OK */
 52		break;
 53	case -ENOENT:
 54		dev_info(&urb->dev->dev,
 55			 "stopped by a call to usb_kill_urb() because of cleaning up a virtual connection\n");
 56		return;
 57	case -ECONNRESET:
 58		dev_info(&urb->dev->dev,
 59			 "unlinked by a call to usb_unlink_urb()\n");
 60		break;
 61	case -EPIPE:
 62		dev_info(&urb->dev->dev, "endpoint %d is stalled\n",
 63			 usb_pipeendpoint(urb->pipe));
 64		break;
 65	case -ESHUTDOWN:
 66		dev_info(&urb->dev->dev, "device removed?\n");
 67		break;
 68	default:
 69		dev_info(&urb->dev->dev,
 70			 "urb completion with non-zero status %d\n",
 71			 urb->status);
 72		break;
 73	}
 74
 75	/*
 76	 * If the server breaks single SG request into the several URBs, the
 77	 * URBs must be reassembled before sending completed URB to the vhci.
 78	 * Don't wake up the tx thread until all the URBs are completed.
 79	 */
 80	if (priv->sgl) {
 81		priv->completed_urbs++;
 82
 83		/* Only save the first error status */
 84		if (urb->status && !priv->urb_status)
 85			priv->urb_status = urb->status;
 86
 87		if (priv->completed_urbs < priv->num_urbs)
 88			return;
 89	}
 90
 91	/* link a urb to the queue of tx. */
 92	spin_lock_irqsave(&sdev->priv_lock, flags);
 93	if (sdev->ud.tcp_socket == NULL) {
 94		usbip_dbg_stub_tx("ignore urb for closed connection\n");
 95		/* It will be freed in stub_device_cleanup_urbs(). */
 96	} else if (priv->unlinking) {
 97		stub_enqueue_ret_unlink(sdev, priv->seqnum, urb->status);
 98		stub_free_priv_and_urb(priv);
 99	} else {
100		list_move_tail(&priv->list, &sdev->priv_tx);
101	}
102	spin_unlock_irqrestore(&sdev->priv_lock, flags);
103
104	/* wake up tx_thread */
105	wake_up(&sdev->tx_waitq);
106}
107
108static inline void setup_base_pdu(struct usbip_header_basic *base,
109				  __u32 command, __u32 seqnum)
110{
111	base->command	= command;
112	base->seqnum	= seqnum;
113	base->devid	= 0;
114	base->ep	= 0;
115	base->direction = 0;
116}
117
118static void setup_ret_submit_pdu(struct usbip_header *rpdu, struct urb *urb)
119{
120	struct stub_priv *priv = (struct stub_priv *) urb->context;
121
122	setup_base_pdu(&rpdu->base, USBIP_RET_SUBMIT, priv->seqnum);
123	usbip_pack_pdu(rpdu, urb, USBIP_RET_SUBMIT, 1);
124}
125
126static void setup_ret_unlink_pdu(struct usbip_header *rpdu,
127				 struct stub_unlink *unlink)
128{
129	setup_base_pdu(&rpdu->base, USBIP_RET_UNLINK, unlink->seqnum);
130	rpdu->u.ret_unlink.status = unlink->status;
131}
132
133static struct stub_priv *dequeue_from_priv_tx(struct stub_device *sdev)
134{
135	unsigned long flags;
136	struct stub_priv *priv, *tmp;
137
138	spin_lock_irqsave(&sdev->priv_lock, flags);
139
140	list_for_each_entry_safe(priv, tmp, &sdev->priv_tx, list) {
141		list_move_tail(&priv->list, &sdev->priv_free);
142		spin_unlock_irqrestore(&sdev->priv_lock, flags);
143		return priv;
144	}
145
146	spin_unlock_irqrestore(&sdev->priv_lock, flags);
147
148	return NULL;
149}
150
151static int stub_send_ret_submit(struct stub_device *sdev)
152{
153	unsigned long flags;
154	struct stub_priv *priv, *tmp;
155
156	struct msghdr msg;
157	size_t txsize;
158
159	size_t total_size = 0;
160
161	while ((priv = dequeue_from_priv_tx(sdev)) != NULL) {
162		struct urb *urb = priv->urbs[0];
163		struct usbip_header pdu_header;
164		struct usbip_iso_packet_descriptor *iso_buffer = NULL;
165		struct kvec *iov = NULL;
166		struct scatterlist *sg;
167		u32 actual_length = 0;
168		int iovnum = 0;
169		int ret;
170		int i;
171
172		txsize = 0;
173		memset(&pdu_header, 0, sizeof(pdu_header));
174		memset(&msg, 0, sizeof(msg));
175
176		if (urb->actual_length > 0 && !urb->transfer_buffer &&
177		   !urb->num_sgs) {
178			dev_err(&sdev->udev->dev,
179				"urb: actual_length %d transfer_buffer null\n",
180				urb->actual_length);
181			return -1;
182		}
183
184		if (usb_pipetype(urb->pipe) == PIPE_ISOCHRONOUS)
185			iovnum = 2 + urb->number_of_packets;
186		else if (usb_pipein(urb->pipe) && urb->actual_length > 0 &&
187			urb->num_sgs)
188			iovnum = 1 + urb->num_sgs;
189		else if (usb_pipein(urb->pipe) && priv->sgl)
190			iovnum = 1 + priv->num_urbs;
191		else
192			iovnum = 2;
193
194		iov = kcalloc(iovnum, sizeof(struct kvec), GFP_KERNEL);
195
196		if (!iov) {
197			usbip_event_add(&sdev->ud, SDEV_EVENT_ERROR_MALLOC);
198			return -1;
199		}
200
201		iovnum = 0;
202
203		/* 1. setup usbip_header */
204		setup_ret_submit_pdu(&pdu_header, urb);
205		usbip_dbg_stub_tx("setup txdata seqnum: %u\n",
206				  pdu_header.base.seqnum);
207
208		if (priv->sgl) {
209			for (i = 0; i < priv->num_urbs; i++)
210				actual_length += priv->urbs[i]->actual_length;
211
212			pdu_header.u.ret_submit.status = priv->urb_status;
213			pdu_header.u.ret_submit.actual_length = actual_length;
214		}
215
216		usbip_header_correct_endian(&pdu_header, 1);
217
218		iov[iovnum].iov_base = &pdu_header;
219		iov[iovnum].iov_len  = sizeof(pdu_header);
220		iovnum++;
221		txsize += sizeof(pdu_header);
222
223		/* 2. setup transfer buffer */
224		if (usb_pipein(urb->pipe) && priv->sgl) {
225			/* If the server split a single SG request into several
226			 * URBs because the server's HCD doesn't support SG,
227			 * reassemble the split URB buffers into a single
228			 * return command.
229			 */
230			for (i = 0; i < priv->num_urbs; i++) {
231				iov[iovnum].iov_base =
232					priv->urbs[i]->transfer_buffer;
233				iov[iovnum].iov_len =
234					priv->urbs[i]->actual_length;
235				iovnum++;
236			}
237			txsize += actual_length;
238		} else if (usb_pipein(urb->pipe) &&
239		    usb_pipetype(urb->pipe) != PIPE_ISOCHRONOUS &&
240		    urb->actual_length > 0) {
241			if (urb->num_sgs) {
242				unsigned int copy = urb->actual_length;
243				unsigned int size;
244
245				for_each_sg(urb->sg, sg, urb->num_sgs, i) {
246					if (copy == 0)
247						break;
248
249					size = min(copy, sg->length);
250					iov[iovnum].iov_base = sg_virt(sg);
251					iov[iovnum].iov_len = size;
252
253					iovnum++;
254					copy -= size;
255				}
256			} else {
257				iov[iovnum].iov_base = urb->transfer_buffer;
258				iov[iovnum].iov_len  = urb->actual_length;
259				iovnum++;
260			}
261			txsize += urb->actual_length;
262		} else if (usb_pipein(urb->pipe) &&
263			   usb_pipetype(urb->pipe) == PIPE_ISOCHRONOUS) {
264			/*
265			 * For isochronous packets: actual length is the sum of
266			 * the actual length of the individual, packets, but as
267			 * the packet offsets are not changed there will be
268			 * padding between the packets. To optimally use the
269			 * bandwidth the padding is not transmitted.
270			 */
271
272			int i;
273
274			for (i = 0; i < urb->number_of_packets; i++) {
275				iov[iovnum].iov_base = urb->transfer_buffer +
276					urb->iso_frame_desc[i].offset;
277				iov[iovnum].iov_len =
278					urb->iso_frame_desc[i].actual_length;
279				iovnum++;
280				txsize += urb->iso_frame_desc[i].actual_length;
281			}
282
283			if (txsize != sizeof(pdu_header) + urb->actual_length) {
284				dev_err(&sdev->udev->dev,
285					"actual length of urb %d does not match iso packet sizes %zu\n",
286					urb->actual_length,
287					txsize-sizeof(pdu_header));
288				kfree(iov);
289				usbip_event_add(&sdev->ud,
290						SDEV_EVENT_ERROR_TCP);
291				return -1;
292			}
293		}
294
295		/* 3. setup iso_packet_descriptor */
296		if (usb_pipetype(urb->pipe) == PIPE_ISOCHRONOUS) {
297			ssize_t len = 0;
298
299			iso_buffer = usbip_alloc_iso_desc_pdu(urb, &len);
300			if (!iso_buffer) {
301				usbip_event_add(&sdev->ud,
302						SDEV_EVENT_ERROR_MALLOC);
303				kfree(iov);
304				return -1;
305			}
306
307			iov[iovnum].iov_base = iso_buffer;
308			iov[iovnum].iov_len  = len;
309			txsize += len;
310			iovnum++;
311		}
312
313		ret = kernel_sendmsg(sdev->ud.tcp_socket, &msg,
314						iov,  iovnum, txsize);
315		if (ret != txsize) {
316			dev_err(&sdev->udev->dev,
317				"sendmsg failed!, retval %d for %zd\n",
318				ret, txsize);
319			kfree(iov);
320			kfree(iso_buffer);
321			usbip_event_add(&sdev->ud, SDEV_EVENT_ERROR_TCP);
322			return -1;
323		}
324
325		kfree(iov);
326		kfree(iso_buffer);
327
328		total_size += txsize;
329	}
330
331	spin_lock_irqsave(&sdev->priv_lock, flags);
332	list_for_each_entry_safe(priv, tmp, &sdev->priv_free, list) {
333		stub_free_priv_and_urb(priv);
334	}
335	spin_unlock_irqrestore(&sdev->priv_lock, flags);
336
337	return total_size;
338}
339
340static struct stub_unlink *dequeue_from_unlink_tx(struct stub_device *sdev)
341{
342	unsigned long flags;
343	struct stub_unlink *unlink, *tmp;
344
345	spin_lock_irqsave(&sdev->priv_lock, flags);
346
347	list_for_each_entry_safe(unlink, tmp, &sdev->unlink_tx, list) {
348		list_move_tail(&unlink->list, &sdev->unlink_free);
349		spin_unlock_irqrestore(&sdev->priv_lock, flags);
350		return unlink;
351	}
352
353	spin_unlock_irqrestore(&sdev->priv_lock, flags);
354
355	return NULL;
356}
357
358static int stub_send_ret_unlink(struct stub_device *sdev)
359{
360	unsigned long flags;
361	struct stub_unlink *unlink, *tmp;
362
363	struct msghdr msg;
364	struct kvec iov[1];
365	size_t txsize;
366
367	size_t total_size = 0;
368
369	while ((unlink = dequeue_from_unlink_tx(sdev)) != NULL) {
370		int ret;
371		struct usbip_header pdu_header;
372
373		txsize = 0;
374		memset(&pdu_header, 0, sizeof(pdu_header));
375		memset(&msg, 0, sizeof(msg));
376		memset(&iov, 0, sizeof(iov));
377
378		usbip_dbg_stub_tx("setup ret unlink %lu\n", unlink->seqnum);
379
380		/* 1. setup usbip_header */
381		setup_ret_unlink_pdu(&pdu_header, unlink);
382		usbip_header_correct_endian(&pdu_header, 1);
383
384		iov[0].iov_base = &pdu_header;
385		iov[0].iov_len  = sizeof(pdu_header);
386		txsize += sizeof(pdu_header);
387
388		ret = kernel_sendmsg(sdev->ud.tcp_socket, &msg, iov,
389				     1, txsize);
390		if (ret != txsize) {
391			dev_err(&sdev->udev->dev,
392				"sendmsg failed!, retval %d for %zd\n",
393				ret, txsize);
394			usbip_event_add(&sdev->ud, SDEV_EVENT_ERROR_TCP);
395			return -1;
396		}
397
398		usbip_dbg_stub_tx("send txdata\n");
399		total_size += txsize;
400	}
401
402	spin_lock_irqsave(&sdev->priv_lock, flags);
403
404	list_for_each_entry_safe(unlink, tmp, &sdev->unlink_free, list) {
405		list_del(&unlink->list);
406		kfree(unlink);
407	}
408
409	spin_unlock_irqrestore(&sdev->priv_lock, flags);
410
411	return total_size;
412}
413
414int stub_tx_loop(void *data)
415{
416	struct usbip_device *ud = data;
417	struct stub_device *sdev = container_of(ud, struct stub_device, ud);
418
419	while (!kthread_should_stop()) {
420		if (usbip_event_happened(ud))
421			break;
422
423		/*
424		 * send_ret_submit comes earlier than send_ret_unlink.  stub_rx
425		 * looks at only priv_init queue. If the completion of a URB is
426		 * earlier than the receive of CMD_UNLINK, priv is moved to
427		 * priv_tx queue and stub_rx does not find the target priv. In
428		 * this case, vhci_rx receives the result of the submit request
429		 * and then receives the result of the unlink request. The
430		 * result of the submit is given back to the usbcore as the
431		 * completion of the unlink request. The request of the
432		 * unlink is ignored. This is ok because a driver who calls
433		 * usb_unlink_urb() understands the unlink was too late by
434		 * getting the status of the given-backed URB which has the
435		 * status of usb_submit_urb().
436		 */
437		if (stub_send_ret_submit(sdev) < 0)
438			break;
439
440		if (stub_send_ret_unlink(sdev) < 0)
441			break;
442
443		wait_event_interruptible(sdev->tx_waitq,
444					 (!list_empty(&sdev->priv_tx) ||
445					  !list_empty(&sdev->unlink_tx) ||
446					  kthread_should_stop()));
447	}
448
449	return 0;
450}