xref: /linux/drivers/usb/usbip/stub_tx.c (revision c95baf12f5077419db01313ab61c2aac007d40cd)
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/socket.h>
8 #include <linux/scatterlist.h>
9 
10 #include "usbip_common.h"
11 #include "stub.h"
12 
13 /* be in spin_lock_irqsave(&sdev->priv_lock, flags) */
stub_enqueue_ret_unlink(struct stub_device * sdev,__u32 seqnum,__u32 status)14 void stub_enqueue_ret_unlink(struct stub_device *sdev, __u32 seqnum,
15 			     __u32 status)
16 {
17 	struct stub_unlink *unlink;
18 
19 	unlink = kzalloc(sizeof(struct stub_unlink), GFP_ATOMIC);
20 	if (!unlink) {
21 		usbip_event_add(&sdev->ud, VDEV_EVENT_ERROR_MALLOC);
22 		return;
23 	}
24 
25 	unlink->seqnum = seqnum;
26 	unlink->status = status;
27 
28 	list_add_tail(&unlink->list, &sdev->unlink_tx);
29 }
30 
31 /**
32  * stub_complete - completion handler of a usbip urb
33  * @urb: pointer to the urb completed
34  *
35  * When a urb has completed, the USB core driver calls this function mostly in
36  * the interrupt context. To return the result of a urb, the completed urb is
37  * linked to the pending list of returning.
38  *
39  */
stub_complete(struct urb * urb)40 void stub_complete(struct urb *urb)
41 {
42 	struct stub_priv *priv = (struct stub_priv *) urb->context;
43 	struct stub_device *sdev = priv->sdev;
44 	unsigned long flags;
45 
46 	usbip_dbg_stub_tx("complete! status %d\n", urb->status);
47 
48 	switch (urb->status) {
49 	case 0:
50 		/* OK */
51 		break;
52 	case -ENOENT:
53 		dev_info(&urb->dev->dev,
54 			 "stopped by a call to usb_kill_urb() because of cleaning up a virtual connection\n");
55 		return;
56 	case -ECONNRESET:
57 		dev_info(&urb->dev->dev,
58 			 "unlinked by a call to usb_unlink_urb()\n");
59 		break;
60 	case -EPIPE:
61 		dev_info(&urb->dev->dev, "endpoint %d is stalled\n",
62 			 usb_pipeendpoint(urb->pipe));
63 		break;
64 	case -ESHUTDOWN:
65 		dev_info(&urb->dev->dev, "device removed?\n");
66 		break;
67 	default:
68 		dev_info(&urb->dev->dev,
69 			 "urb completion with non-zero status %d\n",
70 			 urb->status);
71 		break;
72 	}
73 
74 	/*
75 	 * If the server breaks single SG request into the several URBs, the
76 	 * URBs must be reassembled before sending completed URB to the vhci.
77 	 * Don't wake up the tx thread until all the URBs are completed.
78 	 */
79 	if (priv->sgl) {
80 		priv->completed_urbs++;
81 
82 		/* Only save the first error status */
83 		if (urb->status && !priv->urb_status)
84 			priv->urb_status = urb->status;
85 
86 		if (priv->completed_urbs < priv->num_urbs)
87 			return;
88 	}
89 
90 	/* link a urb to the queue of tx. */
91 	spin_lock_irqsave(&sdev->priv_lock, flags);
92 	if (sdev->ud.tcp_socket == NULL) {
93 		usbip_dbg_stub_tx("ignore urb for closed connection\n");
94 		/* It will be freed in stub_device_cleanup_urbs(). */
95 	} else if (priv->unlinking) {
96 		stub_enqueue_ret_unlink(sdev, priv->seqnum, urb->status);
97 		stub_free_priv_and_urb(priv);
98 	} else {
99 		list_move_tail(&priv->list, &sdev->priv_tx);
100 	}
101 	spin_unlock_irqrestore(&sdev->priv_lock, flags);
102 
103 	/* wake up tx_thread */
104 	wake_up(&sdev->tx_waitq);
105 }
106 
setup_base_pdu(struct usbip_header_basic * base,__u32 command,__u32 seqnum)107 static inline void setup_base_pdu(struct usbip_header_basic *base,
108 				  __u32 command, __u32 seqnum)
109 {
110 	base->command	= command;
111 	base->seqnum	= seqnum;
112 	base->devid	= 0;
113 	base->ep	= 0;
114 	base->direction = 0;
115 }
116 
setup_ret_submit_pdu(struct usbip_header * rpdu,struct urb * urb)117 static void setup_ret_submit_pdu(struct usbip_header *rpdu, struct urb *urb)
118 {
119 	struct stub_priv *priv = (struct stub_priv *) urb->context;
120 
121 	setup_base_pdu(&rpdu->base, USBIP_RET_SUBMIT, priv->seqnum);
122 	usbip_pack_pdu(rpdu, urb, USBIP_RET_SUBMIT, 1);
123 }
124 
setup_ret_unlink_pdu(struct usbip_header * rpdu,struct stub_unlink * unlink)125 static void setup_ret_unlink_pdu(struct usbip_header *rpdu,
126 				 struct stub_unlink *unlink)
127 {
128 	setup_base_pdu(&rpdu->base, USBIP_RET_UNLINK, unlink->seqnum);
129 	rpdu->u.ret_unlink.status = unlink->status;
130 }
131 
dequeue_from_priv_tx(struct stub_device * sdev)132 static struct stub_priv *dequeue_from_priv_tx(struct stub_device *sdev)
133 {
134 	unsigned long flags;
135 	struct stub_priv *priv, *tmp;
136 
137 	spin_lock_irqsave(&sdev->priv_lock, flags);
138 
139 	list_for_each_entry_safe(priv, tmp, &sdev->priv_tx, list) {
140 		list_move_tail(&priv->list, &sdev->priv_free);
141 		spin_unlock_irqrestore(&sdev->priv_lock, flags);
142 		return priv;
143 	}
144 
145 	spin_unlock_irqrestore(&sdev->priv_lock, flags);
146 
147 	return NULL;
148 }
149 
stub_send_ret_submit(struct stub_device * sdev)150 static int stub_send_ret_submit(struct stub_device *sdev)
151 {
152 	unsigned long flags;
153 	struct stub_priv *priv, *tmp;
154 
155 	struct msghdr msg;
156 	size_t txsize;
157 
158 	size_t total_size = 0;
159 
160 	while ((priv = dequeue_from_priv_tx(sdev)) != NULL) {
161 		struct urb *urb = priv->urbs[0];
162 		struct usbip_header pdu_header;
163 		struct usbip_iso_packet_descriptor *iso_buffer = NULL;
164 		struct kvec *iov = NULL;
165 		struct scatterlist *sg;
166 		u32 actual_length = 0;
167 		int iovnum = 0;
168 		int ret;
169 		int i;
170 
171 		txsize = 0;
172 		memset(&pdu_header, 0, sizeof(pdu_header));
173 		memset(&msg, 0, sizeof(msg));
174 
175 		if (urb->actual_length > 0 && !urb->transfer_buffer &&
176 		   !urb->num_sgs) {
177 			dev_err(&sdev->udev->dev,
178 				"urb: actual_length %d transfer_buffer null\n",
179 				urb->actual_length);
180 			return -1;
181 		}
182 
183 		if (usb_pipetype(urb->pipe) == PIPE_ISOCHRONOUS)
184 			iovnum = 2 + urb->number_of_packets;
185 		else if (usb_pipein(urb->pipe) && urb->actual_length > 0 &&
186 			urb->num_sgs)
187 			iovnum = 1 + urb->num_sgs;
188 		else if (usb_pipein(urb->pipe) && priv->sgl)
189 			iovnum = 1 + priv->num_urbs;
190 		else
191 			iovnum = 2;
192 
193 		iov = kcalloc(iovnum, sizeof(struct kvec), GFP_KERNEL);
194 
195 		if (!iov) {
196 			usbip_event_add(&sdev->ud, SDEV_EVENT_ERROR_MALLOC);
197 			return -1;
198 		}
199 
200 		iovnum = 0;
201 
202 		/* 1. setup usbip_header */
203 		setup_ret_submit_pdu(&pdu_header, urb);
204 		usbip_dbg_stub_tx("setup txdata seqnum: %d\n",
205 				  pdu_header.base.seqnum);
206 
207 		if (priv->sgl) {
208 			for (i = 0; i < priv->num_urbs; i++)
209 				actual_length += priv->urbs[i]->actual_length;
210 
211 			pdu_header.u.ret_submit.status = priv->urb_status;
212 			pdu_header.u.ret_submit.actual_length = actual_length;
213 		}
214 
215 		usbip_header_correct_endian(&pdu_header, 1);
216 
217 		iov[iovnum].iov_base = &pdu_header;
218 		iov[iovnum].iov_len  = sizeof(pdu_header);
219 		iovnum++;
220 		txsize += sizeof(pdu_header);
221 
222 		/* 2. setup transfer buffer */
223 		if (usb_pipein(urb->pipe) && priv->sgl) {
224 			/* If the server split a single SG request into several
225 			 * URBs because the server's HCD doesn't support SG,
226 			 * reassemble the split URB buffers into a single
227 			 * return command.
228 			 */
229 			for (i = 0; i < priv->num_urbs; i++) {
230 				iov[iovnum].iov_base =
231 					priv->urbs[i]->transfer_buffer;
232 				iov[iovnum].iov_len =
233 					priv->urbs[i]->actual_length;
234 				iovnum++;
235 			}
236 			txsize += actual_length;
237 		} else if (usb_pipein(urb->pipe) &&
238 		    usb_pipetype(urb->pipe) != PIPE_ISOCHRONOUS &&
239 		    urb->actual_length > 0) {
240 			if (urb->num_sgs) {
241 				unsigned int copy = urb->actual_length;
242 				int size;
243 
244 				for_each_sg(urb->sg, sg, urb->num_sgs, i) {
245 					if (copy == 0)
246 						break;
247 
248 					if (copy < sg->length)
249 						size = copy;
250 					else
251 						size = sg->length;
252 
253 					iov[iovnum].iov_base = sg_virt(sg);
254 					iov[iovnum].iov_len = size;
255 
256 					iovnum++;
257 					copy -= size;
258 				}
259 			} else {
260 				iov[iovnum].iov_base = urb->transfer_buffer;
261 				iov[iovnum].iov_len  = urb->actual_length;
262 				iovnum++;
263 			}
264 			txsize += urb->actual_length;
265 		} else if (usb_pipein(urb->pipe) &&
266 			   usb_pipetype(urb->pipe) == PIPE_ISOCHRONOUS) {
267 			/*
268 			 * For isochronous packets: actual length is the sum of
269 			 * the actual length of the individual, packets, but as
270 			 * the packet offsets are not changed there will be
271 			 * padding between the packets. To optimally use the
272 			 * bandwidth the padding is not transmitted.
273 			 */
274 
275 			int i;
276 
277 			for (i = 0; i < urb->number_of_packets; i++) {
278 				iov[iovnum].iov_base = urb->transfer_buffer +
279 					urb->iso_frame_desc[i].offset;
280 				iov[iovnum].iov_len =
281 					urb->iso_frame_desc[i].actual_length;
282 				iovnum++;
283 				txsize += urb->iso_frame_desc[i].actual_length;
284 			}
285 
286 			if (txsize != sizeof(pdu_header) + urb->actual_length) {
287 				dev_err(&sdev->udev->dev,
288 					"actual length of urb %d does not match iso packet sizes %zu\n",
289 					urb->actual_length,
290 					txsize-sizeof(pdu_header));
291 				kfree(iov);
292 				usbip_event_add(&sdev->ud,
293 						SDEV_EVENT_ERROR_TCP);
294 				return -1;
295 			}
296 		}
297 
298 		/* 3. setup iso_packet_descriptor */
299 		if (usb_pipetype(urb->pipe) == PIPE_ISOCHRONOUS) {
300 			ssize_t len = 0;
301 
302 			iso_buffer = usbip_alloc_iso_desc_pdu(urb, &len);
303 			if (!iso_buffer) {
304 				usbip_event_add(&sdev->ud,
305 						SDEV_EVENT_ERROR_MALLOC);
306 				kfree(iov);
307 				return -1;
308 			}
309 
310 			iov[iovnum].iov_base = iso_buffer;
311 			iov[iovnum].iov_len  = len;
312 			txsize += len;
313 			iovnum++;
314 		}
315 
316 		ret = kernel_sendmsg(sdev->ud.tcp_socket, &msg,
317 						iov,  iovnum, txsize);
318 		if (ret != txsize) {
319 			dev_err(&sdev->udev->dev,
320 				"sendmsg failed!, retval %d for %zd\n",
321 				ret, txsize);
322 			kfree(iov);
323 			kfree(iso_buffer);
324 			usbip_event_add(&sdev->ud, SDEV_EVENT_ERROR_TCP);
325 			return -1;
326 		}
327 
328 		kfree(iov);
329 		kfree(iso_buffer);
330 
331 		total_size += txsize;
332 	}
333 
334 	spin_lock_irqsave(&sdev->priv_lock, flags);
335 	list_for_each_entry_safe(priv, tmp, &sdev->priv_free, list) {
336 		stub_free_priv_and_urb(priv);
337 	}
338 	spin_unlock_irqrestore(&sdev->priv_lock, flags);
339 
340 	return total_size;
341 }
342 
dequeue_from_unlink_tx(struct stub_device * sdev)343 static struct stub_unlink *dequeue_from_unlink_tx(struct stub_device *sdev)
344 {
345 	unsigned long flags;
346 	struct stub_unlink *unlink, *tmp;
347 
348 	spin_lock_irqsave(&sdev->priv_lock, flags);
349 
350 	list_for_each_entry_safe(unlink, tmp, &sdev->unlink_tx, list) {
351 		list_move_tail(&unlink->list, &sdev->unlink_free);
352 		spin_unlock_irqrestore(&sdev->priv_lock, flags);
353 		return unlink;
354 	}
355 
356 	spin_unlock_irqrestore(&sdev->priv_lock, flags);
357 
358 	return NULL;
359 }
360 
stub_send_ret_unlink(struct stub_device * sdev)361 static int stub_send_ret_unlink(struct stub_device *sdev)
362 {
363 	unsigned long flags;
364 	struct stub_unlink *unlink, *tmp;
365 
366 	struct msghdr msg;
367 	struct kvec iov[1];
368 	size_t txsize;
369 
370 	size_t total_size = 0;
371 
372 	while ((unlink = dequeue_from_unlink_tx(sdev)) != NULL) {
373 		int ret;
374 		struct usbip_header pdu_header;
375 
376 		txsize = 0;
377 		memset(&pdu_header, 0, sizeof(pdu_header));
378 		memset(&msg, 0, sizeof(msg));
379 		memset(&iov, 0, sizeof(iov));
380 
381 		usbip_dbg_stub_tx("setup ret unlink %lu\n", unlink->seqnum);
382 
383 		/* 1. setup usbip_header */
384 		setup_ret_unlink_pdu(&pdu_header, unlink);
385 		usbip_header_correct_endian(&pdu_header, 1);
386 
387 		iov[0].iov_base = &pdu_header;
388 		iov[0].iov_len  = sizeof(pdu_header);
389 		txsize += sizeof(pdu_header);
390 
391 		ret = kernel_sendmsg(sdev->ud.tcp_socket, &msg, iov,
392 				     1, txsize);
393 		if (ret != txsize) {
394 			dev_err(&sdev->udev->dev,
395 				"sendmsg failed!, retval %d for %zd\n",
396 				ret, txsize);
397 			usbip_event_add(&sdev->ud, SDEV_EVENT_ERROR_TCP);
398 			return -1;
399 		}
400 
401 		usbip_dbg_stub_tx("send txdata\n");
402 		total_size += txsize;
403 	}
404 
405 	spin_lock_irqsave(&sdev->priv_lock, flags);
406 
407 	list_for_each_entry_safe(unlink, tmp, &sdev->unlink_free, list) {
408 		list_del(&unlink->list);
409 		kfree(unlink);
410 	}
411 
412 	spin_unlock_irqrestore(&sdev->priv_lock, flags);
413 
414 	return total_size;
415 }
416 
stub_tx_loop(void * data)417 int stub_tx_loop(void *data)
418 {
419 	struct usbip_device *ud = data;
420 	struct stub_device *sdev = container_of(ud, struct stub_device, ud);
421 
422 	while (!kthread_should_stop()) {
423 		if (usbip_event_happened(ud))
424 			break;
425 
426 		/*
427 		 * send_ret_submit comes earlier than send_ret_unlink.  stub_rx
428 		 * looks at only priv_init queue. If the completion of a URB is
429 		 * earlier than the receive of CMD_UNLINK, priv is moved to
430 		 * priv_tx queue and stub_rx does not find the target priv. In
431 		 * this case, vhci_rx receives the result of the submit request
432 		 * and then receives the result of the unlink request. The
433 		 * result of the submit is given back to the usbcore as the
434 		 * completion of the unlink request. The request of the
435 		 * unlink is ignored. This is ok because a driver who calls
436 		 * usb_unlink_urb() understands the unlink was too late by
437 		 * getting the status of the given-backed URB which has the
438 		 * status of usb_submit_urb().
439 		 */
440 		if (stub_send_ret_submit(sdev) < 0)
441 			break;
442 
443 		if (stub_send_ret_unlink(sdev) < 0)
444 			break;
445 
446 		wait_event_interruptible(sdev->tx_waitq,
447 					 (!list_empty(&sdev->priv_tx) ||
448 					  !list_empty(&sdev->unlink_tx) ||
449 					  kthread_should_stop()));
450 	}
451 
452 	return 0;
453 }
454