1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * The USB Monitor, inspired by Dave Harding's USBMon.
  4 *
  5 * This is a text format reader.
  6 */
  7
  8#include <linux/kernel.h>
  9#include <linux/list.h>
 10#include <linux/usb.h>
 11#include <linux/slab.h>
 12#include <linux/sched/signal.h>
 13#include <linux/time.h>
 14#include <linux/ktime.h>
 15#include <linux/export.h>
 16#include <linux/mutex.h>
 17#include <linux/debugfs.h>
 18#include <linux/scatterlist.h>
 19#include <linux/uaccess.h>
 20
 21#include "usb_mon.h"
 22
 23/*
 24 * No, we do not want arbitrarily long data strings.
 25 * Use the binary interface if you want to capture bulk data!
 26 */
 27#define DATA_MAX  32
 28
 29/*
 30 * Defined by USB 2.0 clause 9.3, table 9.2.
 31 */
 32#define SETUP_MAX  8
 33
 34/*
 35 * This limit exists to prevent OOMs when the user process stops reading.
 36 * If usbmon were available to unprivileged processes, it might be open
 37 * to a local DoS. But we have to keep to root in order to prevent
 38 * password sniffing from HID devices.
 39 */
 40#define EVENT_MAX  (4*PAGE_SIZE / sizeof(struct mon_event_text))
 41
 42/*
 43 * Potentially unlimited number; we limit it for similar allocations.
 44 * The usbfs limits this to 128, but we're not quite as generous.
 45 */
 46#define ISODESC_MAX   5
 47
 48#define PRINTF_DFL  250   /* with 5 ISOs segs */
 49
 50struct mon_iso_desc {
 51	int status;
 52	unsigned int offset;
 53	unsigned int length;	/* Unsigned here, signed in URB. Historic. */
 54};
 55
 56struct mon_event_text {
 57	struct list_head e_link;
 58	int type;		/* submit, complete, etc. */
 59	unsigned long id;	/* From pointer, most of the time */
 60	unsigned int tstamp;
 61	int busnum;
 62	char devnum;
 63	char epnum;
 64	char is_in;
 65	char xfertype;
 66	int length;		/* Depends on type: xfer length or act length */
 67	int status;
 68	int interval;
 69	int start_frame;
 70	int error_count;
 71	char setup_flag;
 72	char data_flag;
 73	int numdesc;		/* Full number */
 74	struct mon_iso_desc isodesc[ISODESC_MAX];
 75	unsigned char setup[SETUP_MAX];
 76	unsigned char data[DATA_MAX];
 77};
 78
 79#define SLAB_NAME_SZ  30
 80struct mon_reader_text {
 81	struct kmem_cache *e_slab;
 82	int nevents;
 83	struct list_head e_list;
 84	struct mon_reader r;	/* In C, parent class can be placed anywhere */
 85
 86	wait_queue_head_t wait;
 87	int printf_size;
 88	size_t printf_offset;
 89	size_t printf_togo;
 90	char *printf_buf;
 91	struct mutex printf_lock;
 92
 93	char slab_name[SLAB_NAME_SZ];
 94};
 95
 96static struct dentry *mon_dir;		/* Usually /sys/kernel/debug/usbmon */
 97
 98static void mon_text_ctor(void *);
 99
100struct mon_text_ptr {
101	int cnt, limit;
102	char *pbuf;
103};
104
105static struct mon_event_text *
106    mon_text_read_wait(struct mon_reader_text *rp, struct file *file);
107static void mon_text_read_head_t(struct mon_reader_text *rp,
108	struct mon_text_ptr *p, const struct mon_event_text *ep);
109static void mon_text_read_head_u(struct mon_reader_text *rp,
110	struct mon_text_ptr *p, const struct mon_event_text *ep);
111static void mon_text_read_statset(struct mon_reader_text *rp,
112	struct mon_text_ptr *p, const struct mon_event_text *ep);
113static void mon_text_read_intstat(struct mon_reader_text *rp,
114	struct mon_text_ptr *p, const struct mon_event_text *ep);
115static void mon_text_read_isostat(struct mon_reader_text *rp,
116	struct mon_text_ptr *p, const struct mon_event_text *ep);
117static void mon_text_read_isodesc(struct mon_reader_text *rp,
118	struct mon_text_ptr *p, const struct mon_event_text *ep);
119static void mon_text_read_data(struct mon_reader_text *rp,
120    struct mon_text_ptr *p, const struct mon_event_text *ep);
121
122/*
123 * mon_text_submit
124 * mon_text_complete
125 *
126 * May be called from an interrupt.
127 *
128 * This is called with the whole mon_bus locked, so no additional lock.
129 */
130
131static inline char mon_text_get_setup(struct mon_event_text *ep,
132    struct urb *urb, char ev_type, struct mon_bus *mbus)
133{
134
135	if (ep->xfertype != USB_ENDPOINT_XFER_CONTROL || ev_type != 'S')
136		return '-';
137
138	if (urb->setup_packet == NULL)
139		return 'Z';	/* '0' would be not as pretty. */
140
141	memcpy(ep->setup, urb->setup_packet, SETUP_MAX);
142	return 0;
143}
144
145static inline char mon_text_get_data(struct mon_event_text *ep, struct urb *urb,
146    int len, char ev_type, struct mon_bus *mbus)
147{
148	void *src;
149
150	if (len <= 0)
151		return 'L';
152	if (len >= DATA_MAX)
153		len = DATA_MAX;
154
155	if (ep->is_in) {
156		if (ev_type != 'C')
157			return '<';
158	} else {
159		if (ev_type != 'S')
160			return '>';
161	}
162
163	if (urb->num_sgs == 0) {
164		src = urb->transfer_buffer;
165		if (src == NULL)
166			return 'Z';	/* '0' would be not as pretty. */
167	} else {
168		struct scatterlist *sg = urb->sg;
169
170		if (PageHighMem(sg_page(sg)))
171			return 'D';
172
173		/* For the text interface we copy only the first sg buffer */
174		len = min_t(int, sg->length, len);
175		src = sg_virt(sg);
176	}
177
178	memcpy(ep->data, src, len);
179	return 0;
180}
181
182static inline unsigned int mon_get_timestamp(void)
183{
184	struct timespec64 now;
185	unsigned int stamp;
186
187	ktime_get_ts64(&now);
188	stamp = now.tv_sec & 0xFFF;  /* 2^32 = 4294967296. Limit to 4096s. */
189	stamp = stamp * USEC_PER_SEC + now.tv_nsec / NSEC_PER_USEC;
190	return stamp;
191}
192
193static void mon_text_event(struct mon_reader_text *rp, struct urb *urb,
194    char ev_type, int status)
195{
196	struct mon_event_text *ep;
197	unsigned int stamp;
198	struct usb_iso_packet_descriptor *fp;
199	struct mon_iso_desc *dp;
200	int i, ndesc;
201
202	stamp = mon_get_timestamp();
203
204	if (rp->nevents >= EVENT_MAX ||
205	    (ep = kmem_cache_alloc(rp->e_slab, GFP_ATOMIC)) == NULL) {
206		rp->r.m_bus->cnt_text_lost++;
207		return;
208	}
209
210	ep->type = ev_type;
211	ep->id = (unsigned long) urb;
212	ep->busnum = urb->dev->bus->busnum;
213	ep->devnum = urb->dev->devnum;
214	ep->epnum = usb_endpoint_num(&urb->ep->desc);
215	ep->xfertype = usb_endpoint_type(&urb->ep->desc);
216	ep->is_in = usb_urb_dir_in(urb);
217	ep->tstamp = stamp;
218	ep->length = (ev_type == 'S') ?
219	    urb->transfer_buffer_length : urb->actual_length;
220	/* Collecting status makes debugging sense for submits, too */
221	ep->status = status;
222
223	if (ep->xfertype == USB_ENDPOINT_XFER_INT) {
224		ep->interval = urb->interval;
225	} else if (ep->xfertype == USB_ENDPOINT_XFER_ISOC) {
226		ep->interval = urb->interval;
227		ep->start_frame = urb->start_frame;
228		ep->error_count = urb->error_count;
229	}
230	ep->numdesc = urb->number_of_packets;
231	if (ep->xfertype == USB_ENDPOINT_XFER_ISOC &&
232			urb->number_of_packets > 0) {
233		if ((ndesc = urb->number_of_packets) > ISODESC_MAX)
234			ndesc = ISODESC_MAX;
235		fp = urb->iso_frame_desc;
236		dp = ep->isodesc;
237		for (i = 0; i < ndesc; i++) {
238			dp->status = fp->status;
239			dp->offset = fp->offset;
240			dp->length = (ev_type == 'S') ?
241			    fp->length : fp->actual_length;
242			fp++;
243			dp++;
244		}
245		/* Wasteful, but simple to understand: ISO 'C' is sparse. */
246		if (ev_type == 'C')
247			ep->length = urb->transfer_buffer_length;
248	}
249
250	ep->setup_flag = mon_text_get_setup(ep, urb, ev_type, rp->r.m_bus);
251	ep->data_flag = mon_text_get_data(ep, urb, ep->length, ev_type,
252			rp->r.m_bus);
253
254	rp->nevents++;
255	list_add_tail(&ep->e_link, &rp->e_list);
256	wake_up(&rp->wait);
257}
258
259static void mon_text_submit(void *data, struct urb *urb)
260{
261	struct mon_reader_text *rp = data;
262	mon_text_event(rp, urb, 'S', -EINPROGRESS);
263}
264
265static void mon_text_complete(void *data, struct urb *urb, int status)
266{
267	struct mon_reader_text *rp = data;
268	mon_text_event(rp, urb, 'C', status);
269}
270
271static void mon_text_error(void *data, struct urb *urb, int error)
272{
273	struct mon_reader_text *rp = data;
274	struct mon_event_text *ep;
275
276	if (rp->nevents >= EVENT_MAX ||
277	    (ep = kmem_cache_alloc(rp->e_slab, GFP_ATOMIC)) == NULL) {
278		rp->r.m_bus->cnt_text_lost++;
279		return;
280	}
281
282	ep->type = 'E';
283	ep->id = (unsigned long) urb;
284	ep->busnum = urb->dev->bus->busnum;
285	ep->devnum = urb->dev->devnum;
286	ep->epnum = usb_endpoint_num(&urb->ep->desc);
287	ep->xfertype = usb_endpoint_type(&urb->ep->desc);
288	ep->is_in = usb_urb_dir_in(urb);
289	ep->tstamp = mon_get_timestamp();
290	ep->length = 0;
291	ep->status = error;
292
293	ep->setup_flag = '-';
294	ep->data_flag = 'E';
295
296	rp->nevents++;
297	list_add_tail(&ep->e_link, &rp->e_list);
298	wake_up(&rp->wait);
299}
300
301/*
302 * Fetch next event from the circular buffer.
303 */
304static struct mon_event_text *mon_text_fetch(struct mon_reader_text *rp,
305    struct mon_bus *mbus)
306{
307	struct list_head *p;
308	unsigned long flags;
309
310	spin_lock_irqsave(&mbus->lock, flags);
311	if (list_empty(&rp->e_list)) {
312		spin_unlock_irqrestore(&mbus->lock, flags);
313		return NULL;
314	}
315	p = rp->e_list.next;
316	list_del(p);
317	--rp->nevents;
318	spin_unlock_irqrestore(&mbus->lock, flags);
319	return list_entry(p, struct mon_event_text, e_link);
320}
321
322/*
323 */
324static int mon_text_open(struct inode *inode, struct file *file)
325{
326	struct mon_bus *mbus;
327	struct mon_reader_text *rp;
328	int rc;
329
330	mutex_lock(&mon_lock);
331	mbus = inode->i_private;
332
333	rp = kzalloc(sizeof(struct mon_reader_text), GFP_KERNEL);
334	if (rp == NULL) {
335		rc = -ENOMEM;
336		goto err_alloc;
337	}
338	INIT_LIST_HEAD(&rp->e_list);
339	init_waitqueue_head(&rp->wait);
340	mutex_init(&rp->printf_lock);
341
342	rp->printf_size = PRINTF_DFL;
343	rp->printf_buf = kmalloc(rp->printf_size, GFP_KERNEL);
344	if (rp->printf_buf == NULL) {
345		rc = -ENOMEM;
346		goto err_alloc_pr;
347	}
348
349	rp->r.m_bus = mbus;
350	rp->r.r_data = rp;
351	rp->r.rnf_submit = mon_text_submit;
352	rp->r.rnf_error = mon_text_error;
353	rp->r.rnf_complete = mon_text_complete;
354
355	scnprintf(rp->slab_name, SLAB_NAME_SZ, "mon_text_%p", rp);
356	rp->e_slab = kmem_cache_create(rp->slab_name,
357	    sizeof(struct mon_event_text), sizeof(long), 0,
358	    mon_text_ctor);
359	if (rp->e_slab == NULL) {
360		rc = -ENOMEM;
361		goto err_slab;
362	}
363
364	mon_reader_add(mbus, &rp->r);
365
366	file->private_data = rp;
367	mutex_unlock(&mon_lock);
368	return 0;
369
370// err_busy:
371//	kmem_cache_destroy(rp->e_slab);
372err_slab:
373	kfree(rp->printf_buf);
374err_alloc_pr:
375	kfree(rp);
376err_alloc:
377	mutex_unlock(&mon_lock);
378	return rc;
379}
380
381static ssize_t mon_text_copy_to_user(struct mon_reader_text *rp,
382    char __user * const buf, const size_t nbytes)
383{
384	const size_t togo = min(nbytes, rp->printf_togo);
385
386	if (copy_to_user(buf, &rp->printf_buf[rp->printf_offset], togo))
387		return -EFAULT;
388	rp->printf_togo -= togo;
389	rp->printf_offset += togo;
390	return togo;
391}
392
393/* ppos is not advanced since the llseek operation is not permitted. */
394static ssize_t mon_text_read_t(struct file *file, char __user *buf,
395    size_t nbytes, loff_t *ppos)
396{
397	struct mon_reader_text *rp = file->private_data;
398	struct mon_event_text *ep;
399	struct mon_text_ptr ptr;
400	ssize_t ret;
401
402	mutex_lock(&rp->printf_lock);
403
404	if (rp->printf_togo == 0) {
405
406		ep = mon_text_read_wait(rp, file);
407		if (IS_ERR(ep)) {
408			mutex_unlock(&rp->printf_lock);
409			return PTR_ERR(ep);
410		}
411		ptr.cnt = 0;
412		ptr.pbuf = rp->printf_buf;
413		ptr.limit = rp->printf_size;
414
415		mon_text_read_head_t(rp, &ptr, ep);
416		mon_text_read_statset(rp, &ptr, ep);
417		ptr.cnt += scnprintf(ptr.pbuf + ptr.cnt, ptr.limit - ptr.cnt,
418		    " %d", ep->length);
419		mon_text_read_data(rp, &ptr, ep);
420
421		rp->printf_togo = ptr.cnt;
422		rp->printf_offset = 0;
423
424		kmem_cache_free(rp->e_slab, ep);
425	}
426
427	ret = mon_text_copy_to_user(rp, buf, nbytes);
428	mutex_unlock(&rp->printf_lock);
429	return ret;
430}
431
432/* ppos is not advanced since the llseek operation is not permitted. */
433static ssize_t mon_text_read_u(struct file *file, char __user *buf,
434    size_t nbytes, loff_t *ppos)
435{
436	struct mon_reader_text *rp = file->private_data;
437	struct mon_event_text *ep;
438	struct mon_text_ptr ptr;
439	ssize_t ret;
440
441	mutex_lock(&rp->printf_lock);
442
443	if (rp->printf_togo == 0) {
444
445		ep = mon_text_read_wait(rp, file);
446		if (IS_ERR(ep)) {
447			mutex_unlock(&rp->printf_lock);
448			return PTR_ERR(ep);
449		}
450		ptr.cnt = 0;
451		ptr.pbuf = rp->printf_buf;
452		ptr.limit = rp->printf_size;
453
454		mon_text_read_head_u(rp, &ptr, ep);
455		if (ep->type == 'E') {
456			mon_text_read_statset(rp, &ptr, ep);
457		} else if (ep->xfertype == USB_ENDPOINT_XFER_ISOC) {
458			mon_text_read_isostat(rp, &ptr, ep);
459			mon_text_read_isodesc(rp, &ptr, ep);
460		} else if (ep->xfertype == USB_ENDPOINT_XFER_INT) {
461			mon_text_read_intstat(rp, &ptr, ep);
462		} else {
463			mon_text_read_statset(rp, &ptr, ep);
464		}
465		ptr.cnt += scnprintf(ptr.pbuf + ptr.cnt, ptr.limit - ptr.cnt,
466		    " %d", ep->length);
467		mon_text_read_data(rp, &ptr, ep);
468
469		rp->printf_togo = ptr.cnt;
470		rp->printf_offset = 0;
471
472		kmem_cache_free(rp->e_slab, ep);
473	}
474
475	ret = mon_text_copy_to_user(rp, buf, nbytes);
476	mutex_unlock(&rp->printf_lock);
477	return ret;
478}
479
480static struct mon_event_text *mon_text_read_wait(struct mon_reader_text *rp,
481    struct file *file)
482{
483	struct mon_bus *mbus = rp->r.m_bus;
484	DECLARE_WAITQUEUE(waita, current);
485	struct mon_event_text *ep;
486
487	add_wait_queue(&rp->wait, &waita);
488	set_current_state(TASK_INTERRUPTIBLE);
489	while ((ep = mon_text_fetch(rp, mbus)) == NULL) {
490		if (file->f_flags & O_NONBLOCK) {
491			set_current_state(TASK_RUNNING);
492			remove_wait_queue(&rp->wait, &waita);
493			return ERR_PTR(-EWOULDBLOCK);
494		}
495		/*
496		 * We do not count nwaiters, because ->release is supposed
497		 * to be called when all openers are gone only.
498		 */
499		schedule();
500		if (signal_pending(current)) {
501			remove_wait_queue(&rp->wait, &waita);
502			return ERR_PTR(-EINTR);
503		}
504		set_current_state(TASK_INTERRUPTIBLE);
505	}
506	set_current_state(TASK_RUNNING);
507	remove_wait_queue(&rp->wait, &waita);
508	return ep;
509}
510
511static void mon_text_read_head_t(struct mon_reader_text *rp,
512	struct mon_text_ptr *p, const struct mon_event_text *ep)
513{
514	char udir, utype;
515
516	udir = (ep->is_in ? 'i' : 'o');
517	switch (ep->xfertype) {
518	case USB_ENDPOINT_XFER_ISOC:	utype = 'Z'; break;
519	case USB_ENDPOINT_XFER_INT:	utype = 'I'; break;
520	case USB_ENDPOINT_XFER_CONTROL:	utype = 'C'; break;
521	default: /* PIPE_BULK */  utype = 'B';
522	}
523	p->cnt += scnprintf(p->pbuf + p->cnt, p->limit - p->cnt,
524	    "%lx %u %c %c%c:%03u:%02u",
525	    ep->id, ep->tstamp, ep->type,
526	    utype, udir, ep->devnum, ep->epnum);
527}
528
529static void mon_text_read_head_u(struct mon_reader_text *rp,
530	struct mon_text_ptr *p, const struct mon_event_text *ep)
531{
532	char udir, utype;
533
534	udir = (ep->is_in ? 'i' : 'o');
535	switch (ep->xfertype) {
536	case USB_ENDPOINT_XFER_ISOC:	utype = 'Z'; break;
537	case USB_ENDPOINT_XFER_INT:	utype = 'I'; break;
538	case USB_ENDPOINT_XFER_CONTROL:	utype = 'C'; break;
539	default: /* PIPE_BULK */  utype = 'B';
540	}
541	p->cnt += scnprintf(p->pbuf + p->cnt, p->limit - p->cnt,
542	    "%lx %u %c %c%c:%d:%03u:%u",
543	    ep->id, ep->tstamp, ep->type,
544	    utype, udir, ep->busnum, ep->devnum, ep->epnum);
545}
546
547static void mon_text_read_statset(struct mon_reader_text *rp,
548	struct mon_text_ptr *p, const struct mon_event_text *ep)
549{
550
551	if (ep->setup_flag == 0) {   /* Setup packet is present and captured */
552		p->cnt += scnprintf(p->pbuf + p->cnt, p->limit - p->cnt,
553		    " s %02x %02x %04x %04x %04x",
554		    ep->setup[0],
555		    ep->setup[1],
556		    (ep->setup[3] << 8) | ep->setup[2],
557		    (ep->setup[5] << 8) | ep->setup[4],
558		    (ep->setup[7] << 8) | ep->setup[6]);
559	} else if (ep->setup_flag != '-') { /* Unable to capture setup packet */
560		p->cnt += scnprintf(p->pbuf + p->cnt, p->limit - p->cnt,
561		    " %c __ __ ____ ____ ____", ep->setup_flag);
562	} else {                     /* No setup for this kind of URB */
563		p->cnt += scnprintf(p->pbuf + p->cnt, p->limit - p->cnt,
564		    " %d", ep->status);
565	}
566}
567
568static void mon_text_read_intstat(struct mon_reader_text *rp,
569	struct mon_text_ptr *p, const struct mon_event_text *ep)
570{
571	p->cnt += scnprintf(p->pbuf + p->cnt, p->limit - p->cnt,
572	    " %d:%d", ep->status, ep->interval);
573}
574
575static void mon_text_read_isostat(struct mon_reader_text *rp,
576	struct mon_text_ptr *p, const struct mon_event_text *ep)
577{
578	if (ep->type == 'S') {
579		p->cnt += scnprintf(p->pbuf + p->cnt, p->limit - p->cnt,
580		    " %d:%d:%d", ep->status, ep->interval, ep->start_frame);
581	} else {
582		p->cnt += scnprintf(p->pbuf + p->cnt, p->limit - p->cnt,
583		    " %d:%d:%d:%d",
584		    ep->status, ep->interval, ep->start_frame, ep->error_count);
585	}
586}
587
588static void mon_text_read_isodesc(struct mon_reader_text *rp,
589	struct mon_text_ptr *p, const struct mon_event_text *ep)
590{
591	int ndesc;	/* Display this many */
592	int i;
593	const struct mon_iso_desc *dp;
594
595	p->cnt += scnprintf(p->pbuf + p->cnt, p->limit - p->cnt,
596	    " %d", ep->numdesc);
597	ndesc = ep->numdesc;
598	if (ndesc > ISODESC_MAX)
599		ndesc = ISODESC_MAX;
600	if (ndesc < 0)
601		ndesc = 0;
602	dp = ep->isodesc;
603	for (i = 0; i < ndesc; i++) {
604		p->cnt += scnprintf(p->pbuf + p->cnt, p->limit - p->cnt,
605		    " %d:%u:%u", dp->status, dp->offset, dp->length);
606		dp++;
607	}
608}
609
610static void mon_text_read_data(struct mon_reader_text *rp,
611    struct mon_text_ptr *p, const struct mon_event_text *ep)
612{
613	int data_len, i;
614
615	if ((data_len = ep->length) > 0) {
616		if (ep->data_flag == 0) {
617			p->cnt += scnprintf(p->pbuf + p->cnt, p->limit - p->cnt,
618			    " =");
619			if (data_len >= DATA_MAX)
620				data_len = DATA_MAX;
621			for (i = 0; i < data_len; i++) {
622				if (i % 4 == 0) {
623					p->cnt += scnprintf(p->pbuf + p->cnt,
624					    p->limit - p->cnt,
625					    " ");
626				}
627				p->cnt += scnprintf(p->pbuf + p->cnt,
628				    p->limit - p->cnt,
629				    "%02x", ep->data[i]);
630			}
631			p->cnt += scnprintf(p->pbuf + p->cnt, p->limit - p->cnt,
632			    "\n");
633		} else {
634			p->cnt += scnprintf(p->pbuf + p->cnt, p->limit - p->cnt,
635			    " %c\n", ep->data_flag);
636		}
637	} else {
638		p->cnt += scnprintf(p->pbuf + p->cnt, p->limit - p->cnt, "\n");
639	}
640}
641
642static int mon_text_release(struct inode *inode, struct file *file)
643{
644	struct mon_reader_text *rp = file->private_data;
645	struct mon_bus *mbus;
646	/* unsigned long flags; */
647	struct list_head *p;
648	struct mon_event_text *ep;
649
650	mutex_lock(&mon_lock);
651	mbus = inode->i_private;
652
653	if (mbus->nreaders <= 0) {
654		printk(KERN_ERR TAG ": consistency error on close\n");
655		mutex_unlock(&mon_lock);
656		return 0;
657	}
658	mon_reader_del(mbus, &rp->r);
659
660	/*
661	 * In theory, e_list is protected by mbus->lock. However,
662	 * after mon_reader_del has finished, the following is the case:
663	 *  - we are not on reader list anymore, so new events won't be added;
664	 *  - whole mbus may be dropped if it was orphaned.
665	 * So, we better not touch mbus.
666	 */
667	/* spin_lock_irqsave(&mbus->lock, flags); */
668	while (!list_empty(&rp->e_list)) {
669		p = rp->e_list.next;
670		ep = list_entry(p, struct mon_event_text, e_link);
671		list_del(p);
672		--rp->nevents;
673		kmem_cache_free(rp->e_slab, ep);
674	}
675	/* spin_unlock_irqrestore(&mbus->lock, flags); */
676
677	kmem_cache_destroy(rp->e_slab);
678	kfree(rp->printf_buf);
679	kfree(rp);
680
681	mutex_unlock(&mon_lock);
682	return 0;
683}
684
685static const struct file_operations mon_fops_text_t = {
686	.owner =	THIS_MODULE,
687	.open =		mon_text_open,
688	.llseek =	no_llseek,
689	.read =		mon_text_read_t,
690	.release =	mon_text_release,
691};
692
693static const struct file_operations mon_fops_text_u = {
694	.owner =	THIS_MODULE,
695	.open =		mon_text_open,
696	.llseek =	no_llseek,
697	.read =		mon_text_read_u,
698	.release =	mon_text_release,
699};
700
701int mon_text_add(struct mon_bus *mbus, const struct usb_bus *ubus)
702{
703	enum { NAMESZ = 12 };
704	char name[NAMESZ];
705	int busnum = ubus? ubus->busnum: 0;
 
706
707	if (mon_dir == NULL)
708		return 0;
709
710	if (ubus != NULL) {
711		scnprintf(name, NAMESZ, "%dt", busnum);
 
 
712		mbus->dent_t = debugfs_create_file(name, 0600, mon_dir, mbus,
713							     &mon_fops_text_t);
714	}
715
716	scnprintf(name, NAMESZ, "%du", busnum);
 
 
717	mbus->dent_u = debugfs_create_file(name, 0600, mon_dir, mbus,
718					   &mon_fops_text_u);
719
720	scnprintf(name, NAMESZ, "%ds", busnum);
 
 
721	mbus->dent_s = debugfs_create_file(name, 0600, mon_dir, mbus,
722					   &mon_fops_stat);
723
724	return 1;
 
 
 
 
 
 
 
 
 
 
 
725}
726
727void mon_text_del(struct mon_bus *mbus)
728{
729	debugfs_remove(mbus->dent_u);
730	debugfs_remove(mbus->dent_t);
731	debugfs_remove(mbus->dent_s);
732}
733
734/*
735 * Slab interface: constructor.
736 */
737static void mon_text_ctor(void *mem)
738{
739	/*
740	 * Nothing to initialize. No, really!
741	 * So, we fill it with garbage to emulate a reused object.
742	 */
743	memset(mem, 0xe5, sizeof(struct mon_event_text));
744}
745
746int __init mon_text_init(void)
747{
748	mon_dir = debugfs_create_dir("usbmon", usb_debug_root);
749	return 0;
750}
751
752void mon_text_exit(void)
753{
754	debugfs_remove(mon_dir);
755}