summaryrefslogtreecommitdiff
path: root/drivers/infiniband/core/rdma_core.c
blob: 41c31a2bf0938cd1d31d6fa76d26603ea2bae8b2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
/*
 * Copyright (c) 2016, Mellanox Technologies inc.  All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/file.h>
#include <linux/anon_inodes.h>
#include <rdma/ib_verbs.h>
#include <rdma/uverbs_types.h>
#include <linux/rcupdate.h>
#include "uverbs.h"
#include "core_priv.h"
#include "rdma_core.h"

void uverbs_uobject_get(struct ib_uobject *uobject)
{
	kref_get(&uobject->ref);
}

static void uverbs_uobject_free(struct kref *ref)
{
	struct ib_uobject *uobj =
		container_of(ref, struct ib_uobject, ref);

	if (uobj->type->type_class->needs_kfree_rcu)
		kfree_rcu(uobj, rcu);
	else
		kfree(uobj);
}

void uverbs_uobject_put(struct ib_uobject *uobject)
{
	kref_put(&uobject->ref, uverbs_uobject_free);
}

static int uverbs_try_lock_object(struct ib_uobject *uobj, bool exclusive)
{
	/*
	 * When a shared access is required, we use a positive counter. Each
	 * shared access request checks that the value != -1 and increment it.
	 * Exclusive access is required for operations like write or destroy.
	 * In exclusive access mode, we check that the counter is zero (nobody
	 * claimed this object) and we set it to -1. Releasing a shared access
	 * lock is done simply by decreasing the counter. As for exclusive
	 * access locks, since only a single one of them is is allowed
	 * concurrently, setting the counter to zero is enough for releasing
	 * this lock.
	 */
	if (!exclusive)
		return __atomic_add_unless(&uobj->usecnt, 1, -1) == -1 ?
			-EBUSY : 0;

	/* lock is either WRITE or DESTROY - should be exclusive */
	return atomic_cmpxchg(&uobj->usecnt, 0, -1) == 0 ? 0 : -EBUSY;
}

static struct ib_uobject *alloc_uobj(struct ib_ucontext *context,
				     const struct uverbs_obj_type *type)
{
	struct ib_uobject *uobj = kzalloc(type->obj_size, GFP_KERNEL);

	if (!uobj)
		return ERR_PTR(-ENOMEM);
	/*
	 * user_handle should be filled by the handler,
	 * The object is added to the list in the commit stage.
	 */
	uobj->context = context;
	uobj->type = type;
	atomic_set(&uobj->usecnt, 0);
	kref_init(&uobj->ref);

	return uobj;
}

static int idr_add_uobj(struct ib_uobject *uobj)
{
	int ret;

	idr_preload(GFP_KERNEL);
	spin_lock(&uobj->context->ufile->idr_lock);

	/*
	 * We start with allocating an idr pointing to NULL. This represents an
	 * object which isn't initialized yet. We'll replace it later on with
	 * the real object once we commit.
	 */
	ret = idr_alloc(&uobj->context->ufile->idr, NULL, 0,
			min_t(unsigned long, U32_MAX - 1, INT_MAX), GFP_NOWAIT);
	if (ret >= 0)
		uobj->id = ret;

	spin_unlock(&uobj->context->ufile->idr_lock);
	idr_preload_end();

	return ret < 0 ? ret : 0;
}

/*
 * It only removes it from the uobjects list, uverbs_uobject_put() is still
 * required.
 */
static void uverbs_idr_remove_uobj(struct ib_uobject *uobj)
{
	spin_lock(&uobj->context->ufile->idr_lock);
	idr_remove(&uobj->context->ufile->idr, uobj->id);
	spin_unlock(&uobj->context->ufile->idr_lock);
}

/* Returns the ib_uobject or an error. The caller should check for IS_ERR. */
static struct ib_uobject *lookup_get_idr_uobject(const struct uverbs_obj_type *type,
						 struct ib_ucontext *ucontext,
						 int id, bool exclusive)
{
	struct ib_uobject *uobj;

	rcu_read_lock();
	/* object won't be released as we're protected in rcu */
	uobj = idr_find(&ucontext->ufile->idr, id);
	if (!uobj) {
		uobj = ERR_PTR(-ENOENT);
		goto free;
	}

	uverbs_uobject_get(uobj);
free:
	rcu_read_unlock();
	return uobj;
}

static struct ib_uobject *lookup_get_fd_uobject(const struct uverbs_obj_type *type,
						struct ib_ucontext *ucontext,
						int id, bool exclusive)
{
	struct file *f;
	struct ib_uobject *uobject;
	const struct uverbs_obj_fd_type *fd_type =
		container_of(type, struct uverbs_obj_fd_type, type);

	if (exclusive)
		return ERR_PTR(-EOPNOTSUPP);

	f = fget(id);
	if (!f)
		return ERR_PTR(-EBADF);

	uobject = f->private_data;
	/*
	 * fget(id) ensures we are not currently running uverbs_close_fd,
	 * and the caller is expected to ensure that uverbs_close_fd is never
	 * done while a call top lookup is possible.
	 */
	if (f->f_op != fd_type->fops) {
		fput(f);
		return ERR_PTR(-EBADF);
	}

	uverbs_uobject_get(uobject);
	return uobject;
}

struct ib_uobject *rdma_lookup_get_uobject(const struct uverbs_obj_type *type,
					   struct ib_ucontext *ucontext,
					   int id, bool exclusive)
{
	struct ib_uobject *uobj;
	int ret;

	uobj = type->type_class->lookup_get(type, ucontext, id, exclusive);
	if (IS_ERR(uobj))
		return uobj;

	if (uobj->type != type) {
		ret = -EINVAL;
		goto free;
	}

	ret = uverbs_try_lock_object(uobj, exclusive);
	if (ret) {
		WARN(ucontext->cleanup_reason,
		     "ib_uverbs: Trying to lookup_get while cleanup context\n");
		goto free;
	}

	return uobj;
free:
	uobj->type->type_class->lookup_put(uobj, exclusive);
	uverbs_uobject_put(uobj);
	return ERR_PTR(ret);
}

static struct ib_uobject *alloc_begin_idr_uobject(const struct uverbs_obj_type *type,
						  struct ib_ucontext *ucontext)
{
	int ret;
	struct ib_uobject *uobj;

	uobj = alloc_uobj(ucontext, type);
	if (IS_ERR(uobj))
		return uobj;

	ret = idr_add_uobj(uobj);
	if (ret)
		goto uobj_put;

	ret = ib_rdmacg_try_charge(&uobj->cg_obj, ucontext->device,
				   RDMACG_RESOURCE_HCA_OBJECT);
	if (ret)
		goto idr_remove;

	return uobj;

idr_remove:
	uverbs_idr_remove_uobj(uobj);
uobj_put:
	uverbs_uobject_put(uobj);
	return ERR_PTR(ret);
}

static struct ib_uobject *alloc_begin_fd_uobject(const struct uverbs_obj_type *type,
						 struct ib_ucontext *ucontext)
{
	const struct uverbs_obj_fd_type *fd_type =
		container_of(type, struct uverbs_obj_fd_type, type);
	int new_fd;
	struct ib_uobject *uobj;
	struct ib_uobject_file *uobj_file;
	struct file *filp;

	new_fd = get_unused_fd_flags(O_CLOEXEC);
	if (new_fd < 0)
		return ERR_PTR(new_fd);

	uobj = alloc_uobj(ucontext, type);
	if (IS_ERR(uobj)) {
		put_unused_fd(new_fd);
		return uobj;
	}

	uobj_file = container_of(uobj, struct ib_uobject_file, uobj);
	filp = anon_inode_getfile(fd_type->name,
				  fd_type->fops,
				  uobj_file,
				  fd_type->flags);
	if (IS_ERR(filp)) {
		put_unused_fd(new_fd);
		uverbs_uobject_put(uobj);
		return (void *)filp;
	}

	uobj_file->uobj.id = new_fd;
	uobj_file->uobj.object = filp;
	uobj_file->ufile = ucontext->ufile;
	INIT_LIST_HEAD(&uobj->list);
	kref_get(&uobj_file->ufile->ref);

	return uobj;
}

struct ib_uobject *rdma_alloc_begin_uobject(const struct uverbs_obj_type *type,
					    struct ib_ucontext *ucontext)
{
	return type->type_class->alloc_begin(type, ucontext);
}

static void uverbs_uobject_add(struct ib_uobject *uobject)
{
	mutex_lock(&uobject->context->uobjects_lock);
	list_add(&uobject->list, &uobject->context->uobjects);
	mutex_unlock(&uobject->context->uobjects_lock);
}

static int __must_check remove_commit_idr_uobject(struct ib_uobject *uobj,
						  enum rdma_remove_reason why)
{
	const struct uverbs_obj_idr_type *idr_type =
		container_of(uobj->type, struct uverbs_obj_idr_type,
			     type);
	int ret = idr_type->destroy_object(uobj, why);

	/*
	 * We can only fail gracefully if the user requested to destroy the
	 * object. In the rest of the cases, just remove whatever you can.
	 */
	if (why == RDMA_REMOVE_DESTROY && ret)
		return ret;

	ib_rdmacg_uncharge(&uobj->cg_obj, uobj->context->device,
			   RDMACG_RESOURCE_HCA_OBJECT);
	uverbs_idr_remove_uobj(uobj);

	return ret;
}

static void alloc_abort_fd_uobject(struct ib_uobject *uobj)
{
	struct ib_uobject_file *uobj_file =
		container_of(uobj, struct ib_uobject_file, uobj);
	struct file *filp = uobj->object;
	int id = uobj_file->uobj.id;

	/* Unsuccessful NEW */
	fput(filp);
	put_unused_fd(id);
}

static int __must_check remove_commit_fd_uobject(struct ib_uobject *uobj,
						 enum rdma_remove_reason why)
{
	const struct uverbs_obj_fd_type *fd_type =
		container_of(uobj->type, struct uverbs_obj_fd_type, type);
	struct ib_uobject_file *uobj_file =
		container_of(uobj, struct ib_uobject_file, uobj);
	int ret = fd_type->context_closed(uobj_file, why);

	if (why == RDMA_REMOVE_DESTROY && ret)
		return ret;

	if (why == RDMA_REMOVE_DURING_CLEANUP) {
		alloc_abort_fd_uobject(uobj);
		return ret;
	}

	uobj_file->uobj.context = NULL;
	return ret;
}

static void lockdep_check(struct ib_uobject *uobj, bool exclusive)
{
#ifdef CONFIG_LOCKDEP
	if (exclusive)
		WARN_ON(atomic_read(&uobj->usecnt) > 0);
	else
		WARN_ON(atomic_read(&uobj->usecnt) == -1);
#endif
}

static int __must_check _rdma_remove_commit_uobject(struct ib_uobject *uobj,
						    enum rdma_remove_reason why)
{
	int ret;
	struct ib_ucontext *ucontext = uobj->context;

	ret = uobj->type->type_class->remove_commit(uobj, why);
	if (ret && why == RDMA_REMOVE_DESTROY) {
		/* We couldn't remove the object, so just unlock the uobject */
		atomic_set(&uobj->usecnt, 0);
		uobj->type->type_class->lookup_put(uobj, true);
	} else {
		mutex_lock(&ucontext->uobjects_lock);
		list_del(&uobj->list);
		mutex_unlock(&ucontext->uobjects_lock);
		/* put the ref we took when we created the object */
		uverbs_uobject_put(uobj);
	}

	return ret;
}

/* This is called only for user requested DESTROY reasons */
int __must_check rdma_remove_commit_uobject(struct ib_uobject *uobj)
{
	int ret;
	struct ib_ucontext *ucontext = uobj->context;

	/* put the ref count we took at lookup_get */
	uverbs_uobject_put(uobj);
	/* Cleanup is running. Calling this should have been impossible */
	if (!down_read_trylock(&ucontext->cleanup_rwsem)) {
		WARN(true, "ib_uverbs: Cleanup is running while removing an uobject\n");
		return 0;
	}
	lockdep_check(uobj, true);
	ret = _rdma_remove_commit_uobject(uobj, RDMA_REMOVE_DESTROY);

	up_read(&ucontext->cleanup_rwsem);
	return ret;
}

static void alloc_commit_idr_uobject(struct ib_uobject *uobj)
{
	uverbs_uobject_add(uobj);
	spin_lock(&uobj->context->ufile->idr_lock);
	/*
	 * We already allocated this IDR with a NULL object, so
	 * this shouldn't fail.
	 */
	WARN_ON(idr_replace(&uobj->context->ufile->idr,
			    uobj, uobj->id));
	spin_unlock(&uobj->context->ufile->idr_lock);
}

static void alloc_commit_fd_uobject(struct ib_uobject *uobj)
{
	struct ib_uobject_file *uobj_file =
		container_of(uobj, struct ib_uobject_file, uobj);

	uverbs_uobject_add(&uobj_file->uobj);
	fd_install(uobj_file->uobj.id, uobj->object);
	/* This shouldn't be used anymore. Use the file object instead */
	uobj_file->uobj.id = 0;
	/* Get another reference as we export this to the fops */
	uverbs_uobject_get(&uobj_file->uobj);
}

int rdma_alloc_commit_uobject(struct ib_uobject *uobj)
{
	/* Cleanup is running. Calling this should have been impossible */
	if (!down_read_trylock(&uobj->context->cleanup_rwsem)) {
		int ret;

		WARN(true, "ib_uverbs: Cleanup is running while allocating an uobject\n");
		ret = uobj->type->type_class->remove_commit(uobj,
							    RDMA_REMOVE_DURING_CLEANUP);
		if (ret)
			pr_warn("ib_uverbs: cleanup of idr object %d failed\n",
				uobj->id);
		return ret;
	}

	uobj->type->type_class->alloc_commit(uobj);
	up_read(&uobj->context->cleanup_rwsem);

	return 0;
}

static void alloc_abort_idr_uobject(struct ib_uobject *uobj)
{
	uverbs_idr_remove_uobj(uobj);
	ib_rdmacg_uncharge(&uobj->cg_obj, uobj->context->device,
			   RDMACG_RESOURCE_HCA_OBJECT);
	uverbs_uobject_put(uobj);
}

void rdma_alloc_abort_uobject(struct ib_uobject *uobj)
{
	uobj->type->type_class->alloc_abort(uobj);
}

static void lookup_put_idr_uobject(struct ib_uobject *uobj, bool exclusive)
{
}

static void lookup_put_fd_uobject(struct ib_uobject *uobj, bool exclusive)
{
	struct file *filp = uobj->object;

	WARN_ON(exclusive);
	/* This indirectly calls uverbs_close_fd and free the object */
	fput(filp);
}

void rdma_lookup_put_uobject(struct ib_uobject *uobj, bool exclusive)
{
	lockdep_check(uobj, exclusive);
	uobj->type->type_class->lookup_put(uobj, exclusive);
	/*
	 * In order to unlock an object, either decrease its usecnt for
	 * read access or zero it in case of exclusive access. See
	 * uverbs_try_lock_object for locking schema information.
	 */
	if (!exclusive)
		atomic_dec(&uobj->usecnt);
	else
		atomic_set(&uobj->usecnt, 0);

	uverbs_uobject_put(uobj);
}

const struct uverbs_obj_type_class uverbs_idr_class = {
	.alloc_begin = alloc_begin_idr_uobject,
	.lookup_get = lookup_get_idr_uobject,
	.alloc_commit = alloc_commit_idr_uobject,
	.alloc_abort = alloc_abort_idr_uobject,
	.lookup_put = lookup_put_idr_uobject,
	.remove_commit = remove_commit_idr_uobject,
	/*
	 * When we destroy an object, we first just lock it for WRITE and
	 * actually DESTROY it in the finalize stage. So, the problematic
	 * scenario is when we just started the finalize stage of the
	 * destruction (nothing was executed yet). Now, the other thread
	 * fetched the object for READ access, but it didn't lock it yet.
	 * The DESTROY thread continues and starts destroying the object.
	 * When the other thread continue - without the RCU, it would
	 * access freed memory. However, the rcu_read_lock delays the free
	 * until the rcu_read_lock of the READ operation quits. Since the
	 * exclusive lock of the object is still taken by the DESTROY flow, the
	 * READ operation will get -EBUSY and it'll just bail out.
	 */
	.needs_kfree_rcu = true,
};

static void _uverbs_close_fd(struct ib_uobject_file *uobj_file)
{
	struct ib_ucontext *ucontext;
	struct ib_uverbs_file *ufile = uobj_file->ufile;
	int ret;

	mutex_lock(&uobj_file->ufile->cleanup_mutex);

	/* uobject was either already cleaned up or is cleaned up right now anyway */
	if (!uobj_file->uobj.context ||
	    !down_read_trylock(&uobj_file->uobj.context->cleanup_rwsem))
		goto unlock;

	ucontext = uobj_file->uobj.context;
	ret = _rdma_remove_commit_uobject(&uobj_file->uobj, RDMA_REMOVE_CLOSE);
	up_read(&ucontext->cleanup_rwsem);
	if (ret)
		pr_warn("uverbs: unable to clean up uobject file in uverbs_close_fd.\n");
unlock:
	mutex_unlock(&ufile->cleanup_mutex);
}

void uverbs_close_fd(struct file *f)
{
	struct ib_uobject_file *uobj_file = f->private_data;
	struct kref *uverbs_file_ref = &uobj_file->ufile->ref;

	_uverbs_close_fd(uobj_file);
	uverbs_uobject_put(&uobj_file->uobj);
	kref_put(uverbs_file_ref, ib_uverbs_release_file);
}

void uverbs_cleanup_ucontext(struct ib_ucontext *ucontext, bool device_removed)
{
	enum rdma_remove_reason reason = device_removed ?
		RDMA_REMOVE_DRIVER_REMOVE : RDMA_REMOVE_CLOSE;
	unsigned int cur_order = 0;

	ucontext->cleanup_reason = reason;
	/*
	 * Waits for all remove_commit and alloc_commit to finish. Logically, We
	 * want to hold this forever as the context is going to be destroyed,
	 * but we'll release it since it causes a "held lock freed" BUG message.
	 */
	down_write(&ucontext->cleanup_rwsem);

	while (!list_empty(&ucontext->uobjects)) {
		struct ib_uobject *obj, *next_obj;
		unsigned int next_order = UINT_MAX;

		/*
		 * This shouldn't run while executing other commands on this
		 * context. Thus, the only thing we should take care of is
		 * releasing a FD while traversing this list. The FD could be
		 * closed and released from the _release fop of this FD.
		 * In order to mitigate this, we add a lock.
		 * We take and release the lock per order traversal in order
		 * to let other threads (which might still use the FDs) chance
		 * to run.
		 */
		mutex_lock(&ucontext->uobjects_lock);
		list_for_each_entry_safe(obj, next_obj, &ucontext->uobjects,
					 list) {
			if (obj->type->destroy_order == cur_order) {
				int ret;

				/*
				 * if we hit this WARN_ON, that means we are
				 * racing with a lookup_get.
				 */
				WARN_ON(uverbs_try_lock_object(obj, true));
				ret = obj->type->type_class->remove_commit(obj,
									   reason);
				list_del(&obj->list);
				if (ret)
					pr_warn("ib_uverbs: failed to remove uobject id %d order %u\n",
						obj->id, cur_order);
				/* put the ref we took when we created the object */
				uverbs_uobject_put(obj);
			} else {
				next_order = min(next_order,
						 obj->type->destroy_order);
			}
		}
		mutex_unlock(&ucontext->uobjects_lock);
		cur_order = next_order;
	}
	up_write(&ucontext->cleanup_rwsem);
}

void uverbs_initialize_ucontext(struct ib_ucontext *ucontext)
{
	ucontext->cleanup_reason = 0;
	mutex_init(&ucontext->uobjects_lock);
	INIT_LIST_HEAD(&ucontext->uobjects);
	init_rwsem(&ucontext->cleanup_rwsem);
}

const struct uverbs_obj_type_class uverbs_fd_class = {
	.alloc_begin = alloc_begin_fd_uobject,
	.lookup_get = lookup_get_fd_uobject,
	.alloc_commit = alloc_commit_fd_uobject,
	.alloc_abort = alloc_abort_fd_uobject,
	.lookup_put = lookup_put_fd_uobject,
	.remove_commit = remove_commit_fd_uobject,
	.needs_kfree_rcu = false,
};