1 /* 2 * Copyright (c) 2016, Mellanox Technologies inc. All rights reserved. 3 * 4 * This software is available to you under a choice of one of two 5 * licenses. You may choose to be licensed under the terms of the GNU 6 * General Public License (GPL) Version 2, available from the file 7 * COPYING in the main directory of this source tree, or the 8 * OpenIB.org BSD license below: 9 * 10 * Redistribution and use in source and binary forms, with or 11 * without modification, are permitted provided that the following 12 * conditions are met: 13 * 14 * - Redistributions of source code must retain the above 15 * copyright notice, this list of conditions and the following 16 * disclaimer. 17 * 18 * - Redistributions in binary form must reproduce the above 19 * copyright notice, this list of conditions and the following 20 * disclaimer in the documentation and/or other materials 21 * provided with the distribution. 22 * 23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS 27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN 28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 30 * SOFTWARE. 31 */ 32 33 #include <asm/atomic.h> 34 #include <linux/file.h> 35 #include <linux/lockdep.h> 36 #include <rdma/ib_verbs.h> 37 #include <rdma/uverbs_types.h> 38 #include <linux/rcupdate.h> 39 #include <rdma/uverbs_ioctl.h> 40 #include <rdma/rdma_user_ioctl.h> 41 #include "uverbs.h" 42 #include "core_priv.h" 43 #include "rdma_core.h" 44 45 static void uverbs_uobject_free(struct kref *ref) 46 { 47 kfree_rcu(container_of(ref, struct ib_uobject, ref), rcu); 48 } 49 50 /* 51 * In order to indicate we no longer needs this uobject, uverbs_uobject_put 52 * is called. When the reference count is decreased, the uobject is freed. 53 * For example, this is used when attaching a completion channel to a CQ. 54 */ 55 void uverbs_uobject_put(struct ib_uobject *uobject) 56 { 57 kref_put(&uobject->ref, uverbs_uobject_free); 58 } 59 EXPORT_SYMBOL(uverbs_uobject_put); 60 61 static int uverbs_try_lock_object(struct ib_uobject *uobj, 62 enum rdma_lookup_mode mode) 63 { 64 /* 65 * When a shared access is required, we use a positive counter. Each 66 * shared access request checks that the value != -1 and increment it. 67 * Exclusive access is required for operations like write or destroy. 68 * In exclusive access mode, we check that the counter is zero (nobody 69 * claimed this object) and we set it to -1. Releasing a shared access 70 * lock is done simply by decreasing the counter. As for exclusive 71 * access locks, since only a single one of them is allowed 72 * concurrently, setting the counter to zero is enough for releasing 73 * this lock. 74 */ 75 switch (mode) { 76 case UVERBS_LOOKUP_READ: 77 return atomic_fetch_add_unless(&uobj->usecnt, 1, -1) == -1 ? 78 -EBUSY : 0; 79 case UVERBS_LOOKUP_WRITE: 80 /* lock is exclusive */ 81 return atomic_cmpxchg(&uobj->usecnt, 0, -1) == 0 ? 0 : -EBUSY; 82 case UVERBS_LOOKUP_DESTROY: 83 return 0; 84 } 85 return 0; 86 } 87 88 static void assert_uverbs_usecnt(struct ib_uobject *uobj, 89 enum rdma_lookup_mode mode) 90 { 91 #ifdef CONFIG_LOCKDEP 92 switch (mode) { 93 case UVERBS_LOOKUP_READ: 94 WARN_ON(atomic_read(&uobj->usecnt) <= 0); 95 break; 96 case UVERBS_LOOKUP_WRITE: 97 WARN_ON(atomic_read(&uobj->usecnt) != -1); 98 break; 99 case UVERBS_LOOKUP_DESTROY: 100 break; 101 } 102 #endif 103 } 104 105 /* 106 * This must be called with the hw_destroy_rwsem locked for read or write, 107 * also the uobject itself must be locked for write. 108 * 109 * Upon return the HW object is guaranteed to be destroyed. 110 * 111 * For RDMA_REMOVE_ABORT, the hw_destroy_rwsem is not required to be held, 112 * however the type's allocat_commit function cannot have been called and the 113 * uobject cannot be on the uobjects_lists 114 * 115 * For RDMA_REMOVE_DESTROY the caller shold be holding a kref (eg via 116 * rdma_lookup_get_uobject) and the object is left in a state where the caller 117 * needs to call rdma_lookup_put_uobject. 118 * 119 * For all other destroy modes this function internally unlocks the uobject 120 * and consumes the kref on the uobj. 121 */ 122 static int uverbs_destroy_uobject(struct ib_uobject *uobj, 123 enum rdma_remove_reason reason, 124 struct uverbs_attr_bundle *attrs) 125 { 126 struct ib_uverbs_file *ufile = attrs->ufile; 127 unsigned long flags; 128 int ret; 129 130 lockdep_assert_held(&ufile->hw_destroy_rwsem); 131 assert_uverbs_usecnt(uobj, UVERBS_LOOKUP_WRITE); 132 133 if (reason == RDMA_REMOVE_ABORT) { 134 WARN_ON(!list_empty(&uobj->list)); 135 WARN_ON(!uobj->context); 136 uobj->uapi_object->type_class->alloc_abort(uobj); 137 } else if (uobj->object) { 138 ret = uobj->uapi_object->type_class->destroy_hw(uobj, reason, 139 attrs); 140 if (ret) { 141 if (ib_is_destroy_retryable(ret, reason, uobj)) 142 return ret; 143 144 /* Nothing to be done, dangle the memory and move on */ 145 WARN(true, 146 "ib_uverbs: failed to remove uobject id %d, driver err=%d", 147 uobj->id, ret); 148 } 149 150 uobj->object = NULL; 151 } 152 153 uobj->context = NULL; 154 155 /* 156 * For DESTROY the usecnt is held write locked, the caller is expected 157 * to put it unlock and put the object when done with it. Only DESTROY 158 * can remove the IDR handle. 159 */ 160 if (reason != RDMA_REMOVE_DESTROY) 161 atomic_set(&uobj->usecnt, 0); 162 else 163 uobj->uapi_object->type_class->remove_handle(uobj); 164 165 if (!list_empty(&uobj->list)) { 166 spin_lock_irqsave(&ufile->uobjects_lock, flags); 167 list_del_init(&uobj->list); 168 spin_unlock_irqrestore(&ufile->uobjects_lock, flags); 169 170 /* 171 * Pairs with the get in rdma_alloc_commit_uobject(), could 172 * destroy uobj. 173 */ 174 uverbs_uobject_put(uobj); 175 } 176 177 /* 178 * When aborting the stack kref remains owned by the core code, and is 179 * not transferred into the type. Pairs with the get in alloc_uobj 180 */ 181 if (reason == RDMA_REMOVE_ABORT) 182 uverbs_uobject_put(uobj); 183 184 return 0; 185 } 186 187 /* 188 * This calls uverbs_destroy_uobject() using the RDMA_REMOVE_DESTROY 189 * sequence. It should only be used from command callbacks. On success the 190 * caller must pair this with rdma_lookup_put_uobject(LOOKUP_WRITE). This 191 * version requires the caller to have already obtained an 192 * LOOKUP_DESTROY uobject kref. 193 */ 194 int uobj_destroy(struct ib_uobject *uobj, struct uverbs_attr_bundle *attrs) 195 { 196 struct ib_uverbs_file *ufile = attrs->ufile; 197 int ret; 198 199 down_read(&ufile->hw_destroy_rwsem); 200 201 ret = uverbs_try_lock_object(uobj, UVERBS_LOOKUP_WRITE); 202 if (ret) 203 goto out_unlock; 204 205 ret = uverbs_destroy_uobject(uobj, RDMA_REMOVE_DESTROY, attrs); 206 if (ret) { 207 atomic_set(&uobj->usecnt, 0); 208 goto out_unlock; 209 } 210 211 out_unlock: 212 up_read(&ufile->hw_destroy_rwsem); 213 return ret; 214 } 215 216 /* 217 * uobj_get_destroy destroys the HW object and returns a handle to the uobj 218 * with a NULL object pointer. The caller must pair this with 219 * uverbs_put_destroy. 220 */ 221 struct ib_uobject *__uobj_get_destroy(const struct uverbs_api_object *obj, 222 u32 id, struct uverbs_attr_bundle *attrs) 223 { 224 struct ib_uobject *uobj; 225 int ret; 226 227 uobj = rdma_lookup_get_uobject(obj, attrs->ufile, id, 228 UVERBS_LOOKUP_DESTROY, attrs); 229 if (IS_ERR(uobj)) 230 return uobj; 231 232 ret = uobj_destroy(uobj, attrs); 233 if (ret) { 234 rdma_lookup_put_uobject(uobj, UVERBS_LOOKUP_DESTROY); 235 return ERR_PTR(ret); 236 } 237 238 return uobj; 239 } 240 241 /* 242 * Does both uobj_get_destroy() and uobj_put_destroy(). Returns 0 on success 243 * (negative errno on failure). For use by callers that do not need the uobj. 244 */ 245 int __uobj_perform_destroy(const struct uverbs_api_object *obj, u32 id, 246 struct uverbs_attr_bundle *attrs) 247 { 248 struct ib_uobject *uobj; 249 250 uobj = __uobj_get_destroy(obj, id, attrs); 251 if (IS_ERR(uobj)) 252 return PTR_ERR(uobj); 253 254 rdma_lookup_put_uobject(uobj, UVERBS_LOOKUP_WRITE); 255 return 0; 256 } 257 258 /* alloc_uobj must be undone by uverbs_destroy_uobject() */ 259 static struct ib_uobject *alloc_uobj(struct uverbs_attr_bundle *attrs, 260 const struct uverbs_api_object *obj) 261 { 262 struct ib_uverbs_file *ufile = attrs->ufile; 263 struct ib_uobject *uobj; 264 265 if (!attrs->context) { 266 struct ib_ucontext *ucontext = 267 ib_uverbs_get_ucontext_file(ufile); 268 269 if (IS_ERR(ucontext)) 270 return ERR_CAST(ucontext); 271 attrs->context = ucontext; 272 } 273 274 uobj = kzalloc(obj->type_attrs->obj_size, GFP_KERNEL); 275 if (!uobj) 276 return ERR_PTR(-ENOMEM); 277 /* 278 * user_handle should be filled by the handler, 279 * The object is added to the list in the commit stage. 280 */ 281 uobj->ufile = ufile; 282 uobj->context = attrs->context; 283 INIT_LIST_HEAD(&uobj->list); 284 uobj->uapi_object = obj; 285 /* 286 * Allocated objects start out as write locked to deny any other 287 * syscalls from accessing them until they are committed. See 288 * rdma_alloc_commit_uobject 289 */ 290 atomic_set(&uobj->usecnt, -1); 291 kref_init(&uobj->ref); 292 293 return uobj; 294 } 295 296 #define NULL_IB_UOBJECT ((struct ib_uobject *)1) 297 298 static int idr_add_uobj(struct ib_uobject *uobj) 299 { 300 /* 301 * We start with allocating an idr pointing to NULL. This represents an 302 * object which isn't initialized yet. We'll replace it later on with 303 * the real object once we commit. 304 */ 305 return xa_alloc(&uobj->ufile->idr, &uobj->id, NULL_IB_UOBJECT, xa_limit_32b, 306 GFP_KERNEL); 307 } 308 309 /* Returns the ib_uobject or an error. The caller should check for IS_ERR. */ 310 static struct ib_uobject * 311 lookup_get_idr_uobject(const struct uverbs_api_object *obj, 312 struct ib_uverbs_file *ufile, s64 id, 313 enum rdma_lookup_mode mode) 314 { 315 struct ib_uobject *uobj; 316 317 if (id < 0 || id > ULONG_MAX) 318 return ERR_PTR(-EINVAL); 319 320 rcu_read_lock(); 321 /* 322 * The idr_find is guaranteed to return a pointer to something that 323 * isn't freed yet, or NULL, as the free after idr_remove goes through 324 * kfree_rcu(). However the object may still have been released and 325 * kfree() could be called at any time. 326 */ 327 uobj = xa_load(&ufile->idr, id); 328 if (!uobj || uobj == NULL_IB_UOBJECT || !kref_get_unless_zero(&uobj->ref)) 329 uobj = ERR_PTR(-ENOENT); 330 rcu_read_unlock(); 331 return uobj; 332 } 333 334 static struct ib_uobject * 335 lookup_get_fd_uobject(const struct uverbs_api_object *obj, 336 struct ib_uverbs_file *ufile, s64 id, 337 enum rdma_lookup_mode mode) 338 { 339 const struct uverbs_obj_fd_type *fd_type; 340 struct file *f; 341 struct ib_uobject *uobject; 342 int fdno = id; 343 344 if (fdno != id) 345 return ERR_PTR(-EINVAL); 346 347 if (mode != UVERBS_LOOKUP_READ) 348 return ERR_PTR(-EOPNOTSUPP); 349 350 if (!obj->type_attrs) 351 return ERR_PTR(-EIO); 352 fd_type = 353 container_of(obj->type_attrs, struct uverbs_obj_fd_type, type); 354 355 f = fget(fdno); 356 if (!f) 357 return ERR_PTR(-EBADF); 358 359 uobject = f->private_data; 360 /* 361 * fget(id) ensures we are not currently running 362 * uverbs_uobject_fd_release(), and the caller is expected to ensure 363 * that release is never done while a call to lookup is possible. 364 */ 365 if (f->f_op != fd_type->fops) { 366 fput(f); 367 return ERR_PTR(-EBADF); 368 } 369 370 uverbs_uobject_get(uobject); 371 return uobject; 372 } 373 374 struct ib_uobject *rdma_lookup_get_uobject(const struct uverbs_api_object *obj, 375 struct ib_uverbs_file *ufile, s64 id, 376 enum rdma_lookup_mode mode, 377 struct uverbs_attr_bundle *attrs) 378 { 379 struct ib_uobject *uobj; 380 int ret; 381 382 if (obj == ERR_PTR(-ENOMSG)) { 383 /* must be UVERBS_IDR_ANY_OBJECT, see uapi_get_object() */ 384 uobj = lookup_get_idr_uobject(NULL, ufile, id, mode); 385 if (IS_ERR(uobj)) 386 return uobj; 387 } else { 388 if (IS_ERR(obj)) 389 return ERR_PTR(-EINVAL); 390 391 uobj = obj->type_class->lookup_get(obj, ufile, id, mode); 392 if (IS_ERR(uobj)) 393 return uobj; 394 395 if (uobj->uapi_object != obj) { 396 ret = -EINVAL; 397 goto free; 398 } 399 } 400 401 /* 402 * If we have been disassociated block every command except for 403 * DESTROY based commands. 404 */ 405 if (mode != UVERBS_LOOKUP_DESTROY && 406 !srcu_dereference(ufile->device->ib_dev, 407 &ufile->device->disassociate_srcu)) { 408 ret = -EIO; 409 goto free; 410 } 411 412 ret = uverbs_try_lock_object(uobj, mode); 413 if (ret) 414 goto free; 415 if (attrs) 416 attrs->context = uobj->context; 417 418 return uobj; 419 free: 420 uobj->uapi_object->type_class->lookup_put(uobj, mode); 421 uverbs_uobject_put(uobj); 422 return ERR_PTR(ret); 423 } 424 425 static struct ib_uobject * 426 alloc_begin_idr_uobject(const struct uverbs_api_object *obj, 427 struct uverbs_attr_bundle *attrs) 428 { 429 int ret; 430 struct ib_uobject *uobj; 431 432 uobj = alloc_uobj(attrs, obj); 433 if (IS_ERR(uobj)) 434 return uobj; 435 436 ret = idr_add_uobj(uobj); 437 if (ret) 438 goto uobj_put; 439 440 ret = ib_rdmacg_try_charge(&uobj->cg_obj, uobj->context->device, 441 RDMACG_RESOURCE_HCA_OBJECT); 442 if (ret) 443 goto remove; 444 445 return uobj; 446 447 remove: 448 xa_erase(&attrs->ufile->idr, uobj->id); 449 uobj_put: 450 uverbs_uobject_put(uobj); 451 return ERR_PTR(ret); 452 } 453 454 static struct ib_uobject * 455 alloc_begin_fd_uobject(const struct uverbs_api_object *obj, 456 struct uverbs_attr_bundle *attrs) 457 { 458 const struct uverbs_obj_fd_type *fd_type = 459 container_of(obj->type_attrs, struct uverbs_obj_fd_type, type); 460 int new_fd; 461 struct ib_uobject *uobj; 462 struct file *filp; 463 464 if (WARN_ON(fd_type->fops->release != &uverbs_uobject_fd_release)) 465 return ERR_PTR(-EINVAL); 466 467 new_fd = get_unused_fd_flags(O_CLOEXEC); 468 if (new_fd < 0) 469 return ERR_PTR(new_fd); 470 471 uobj = alloc_uobj(attrs, obj); 472 if (IS_ERR(uobj)) 473 goto err_fd; 474 475 /* Note that uverbs_uobject_fd_release() is called during abort */ 476 filp = alloc_file(fd_type->flags, fd_type->fops); 477 if (IS_ERR(filp)) { 478 uobj = ERR_CAST(filp); 479 goto err_uobj; 480 } 481 uobj->object = filp; 482 483 uobj->id = new_fd; 484 return uobj; 485 486 err_uobj: 487 uverbs_uobject_put(uobj); 488 err_fd: 489 put_unused_fd(new_fd); 490 return uobj; 491 } 492 493 struct ib_uobject *rdma_alloc_begin_uobject(const struct uverbs_api_object *obj, 494 struct uverbs_attr_bundle *attrs) 495 { 496 struct ib_uverbs_file *ufile = attrs->ufile; 497 struct ib_uobject *ret; 498 499 if (IS_ERR(obj)) 500 return ERR_PTR(-EINVAL); 501 502 /* 503 * The hw_destroy_rwsem is held across the entire object creation and 504 * released during rdma_alloc_commit_uobject or 505 * rdma_alloc_abort_uobject 506 */ 507 if (!down_read_trylock(&ufile->hw_destroy_rwsem)) 508 return ERR_PTR(-EIO); 509 510 ret = obj->type_class->alloc_begin(obj, attrs); 511 if (IS_ERR(ret)) { 512 up_read(&ufile->hw_destroy_rwsem); 513 return ret; 514 } 515 return ret; 516 } 517 518 static void alloc_abort_idr_uobject(struct ib_uobject *uobj) 519 { 520 xa_erase(&uobj->ufile->idr, uobj->id); 521 } 522 523 static int __must_check destroy_hw_idr_uobject(struct ib_uobject *uobj, 524 enum rdma_remove_reason why, 525 struct uverbs_attr_bundle *attrs) 526 { 527 const struct uverbs_obj_idr_type *idr_type = 528 container_of(uobj->uapi_object->type_attrs, 529 struct uverbs_obj_idr_type, type); 530 int ret = idr_type->destroy_object(uobj, why, attrs); 531 532 /* 533 * We can only fail gracefully if the user requested to destroy the 534 * object or when a retry may be called upon an error. 535 * In the rest of the cases, just remove whatever you can. 536 */ 537 if (ib_is_destroy_retryable(ret, why, uobj)) 538 return ret; 539 540 if (why == RDMA_REMOVE_ABORT) 541 return 0; 542 543 return 0; 544 } 545 546 static void remove_handle_idr_uobject(struct ib_uobject *uobj) 547 { 548 xa_erase(&uobj->ufile->idr, uobj->id); 549 /* Matches the kref in alloc_commit_idr_uobject */ 550 uverbs_uobject_put(uobj); 551 } 552 553 static void alloc_abort_fd_uobject(struct ib_uobject *uobj) 554 { 555 struct file *filp = uobj->object; 556 557 fput(filp); 558 put_unused_fd(uobj->id); 559 } 560 561 static int __must_check destroy_hw_fd_uobject(struct ib_uobject *uobj, 562 enum rdma_remove_reason why, 563 struct uverbs_attr_bundle *attrs) 564 { 565 const struct uverbs_obj_fd_type *fd_type = container_of( 566 uobj->uapi_object->type_attrs, struct uverbs_obj_fd_type, type); 567 int ret = fd_type->destroy_object(uobj, why); 568 569 if (ib_is_destroy_retryable(ret, why, uobj)) 570 return ret; 571 572 return 0; 573 } 574 575 static void remove_handle_fd_uobject(struct ib_uobject *uobj) 576 { 577 } 578 579 static void alloc_commit_idr_uobject(struct ib_uobject *uobj) 580 { 581 struct ib_uverbs_file *ufile = uobj->ufile; 582 void *old; 583 584 /* 585 * We already allocated this IDR with a NULL object, so 586 * this shouldn't fail. 587 * 588 * NOTE: Storing the uobj transfers our kref on uobj to the XArray. 589 * It will be put by remove_commit_idr_uobject() 590 */ 591 old = xa_store(&ufile->idr, uobj->id, uobj, GFP_KERNEL); 592 WARN_ON(old != NULL_IB_UOBJECT); 593 } 594 595 static void alloc_commit_fd_uobject(struct ib_uobject *uobj) 596 { 597 int fd = uobj->id; 598 struct file *filp = uobj->object; 599 600 /* Matching put will be done in uverbs_uobject_fd_release() */ 601 kref_get(&uobj->ufile->ref); 602 603 /* This shouldn't be used anymore. Use the file object instead */ 604 uobj->id = 0; 605 606 /* 607 * NOTE: Once we install the file we loose ownership of our kref on 608 * uobj. It will be put by uverbs_uobject_fd_release() 609 */ 610 filp->private_data = uobj; 611 fd_install(fd, filp); 612 } 613 614 /* 615 * In all cases rdma_alloc_commit_uobject() consumes the kref to uobj and the 616 * caller can no longer assume uobj is valid. If this function fails it 617 * destroys the uboject, including the attached HW object. 618 */ 619 void rdma_alloc_commit_uobject(struct ib_uobject *uobj, 620 struct uverbs_attr_bundle *attrs) 621 { 622 struct ib_uverbs_file *ufile = attrs->ufile; 623 624 /* alloc_commit consumes the uobj kref */ 625 uobj->uapi_object->type_class->alloc_commit(uobj); 626 627 /* kref is held so long as the uobj is on the uobj list. */ 628 uverbs_uobject_get(uobj); 629 spin_lock_irq(&ufile->uobjects_lock); 630 list_add(&uobj->list, &ufile->uobjects); 631 spin_unlock_irq(&ufile->uobjects_lock); 632 633 /* matches atomic_set(-1) in alloc_uobj */ 634 atomic_set(&uobj->usecnt, 0); 635 636 /* Matches the down_read in rdma_alloc_begin_uobject */ 637 up_read(&ufile->hw_destroy_rwsem); 638 } 639 640 /* 641 * This consumes the kref for uobj. It is up to the caller to unwind the HW 642 * object and anything else connected to uobj before calling this. 643 */ 644 void rdma_alloc_abort_uobject(struct ib_uobject *uobj, 645 struct uverbs_attr_bundle *attrs) 646 { 647 struct ib_uverbs_file *ufile = uobj->ufile; 648 649 uverbs_destroy_uobject(uobj, RDMA_REMOVE_ABORT, attrs); 650 651 /* Matches the down_read in rdma_alloc_begin_uobject */ 652 up_read(&ufile->hw_destroy_rwsem); 653 } 654 655 static void lookup_put_idr_uobject(struct ib_uobject *uobj, 656 enum rdma_lookup_mode mode) 657 { 658 } 659 660 static void lookup_put_fd_uobject(struct ib_uobject *uobj, 661 enum rdma_lookup_mode mode) 662 { 663 struct file *filp = uobj->object; 664 665 WARN_ON(mode != UVERBS_LOOKUP_READ); 666 /* 667 * This indirectly calls uverbs_uobject_fd_release() and free the 668 * object 669 */ 670 fput(filp); 671 } 672 673 void rdma_lookup_put_uobject(struct ib_uobject *uobj, 674 enum rdma_lookup_mode mode) 675 { 676 assert_uverbs_usecnt(uobj, mode); 677 uobj->uapi_object->type_class->lookup_put(uobj, mode); 678 /* 679 * In order to unlock an object, either decrease its usecnt for 680 * read access or zero it in case of exclusive access. See 681 * uverbs_try_lock_object for locking schema information. 682 */ 683 switch (mode) { 684 case UVERBS_LOOKUP_READ: 685 atomic_dec(&uobj->usecnt); 686 break; 687 case UVERBS_LOOKUP_WRITE: 688 atomic_set(&uobj->usecnt, 0); 689 break; 690 case UVERBS_LOOKUP_DESTROY: 691 break; 692 } 693 694 /* Pairs with the kref obtained by type->lookup_get */ 695 uverbs_uobject_put(uobj); 696 } 697 698 void setup_ufile_idr_uobject(struct ib_uverbs_file *ufile) 699 { 700 xa_init_flags(&ufile->idr, XA_FLAGS_ALLOC); 701 } 702 703 void release_ufile_idr_uobject(struct ib_uverbs_file *ufile) 704 { 705 struct ib_uobject *entry; 706 unsigned long id; 707 708 /* 709 * At this point uverbs_cleanup_ufile() is guaranteed to have run, and 710 * there are no HW objects left, however the xarray is still populated 711 * with anything that has not been cleaned up by userspace. Since the 712 * kref on ufile is 0, nothing is allowed to call lookup_get. 713 * 714 * This is an optimized equivalent to remove_handle_idr_uobject 715 */ 716 xa_for_each(&ufile->idr, id, entry) { 717 WARN_ON(entry->object); 718 uverbs_uobject_put(entry); 719 } 720 721 xa_destroy(&ufile->idr); 722 } 723 724 const struct uverbs_obj_type_class uverbs_idr_class = { 725 .alloc_begin = alloc_begin_idr_uobject, 726 .lookup_get = lookup_get_idr_uobject, 727 .alloc_commit = alloc_commit_idr_uobject, 728 .alloc_abort = alloc_abort_idr_uobject, 729 .lookup_put = lookup_put_idr_uobject, 730 .destroy_hw = destroy_hw_idr_uobject, 731 .remove_handle = remove_handle_idr_uobject, 732 }; 733 EXPORT_SYMBOL(uverbs_idr_class); 734 735 /* 736 * Users of UVERBS_TYPE_ALLOC_FD should set this function as the struct 737 * file_operations release method. 738 */ 739 int uverbs_uobject_fd_release(struct inode *inode, struct file *filp) 740 { 741 struct ib_uverbs_file *ufile; 742 struct ib_uobject *uobj; 743 744 /* 745 * This can only happen if the fput came from alloc_abort_fd_uobject() 746 */ 747 if (!filp->private_data) 748 return 0; 749 uobj = filp->private_data; 750 ufile = uobj->ufile; 751 752 if (down_read_trylock(&ufile->hw_destroy_rwsem)) { 753 struct uverbs_attr_bundle attrs = { 754 .context = uobj->context, 755 .ufile = ufile, 756 }; 757 758 /* 759 * lookup_get_fd_uobject holds the kref on the struct file any 760 * time a FD uobj is locked, which prevents this release 761 * method from being invoked. Meaning we can always get the 762 * write lock here, or we have a kernel bug. 763 */ 764 WARN_ON(uverbs_try_lock_object(uobj, UVERBS_LOOKUP_WRITE)); 765 uverbs_destroy_uobject(uobj, RDMA_REMOVE_CLOSE, &attrs); 766 up_read(&ufile->hw_destroy_rwsem); 767 } 768 769 /* Matches the get in alloc_commit_fd_uobject() */ 770 kref_put(&ufile->ref, ib_uverbs_release_file); 771 772 /* Pairs with filp->private_data in alloc_begin_fd_uobject */ 773 uverbs_uobject_put(uobj); 774 return 0; 775 } 776 EXPORT_SYMBOL(uverbs_uobject_fd_release); 777 778 /* 779 * Drop the ucontext off the ufile and completely disconnect it from the 780 * ib_device 781 */ 782 static void ufile_destroy_ucontext(struct ib_uverbs_file *ufile, 783 enum rdma_remove_reason reason) 784 { 785 struct ib_ucontext *ucontext = ufile->ucontext; 786 struct ib_device *ib_dev = ucontext->device; 787 788 /* 789 * If we are closing the FD then the user mmap VMAs must have 790 * already been destroyed as they hold on to the filep, otherwise 791 * they need to be zap'd. 792 */ 793 if (reason == RDMA_REMOVE_DRIVER_REMOVE) { 794 uverbs_user_mmap_disassociate(ufile); 795 if (ib_dev->disassociate_ucontext) 796 ib_dev->disassociate_ucontext(ucontext); 797 } 798 799 ib_dev->dealloc_ucontext(ucontext); 800 WARN_ON(!xa_empty(&ucontext->mmap_xa)); 801 kfree(ucontext); 802 803 ufile->ucontext = NULL; 804 } 805 806 static int __uverbs_cleanup_ufile(struct ib_uverbs_file *ufile, 807 enum rdma_remove_reason reason) 808 { 809 struct ib_uobject *obj, *next_obj; 810 int ret = -EINVAL; 811 struct uverbs_attr_bundle attrs = { .ufile = ufile }; 812 813 /* 814 * This shouldn't run while executing other commands on this 815 * context. Thus, the only thing we should take care of is 816 * releasing a FD while traversing this list. The FD could be 817 * closed and released from the _release fop of this FD. 818 * In order to mitigate this, we add a lock. 819 * We take and release the lock per traversal in order to let 820 * other threads (which might still use the FDs) chance to run. 821 */ 822 list_for_each_entry_safe(obj, next_obj, &ufile->uobjects, list) { 823 attrs.context = obj->context; 824 /* 825 * if we hit this WARN_ON, that means we are 826 * racing with a lookup_get. 827 */ 828 WARN_ON(uverbs_try_lock_object(obj, UVERBS_LOOKUP_WRITE)); 829 if (!uverbs_destroy_uobject(obj, reason, &attrs)) 830 ret = 0; 831 else 832 atomic_set(&obj->usecnt, 0); 833 } 834 return ret; 835 } 836 837 /* 838 * Destroy the uncontext and every uobject associated with it. 839 * 840 * This is internally locked and can be called in parallel from multiple 841 * contexts. 842 */ 843 void uverbs_destroy_ufile_hw(struct ib_uverbs_file *ufile, 844 enum rdma_remove_reason reason) 845 { 846 down_write(&ufile->hw_destroy_rwsem); 847 848 /* 849 * If a ucontext was never created then we can't have any uobjects to 850 * cleanup, nothing to do. 851 */ 852 if (!ufile->ucontext) 853 goto done; 854 855 ufile->ucontext->closing = true; 856 ufile->ucontext->cleanup_retryable = true; 857 while (!list_empty(&ufile->uobjects)) 858 if (__uverbs_cleanup_ufile(ufile, reason)) { 859 /* 860 * No entry was cleaned-up successfully during this 861 * iteration 862 */ 863 break; 864 } 865 866 ufile->ucontext->cleanup_retryable = false; 867 if (!list_empty(&ufile->uobjects)) 868 __uverbs_cleanup_ufile(ufile, reason); 869 870 ufile_destroy_ucontext(ufile, reason); 871 872 done: 873 up_write(&ufile->hw_destroy_rwsem); 874 } 875 876 const struct uverbs_obj_type_class uverbs_fd_class = { 877 .alloc_begin = alloc_begin_fd_uobject, 878 .lookup_get = lookup_get_fd_uobject, 879 .alloc_commit = alloc_commit_fd_uobject, 880 .alloc_abort = alloc_abort_fd_uobject, 881 .lookup_put = lookup_put_fd_uobject, 882 .destroy_hw = destroy_hw_fd_uobject, 883 .remove_handle = remove_handle_fd_uobject, 884 }; 885 EXPORT_SYMBOL(uverbs_fd_class); 886 887 struct ib_uobject * 888 uverbs_get_uobject_from_file(u16 object_id, enum uverbs_obj_access access, 889 s64 id, struct uverbs_attr_bundle *attrs) 890 { 891 const struct uverbs_api_object *obj = 892 uapi_get_object(attrs->ufile->device->uapi, object_id); 893 894 switch (access) { 895 case UVERBS_ACCESS_READ: 896 return rdma_lookup_get_uobject(obj, attrs->ufile, id, 897 UVERBS_LOOKUP_READ, attrs); 898 case UVERBS_ACCESS_DESTROY: 899 /* Actual destruction is done inside uverbs_handle_method */ 900 return rdma_lookup_get_uobject(obj, attrs->ufile, id, 901 UVERBS_LOOKUP_DESTROY, attrs); 902 case UVERBS_ACCESS_WRITE: 903 return rdma_lookup_get_uobject(obj, attrs->ufile, id, 904 UVERBS_LOOKUP_WRITE, attrs); 905 case UVERBS_ACCESS_NEW: 906 return rdma_alloc_begin_uobject(obj, attrs); 907 default: 908 WARN_ON(true); 909 return ERR_PTR(-EOPNOTSUPP); 910 } 911 } 912 913 void uverbs_finalize_object(struct ib_uobject *uobj, 914 enum uverbs_obj_access access, bool commit, 915 struct uverbs_attr_bundle *attrs) 916 { 917 /* 918 * refcounts should be handled at the object level and not at the 919 * uobject level. Refcounts of the objects themselves are done in 920 * handlers. 921 */ 922 923 switch (access) { 924 case UVERBS_ACCESS_READ: 925 rdma_lookup_put_uobject(uobj, UVERBS_LOOKUP_READ); 926 break; 927 case UVERBS_ACCESS_WRITE: 928 rdma_lookup_put_uobject(uobj, UVERBS_LOOKUP_WRITE); 929 break; 930 case UVERBS_ACCESS_DESTROY: 931 if (uobj) 932 rdma_lookup_put_uobject(uobj, UVERBS_LOOKUP_DESTROY); 933 break; 934 case UVERBS_ACCESS_NEW: 935 if (commit) 936 rdma_alloc_commit_uobject(uobj, attrs); 937 else 938 rdma_alloc_abort_uobject(uobj, attrs); 939 break; 940 default: 941 WARN_ON(true); 942 } 943 } 944