1 /* 2 * Copyright © 2008-2015 Intel Corporation 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a 5 * copy of this software and associated documentation files (the "Software"), 6 * to deal in the Software without restriction, including without limitation 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 8 * and/or sell copies of the Software, and to permit persons to whom the 9 * Software is furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice (including the next 12 * paragraph) shall be included in all copies or substantial portions of the 13 * Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 21 * IN THE SOFTWARE. 22 * 23 */ 24 25 #ifndef I915_GEM_REQUEST_H 26 #define I915_GEM_REQUEST_H 27 28 #include <linux/dma-fence.h> 29 30 #include "i915_gem.h" 31 #include "i915_sw_fence.h" 32 33 #include <uapi/drm/i915_drm.h> 34 35 struct drm_file; 36 struct drm_i915_gem_object; 37 struct drm_i915_gem_request; 38 39 struct intel_wait { 40 struct rb_node node; 41 struct task_struct *tsk; 42 struct drm_i915_gem_request *request; 43 u32 seqno; 44 }; 45 46 struct intel_signal_node { 47 struct rb_node node; 48 struct intel_wait wait; 49 }; 50 51 struct i915_dependency { 52 struct i915_priotree *signaler; 53 struct list_head signal_link; 54 struct list_head wait_link; 55 struct list_head dfs_link; 56 unsigned long flags; 57 #define I915_DEPENDENCY_ALLOC BIT(0) 58 }; 59 60 /* Requests exist in a complex web of interdependencies. Each request 61 * has to wait for some other request to complete before it is ready to be run 62 * (e.g. we have to wait until the pixels have been rendering into a texture 63 * before we can copy from it). We track the readiness of a request in terms 64 * of fences, but we also need to keep the dependency tree for the lifetime 65 * of the request (beyond the life of an individual fence). We use the tree 66 * at various points to reorder the requests whilst keeping the requests 67 * in order with respect to their various dependencies. 68 */ 69 struct i915_priotree { 70 struct list_head signalers_list; /* those before us, we depend upon */ 71 struct list_head waiters_list; /* those after us, they depend upon us */ 72 struct list_head link; 73 int priority; 74 }; 75 76 enum { 77 I915_PRIORITY_MIN = I915_CONTEXT_MIN_USER_PRIORITY - 1, 78 I915_PRIORITY_NORMAL = I915_CONTEXT_DEFAULT_PRIORITY, 79 I915_PRIORITY_MAX = I915_CONTEXT_MAX_USER_PRIORITY + 1, 80 81 I915_PRIORITY_INVALID = INT_MIN 82 }; 83 84 struct i915_gem_capture_list { 85 struct i915_gem_capture_list *next; 86 struct i915_vma *vma; 87 }; 88 89 /** 90 * Request queue structure. 91 * 92 * The request queue allows us to note sequence numbers that have been emitted 93 * and may be associated with active buffers to be retired. 94 * 95 * By keeping this list, we can avoid having to do questionable sequence 96 * number comparisons on buffer last_read|write_seqno. It also allows an 97 * emission time to be associated with the request for tracking how far ahead 98 * of the GPU the submission is. 99 * 100 * When modifying this structure be very aware that we perform a lockless 101 * RCU lookup of it that may race against reallocation of the struct 102 * from the slab freelist. We intentionally do not zero the structure on 103 * allocation so that the lookup can use the dangling pointers (and is 104 * cogniscent that those pointers may be wrong). Instead, everything that 105 * needs to be initialised must be done so explicitly. 106 * 107 * The requests are reference counted. 108 */ 109 struct drm_i915_gem_request { 110 struct dma_fence fence; 111 spinlock_t lock; 112 113 /** On Which ring this request was generated */ 114 struct drm_i915_private *i915; 115 116 /** 117 * Context and ring buffer related to this request 118 * Contexts are refcounted, so when this request is associated with a 119 * context, we must increment the context's refcount, to guarantee that 120 * it persists while any request is linked to it. Requests themselves 121 * are also refcounted, so the request will only be freed when the last 122 * reference to it is dismissed, and the code in 123 * i915_gem_request_free() will then decrement the refcount on the 124 * context. 125 */ 126 struct i915_gem_context *ctx; 127 struct intel_engine_cs *engine; 128 struct intel_ring *ring; 129 struct intel_timeline *timeline; 130 struct intel_signal_node signaling; 131 132 /* Fences for the various phases in the request's lifetime. 133 * 134 * The submit fence is used to await upon all of the request's 135 * dependencies. When it is signaled, the request is ready to run. 136 * It is used by the driver to then queue the request for execution. 137 */ 138 struct i915_sw_fence submit; 139 wait_queue_entry_t submitq; 140 wait_queue_head_t execute; 141 142 /* A list of everyone we wait upon, and everyone who waits upon us. 143 * Even though we will not be submitted to the hardware before the 144 * submit fence is signaled (it waits for all external events as well 145 * as our own requests), the scheduler still needs to know the 146 * dependency tree for the lifetime of the request (from execbuf 147 * to retirement), i.e. bidirectional dependency information for the 148 * request not tied to individual fences. 149 */ 150 struct i915_priotree priotree; 151 struct i915_dependency dep; 152 153 /** GEM sequence number associated with this request on the 154 * global execution timeline. It is zero when the request is not 155 * on the HW queue (i.e. not on the engine timeline list). 156 * Its value is guarded by the timeline spinlock. 157 */ 158 u32 global_seqno; 159 160 /** Position in the ring of the start of the request */ 161 u32 head; 162 163 /** 164 * Position in the ring of the start of the postfix. 165 * This is required to calculate the maximum available ring space 166 * without overwriting the postfix. 167 */ 168 u32 postfix; 169 170 /** Position in the ring of the end of the whole request */ 171 u32 tail; 172 173 /** Position in the ring of the end of any workarounds after the tail */ 174 u32 wa_tail; 175 176 /** Preallocate space in the ring for the emitting the request */ 177 u32 reserved_space; 178 179 /** Batch buffer related to this request if any (used for 180 * error state dump only). 181 */ 182 struct i915_vma *batch; 183 /** Additional buffers requested by userspace to be captured upon 184 * a GPU hang. The vma/obj on this list are protected by their 185 * active reference - all objects on this list must also be 186 * on the active_list (of their final request). 187 */ 188 struct i915_gem_capture_list *capture_list; 189 struct list_head active_list; 190 191 /** Time at which this request was emitted, in jiffies. */ 192 unsigned long emitted_jiffies; 193 194 bool waitboost; 195 196 /** engine->request_list entry for this request */ 197 struct list_head link; 198 199 /** ring->request_list entry for this request */ 200 struct list_head ring_link; 201 202 struct drm_i915_file_private *file_priv; 203 /** file_priv list entry for this request */ 204 struct list_head client_link; 205 }; 206 207 extern const struct dma_fence_ops i915_fence_ops; 208 209 static inline bool dma_fence_is_i915(const struct dma_fence *fence) 210 { 211 return fence->ops == &i915_fence_ops; 212 } 213 214 struct drm_i915_gem_request * __must_check 215 i915_gem_request_alloc(struct intel_engine_cs *engine, 216 struct i915_gem_context *ctx); 217 void i915_gem_request_retire_upto(struct drm_i915_gem_request *req); 218 219 static inline struct drm_i915_gem_request * 220 to_request(struct dma_fence *fence) 221 { 222 /* We assume that NULL fence/request are interoperable */ 223 BUILD_BUG_ON(offsetof(struct drm_i915_gem_request, fence) != 0); 224 GEM_BUG_ON(fence && !dma_fence_is_i915(fence)); 225 return container_of(fence, struct drm_i915_gem_request, fence); 226 } 227 228 static inline struct drm_i915_gem_request * 229 i915_gem_request_get(struct drm_i915_gem_request *req) 230 { 231 return to_request(dma_fence_get(&req->fence)); 232 } 233 234 static inline struct drm_i915_gem_request * 235 i915_gem_request_get_rcu(struct drm_i915_gem_request *req) 236 { 237 return to_request(dma_fence_get_rcu(&req->fence)); 238 } 239 240 static inline void 241 i915_gem_request_put(struct drm_i915_gem_request *req) 242 { 243 dma_fence_put(&req->fence); 244 } 245 246 static inline void i915_gem_request_assign(struct drm_i915_gem_request **pdst, 247 struct drm_i915_gem_request *src) 248 { 249 if (src) 250 i915_gem_request_get(src); 251 252 if (*pdst) 253 i915_gem_request_put(*pdst); 254 255 *pdst = src; 256 } 257 258 /** 259 * i915_gem_request_global_seqno - report the current global seqno 260 * @request - the request 261 * 262 * A request is assigned a global seqno only when it is on the hardware 263 * execution queue. The global seqno can be used to maintain a list of 264 * requests on the same engine in retirement order, for example for 265 * constructing a priority queue for waiting. Prior to its execution, or 266 * if it is subsequently removed in the event of preemption, its global 267 * seqno is zero. As both insertion and removal from the execution queue 268 * may operate in IRQ context, it is not guarded by the usual struct_mutex 269 * BKL. Instead those relying on the global seqno must be prepared for its 270 * value to change between reads. Only when the request is complete can 271 * the global seqno be stable (due to the memory barriers on submitting 272 * the commands to the hardware to write the breadcrumb, if the HWS shows 273 * that it has passed the global seqno and the global seqno is unchanged 274 * after the read, it is indeed complete). 275 */ 276 static u32 277 i915_gem_request_global_seqno(const struct drm_i915_gem_request *request) 278 { 279 return READ_ONCE(request->global_seqno); 280 } 281 282 int 283 i915_gem_request_await_object(struct drm_i915_gem_request *to, 284 struct drm_i915_gem_object *obj, 285 bool write); 286 int i915_gem_request_await_dma_fence(struct drm_i915_gem_request *req, 287 struct dma_fence *fence); 288 289 void __i915_add_request(struct drm_i915_gem_request *req, bool flush_caches); 290 #define i915_add_request(req) \ 291 __i915_add_request(req, false) 292 293 void __i915_gem_request_submit(struct drm_i915_gem_request *request); 294 void i915_gem_request_submit(struct drm_i915_gem_request *request); 295 296 void __i915_gem_request_unsubmit(struct drm_i915_gem_request *request); 297 void i915_gem_request_unsubmit(struct drm_i915_gem_request *request); 298 299 struct intel_rps_client; 300 #define NO_WAITBOOST ERR_PTR(-1) 301 #define IS_RPS_CLIENT(p) (!IS_ERR(p)) 302 #define IS_RPS_USER(p) (!IS_ERR_OR_NULL(p)) 303 304 long i915_wait_request(struct drm_i915_gem_request *req, 305 unsigned int flags, 306 long timeout) 307 __attribute__((nonnull(1))); 308 #define I915_WAIT_INTERRUPTIBLE BIT(0) 309 #define I915_WAIT_LOCKED BIT(1) /* struct_mutex held, handle GPU reset */ 310 #define I915_WAIT_ALL BIT(2) /* used by i915_gem_object_wait() */ 311 312 static inline u32 intel_engine_get_seqno(struct intel_engine_cs *engine); 313 314 /** 315 * Returns true if seq1 is later than seq2. 316 */ 317 static inline bool i915_seqno_passed(u32 seq1, u32 seq2) 318 { 319 return (s32)(seq1 - seq2) >= 0; 320 } 321 322 static inline bool 323 __i915_gem_request_completed(const struct drm_i915_gem_request *req, u32 seqno) 324 { 325 GEM_BUG_ON(!seqno); 326 return i915_seqno_passed(intel_engine_get_seqno(req->engine), seqno) && 327 seqno == i915_gem_request_global_seqno(req); 328 } 329 330 static inline bool 331 i915_gem_request_completed(const struct drm_i915_gem_request *req) 332 { 333 u32 seqno; 334 335 seqno = i915_gem_request_global_seqno(req); 336 if (!seqno) 337 return false; 338 339 return __i915_gem_request_completed(req, seqno); 340 } 341 342 /* We treat requests as fences. This is not be to confused with our 343 * "fence registers" but pipeline synchronisation objects ala GL_ARB_sync. 344 * We use the fences to synchronize access from the CPU with activity on the 345 * GPU, for example, we should not rewrite an object's PTE whilst the GPU 346 * is reading them. We also track fences at a higher level to provide 347 * implicit synchronisation around GEM objects, e.g. set-domain will wait 348 * for outstanding GPU rendering before marking the object ready for CPU 349 * access, or a pageflip will wait until the GPU is complete before showing 350 * the frame on the scanout. 351 * 352 * In order to use a fence, the object must track the fence it needs to 353 * serialise with. For example, GEM objects want to track both read and 354 * write access so that we can perform concurrent read operations between 355 * the CPU and GPU engines, as well as waiting for all rendering to 356 * complete, or waiting for the last GPU user of a "fence register". The 357 * object then embeds a #i915_gem_active to track the most recent (in 358 * retirement order) request relevant for the desired mode of access. 359 * The #i915_gem_active is updated with i915_gem_active_set() to track the 360 * most recent fence request, typically this is done as part of 361 * i915_vma_move_to_active(). 362 * 363 * When the #i915_gem_active completes (is retired), it will 364 * signal its completion to the owner through a callback as well as mark 365 * itself as idle (i915_gem_active.request == NULL). The owner 366 * can then perform any action, such as delayed freeing of an active 367 * resource including itself. 368 */ 369 struct i915_gem_active; 370 371 typedef void (*i915_gem_retire_fn)(struct i915_gem_active *, 372 struct drm_i915_gem_request *); 373 374 struct i915_gem_active { 375 struct drm_i915_gem_request __rcu *request; 376 struct list_head link; 377 i915_gem_retire_fn retire; 378 }; 379 380 void i915_gem_retire_noop(struct i915_gem_active *, 381 struct drm_i915_gem_request *request); 382 383 /** 384 * init_request_active - prepares the activity tracker for use 385 * @active - the active tracker 386 * @func - a callback when then the tracker is retired (becomes idle), 387 * can be NULL 388 * 389 * init_request_active() prepares the embedded @active struct for use as 390 * an activity tracker, that is for tracking the last known active request 391 * associated with it. When the last request becomes idle, when it is retired 392 * after completion, the optional callback @func is invoked. 393 */ 394 static inline void 395 init_request_active(struct i915_gem_active *active, 396 i915_gem_retire_fn retire) 397 { 398 INIT_LIST_HEAD(&active->link); 399 active->retire = retire ?: i915_gem_retire_noop; 400 } 401 402 /** 403 * i915_gem_active_set - updates the tracker to watch the current request 404 * @active - the active tracker 405 * @request - the request to watch 406 * 407 * i915_gem_active_set() watches the given @request for completion. Whilst 408 * that @request is busy, the @active reports busy. When that @request is 409 * retired, the @active tracker is updated to report idle. 410 */ 411 static inline void 412 i915_gem_active_set(struct i915_gem_active *active, 413 struct drm_i915_gem_request *request) 414 { 415 list_move(&active->link, &request->active_list); 416 rcu_assign_pointer(active->request, request); 417 } 418 419 /** 420 * i915_gem_active_set_retire_fn - updates the retirement callback 421 * @active - the active tracker 422 * @fn - the routine called when the request is retired 423 * @mutex - struct_mutex used to guard retirements 424 * 425 * i915_gem_active_set_retire_fn() updates the function pointer that 426 * is called when the final request associated with the @active tracker 427 * is retired. 428 */ 429 static inline void 430 i915_gem_active_set_retire_fn(struct i915_gem_active *active, 431 i915_gem_retire_fn fn, 432 struct lock *mutex) 433 { 434 lockdep_assert_held(mutex); 435 active->retire = fn ?: i915_gem_retire_noop; 436 } 437 438 static inline struct drm_i915_gem_request * 439 __i915_gem_active_peek(const struct i915_gem_active *active) 440 { 441 /* Inside the error capture (running with the driver in an unknown 442 * state), we want to bend the rules slightly (a lot). 443 * 444 * Work is in progress to make it safer, in the meantime this keeps 445 * the known issue from spamming the logs. 446 */ 447 return rcu_dereference_protected(active->request, 1); 448 } 449 450 /** 451 * i915_gem_active_raw - return the active request 452 * @active - the active tracker 453 * 454 * i915_gem_active_raw() returns the current request being tracked, or NULL. 455 * It does not obtain a reference on the request for the caller, so the caller 456 * must hold struct_mutex. 457 */ 458 static inline struct drm_i915_gem_request * 459 i915_gem_active_raw(const struct i915_gem_active *active, struct lock *mutex) 460 { 461 return rcu_dereference_protected(active->request, 462 lockdep_is_held(mutex)); 463 } 464 465 /** 466 * i915_gem_active_peek - report the active request being monitored 467 * @active - the active tracker 468 * 469 * i915_gem_active_peek() returns the current request being tracked if 470 * still active, or NULL. It does not obtain a reference on the request 471 * for the caller, so the caller must hold struct_mutex. 472 */ 473 static inline struct drm_i915_gem_request * 474 i915_gem_active_peek(const struct i915_gem_active *active, struct lock *mutex) 475 { 476 struct drm_i915_gem_request *request; 477 478 request = i915_gem_active_raw(active, mutex); 479 if (!request || i915_gem_request_completed(request)) 480 return NULL; 481 482 return request; 483 } 484 485 /** 486 * i915_gem_active_get - return a reference to the active request 487 * @active - the active tracker 488 * 489 * i915_gem_active_get() returns a reference to the active request, or NULL 490 * if the active tracker is idle. The caller must hold struct_mutex. 491 */ 492 static inline struct drm_i915_gem_request * 493 i915_gem_active_get(const struct i915_gem_active *active, struct lock *mutex) 494 { 495 return i915_gem_request_get(i915_gem_active_peek(active, mutex)); 496 } 497 498 /** 499 * __i915_gem_active_get_rcu - return a reference to the active request 500 * @active - the active tracker 501 * 502 * __i915_gem_active_get() returns a reference to the active request, or NULL 503 * if the active tracker is idle. The caller must hold the RCU read lock, but 504 * the returned pointer is safe to use outside of RCU. 505 */ 506 static inline struct drm_i915_gem_request * 507 __i915_gem_active_get_rcu(const struct i915_gem_active *active) 508 { 509 /* Performing a lockless retrieval of the active request is super 510 * tricky. SLAB_TYPESAFE_BY_RCU merely guarantees that the backing 511 * slab of request objects will not be freed whilst we hold the 512 * RCU read lock. It does not guarantee that the request itself 513 * will not be freed and then *reused*. Viz, 514 * 515 * Thread A Thread B 516 * 517 * req = active.request 518 * retire(req) -> free(req); 519 * (req is now first on the slab freelist) 520 * active.request = NULL 521 * 522 * req = new submission on a new object 523 * ref(req) 524 * 525 * To prevent the request from being reused whilst the caller 526 * uses it, we take a reference like normal. Whilst acquiring 527 * the reference we check that it is not in a destroyed state 528 * (refcnt == 0). That prevents the request being reallocated 529 * whilst the caller holds on to it. To check that the request 530 * was not reallocated as we acquired the reference we have to 531 * check that our request remains the active request across 532 * the lookup, in the same manner as a seqlock. The visibility 533 * of the pointer versus the reference counting is controlled 534 * by using RCU barriers (rcu_dereference and rcu_assign_pointer). 535 * 536 * In the middle of all that, we inspect whether the request is 537 * complete. Retiring is lazy so the request may be completed long 538 * before the active tracker is updated. Querying whether the 539 * request is complete is far cheaper (as it involves no locked 540 * instructions setting cachelines to exclusive) than acquiring 541 * the reference, so we do it first. The RCU read lock ensures the 542 * pointer dereference is valid, but does not ensure that the 543 * seqno nor HWS is the right one! However, if the request was 544 * reallocated, that means the active tracker's request was complete. 545 * If the new request is also complete, then both are and we can 546 * just report the active tracker is idle. If the new request is 547 * incomplete, then we acquire a reference on it and check that 548 * it remained the active request. 549 * 550 * It is then imperative that we do not zero the request on 551 * reallocation, so that we can chase the dangling pointers! 552 * See i915_gem_request_alloc(). 553 */ 554 do { 555 struct drm_i915_gem_request *request; 556 557 request = rcu_dereference(active->request); 558 if (!request || i915_gem_request_completed(request)) 559 return NULL; 560 561 /* An especially silly compiler could decide to recompute the 562 * result of i915_gem_request_completed, more specifically 563 * re-emit the load for request->fence.seqno. A race would catch 564 * a later seqno value, which could flip the result from true to 565 * false. Which means part of the instructions below might not 566 * be executed, while later on instructions are executed. Due to 567 * barriers within the refcounting the inconsistency can't reach 568 * past the call to i915_gem_request_get_rcu, but not executing 569 * that while still executing i915_gem_request_put() creates 570 * havoc enough. Prevent this with a compiler barrier. 571 */ 572 barrier(); 573 574 request = i915_gem_request_get_rcu(request); 575 576 /* What stops the following rcu_access_pointer() from occurring 577 * before the above i915_gem_request_get_rcu()? If we were 578 * to read the value before pausing to get the reference to 579 * the request, we may not notice a change in the active 580 * tracker. 581 * 582 * The rcu_access_pointer() is a mere compiler barrier, which 583 * means both the CPU and compiler are free to perform the 584 * memory read without constraint. The compiler only has to 585 * ensure that any operations after the rcu_access_pointer() 586 * occur afterwards in program order. This means the read may 587 * be performed earlier by an out-of-order CPU, or adventurous 588 * compiler. 589 * 590 * The atomic operation at the heart of 591 * i915_gem_request_get_rcu(), see dma_fence_get_rcu(), is 592 * atomic_inc_not_zero() which is only a full memory barrier 593 * when successful. That is, if i915_gem_request_get_rcu() 594 * returns the request (and so with the reference counted 595 * incremented) then the following read for rcu_access_pointer() 596 * must occur after the atomic operation and so confirm 597 * that this request is the one currently being tracked. 598 * 599 * The corresponding write barrier is part of 600 * rcu_assign_pointer(). 601 */ 602 if (!request || request == rcu_access_pointer(active->request)) 603 return rcu_pointer_handoff(request); 604 605 i915_gem_request_put(request); 606 } while (1); 607 } 608 609 /** 610 * i915_gem_active_get_unlocked - return a reference to the active request 611 * @active - the active tracker 612 * 613 * i915_gem_active_get_unlocked() returns a reference to the active request, 614 * or NULL if the active tracker is idle. The reference is obtained under RCU, 615 * so no locking is required by the caller. 616 * 617 * The reference should be freed with i915_gem_request_put(). 618 */ 619 static inline struct drm_i915_gem_request * 620 i915_gem_active_get_unlocked(const struct i915_gem_active *active) 621 { 622 struct drm_i915_gem_request *request; 623 624 rcu_read_lock(); 625 request = __i915_gem_active_get_rcu(active); 626 rcu_read_unlock(); 627 628 return request; 629 } 630 631 /** 632 * i915_gem_active_isset - report whether the active tracker is assigned 633 * @active - the active tracker 634 * 635 * i915_gem_active_isset() returns true if the active tracker is currently 636 * assigned to a request. Due to the lazy retiring, that request may be idle 637 * and this may report stale information. 638 */ 639 static inline bool 640 i915_gem_active_isset(const struct i915_gem_active *active) 641 { 642 return rcu_access_pointer(active->request); 643 } 644 645 /** 646 * i915_gem_active_wait - waits until the request is completed 647 * @active - the active request on which to wait 648 * @flags - how to wait 649 * @timeout - how long to wait at most 650 * @rps - userspace client to charge for a waitboost 651 * 652 * i915_gem_active_wait() waits until the request is completed before 653 * returning, without requiring any locks to be held. Note that it does not 654 * retire any requests before returning. 655 * 656 * This function relies on RCU in order to acquire the reference to the active 657 * request without holding any locks. See __i915_gem_active_get_rcu() for the 658 * glory details on how that is managed. Once the reference is acquired, we 659 * can then wait upon the request, and afterwards release our reference, 660 * free of any locking. 661 * 662 * This function wraps i915_wait_request(), see it for the full details on 663 * the arguments. 664 * 665 * Returns 0 if successful, or a negative error code. 666 */ 667 static inline int 668 i915_gem_active_wait(const struct i915_gem_active *active, unsigned int flags) 669 { 670 struct drm_i915_gem_request *request; 671 long ret = 0; 672 673 request = i915_gem_active_get_unlocked(active); 674 if (request) { 675 ret = i915_wait_request(request, flags, MAX_SCHEDULE_TIMEOUT); 676 i915_gem_request_put(request); 677 } 678 679 return ret < 0 ? ret : 0; 680 } 681 682 /** 683 * i915_gem_active_retire - waits until the request is retired 684 * @active - the active request on which to wait 685 * 686 * i915_gem_active_retire() waits until the request is completed, 687 * and then ensures that at least the retirement handler for this 688 * @active tracker is called before returning. If the @active 689 * tracker is idle, the function returns immediately. 690 */ 691 static inline int __must_check 692 i915_gem_active_retire(struct i915_gem_active *active, 693 struct lock *mutex) 694 { 695 struct drm_i915_gem_request *request; 696 long ret; 697 698 request = i915_gem_active_raw(active, mutex); 699 if (!request) 700 return 0; 701 702 ret = i915_wait_request(request, 703 I915_WAIT_INTERRUPTIBLE | I915_WAIT_LOCKED, 704 MAX_SCHEDULE_TIMEOUT); 705 if (ret < 0) 706 return ret; 707 708 list_del_init(&active->link); 709 RCU_INIT_POINTER(active->request, NULL); 710 711 active->retire(active, request); 712 713 return 0; 714 } 715 716 #define for_each_active(mask, idx) \ 717 for (; mask ? idx = ffs(mask) - 1, 1 : 0; mask &= ~BIT(idx)) 718 719 #endif /* I915_GEM_REQUEST_H */ 720