1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause OR GPL-2.0
3 *
4 * Copyright (c) 2004 Topspin Communications. All rights reserved.
5 * Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
6 *
7 * This software is available to you under a choice of one of two
8 * licenses. You may choose to be licensed under the terms of the GNU
9 * General Public License (GPL) Version 2, available from the file
10 * COPYING in the main directory of this source tree, or the
11 * OpenIB.org BSD license below:
12 *
13 * Redistribution and use in source and binary forms, with or
14 * without modification, are permitted provided that the following
15 * conditions are met:
16 *
17 * - Redistributions of source code must retain the above
18 * copyright notice, this list of conditions and the following
19 * disclaimer.
20 *
21 * - Redistributions in binary form must reproduce the above
22 * copyright notice, this list of conditions and the following
23 * disclaimer in the documentation and/or other materials
24 * provided with the distribution.
25 *
26 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
27 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
28 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
29 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
30 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
31 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
32 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
33 * SOFTWARE.
34 */
35
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
38
39 #include <linux/errno.h>
40 #include <linux/spinlock.h>
41 #include <linux/slab.h>
42 #include <linux/jhash.h>
43 #include <linux/kthread.h>
44 #include <linux/wait.h>
45
46 #include <rdma/ib_fmr_pool.h>
47
48 #include "core_priv.h"
49
50 #define PFX "fmr_pool: "
51
52 enum {
53 IB_FMR_MAX_REMAPS = 32,
54
55 IB_FMR_HASH_BITS = 8,
56 IB_FMR_HASH_SIZE = 1 << IB_FMR_HASH_BITS,
57 IB_FMR_HASH_MASK = IB_FMR_HASH_SIZE - 1
58 };
59
60 /*
61 * If an FMR is not in use, then the list member will point to either
62 * its pool's free_list (if the FMR can be mapped again; that is,
63 * remap_count < pool->max_remaps) or its pool's dirty_list (if the
64 * FMR needs to be unmapped before being remapped). In either of
65 * these cases it is a bug if the ref_count is not 0. In other words,
66 * if ref_count is > 0, then the list member must not be linked into
67 * either free_list or dirty_list.
68 *
69 * The cache_node member is used to link the FMR into a cache bucket
70 * (if caching is enabled). This is independent of the reference
71 * count of the FMR. When a valid FMR is released, its ref_count is
72 * decremented, and if ref_count reaches 0, the FMR is placed in
73 * either free_list or dirty_list as appropriate. However, it is not
74 * removed from the cache and may be "revived" if a call to
75 * ib_fmr_register_physical() occurs before the FMR is remapped. In
76 * this case we just increment the ref_count and remove the FMR from
77 * free_list/dirty_list.
78 *
79 * Before we remap an FMR from free_list, we remove it from the cache
80 * (to prevent another user from obtaining a stale FMR). When an FMR
81 * is released, we add it to the tail of the free list, so that our
82 * cache eviction policy is "least recently used."
83 *
84 * All manipulation of ref_count, list and cache_node is protected by
85 * pool_lock to maintain consistency.
86 */
87
88 struct ib_fmr_pool {
89 spinlock_t pool_lock;
90
91 int pool_size;
92 int max_pages;
93 int max_remaps;
94 int dirty_watermark;
95 int dirty_len;
96 struct list_head free_list;
97 struct list_head dirty_list;
98 struct hlist_head *cache_bucket;
99
100 void (*flush_function)(struct ib_fmr_pool *pool,
101 void * arg);
102 void *flush_arg;
103
104 struct task_struct *thread;
105
106 atomic_t req_ser;
107 atomic_t flush_ser;
108
109 wait_queue_head_t force_wait;
110 };
111
112 static inline u32 ib_fmr_hash(u64 first_page)
113 {
114 return jhash_2words((u32) first_page, (u32) (first_page >> 32), 0) &
115 (IB_FMR_HASH_SIZE - 1);
116 }
117
118 /* Caller must hold pool_lock */
119 static inline struct ib_pool_fmr *ib_fmr_cache_lookup(struct ib_fmr_pool *pool,
120 u64 *page_list,
121 int page_list_len,
122 u64 io_virtual_address)
123 {
124 struct hlist_head *bucket;
125 struct ib_pool_fmr *fmr;
126
127 if (!pool->cache_bucket)
128 return NULL;
129
130 bucket = pool->cache_bucket + ib_fmr_hash(*page_list);
131
132 hlist_for_each_entry(fmr, bucket, cache_node)
133 if (io_virtual_address == fmr->io_virtual_address &&
134 page_list_len == fmr->page_list_len &&
135 !memcmp(page_list, fmr->page_list,
136 page_list_len * sizeof *page_list))
137 return fmr;
138
139 return NULL;
140 }
141
142 static void ib_fmr_batch_release(struct ib_fmr_pool *pool)
143 {
144 int ret;
145 struct ib_pool_fmr *fmr;
146 LIST_HEAD(unmap_list);
147 LIST_HEAD(fmr_list);
148
149 spin_lock_irq(&pool->pool_lock);
150
151 list_for_each_entry(fmr, &pool->dirty_list, list) {
152 hlist_del_init(&fmr->cache_node);
153 fmr->remap_count = 0;
154 list_add_tail(&fmr->fmr->list, &fmr_list);
155
156 #ifdef DEBUG
157 if (fmr->ref_count !=0) {
158 pr_warn(PFX "Unmapping FMR %p with ref count %d\n",
159 fmr, fmr->ref_count);
160 }
161 #endif
162 }
163
164 list_splice_init(&pool->dirty_list, &unmap_list);
165 pool->dirty_len = 0;
166
167 spin_unlock_irq(&pool->pool_lock);
168
169 if (list_empty(&unmap_list)) {
170 return;
171 }
172
173 ret = ib_unmap_fmr(&fmr_list);
174 if (ret)
175 pr_warn(PFX "ib_unmap_fmr returned %d\n", ret);
176
177 spin_lock_irq(&pool->pool_lock);
178 list_splice(&unmap_list, &pool->free_list);
179 spin_unlock_irq(&pool->pool_lock);
180 }
181
182 static int ib_fmr_cleanup_thread(void *pool_ptr)
183 {
184 struct ib_fmr_pool *pool = pool_ptr;
185
186 do {
187 if (atomic_read(&pool->flush_ser) - atomic_read(&pool->req_ser) < 0) {
188 ib_fmr_batch_release(pool);
189
190 atomic_inc(&pool->flush_ser);
191 wake_up_interruptible(&pool->force_wait);
192
193 if (pool->flush_function)
194 pool->flush_function(pool, pool->flush_arg);
195 }
196
197 set_current_state(TASK_INTERRUPTIBLE);
198 if (atomic_read(&pool->flush_ser) - atomic_read(&pool->req_ser) >= 0 &&
199 !kthread_should_stop())
200 schedule();
201 __set_current_state(TASK_RUNNING);
202 } while (!kthread_should_stop());
203
204 return 0;
205 }
206
207 /**
208 * ib_create_fmr_pool - Create an FMR pool
209 * @pd:Protection domain for FMRs
210 * @params:FMR pool parameters
211 *
212 * Create a pool of FMRs. Return value is pointer to new pool or
213 * error code if creation failed.
214 */
215 struct ib_fmr_pool *ib_create_fmr_pool(struct ib_pd *pd,
216 struct ib_fmr_pool_param *params)
217 {
218 struct ib_device *device;
219 struct ib_fmr_pool *pool;
220 int i;
221 int ret;
222 int max_remaps;
223
224 if (!params)
225 return ERR_PTR(-EINVAL);
226
227 device = pd->device;
228 if (!device->alloc_fmr || !device->dealloc_fmr ||
229 !device->map_phys_fmr || !device->unmap_fmr) {
230 pr_info(PFX "Device %s does not support FMRs\n", device->name);
231 return ERR_PTR(-ENOSYS);
232 }
233
234 if (!device->attrs.max_map_per_fmr)
235 max_remaps = IB_FMR_MAX_REMAPS;
236 else
237 max_remaps = device->attrs.max_map_per_fmr;
238
239 pool = kmalloc(sizeof *pool, GFP_KERNEL);
240 if (!pool)
241 return ERR_PTR(-ENOMEM);
242
243 pool->cache_bucket = NULL;
244 pool->flush_function = params->flush_function;
245 pool->flush_arg = params->flush_arg;
246
247 INIT_LIST_HEAD(&pool->free_list);
248 INIT_LIST_HEAD(&pool->dirty_list);
249
250 if (params->cache) {
251 pool->cache_bucket =
252 kmalloc(IB_FMR_HASH_SIZE * sizeof *pool->cache_bucket,
253 GFP_KERNEL);
254 if (!pool->cache_bucket) {
255 pr_warn(PFX "Failed to allocate cache in pool\n");
256 ret = -ENOMEM;
257 goto out_free_pool;
258 }
259
260 for (i = 0; i < IB_FMR_HASH_SIZE; ++i)
261 INIT_HLIST_HEAD(pool->cache_bucket + i);
262 }
263
264 pool->pool_size = 0;
265 pool->max_pages = params->max_pages_per_fmr;
266 pool->max_remaps = max_remaps;
267 pool->dirty_watermark = params->dirty_watermark;
268 pool->dirty_len = 0;
269 spin_lock_init(&pool->pool_lock);
270 atomic_set(&pool->req_ser, 0);
271 atomic_set(&pool->flush_ser, 0);
272 init_waitqueue_head(&pool->force_wait);
273
274 pool->thread = kthread_run(ib_fmr_cleanup_thread,
275 pool,
276 "ib_fmr(%s)",
277 device->name);
278 if (IS_ERR(pool->thread)) {
279 pr_warn(PFX "couldn't start cleanup thread\n");
280 ret = PTR_ERR(pool->thread);
281 goto out_free_pool;
282 }
283
284 {
285 struct ib_pool_fmr *fmr;
286 struct ib_fmr_attr fmr_attr = {
287 .max_pages = params->max_pages_per_fmr,
288 .max_maps = pool->max_remaps,
289 .page_shift = params->page_shift
290 };
291 int bytes_per_fmr = sizeof *fmr;
292
293 if (pool->cache_bucket)
294 bytes_per_fmr += params->max_pages_per_fmr * sizeof (u64);
295
296 for (i = 0; i < params->pool_size; ++i) {
297 fmr = kmalloc(bytes_per_fmr, GFP_KERNEL);
298 if (!fmr)
299 goto out_fail;
300
301 fmr->pool = pool;
302 fmr->remap_count = 0;
303 fmr->ref_count = 0;
304 INIT_HLIST_NODE(&fmr->cache_node);
305
306 fmr->fmr = ib_alloc_fmr(pd, params->access, &fmr_attr);
307 if (IS_ERR(fmr->fmr)) {
308 pr_warn(PFX "fmr_create failed for FMR %d\n",
309 i);
310 kfree(fmr);
311 goto out_fail;
312 }
313
314 list_add_tail(&fmr->list, &pool->free_list);
315 ++pool->pool_size;
316 }
317 }
318
319 return pool;
320
321 out_free_pool:
322 kfree(pool->cache_bucket);
323 kfree(pool);
324
325 return ERR_PTR(ret);
326
327 out_fail:
328 ib_destroy_fmr_pool(pool);
329
330 return ERR_PTR(-ENOMEM);
331 }
332 EXPORT_SYMBOL(ib_create_fmr_pool);
333
334 /**
335 * ib_destroy_fmr_pool - Free FMR pool
336 * @pool:FMR pool to free
337 *
338 * Destroy an FMR pool and free all associated resources.
339 */
340 void ib_destroy_fmr_pool(struct ib_fmr_pool *pool)
341 {
342 struct ib_pool_fmr *fmr;
343 struct ib_pool_fmr *tmp;
344 LIST_HEAD(fmr_list);
345 int i;
346
347 kthread_stop(pool->thread);
348 ib_fmr_batch_release(pool);
349
350 i = 0;
351 list_for_each_entry_safe(fmr, tmp, &pool->free_list, list) {
352 if (fmr->remap_count) {
353 INIT_LIST_HEAD(&fmr_list);
354 list_add_tail(&fmr->fmr->list, &fmr_list);
355 ib_unmap_fmr(&fmr_list);
356 }
357 ib_dealloc_fmr(fmr->fmr);
358 list_del(&fmr->list);
359 kfree(fmr);
360 ++i;
361 }
362
363 if (i < pool->pool_size)
364 pr_warn(PFX "pool still has %d regions registered\n",
365 pool->pool_size - i);
366
367 kfree(pool->cache_bucket);
368 kfree(pool);
369 }
370 EXPORT_SYMBOL(ib_destroy_fmr_pool);
371
372 /**
373 * ib_flush_fmr_pool - Invalidate all unmapped FMRs
374 * @pool:FMR pool to flush
375 *
376 * Ensure that all unmapped FMRs are fully invalidated.
377 */
378 int ib_flush_fmr_pool(struct ib_fmr_pool *pool)
379 {
380 int serial;
381 struct ib_pool_fmr *fmr, *next;
382
383 /*
384 * The free_list holds FMRs that may have been used
385 * but have not been remapped enough times to be dirty.
386 * Put them on the dirty list now so that the cleanup
387 * thread will reap them too.
388 */
389 spin_lock_irq(&pool->pool_lock);
390 list_for_each_entry_safe(fmr, next, &pool->free_list, list) {
391 if (fmr->remap_count > 0)
392 list_move(&fmr->list, &pool->dirty_list);
393 }
394 spin_unlock_irq(&pool->pool_lock);
395
396 serial = atomic_inc_return(&pool->req_ser);
397 wake_up_process(pool->thread);
398
399 if (wait_event_interruptible(pool->force_wait,
400 atomic_read(&pool->flush_ser) - serial >= 0))
401 return -EINTR;
402
403 return 0;
404 }
405 EXPORT_SYMBOL(ib_flush_fmr_pool);
406
407 /**
408 * ib_fmr_pool_map_phys -
409 * @pool:FMR pool to allocate FMR from
410 * @page_list:List of pages to map
411 * @list_len:Number of pages in @page_list
412 * @io_virtual_address:I/O virtual address for new FMR
413 *
414 * Map an FMR from an FMR pool.
415 */
416 struct ib_pool_fmr *ib_fmr_pool_map_phys(struct ib_fmr_pool *pool_handle,
417 u64 *page_list,
418 int list_len,
419 u64 io_virtual_address)
420 {
421 struct ib_fmr_pool *pool = pool_handle;
422 struct ib_pool_fmr *fmr;
423 unsigned long flags;
424 int result;
425
426 if (list_len < 1 || list_len > pool->max_pages)
427 return ERR_PTR(-EINVAL);
428
429 spin_lock_irqsave(&pool->pool_lock, flags);
430 fmr = ib_fmr_cache_lookup(pool,
431 page_list,
432 list_len,
433 io_virtual_address);
434 if (fmr) {
435 /* found in cache */
436 ++fmr->ref_count;
437 if (fmr->ref_count == 1) {
438 list_del(&fmr->list);
439 }
440
441 spin_unlock_irqrestore(&pool->pool_lock, flags);
442
443 return fmr;
444 }
445
446 if (list_empty(&pool->free_list)) {
447 spin_unlock_irqrestore(&pool->pool_lock, flags);
448 return ERR_PTR(-EAGAIN);
449 }
450
451 fmr = list_entry(pool->free_list.next, struct ib_pool_fmr, list);
452 list_del(&fmr->list);
453 hlist_del_init(&fmr->cache_node);
454 spin_unlock_irqrestore(&pool->pool_lock, flags);
455
456 result = ib_map_phys_fmr(fmr->fmr, page_list, list_len,
457 io_virtual_address);
458
459 if (result) {
460 spin_lock_irqsave(&pool->pool_lock, flags);
461 list_add(&fmr->list, &pool->free_list);
462 spin_unlock_irqrestore(&pool->pool_lock, flags);
463
464 pr_warn(PFX "fmr_map returns %d\n", result);
465
466 return ERR_PTR(result);
467 }
468
469 ++fmr->remap_count;
470 fmr->ref_count = 1;
471
472 if (pool->cache_bucket) {
473 fmr->io_virtual_address = io_virtual_address;
474 fmr->page_list_len = list_len;
475 memcpy(fmr->page_list, page_list, list_len * sizeof(*page_list));
476
477 spin_lock_irqsave(&pool->pool_lock, flags);
478 hlist_add_head(&fmr->cache_node,
479 pool->cache_bucket + ib_fmr_hash(fmr->page_list[0]));
480 spin_unlock_irqrestore(&pool->pool_lock, flags);
481 }
482
483 return fmr;
484 }
485 EXPORT_SYMBOL(ib_fmr_pool_map_phys);
486
487 /**
488 * ib_fmr_pool_unmap - Unmap FMR
489 * @fmr:FMR to unmap
490 *
491 * Unmap an FMR. The FMR mapping may remain valid until the FMR is
492 * reused (or until ib_flush_fmr_pool() is called).
493 */
494 int ib_fmr_pool_unmap(struct ib_pool_fmr *fmr)
495 {
496 struct ib_fmr_pool *pool;
497 unsigned long flags;
498
499 pool = fmr->pool;
500
501 spin_lock_irqsave(&pool->pool_lock, flags);
502
503 --fmr->ref_count;
504 if (!fmr->ref_count) {
505 if (fmr->remap_count < pool->max_remaps) {
506 list_add_tail(&fmr->list, &pool->free_list);
507 } else {
508 list_add_tail(&fmr->list, &pool->dirty_list);
509 if (++pool->dirty_len >= pool->dirty_watermark) {
510 atomic_inc(&pool->req_ser);
511 wake_up_process(pool->thread);
512 }
513 }
514 }
515
516 #ifdef DEBUG
517 if (fmr->ref_count < 0)
518 pr_warn(PFX "FMR %p has ref count %d < 0\n",
519 fmr, fmr->ref_count);
520 #endif
521
522 spin_unlock_irqrestore(&pool->pool_lock, flags);
523
524 return 0;
525 }
526 EXPORT_SYMBOL(ib_fmr_pool_unmap);
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