1 /*
2 * Copyright (c) 2004 Topspin Communications. All rights reserved.
3 * Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
4 *
5 * This software is available to you under a choice of one of two
6 * licenses. You may choose to be licensed under the terms of the GNU
7 * General Public License (GPL) Version 2, available from the file
8 * COPYING in the main directory of this source tree, or the
9 * OpenIB.org BSD license below:
10 *
11 * Redistribution and use in source and binary forms, with or
12 * without modification, are permitted provided that the following
13 * conditions are met:
14 *
15 * - Redistributions of source code must retain the above
16 * copyright notice, this list of conditions and the following
17 * disclaimer.
18 *
19 * - Redistributions in binary form must reproduce the above
20 * copyright notice, this list of conditions and the following
21 * disclaimer in the documentation and/or other materials
22 * provided with the distribution.
23 *
24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
28 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
29 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
30 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
31 * SOFTWARE.
32 */
33
34 #include <linux/errno.h>
35 #include <linux/spinlock.h>
36 #include <linux/slab.h>
37 #include <linux/jhash.h>
38 #include <linux/kthread.h>
39
40 #include <rdma/ib_fmr_pool.h>
41
42 #include "core_priv.h"
43
44 #define PFX "fmr_pool: "
45
46 enum {
47 IB_FMR_MAX_REMAPS = 32,
48
49 IB_FMR_HASH_BITS = 8,
50 IB_FMR_HASH_SIZE = 1 << IB_FMR_HASH_BITS,
51 IB_FMR_HASH_MASK = IB_FMR_HASH_SIZE - 1
52 };
53
54 /*
55 * If an FMR is not in use, then the list member will point to either
56 * its pool's free_list (if the FMR can be mapped again; that is,
57 * remap_count < pool->max_remaps) or its pool's dirty_list (if the
58 * FMR needs to be unmapped before being remapped). In either of
59 * these cases it is a bug if the ref_count is not 0. In other words,
60 * if ref_count is > 0, then the list member must not be linked into
61 * either free_list or dirty_list.
62 *
63 * The cache_node member is used to link the FMR into a cache bucket
64 * (if caching is enabled). This is independent of the reference
65 * count of the FMR. When a valid FMR is released, its ref_count is
66 * decremented, and if ref_count reaches 0, the FMR is placed in
67 * either free_list or dirty_list as appropriate. However, it is not
68 * removed from the cache and may be "revived" if a call to
69 * ib_fmr_register_physical() occurs before the FMR is remapped. In
70 * this case we just increment the ref_count and remove the FMR from
71 * free_list/dirty_list.
72 *
73 * Before we remap an FMR from free_list, we remove it from the cache
74 * (to prevent another user from obtaining a stale FMR). When an FMR
75 * is released, we add it to the tail of the free list, so that our
76 * cache eviction policy is "least recently used."
77 *
78 * All manipulation of ref_count, list and cache_node is protected by
79 * pool_lock to maintain consistency.
80 */
81
82 struct ib_fmr_pool {
83 spinlock_t pool_lock;
84
85 int pool_size;
86 int max_pages;
87 int max_remaps;
88 int dirty_watermark;
89 int dirty_len;
90 struct list_head free_list;
91 struct list_head dirty_list;
92 struct hlist_head *cache_bucket;
93
94 void (*flush_function)(struct ib_fmr_pool *pool,
95 void * arg);
96 void *flush_arg;
97
98 struct task_struct *thread;
99
100 atomic_t req_ser;
101 atomic_t flush_ser;
102
103 wait_queue_head_t force_wait;
104 };
105
ib_fmr_hash(u64 first_page)106 static inline u32 ib_fmr_hash(u64 first_page)
107 {
108 return jhash_2words((u32) first_page, (u32) (first_page >> 32), 0) &
109 (IB_FMR_HASH_SIZE - 1);
110 }
111
112 /* Caller must hold pool_lock */
ib_fmr_cache_lookup(struct ib_fmr_pool * pool,u64 * page_list,int page_list_len,u64 io_virtual_address)113 static inline struct ib_pool_fmr *ib_fmr_cache_lookup(struct ib_fmr_pool *pool,
114 u64 *page_list,
115 int page_list_len,
116 u64 io_virtual_address)
117 {
118 struct hlist_head *bucket;
119 struct ib_pool_fmr *fmr;
120 struct hlist_node *pos;
121
122 if (!pool->cache_bucket)
123 return NULL;
124
125 bucket = pool->cache_bucket + ib_fmr_hash(*page_list);
126
127 hlist_for_each_entry(fmr, pos, bucket, cache_node)
128 if (io_virtual_address == fmr->io_virtual_address &&
129 page_list_len == fmr->page_list_len &&
130 !memcmp(page_list, fmr->page_list,
131 page_list_len * sizeof *page_list))
132 return fmr;
133
134 return NULL;
135 }
136
ib_fmr_batch_release(struct ib_fmr_pool * pool)137 static void ib_fmr_batch_release(struct ib_fmr_pool *pool)
138 {
139 int ret;
140 struct ib_pool_fmr *fmr;
141 LIST_HEAD(unmap_list);
142 LIST_HEAD(fmr_list);
143
144 spin_lock_irq(&pool->pool_lock);
145
146 list_for_each_entry(fmr, &pool->dirty_list, list) {
147 hlist_del_init(&fmr->cache_node);
148 fmr->remap_count = 0;
149 list_add_tail(&fmr->fmr->list, &fmr_list);
150
151 #ifdef DEBUG
152 if (fmr->ref_count !=0) {
153 printk(KERN_WARNING PFX "Unmapping FMR 0x%08x with ref count %d\n",
154 fmr, fmr->ref_count);
155 }
156 #endif
157 }
158
159 list_splice_init(&pool->dirty_list, &unmap_list);
160 pool->dirty_len = 0;
161
162 spin_unlock_irq(&pool->pool_lock);
163
164 if (list_empty(&unmap_list)) {
165 return;
166 }
167
168 ret = ib_unmap_fmr(&fmr_list);
169 if (ret)
170 printk(KERN_WARNING PFX "ib_unmap_fmr returned %d\n", ret);
171
172 spin_lock_irq(&pool->pool_lock);
173 list_splice(&unmap_list, &pool->free_list);
174 spin_unlock_irq(&pool->pool_lock);
175 }
176
ib_fmr_cleanup_thread(void * pool_ptr)177 static int ib_fmr_cleanup_thread(void *pool_ptr)
178 {
179 struct ib_fmr_pool *pool = pool_ptr;
180
181 do {
182 if (atomic_read(&pool->flush_ser) - atomic_read(&pool->req_ser) < 0) {
183 ib_fmr_batch_release(pool);
184
185 atomic_inc(&pool->flush_ser);
186 wake_up_interruptible(&pool->force_wait);
187
188 if (pool->flush_function)
189 pool->flush_function(pool, pool->flush_arg);
190 }
191
192 set_current_state(TASK_INTERRUPTIBLE);
193 if (atomic_read(&pool->flush_ser) - atomic_read(&pool->req_ser) >= 0 &&
194 !kthread_should_stop())
195 schedule();
196 __set_current_state(TASK_RUNNING);
197 } while (!kthread_should_stop());
198
199 return 0;
200 }
201
202 /**
203 * ib_create_fmr_pool - Create an FMR pool
204 * @pd:Protection domain for FMRs
205 * @params:FMR pool parameters
206 *
207 * Create a pool of FMRs. Return value is pointer to new pool or
208 * error code if creation failed.
209 */
ib_create_fmr_pool(struct ib_pd * pd,struct ib_fmr_pool_param * params)210 struct ib_fmr_pool *ib_create_fmr_pool(struct ib_pd *pd,
211 struct ib_fmr_pool_param *params)
212 {
213 struct ib_device *device;
214 struct ib_fmr_pool *pool;
215 struct ib_device_attr *attr;
216 int i;
217 int ret;
218 int max_remaps;
219
220 if (!params)
221 return ERR_PTR(-EINVAL);
222
223 device = pd->device;
224 if (!device->alloc_fmr || !device->dealloc_fmr ||
225 !device->map_phys_fmr || !device->unmap_fmr) {
226 printk(KERN_INFO PFX "Device %s does not support FMRs\n",
227 device->name);
228 return ERR_PTR(-ENOSYS);
229 }
230
231 attr = kmalloc(sizeof *attr, GFP_KERNEL);
232 if (!attr) {
233 printk(KERN_WARNING PFX "couldn't allocate device attr struct\n");
234 return ERR_PTR(-ENOMEM);
235 }
236
237 ret = ib_query_device(device, attr);
238 if (ret) {
239 printk(KERN_WARNING PFX "couldn't query device: %d\n", ret);
240 kfree(attr);
241 return ERR_PTR(ret);
242 }
243
244 if (!attr->max_map_per_fmr)
245 max_remaps = IB_FMR_MAX_REMAPS;
246 else
247 max_remaps = attr->max_map_per_fmr;
248
249 kfree(attr);
250
251 pool = kmalloc(sizeof *pool, GFP_KERNEL);
252 if (!pool) {
253 printk(KERN_WARNING PFX "couldn't allocate pool struct\n");
254 return ERR_PTR(-ENOMEM);
255 }
256
257 pool->cache_bucket = NULL;
258
259 pool->flush_function = params->flush_function;
260 pool->flush_arg = params->flush_arg;
261
262 INIT_LIST_HEAD(&pool->free_list);
263 INIT_LIST_HEAD(&pool->dirty_list);
264
265 if (params->cache) {
266 pool->cache_bucket =
267 kmalloc(IB_FMR_HASH_SIZE * sizeof *pool->cache_bucket,
268 GFP_KERNEL);
269 if (!pool->cache_bucket) {
270 printk(KERN_WARNING PFX "Failed to allocate cache in pool\n");
271 ret = -ENOMEM;
272 goto out_free_pool;
273 }
274
275 for (i = 0; i < IB_FMR_HASH_SIZE; ++i)
276 INIT_HLIST_HEAD(pool->cache_bucket + i);
277 }
278
279 pool->pool_size = 0;
280 pool->max_pages = params->max_pages_per_fmr;
281 pool->max_remaps = max_remaps;
282 pool->dirty_watermark = params->dirty_watermark;
283 pool->dirty_len = 0;
284 spin_lock_init(&pool->pool_lock);
285 atomic_set(&pool->req_ser, 0);
286 atomic_set(&pool->flush_ser, 0);
287 init_waitqueue_head(&pool->force_wait);
288
289 pool->thread = kthread_run(ib_fmr_cleanup_thread,
290 pool,
291 "ib_fmr(%s)",
292 device->name);
293 if (IS_ERR(pool->thread)) {
294 printk(KERN_WARNING PFX "couldn't start cleanup thread\n");
295 ret = PTR_ERR(pool->thread);
296 goto out_free_pool;
297 }
298
299 {
300 struct ib_pool_fmr *fmr;
301 struct ib_fmr_attr fmr_attr = {
302 .max_pages = params->max_pages_per_fmr,
303 .max_maps = pool->max_remaps,
304 .page_shift = params->page_shift
305 };
306 int bytes_per_fmr = sizeof *fmr;
307
308 if (pool->cache_bucket)
309 bytes_per_fmr += params->max_pages_per_fmr * sizeof (u64);
310
311 for (i = 0; i < params->pool_size; ++i) {
312 fmr = kmalloc(bytes_per_fmr, GFP_KERNEL);
313 if (!fmr) {
314 printk(KERN_WARNING PFX "failed to allocate fmr "
315 "struct for FMR %d\n", i);
316 goto out_fail;
317 }
318
319 fmr->pool = pool;
320 fmr->remap_count = 0;
321 fmr->ref_count = 0;
322 INIT_HLIST_NODE(&fmr->cache_node);
323
324 fmr->fmr = ib_alloc_fmr(pd, params->access, &fmr_attr);
325 if (IS_ERR(fmr->fmr)) {
326 printk(KERN_WARNING PFX "fmr_create failed "
327 "for FMR %d\n", i);
328 kfree(fmr);
329 goto out_fail;
330 }
331
332 list_add_tail(&fmr->list, &pool->free_list);
333 ++pool->pool_size;
334 }
335 }
336
337 return pool;
338
339 out_free_pool:
340 kfree(pool->cache_bucket);
341 kfree(pool);
342
343 return ERR_PTR(ret);
344
345 out_fail:
346 ib_destroy_fmr_pool(pool);
347
348 return ERR_PTR(-ENOMEM);
349 }
350 EXPORT_SYMBOL(ib_create_fmr_pool);
351
352 /**
353 * ib_destroy_fmr_pool - Free FMR pool
354 * @pool:FMR pool to free
355 *
356 * Destroy an FMR pool and free all associated resources.
357 */
ib_destroy_fmr_pool(struct ib_fmr_pool * pool)358 void ib_destroy_fmr_pool(struct ib_fmr_pool *pool)
359 {
360 struct ib_pool_fmr *fmr;
361 struct ib_pool_fmr *tmp;
362 LIST_HEAD(fmr_list);
363 int i;
364
365 kthread_stop(pool->thread);
366 ib_fmr_batch_release(pool);
367
368 i = 0;
369 list_for_each_entry_safe(fmr, tmp, &pool->free_list, list) {
370 if (fmr->remap_count) {
371 INIT_LIST_HEAD(&fmr_list);
372 list_add_tail(&fmr->fmr->list, &fmr_list);
373 ib_unmap_fmr(&fmr_list);
374 }
375 ib_dealloc_fmr(fmr->fmr);
376 list_del(&fmr->list);
377 kfree(fmr);
378 ++i;
379 }
380
381 if (i < pool->pool_size)
382 printk(KERN_WARNING PFX "pool still has %d regions registered\n",
383 pool->pool_size - i);
384
385 kfree(pool->cache_bucket);
386 kfree(pool);
387 }
388 EXPORT_SYMBOL(ib_destroy_fmr_pool);
389
390 /**
391 * ib_flush_fmr_pool - Invalidate all unmapped FMRs
392 * @pool:FMR pool to flush
393 *
394 * Ensure that all unmapped FMRs are fully invalidated.
395 */
ib_flush_fmr_pool(struct ib_fmr_pool * pool)396 int ib_flush_fmr_pool(struct ib_fmr_pool *pool)
397 {
398 int serial;
399 struct ib_pool_fmr *fmr, *next;
400
401 /*
402 * The free_list holds FMRs that may have been used
403 * but have not been remapped enough times to be dirty.
404 * Put them on the dirty list now so that the cleanup
405 * thread will reap them too.
406 */
407 spin_lock_irq(&pool->pool_lock);
408 list_for_each_entry_safe(fmr, next, &pool->free_list, list) {
409 if (fmr->remap_count > 0)
410 list_move(&fmr->list, &pool->dirty_list);
411 }
412 spin_unlock_irq(&pool->pool_lock);
413
414 serial = atomic_inc_return(&pool->req_ser);
415 wake_up_process(pool->thread);
416
417 if (wait_event_interruptible(pool->force_wait,
418 atomic_read(&pool->flush_ser) - serial >= 0))
419 return -EINTR;
420
421 return 0;
422 }
423 EXPORT_SYMBOL(ib_flush_fmr_pool);
424
425 /**
426 * ib_fmr_pool_map_phys -
427 * @pool:FMR pool to allocate FMR from
428 * @page_list:List of pages to map
429 * @list_len:Number of pages in @page_list
430 * @io_virtual_address:I/O virtual address for new FMR
431 *
432 * Map an FMR from an FMR pool.
433 */
ib_fmr_pool_map_phys(struct ib_fmr_pool * pool_handle,u64 * page_list,int list_len,u64 io_virtual_address)434 struct ib_pool_fmr *ib_fmr_pool_map_phys(struct ib_fmr_pool *pool_handle,
435 u64 *page_list,
436 int list_len,
437 u64 io_virtual_address)
438 {
439 struct ib_fmr_pool *pool = pool_handle;
440 struct ib_pool_fmr *fmr;
441 unsigned long flags;
442 int result;
443
444 if (list_len < 1 || list_len > pool->max_pages)
445 return ERR_PTR(-EINVAL);
446
447 spin_lock_irqsave(&pool->pool_lock, flags);
448 fmr = ib_fmr_cache_lookup(pool,
449 page_list,
450 list_len,
451 io_virtual_address);
452 if (fmr) {
453 /* found in cache */
454 ++fmr->ref_count;
455 if (fmr->ref_count == 1) {
456 list_del(&fmr->list);
457 }
458
459 spin_unlock_irqrestore(&pool->pool_lock, flags);
460
461 return fmr;
462 }
463
464 if (list_empty(&pool->free_list)) {
465 spin_unlock_irqrestore(&pool->pool_lock, flags);
466 return ERR_PTR(-EAGAIN);
467 }
468
469 fmr = list_entry(pool->free_list.next, struct ib_pool_fmr, list);
470 list_del(&fmr->list);
471 hlist_del_init(&fmr->cache_node);
472 spin_unlock_irqrestore(&pool->pool_lock, flags);
473
474 result = ib_map_phys_fmr(fmr->fmr, page_list, list_len,
475 io_virtual_address);
476
477 if (result) {
478 spin_lock_irqsave(&pool->pool_lock, flags);
479 list_add(&fmr->list, &pool->free_list);
480 spin_unlock_irqrestore(&pool->pool_lock, flags);
481
482 printk(KERN_WARNING PFX "fmr_map returns %d\n", result);
483
484 return ERR_PTR(result);
485 }
486
487 ++fmr->remap_count;
488 fmr->ref_count = 1;
489
490 if (pool->cache_bucket) {
491 fmr->io_virtual_address = io_virtual_address;
492 fmr->page_list_len = list_len;
493 memcpy(fmr->page_list, page_list, list_len * sizeof(*page_list));
494
495 spin_lock_irqsave(&pool->pool_lock, flags);
496 hlist_add_head(&fmr->cache_node,
497 pool->cache_bucket + ib_fmr_hash(fmr->page_list[0]));
498 spin_unlock_irqrestore(&pool->pool_lock, flags);
499 }
500
501 return fmr;
502 }
503 EXPORT_SYMBOL(ib_fmr_pool_map_phys);
504
505 /**
506 * ib_fmr_pool_unmap - Unmap FMR
507 * @fmr:FMR to unmap
508 *
509 * Unmap an FMR. The FMR mapping may remain valid until the FMR is
510 * reused (or until ib_flush_fmr_pool() is called).
511 */
ib_fmr_pool_unmap(struct ib_pool_fmr * fmr)512 int ib_fmr_pool_unmap(struct ib_pool_fmr *fmr)
513 {
514 struct ib_fmr_pool *pool;
515 unsigned long flags;
516
517 pool = fmr->pool;
518
519 spin_lock_irqsave(&pool->pool_lock, flags);
520
521 --fmr->ref_count;
522 if (!fmr->ref_count) {
523 if (fmr->remap_count < pool->max_remaps) {
524 list_add_tail(&fmr->list, &pool->free_list);
525 } else {
526 list_add_tail(&fmr->list, &pool->dirty_list);
527 if (++pool->dirty_len >= pool->dirty_watermark) {
528 atomic_inc(&pool->req_ser);
529 wake_up_process(pool->thread);
530 }
531 }
532 }
533
534 #ifdef DEBUG
535 if (fmr->ref_count < 0)
536 printk(KERN_WARNING PFX "FMR %p has ref count %d < 0\n",
537 fmr, fmr->ref_count);
538 #endif
539
540 spin_unlock_irqrestore(&pool->pool_lock, flags);
541
542 return 0;
543 }
544 EXPORT_SYMBOL(ib_fmr_pool_unmap);
545