Merge git://git.infradead.org/iommu-2.6
[linux-2.6] / drivers / infiniband / core / fmr_pool.c
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
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 */
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
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
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  */
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  */
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  */
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  */
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  */
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);