RDS: remove __init and __exit annotation
[linux-2.6.git] / net / rds / ib_rdma.c
1 /*
2  * Copyright (c) 2006 Oracle.  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 <linux/kernel.h>
34 #include <linux/slab.h>
35 #include <linux/rculist.h>
36
37 #include "rds.h"
38 #include "ib.h"
39 #include "xlist.h"
40
41 static DEFINE_PER_CPU(unsigned long, clean_list_grace);
42 #define CLEAN_LIST_BUSY_BIT 0
43
44 /*
45  * This is stored as mr->r_trans_private.
46  */
47 struct rds_ib_mr {
48         struct rds_ib_device    *device;
49         struct rds_ib_mr_pool   *pool;
50         struct ib_fmr           *fmr;
51
52         struct xlist_head       xlist;
53
54         /* unmap_list is for freeing */
55         struct list_head        unmap_list;
56         unsigned int            remap_count;
57
58         struct scatterlist      *sg;
59         unsigned int            sg_len;
60         u64                     *dma;
61         int                     sg_dma_len;
62 };
63
64 /*
65  * Our own little FMR pool
66  */
67 struct rds_ib_mr_pool {
68         struct mutex            flush_lock;             /* serialize fmr invalidate */
69         struct delayed_work     flush_worker;           /* flush worker */
70
71         atomic_t                item_count;             /* total # of MRs */
72         atomic_t                dirty_count;            /* # dirty of MRs */
73
74         struct xlist_head       drop_list;              /* MRs that have reached their max_maps limit */
75         struct xlist_head       free_list;              /* unused MRs */
76         struct xlist_head       clean_list;             /* global unused & unamapped MRs */
77         wait_queue_head_t       flush_wait;
78
79         atomic_t                free_pinned;            /* memory pinned by free MRs */
80         unsigned long           max_items;
81         unsigned long           max_items_soft;
82         unsigned long           max_free_pinned;
83         struct ib_fmr_attr      fmr_attr;
84 };
85
86 static int rds_ib_flush_mr_pool(struct rds_ib_mr_pool *pool, int free_all, struct rds_ib_mr **);
87 static void rds_ib_teardown_mr(struct rds_ib_mr *ibmr);
88 static void rds_ib_mr_pool_flush_worker(struct work_struct *work);
89
90 static struct rds_ib_device *rds_ib_get_device(__be32 ipaddr)
91 {
92         struct rds_ib_device *rds_ibdev;
93         struct rds_ib_ipaddr *i_ipaddr;
94
95         list_for_each_entry(rds_ibdev, &rds_ib_devices, list) {
96                 rcu_read_lock();
97                 list_for_each_entry_rcu(i_ipaddr, &rds_ibdev->ipaddr_list, list) {
98                         if (i_ipaddr->ipaddr == ipaddr) {
99                                 atomic_inc(&rds_ibdev->refcount);
100                                 rcu_read_unlock();
101                                 return rds_ibdev;
102                         }
103                 }
104                 rcu_read_unlock();
105         }
106
107         return NULL;
108 }
109
110 static int rds_ib_add_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
111 {
112         struct rds_ib_ipaddr *i_ipaddr;
113
114         i_ipaddr = kmalloc(sizeof *i_ipaddr, GFP_KERNEL);
115         if (!i_ipaddr)
116                 return -ENOMEM;
117
118         i_ipaddr->ipaddr = ipaddr;
119
120         spin_lock_irq(&rds_ibdev->spinlock);
121         list_add_tail_rcu(&i_ipaddr->list, &rds_ibdev->ipaddr_list);
122         spin_unlock_irq(&rds_ibdev->spinlock);
123
124         return 0;
125 }
126
127 static void rds_ib_remove_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
128 {
129         struct rds_ib_ipaddr *i_ipaddr;
130         struct rds_ib_ipaddr *to_free = NULL;
131
132
133         spin_lock_irq(&rds_ibdev->spinlock);
134         list_for_each_entry_rcu(i_ipaddr, &rds_ibdev->ipaddr_list, list) {
135                 if (i_ipaddr->ipaddr == ipaddr) {
136                         list_del_rcu(&i_ipaddr->list);
137                         to_free = i_ipaddr;
138                         break;
139                 }
140         }
141         spin_unlock_irq(&rds_ibdev->spinlock);
142
143         if (to_free) {
144                 synchronize_rcu();
145                 kfree(to_free);
146         }
147 }
148
149 int rds_ib_update_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
150 {
151         struct rds_ib_device *rds_ibdev_old;
152
153         rds_ibdev_old = rds_ib_get_device(ipaddr);
154         if (rds_ibdev_old) {
155                 rds_ib_remove_ipaddr(rds_ibdev_old, ipaddr);
156                 rds_ib_dev_put(rds_ibdev_old);
157         }
158
159         return rds_ib_add_ipaddr(rds_ibdev, ipaddr);
160 }
161
162 void rds_ib_add_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *conn)
163 {
164         struct rds_ib_connection *ic = conn->c_transport_data;
165
166         /* conn was previously on the nodev_conns_list */
167         spin_lock_irq(&ib_nodev_conns_lock);
168         BUG_ON(list_empty(&ib_nodev_conns));
169         BUG_ON(list_empty(&ic->ib_node));
170         list_del(&ic->ib_node);
171
172         spin_lock_irq(&rds_ibdev->spinlock);
173         list_add_tail(&ic->ib_node, &rds_ibdev->conn_list);
174         spin_unlock_irq(&rds_ibdev->spinlock);
175         spin_unlock_irq(&ib_nodev_conns_lock);
176
177         ic->rds_ibdev = rds_ibdev;
178         atomic_inc(&rds_ibdev->refcount);
179 }
180
181 void rds_ib_remove_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *conn)
182 {
183         struct rds_ib_connection *ic = conn->c_transport_data;
184
185         /* place conn on nodev_conns_list */
186         spin_lock(&ib_nodev_conns_lock);
187
188         spin_lock_irq(&rds_ibdev->spinlock);
189         BUG_ON(list_empty(&ic->ib_node));
190         list_del(&ic->ib_node);
191         spin_unlock_irq(&rds_ibdev->spinlock);
192
193         list_add_tail(&ic->ib_node, &ib_nodev_conns);
194
195         spin_unlock(&ib_nodev_conns_lock);
196
197         ic->rds_ibdev = NULL;
198         rds_ib_dev_put(rds_ibdev);
199 }
200
201 void rds_ib_destroy_nodev_conns(void)
202 {
203         struct rds_ib_connection *ic, *_ic;
204         LIST_HEAD(tmp_list);
205
206         /* avoid calling conn_destroy with irqs off */
207         spin_lock_irq(&ib_nodev_conns_lock);
208         list_splice(&ib_nodev_conns, &tmp_list);
209         spin_unlock_irq(&ib_nodev_conns_lock);
210
211         list_for_each_entry_safe(ic, _ic, &tmp_list, ib_node)
212                 rds_conn_destroy(ic->conn);
213 }
214
215 struct rds_ib_mr_pool *rds_ib_create_mr_pool(struct rds_ib_device *rds_ibdev)
216 {
217         struct rds_ib_mr_pool *pool;
218
219         pool = kzalloc(sizeof(*pool), GFP_KERNEL);
220         if (!pool)
221                 return ERR_PTR(-ENOMEM);
222
223         INIT_XLIST_HEAD(&pool->free_list);
224         INIT_XLIST_HEAD(&pool->drop_list);
225         INIT_XLIST_HEAD(&pool->clean_list);
226         mutex_init(&pool->flush_lock);
227         init_waitqueue_head(&pool->flush_wait);
228         INIT_DELAYED_WORK(&pool->flush_worker, rds_ib_mr_pool_flush_worker);
229
230         pool->fmr_attr.max_pages = fmr_message_size;
231         pool->fmr_attr.max_maps = rds_ibdev->fmr_max_remaps;
232         pool->fmr_attr.page_shift = PAGE_SHIFT;
233         pool->max_free_pinned = rds_ibdev->max_fmrs * fmr_message_size / 4;
234
235         /* We never allow more than max_items MRs to be allocated.
236          * When we exceed more than max_items_soft, we start freeing
237          * items more aggressively.
238          * Make sure that max_items > max_items_soft > max_items / 2
239          */
240         pool->max_items_soft = rds_ibdev->max_fmrs * 3 / 4;
241         pool->max_items = rds_ibdev->max_fmrs;
242
243         return pool;
244 }
245
246 void rds_ib_get_mr_info(struct rds_ib_device *rds_ibdev, struct rds_info_rdma_connection *iinfo)
247 {
248         struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
249
250         iinfo->rdma_mr_max = pool->max_items;
251         iinfo->rdma_mr_size = pool->fmr_attr.max_pages;
252 }
253
254 void rds_ib_destroy_mr_pool(struct rds_ib_mr_pool *pool)
255 {
256         cancel_delayed_work_sync(&pool->flush_worker);
257         rds_ib_flush_mr_pool(pool, 1, NULL);
258         WARN_ON(atomic_read(&pool->item_count));
259         WARN_ON(atomic_read(&pool->free_pinned));
260         kfree(pool);
261 }
262
263 static void refill_local(struct rds_ib_mr_pool *pool, struct xlist_head *xl,
264                          struct rds_ib_mr **ibmr_ret)
265 {
266         struct xlist_head *ibmr_xl;
267         ibmr_xl = xlist_del_head_fast(xl);
268         *ibmr_ret = list_entry(ibmr_xl, struct rds_ib_mr, xlist);
269 }
270
271 static inline struct rds_ib_mr *rds_ib_reuse_fmr(struct rds_ib_mr_pool *pool)
272 {
273         struct rds_ib_mr *ibmr = NULL;
274         struct xlist_head *ret;
275         unsigned long *flag;
276
277         preempt_disable();
278         flag = &__get_cpu_var(clean_list_grace);
279         set_bit(CLEAN_LIST_BUSY_BIT, flag);
280         ret = xlist_del_head(&pool->clean_list);
281         if (ret)
282                 ibmr = list_entry(ret, struct rds_ib_mr, xlist);
283
284         clear_bit(CLEAN_LIST_BUSY_BIT, flag);
285         preempt_enable();
286         return ibmr;
287 }
288
289 static inline void wait_clean_list_grace(void)
290 {
291         int cpu;
292         unsigned long *flag;
293
294         for_each_online_cpu(cpu) {
295                 flag = &per_cpu(clean_list_grace, cpu);
296                 while (test_bit(CLEAN_LIST_BUSY_BIT, flag))
297                         cpu_relax();
298         }
299 }
300
301 static struct rds_ib_mr *rds_ib_alloc_fmr(struct rds_ib_device *rds_ibdev)
302 {
303         struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
304         struct rds_ib_mr *ibmr = NULL;
305         int err = 0, iter = 0;
306
307         while (1) {
308                 ibmr = rds_ib_reuse_fmr(pool);
309                 if (ibmr)
310                         return ibmr;
311
312                 /* No clean MRs - now we have the choice of either
313                  * allocating a fresh MR up to the limit imposed by the
314                  * driver, or flush any dirty unused MRs.
315                  * We try to avoid stalling in the send path if possible,
316                  * so we allocate as long as we're allowed to.
317                  *
318                  * We're fussy with enforcing the FMR limit, though. If the driver
319                  * tells us we can't use more than N fmrs, we shouldn't start
320                  * arguing with it */
321                 if (atomic_inc_return(&pool->item_count) <= pool->max_items)
322                         break;
323
324                 atomic_dec(&pool->item_count);
325
326                 if (++iter > 2) {
327                         rds_ib_stats_inc(s_ib_rdma_mr_pool_depleted);
328                         return ERR_PTR(-EAGAIN);
329                 }
330
331                 /* We do have some empty MRs. Flush them out. */
332                 rds_ib_stats_inc(s_ib_rdma_mr_pool_wait);
333                 rds_ib_flush_mr_pool(pool, 0, &ibmr);
334                 if (ibmr)
335                         return ibmr;
336         }
337
338         ibmr = kzalloc_node(sizeof(*ibmr), GFP_KERNEL, rdsibdev_to_node(rds_ibdev));
339         if (!ibmr) {
340                 err = -ENOMEM;
341                 goto out_no_cigar;
342         }
343
344         memset(ibmr, 0, sizeof(*ibmr));
345
346         ibmr->fmr = ib_alloc_fmr(rds_ibdev->pd,
347                         (IB_ACCESS_LOCAL_WRITE |
348                          IB_ACCESS_REMOTE_READ |
349                          IB_ACCESS_REMOTE_WRITE|
350                          IB_ACCESS_REMOTE_ATOMIC),
351                         &pool->fmr_attr);
352         if (IS_ERR(ibmr->fmr)) {
353                 err = PTR_ERR(ibmr->fmr);
354                 ibmr->fmr = NULL;
355                 printk(KERN_WARNING "RDS/IB: ib_alloc_fmr failed (err=%d)\n", err);
356                 goto out_no_cigar;
357         }
358
359         rds_ib_stats_inc(s_ib_rdma_mr_alloc);
360         return ibmr;
361
362 out_no_cigar:
363         if (ibmr) {
364                 if (ibmr->fmr)
365                         ib_dealloc_fmr(ibmr->fmr);
366                 kfree(ibmr);
367         }
368         atomic_dec(&pool->item_count);
369         return ERR_PTR(err);
370 }
371
372 static int rds_ib_map_fmr(struct rds_ib_device *rds_ibdev, struct rds_ib_mr *ibmr,
373                struct scatterlist *sg, unsigned int nents)
374 {
375         struct ib_device *dev = rds_ibdev->dev;
376         struct scatterlist *scat = sg;
377         u64 io_addr = 0;
378         u64 *dma_pages;
379         u32 len;
380         int page_cnt, sg_dma_len;
381         int i, j;
382         int ret;
383
384         sg_dma_len = ib_dma_map_sg(dev, sg, nents,
385                                  DMA_BIDIRECTIONAL);
386         if (unlikely(!sg_dma_len)) {
387                 printk(KERN_WARNING "RDS/IB: dma_map_sg failed!\n");
388                 return -EBUSY;
389         }
390
391         len = 0;
392         page_cnt = 0;
393
394         for (i = 0; i < sg_dma_len; ++i) {
395                 unsigned int dma_len = ib_sg_dma_len(dev, &scat[i]);
396                 u64 dma_addr = ib_sg_dma_address(dev, &scat[i]);
397
398                 if (dma_addr & ~PAGE_MASK) {
399                         if (i > 0)
400                                 return -EINVAL;
401                         else
402                                 ++page_cnt;
403                 }
404                 if ((dma_addr + dma_len) & ~PAGE_MASK) {
405                         if (i < sg_dma_len - 1)
406                                 return -EINVAL;
407                         else
408                                 ++page_cnt;
409                 }
410
411                 len += dma_len;
412         }
413
414         page_cnt += len >> PAGE_SHIFT;
415         if (page_cnt > fmr_message_size)
416                 return -EINVAL;
417
418         dma_pages = kmalloc_node(sizeof(u64) * page_cnt, GFP_ATOMIC,
419                                  rdsibdev_to_node(rds_ibdev));
420         if (!dma_pages)
421                 return -ENOMEM;
422
423         page_cnt = 0;
424         for (i = 0; i < sg_dma_len; ++i) {
425                 unsigned int dma_len = ib_sg_dma_len(dev, &scat[i]);
426                 u64 dma_addr = ib_sg_dma_address(dev, &scat[i]);
427
428                 for (j = 0; j < dma_len; j += PAGE_SIZE)
429                         dma_pages[page_cnt++] =
430                                 (dma_addr & PAGE_MASK) + j;
431         }
432
433         ret = ib_map_phys_fmr(ibmr->fmr,
434                                    dma_pages, page_cnt, io_addr);
435         if (ret)
436                 goto out;
437
438         /* Success - we successfully remapped the MR, so we can
439          * safely tear down the old mapping. */
440         rds_ib_teardown_mr(ibmr);
441
442         ibmr->sg = scat;
443         ibmr->sg_len = nents;
444         ibmr->sg_dma_len = sg_dma_len;
445         ibmr->remap_count++;
446
447         rds_ib_stats_inc(s_ib_rdma_mr_used);
448         ret = 0;
449
450 out:
451         kfree(dma_pages);
452
453         return ret;
454 }
455
456 void rds_ib_sync_mr(void *trans_private, int direction)
457 {
458         struct rds_ib_mr *ibmr = trans_private;
459         struct rds_ib_device *rds_ibdev = ibmr->device;
460
461         switch (direction) {
462         case DMA_FROM_DEVICE:
463                 ib_dma_sync_sg_for_cpu(rds_ibdev->dev, ibmr->sg,
464                         ibmr->sg_dma_len, DMA_BIDIRECTIONAL);
465                 break;
466         case DMA_TO_DEVICE:
467                 ib_dma_sync_sg_for_device(rds_ibdev->dev, ibmr->sg,
468                         ibmr->sg_dma_len, DMA_BIDIRECTIONAL);
469                 break;
470         }
471 }
472
473 static void __rds_ib_teardown_mr(struct rds_ib_mr *ibmr)
474 {
475         struct rds_ib_device *rds_ibdev = ibmr->device;
476
477         if (ibmr->sg_dma_len) {
478                 ib_dma_unmap_sg(rds_ibdev->dev,
479                                 ibmr->sg, ibmr->sg_len,
480                                 DMA_BIDIRECTIONAL);
481                 ibmr->sg_dma_len = 0;
482         }
483
484         /* Release the s/g list */
485         if (ibmr->sg_len) {
486                 unsigned int i;
487
488                 for (i = 0; i < ibmr->sg_len; ++i) {
489                         struct page *page = sg_page(&ibmr->sg[i]);
490
491                         /* FIXME we need a way to tell a r/w MR
492                          * from a r/o MR */
493                         BUG_ON(irqs_disabled());
494                         set_page_dirty(page);
495                         put_page(page);
496                 }
497                 kfree(ibmr->sg);
498
499                 ibmr->sg = NULL;
500                 ibmr->sg_len = 0;
501         }
502 }
503
504 static void rds_ib_teardown_mr(struct rds_ib_mr *ibmr)
505 {
506         unsigned int pinned = ibmr->sg_len;
507
508         __rds_ib_teardown_mr(ibmr);
509         if (pinned) {
510                 struct rds_ib_device *rds_ibdev = ibmr->device;
511                 struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
512
513                 atomic_sub(pinned, &pool->free_pinned);
514         }
515 }
516
517 static inline unsigned int rds_ib_flush_goal(struct rds_ib_mr_pool *pool, int free_all)
518 {
519         unsigned int item_count;
520
521         item_count = atomic_read(&pool->item_count);
522         if (free_all)
523                 return item_count;
524
525         return 0;
526 }
527
528 /*
529  * given an xlist of mrs, put them all into the list_head for more processing
530  */
531 static void xlist_append_to_list(struct xlist_head *xlist, struct list_head *list)
532 {
533         struct rds_ib_mr *ibmr;
534         struct xlist_head splice;
535         struct xlist_head *cur;
536         struct xlist_head *next;
537
538         splice.next = NULL;
539         xlist_splice(xlist, &splice);
540         cur = splice.next;
541         while (cur) {
542                 next = cur->next;
543                 ibmr = list_entry(cur, struct rds_ib_mr, xlist);
544                 list_add_tail(&ibmr->unmap_list, list);
545                 cur = next;
546         }
547 }
548
549 /*
550  * this takes a list head of mrs and turns it into an xlist of clusters.
551  * each cluster has an xlist of MR_CLUSTER_SIZE mrs that are ready for
552  * reuse.
553  */
554 static void list_append_to_xlist(struct rds_ib_mr_pool *pool,
555                                 struct list_head *list, struct xlist_head *xlist,
556                                 struct xlist_head **tail_ret)
557 {
558         struct rds_ib_mr *ibmr;
559         struct xlist_head *cur_mr = xlist;
560         struct xlist_head *tail_mr = NULL;
561
562         list_for_each_entry(ibmr, list, unmap_list) {
563                 tail_mr = &ibmr->xlist;
564                 tail_mr->next = NULL;
565                 cur_mr->next = tail_mr;
566                 cur_mr = tail_mr;
567         }
568         *tail_ret = tail_mr;
569 }
570
571 /*
572  * Flush our pool of MRs.
573  * At a minimum, all currently unused MRs are unmapped.
574  * If the number of MRs allocated exceeds the limit, we also try
575  * to free as many MRs as needed to get back to this limit.
576  */
577 static int rds_ib_flush_mr_pool(struct rds_ib_mr_pool *pool,
578                                 int free_all, struct rds_ib_mr **ibmr_ret)
579 {
580         struct rds_ib_mr *ibmr, *next;
581         struct xlist_head clean_xlist;
582         struct xlist_head *clean_tail;
583         LIST_HEAD(unmap_list);
584         LIST_HEAD(fmr_list);
585         unsigned long unpinned = 0;
586         unsigned int nfreed = 0, ncleaned = 0, free_goal;
587         int ret = 0;
588
589         rds_ib_stats_inc(s_ib_rdma_mr_pool_flush);
590
591         if (ibmr_ret) {
592                 DEFINE_WAIT(wait);
593                 while(!mutex_trylock(&pool->flush_lock)) {
594                         ibmr = rds_ib_reuse_fmr(pool);
595                         if (ibmr) {
596                                 *ibmr_ret = ibmr;
597                                 finish_wait(&pool->flush_wait, &wait);
598                                 goto out_nolock;
599                         }
600
601                         prepare_to_wait(&pool->flush_wait, &wait,
602                                         TASK_UNINTERRUPTIBLE);
603                         if (xlist_empty(&pool->clean_list))
604                                 schedule();
605
606                         ibmr = rds_ib_reuse_fmr(pool);
607                         if (ibmr) {
608                                 *ibmr_ret = ibmr;
609                                 finish_wait(&pool->flush_wait, &wait);
610                                 goto out_nolock;
611                         }
612                 }
613                 finish_wait(&pool->flush_wait, &wait);
614         } else
615                 mutex_lock(&pool->flush_lock);
616
617         if (ibmr_ret) {
618                 ibmr = rds_ib_reuse_fmr(pool);
619                 if (ibmr) {
620                         *ibmr_ret = ibmr;
621                         goto out;
622                 }
623         }
624
625         /* Get the list of all MRs to be dropped. Ordering matters -
626          * we want to put drop_list ahead of free_list.
627          */
628         xlist_append_to_list(&pool->drop_list, &unmap_list);
629         xlist_append_to_list(&pool->free_list, &unmap_list);
630         if (free_all)
631                 xlist_append_to_list(&pool->clean_list, &unmap_list);
632
633         free_goal = rds_ib_flush_goal(pool, free_all);
634
635         if (list_empty(&unmap_list))
636                 goto out;
637
638         /* String all ib_mr's onto one list and hand them to ib_unmap_fmr */
639         list_for_each_entry(ibmr, &unmap_list, unmap_list)
640                 list_add(&ibmr->fmr->list, &fmr_list);
641
642         ret = ib_unmap_fmr(&fmr_list);
643         if (ret)
644                 printk(KERN_WARNING "RDS/IB: ib_unmap_fmr failed (err=%d)\n", ret);
645
646         /* Now we can destroy the DMA mapping and unpin any pages */
647         list_for_each_entry_safe(ibmr, next, &unmap_list, unmap_list) {
648                 unpinned += ibmr->sg_len;
649                 __rds_ib_teardown_mr(ibmr);
650                 if (nfreed < free_goal || ibmr->remap_count >= pool->fmr_attr.max_maps) {
651                         rds_ib_stats_inc(s_ib_rdma_mr_free);
652                         list_del(&ibmr->unmap_list);
653                         ib_dealloc_fmr(ibmr->fmr);
654                         kfree(ibmr);
655                         nfreed++;
656                 }
657                 ncleaned++;
658         }
659
660         if (!list_empty(&unmap_list)) {
661                 /* we have to make sure that none of the things we're about
662                  * to put on the clean list would race with other cpus trying
663                  * to pull items off.  The xlist would explode if we managed to
664                  * remove something from the clean list and then add it back again
665                  * while another CPU was spinning on that same item in xlist_del_head.
666                  *
667                  * This is pretty unlikely, but just in case  wait for an xlist grace period
668                  * here before adding anything back into the clean list.
669                  */
670                 wait_clean_list_grace();
671
672                 list_append_to_xlist(pool, &unmap_list, &clean_xlist, &clean_tail);
673                 if (ibmr_ret)
674                         refill_local(pool, &clean_xlist, ibmr_ret);
675
676                 /* refill_local may have emptied our list */
677                 if (!xlist_empty(&clean_xlist))
678                         xlist_add(clean_xlist.next, clean_tail, &pool->clean_list);
679
680         }
681
682         atomic_sub(unpinned, &pool->free_pinned);
683         atomic_sub(ncleaned, &pool->dirty_count);
684         atomic_sub(nfreed, &pool->item_count);
685
686 out:
687         mutex_unlock(&pool->flush_lock);
688         if (waitqueue_active(&pool->flush_wait))
689                 wake_up(&pool->flush_wait);
690 out_nolock:
691         return ret;
692 }
693
694 struct workqueue_struct *rds_ib_fmr_wq;
695
696 int rds_ib_fmr_init(void)
697 {
698         rds_ib_fmr_wq = create_workqueue("rds_fmr_flushd");
699         if (!rds_ib_fmr_wq)
700                 return -ENOMEM;
701         return 0;
702 }
703
704 /*
705  * By the time this is called all the IB devices should have been torn down and
706  * had their pools freed.  As each pool is freed its work struct is waited on,
707  * so the pool flushing work queue should be idle by the time we get here.
708  */
709 void rds_ib_fmr_exit(void)
710 {
711         destroy_workqueue(rds_ib_fmr_wq);
712 }
713
714 static void rds_ib_mr_pool_flush_worker(struct work_struct *work)
715 {
716         struct rds_ib_mr_pool *pool = container_of(work, struct rds_ib_mr_pool, flush_worker.work);
717
718         rds_ib_flush_mr_pool(pool, 0, NULL);
719 }
720
721 void rds_ib_free_mr(void *trans_private, int invalidate)
722 {
723         struct rds_ib_mr *ibmr = trans_private;
724         struct rds_ib_device *rds_ibdev = ibmr->device;
725         struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
726
727         rdsdebug("RDS/IB: free_mr nents %u\n", ibmr->sg_len);
728
729         /* Return it to the pool's free list */
730         if (ibmr->remap_count >= pool->fmr_attr.max_maps)
731                 xlist_add(&ibmr->xlist, &ibmr->xlist, &pool->drop_list);
732         else
733                 xlist_add(&ibmr->xlist, &ibmr->xlist, &pool->free_list);
734
735         atomic_add(ibmr->sg_len, &pool->free_pinned);
736         atomic_inc(&pool->dirty_count);
737
738         /* If we've pinned too many pages, request a flush */
739         if (atomic_read(&pool->free_pinned) >= pool->max_free_pinned ||
740             atomic_read(&pool->dirty_count) >= pool->max_items / 10)
741                 queue_delayed_work(rds_ib_fmr_wq, &pool->flush_worker, 10);
742
743         if (invalidate) {
744                 if (likely(!in_interrupt())) {
745                         rds_ib_flush_mr_pool(pool, 0, NULL);
746                 } else {
747                         /* We get here if the user created a MR marked
748                          * as use_once and invalidate at the same time. */
749                         queue_delayed_work(rds_ib_fmr_wq,
750                                            &pool->flush_worker, 10);
751                 }
752         }
753
754         rds_ib_dev_put(rds_ibdev);
755 }
756
757 void rds_ib_flush_mrs(void)
758 {
759         struct rds_ib_device *rds_ibdev;
760
761         list_for_each_entry(rds_ibdev, &rds_ib_devices, list) {
762                 struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
763
764                 if (pool)
765                         rds_ib_flush_mr_pool(pool, 0, NULL);
766         }
767 }
768
769 void *rds_ib_get_mr(struct scatterlist *sg, unsigned long nents,
770                     struct rds_sock *rs, u32 *key_ret)
771 {
772         struct rds_ib_device *rds_ibdev;
773         struct rds_ib_mr *ibmr = NULL;
774         int ret;
775
776         rds_ibdev = rds_ib_get_device(rs->rs_bound_addr);
777         if (!rds_ibdev) {
778                 ret = -ENODEV;
779                 goto out;
780         }
781
782         if (!rds_ibdev->mr_pool) {
783                 ret = -ENODEV;
784                 goto out;
785         }
786
787         ibmr = rds_ib_alloc_fmr(rds_ibdev);
788         if (IS_ERR(ibmr))
789                 return ibmr;
790
791         ret = rds_ib_map_fmr(rds_ibdev, ibmr, sg, nents);
792         if (ret == 0)
793                 *key_ret = ibmr->fmr->rkey;
794         else
795                 printk(KERN_WARNING "RDS/IB: map_fmr failed (errno=%d)\n", ret);
796
797         ibmr->device = rds_ibdev;
798         rds_ibdev = NULL;
799
800  out:
801         if (ret) {
802                 if (ibmr)
803                         rds_ib_free_mr(ibmr, 0);
804                 ibmr = ERR_PTR(ret);
805         }
806         if (rds_ibdev)
807                 rds_ib_dev_put(rds_ibdev);
808         return ibmr;
809 }
810