net, rds, Replace xlist in net/rds/xlist.h with llist
[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 #include <linux/llist.h>
37
38 #include "rds.h"
39 #include "ib.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 llist_node       llnode;
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 llist_head       drop_list;              /* MRs that have reached their max_maps limit */
75         struct llist_head       free_list;              /* unused MRs */
76         struct llist_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         rcu_read_lock();
96         list_for_each_entry_rcu(rds_ibdev, &rds_ib_devices, list) {
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         }
105         rcu_read_unlock();
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(&rds_ibdev->spinlock);
173         list_add_tail(&ic->ib_node, &rds_ibdev->conn_list);
174         spin_unlock(&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_llist_head(&pool->free_list);
224         init_llist_head(&pool->drop_list);
225         init_llist_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 inline struct rds_ib_mr *rds_ib_reuse_fmr(struct rds_ib_mr_pool *pool)
264 {
265         struct rds_ib_mr *ibmr = NULL;
266         struct llist_node *ret;
267         unsigned long *flag;
268
269         preempt_disable();
270         flag = &__get_cpu_var(clean_list_grace);
271         set_bit(CLEAN_LIST_BUSY_BIT, flag);
272         ret = llist_del_first(&pool->clean_list);
273         if (ret)
274                 ibmr = llist_entry(ret, struct rds_ib_mr, llnode);
275
276         clear_bit(CLEAN_LIST_BUSY_BIT, flag);
277         preempt_enable();
278         return ibmr;
279 }
280
281 static inline void wait_clean_list_grace(void)
282 {
283         int cpu;
284         unsigned long *flag;
285
286         for_each_online_cpu(cpu) {
287                 flag = &per_cpu(clean_list_grace, cpu);
288                 while (test_bit(CLEAN_LIST_BUSY_BIT, flag))
289                         cpu_relax();
290         }
291 }
292
293 static struct rds_ib_mr *rds_ib_alloc_fmr(struct rds_ib_device *rds_ibdev)
294 {
295         struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
296         struct rds_ib_mr *ibmr = NULL;
297         int err = 0, iter = 0;
298
299         if (atomic_read(&pool->dirty_count) >= pool->max_items / 10)
300                 schedule_delayed_work(&pool->flush_worker, 10);
301
302         while (1) {
303                 ibmr = rds_ib_reuse_fmr(pool);
304                 if (ibmr)
305                         return ibmr;
306
307                 /* No clean MRs - now we have the choice of either
308                  * allocating a fresh MR up to the limit imposed by the
309                  * driver, or flush any dirty unused MRs.
310                  * We try to avoid stalling in the send path if possible,
311                  * so we allocate as long as we're allowed to.
312                  *
313                  * We're fussy with enforcing the FMR limit, though. If the driver
314                  * tells us we can't use more than N fmrs, we shouldn't start
315                  * arguing with it */
316                 if (atomic_inc_return(&pool->item_count) <= pool->max_items)
317                         break;
318
319                 atomic_dec(&pool->item_count);
320
321                 if (++iter > 2) {
322                         rds_ib_stats_inc(s_ib_rdma_mr_pool_depleted);
323                         return ERR_PTR(-EAGAIN);
324                 }
325
326                 /* We do have some empty MRs. Flush them out. */
327                 rds_ib_stats_inc(s_ib_rdma_mr_pool_wait);
328                 rds_ib_flush_mr_pool(pool, 0, &ibmr);
329                 if (ibmr)
330                         return ibmr;
331         }
332
333         ibmr = kzalloc_node(sizeof(*ibmr), GFP_KERNEL, rdsibdev_to_node(rds_ibdev));
334         if (!ibmr) {
335                 err = -ENOMEM;
336                 goto out_no_cigar;
337         }
338
339         memset(ibmr, 0, sizeof(*ibmr));
340
341         ibmr->fmr = ib_alloc_fmr(rds_ibdev->pd,
342                         (IB_ACCESS_LOCAL_WRITE |
343                          IB_ACCESS_REMOTE_READ |
344                          IB_ACCESS_REMOTE_WRITE|
345                          IB_ACCESS_REMOTE_ATOMIC),
346                         &pool->fmr_attr);
347         if (IS_ERR(ibmr->fmr)) {
348                 err = PTR_ERR(ibmr->fmr);
349                 ibmr->fmr = NULL;
350                 printk(KERN_WARNING "RDS/IB: ib_alloc_fmr failed (err=%d)\n", err);
351                 goto out_no_cigar;
352         }
353
354         rds_ib_stats_inc(s_ib_rdma_mr_alloc);
355         return ibmr;
356
357 out_no_cigar:
358         if (ibmr) {
359                 if (ibmr->fmr)
360                         ib_dealloc_fmr(ibmr->fmr);
361                 kfree(ibmr);
362         }
363         atomic_dec(&pool->item_count);
364         return ERR_PTR(err);
365 }
366
367 static int rds_ib_map_fmr(struct rds_ib_device *rds_ibdev, struct rds_ib_mr *ibmr,
368                struct scatterlist *sg, unsigned int nents)
369 {
370         struct ib_device *dev = rds_ibdev->dev;
371         struct scatterlist *scat = sg;
372         u64 io_addr = 0;
373         u64 *dma_pages;
374         u32 len;
375         int page_cnt, sg_dma_len;
376         int i, j;
377         int ret;
378
379         sg_dma_len = ib_dma_map_sg(dev, sg, nents,
380                                  DMA_BIDIRECTIONAL);
381         if (unlikely(!sg_dma_len)) {
382                 printk(KERN_WARNING "RDS/IB: dma_map_sg failed!\n");
383                 return -EBUSY;
384         }
385
386         len = 0;
387         page_cnt = 0;
388
389         for (i = 0; i < sg_dma_len; ++i) {
390                 unsigned int dma_len = ib_sg_dma_len(dev, &scat[i]);
391                 u64 dma_addr = ib_sg_dma_address(dev, &scat[i]);
392
393                 if (dma_addr & ~PAGE_MASK) {
394                         if (i > 0)
395                                 return -EINVAL;
396                         else
397                                 ++page_cnt;
398                 }
399                 if ((dma_addr + dma_len) & ~PAGE_MASK) {
400                         if (i < sg_dma_len - 1)
401                                 return -EINVAL;
402                         else
403                                 ++page_cnt;
404                 }
405
406                 len += dma_len;
407         }
408
409         page_cnt += len >> PAGE_SHIFT;
410         if (page_cnt > fmr_message_size)
411                 return -EINVAL;
412
413         dma_pages = kmalloc_node(sizeof(u64) * page_cnt, GFP_ATOMIC,
414                                  rdsibdev_to_node(rds_ibdev));
415         if (!dma_pages)
416                 return -ENOMEM;
417
418         page_cnt = 0;
419         for (i = 0; i < sg_dma_len; ++i) {
420                 unsigned int dma_len = ib_sg_dma_len(dev, &scat[i]);
421                 u64 dma_addr = ib_sg_dma_address(dev, &scat[i]);
422
423                 for (j = 0; j < dma_len; j += PAGE_SIZE)
424                         dma_pages[page_cnt++] =
425                                 (dma_addr & PAGE_MASK) + j;
426         }
427
428         ret = ib_map_phys_fmr(ibmr->fmr,
429                                    dma_pages, page_cnt, io_addr);
430         if (ret)
431                 goto out;
432
433         /* Success - we successfully remapped the MR, so we can
434          * safely tear down the old mapping. */
435         rds_ib_teardown_mr(ibmr);
436
437         ibmr->sg = scat;
438         ibmr->sg_len = nents;
439         ibmr->sg_dma_len = sg_dma_len;
440         ibmr->remap_count++;
441
442         rds_ib_stats_inc(s_ib_rdma_mr_used);
443         ret = 0;
444
445 out:
446         kfree(dma_pages);
447
448         return ret;
449 }
450
451 void rds_ib_sync_mr(void *trans_private, int direction)
452 {
453         struct rds_ib_mr *ibmr = trans_private;
454         struct rds_ib_device *rds_ibdev = ibmr->device;
455
456         switch (direction) {
457         case DMA_FROM_DEVICE:
458                 ib_dma_sync_sg_for_cpu(rds_ibdev->dev, ibmr->sg,
459                         ibmr->sg_dma_len, DMA_BIDIRECTIONAL);
460                 break;
461         case DMA_TO_DEVICE:
462                 ib_dma_sync_sg_for_device(rds_ibdev->dev, ibmr->sg,
463                         ibmr->sg_dma_len, DMA_BIDIRECTIONAL);
464                 break;
465         }
466 }
467
468 static void __rds_ib_teardown_mr(struct rds_ib_mr *ibmr)
469 {
470         struct rds_ib_device *rds_ibdev = ibmr->device;
471
472         if (ibmr->sg_dma_len) {
473                 ib_dma_unmap_sg(rds_ibdev->dev,
474                                 ibmr->sg, ibmr->sg_len,
475                                 DMA_BIDIRECTIONAL);
476                 ibmr->sg_dma_len = 0;
477         }
478
479         /* Release the s/g list */
480         if (ibmr->sg_len) {
481                 unsigned int i;
482
483                 for (i = 0; i < ibmr->sg_len; ++i) {
484                         struct page *page = sg_page(&ibmr->sg[i]);
485
486                         /* FIXME we need a way to tell a r/w MR
487                          * from a r/o MR */
488                         BUG_ON(irqs_disabled());
489                         set_page_dirty(page);
490                         put_page(page);
491                 }
492                 kfree(ibmr->sg);
493
494                 ibmr->sg = NULL;
495                 ibmr->sg_len = 0;
496         }
497 }
498
499 static void rds_ib_teardown_mr(struct rds_ib_mr *ibmr)
500 {
501         unsigned int pinned = ibmr->sg_len;
502
503         __rds_ib_teardown_mr(ibmr);
504         if (pinned) {
505                 struct rds_ib_device *rds_ibdev = ibmr->device;
506                 struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
507
508                 atomic_sub(pinned, &pool->free_pinned);
509         }
510 }
511
512 static inline unsigned int rds_ib_flush_goal(struct rds_ib_mr_pool *pool, int free_all)
513 {
514         unsigned int item_count;
515
516         item_count = atomic_read(&pool->item_count);
517         if (free_all)
518                 return item_count;
519
520         return 0;
521 }
522
523 /*
524  * given an llist of mrs, put them all into the list_head for more processing
525  */
526 static void llist_append_to_list(struct llist_head *llist, struct list_head *list)
527 {
528         struct rds_ib_mr *ibmr;
529         struct llist_node *node;
530         struct llist_node *next;
531
532         node = llist_del_all(llist);
533         while (node) {
534                 next = node->next;
535                 ibmr = llist_entry(node, struct rds_ib_mr, llnode);
536                 list_add_tail(&ibmr->unmap_list, list);
537                 node = next;
538         }
539 }
540
541 /*
542  * this takes a list head of mrs and turns it into linked llist nodes
543  * of clusters.  Each cluster has linked llist nodes of
544  * MR_CLUSTER_SIZE mrs that are ready for reuse.
545  */
546 static void list_to_llist_nodes(struct rds_ib_mr_pool *pool,
547                                 struct list_head *list,
548                                 struct llist_node **nodes_head,
549                                 struct llist_node **nodes_tail)
550 {
551         struct rds_ib_mr *ibmr;
552         struct llist_node *cur = NULL;
553         struct llist_node **next = nodes_head;
554
555         list_for_each_entry(ibmr, list, unmap_list) {
556                 cur = &ibmr->llnode;
557                 *next = cur;
558                 next = &cur->next;
559         }
560         *next = NULL;
561         *nodes_tail = cur;
562 }
563
564 /*
565  * Flush our pool of MRs.
566  * At a minimum, all currently unused MRs are unmapped.
567  * If the number of MRs allocated exceeds the limit, we also try
568  * to free as many MRs as needed to get back to this limit.
569  */
570 static int rds_ib_flush_mr_pool(struct rds_ib_mr_pool *pool,
571                                 int free_all, struct rds_ib_mr **ibmr_ret)
572 {
573         struct rds_ib_mr *ibmr, *next;
574         struct llist_node *clean_nodes;
575         struct llist_node *clean_tail;
576         LIST_HEAD(unmap_list);
577         LIST_HEAD(fmr_list);
578         unsigned long unpinned = 0;
579         unsigned int nfreed = 0, ncleaned = 0, free_goal;
580         int ret = 0;
581
582         rds_ib_stats_inc(s_ib_rdma_mr_pool_flush);
583
584         if (ibmr_ret) {
585                 DEFINE_WAIT(wait);
586                 while(!mutex_trylock(&pool->flush_lock)) {
587                         ibmr = rds_ib_reuse_fmr(pool);
588                         if (ibmr) {
589                                 *ibmr_ret = ibmr;
590                                 finish_wait(&pool->flush_wait, &wait);
591                                 goto out_nolock;
592                         }
593
594                         prepare_to_wait(&pool->flush_wait, &wait,
595                                         TASK_UNINTERRUPTIBLE);
596                         if (llist_empty(&pool->clean_list))
597                                 schedule();
598
599                         ibmr = rds_ib_reuse_fmr(pool);
600                         if (ibmr) {
601                                 *ibmr_ret = ibmr;
602                                 finish_wait(&pool->flush_wait, &wait);
603                                 goto out_nolock;
604                         }
605                 }
606                 finish_wait(&pool->flush_wait, &wait);
607         } else
608                 mutex_lock(&pool->flush_lock);
609
610         if (ibmr_ret) {
611                 ibmr = rds_ib_reuse_fmr(pool);
612                 if (ibmr) {
613                         *ibmr_ret = ibmr;
614                         goto out;
615                 }
616         }
617
618         /* Get the list of all MRs to be dropped. Ordering matters -
619          * we want to put drop_list ahead of free_list.
620          */
621         llist_append_to_list(&pool->drop_list, &unmap_list);
622         llist_append_to_list(&pool->free_list, &unmap_list);
623         if (free_all)
624                 llist_append_to_list(&pool->clean_list, &unmap_list);
625
626         free_goal = rds_ib_flush_goal(pool, free_all);
627
628         if (list_empty(&unmap_list))
629                 goto out;
630
631         /* String all ib_mr's onto one list and hand them to ib_unmap_fmr */
632         list_for_each_entry(ibmr, &unmap_list, unmap_list)
633                 list_add(&ibmr->fmr->list, &fmr_list);
634
635         ret = ib_unmap_fmr(&fmr_list);
636         if (ret)
637                 printk(KERN_WARNING "RDS/IB: ib_unmap_fmr failed (err=%d)\n", ret);
638
639         /* Now we can destroy the DMA mapping and unpin any pages */
640         list_for_each_entry_safe(ibmr, next, &unmap_list, unmap_list) {
641                 unpinned += ibmr->sg_len;
642                 __rds_ib_teardown_mr(ibmr);
643                 if (nfreed < free_goal || ibmr->remap_count >= pool->fmr_attr.max_maps) {
644                         rds_ib_stats_inc(s_ib_rdma_mr_free);
645                         list_del(&ibmr->unmap_list);
646                         ib_dealloc_fmr(ibmr->fmr);
647                         kfree(ibmr);
648                         nfreed++;
649                 }
650                 ncleaned++;
651         }
652
653         if (!list_empty(&unmap_list)) {
654                 /* we have to make sure that none of the things we're about
655                  * to put on the clean list would race with other cpus trying
656                  * to pull items off.  The llist would explode if we managed to
657                  * remove something from the clean list and then add it back again
658                  * while another CPU was spinning on that same item in llist_del_first.
659                  *
660                  * This is pretty unlikely, but just in case  wait for an llist grace period
661                  * here before adding anything back into the clean list.
662                  */
663                 wait_clean_list_grace();
664
665                 list_to_llist_nodes(pool, &unmap_list, &clean_nodes, &clean_tail);
666                 if (ibmr_ret)
667                         *ibmr_ret = llist_entry(clean_nodes, struct rds_ib_mr, llnode);
668
669                 /* more than one entry in llist nodes */
670                 if (clean_nodes->next)
671                         llist_add_batch(clean_nodes->next, clean_tail, &pool->clean_list);
672
673         }
674
675         atomic_sub(unpinned, &pool->free_pinned);
676         atomic_sub(ncleaned, &pool->dirty_count);
677         atomic_sub(nfreed, &pool->item_count);
678
679 out:
680         mutex_unlock(&pool->flush_lock);
681         if (waitqueue_active(&pool->flush_wait))
682                 wake_up(&pool->flush_wait);
683 out_nolock:
684         return ret;
685 }
686
687 static void rds_ib_mr_pool_flush_worker(struct work_struct *work)
688 {
689         struct rds_ib_mr_pool *pool = container_of(work, struct rds_ib_mr_pool, flush_worker.work);
690
691         rds_ib_flush_mr_pool(pool, 0, NULL);
692 }
693
694 void rds_ib_free_mr(void *trans_private, int invalidate)
695 {
696         struct rds_ib_mr *ibmr = trans_private;
697         struct rds_ib_device *rds_ibdev = ibmr->device;
698         struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
699
700         rdsdebug("RDS/IB: free_mr nents %u\n", ibmr->sg_len);
701
702         /* Return it to the pool's free list */
703         if (ibmr->remap_count >= pool->fmr_attr.max_maps)
704                 llist_add(&ibmr->llnode, &pool->drop_list);
705         else
706                 llist_add(&ibmr->llnode, &pool->free_list);
707
708         atomic_add(ibmr->sg_len, &pool->free_pinned);
709         atomic_inc(&pool->dirty_count);
710
711         /* If we've pinned too many pages, request a flush */
712         if (atomic_read(&pool->free_pinned) >= pool->max_free_pinned ||
713             atomic_read(&pool->dirty_count) >= pool->max_items / 10)
714                 schedule_delayed_work(&pool->flush_worker, 10);
715
716         if (invalidate) {
717                 if (likely(!in_interrupt())) {
718                         rds_ib_flush_mr_pool(pool, 0, NULL);
719                 } else {
720                         /* We get here if the user created a MR marked
721                          * as use_once and invalidate at the same time. */
722                         schedule_delayed_work(&pool->flush_worker, 10);
723                 }
724         }
725
726         rds_ib_dev_put(rds_ibdev);
727 }
728
729 void rds_ib_flush_mrs(void)
730 {
731         struct rds_ib_device *rds_ibdev;
732
733         down_read(&rds_ib_devices_lock);
734         list_for_each_entry(rds_ibdev, &rds_ib_devices, list) {
735                 struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
736
737                 if (pool)
738                         rds_ib_flush_mr_pool(pool, 0, NULL);
739         }
740         up_read(&rds_ib_devices_lock);
741 }
742
743 void *rds_ib_get_mr(struct scatterlist *sg, unsigned long nents,
744                     struct rds_sock *rs, u32 *key_ret)
745 {
746         struct rds_ib_device *rds_ibdev;
747         struct rds_ib_mr *ibmr = NULL;
748         int ret;
749
750         rds_ibdev = rds_ib_get_device(rs->rs_bound_addr);
751         if (!rds_ibdev) {
752                 ret = -ENODEV;
753                 goto out;
754         }
755
756         if (!rds_ibdev->mr_pool) {
757                 ret = -ENODEV;
758                 goto out;
759         }
760
761         ibmr = rds_ib_alloc_fmr(rds_ibdev);
762         if (IS_ERR(ibmr))
763                 return ibmr;
764
765         ret = rds_ib_map_fmr(rds_ibdev, ibmr, sg, nents);
766         if (ret == 0)
767                 *key_ret = ibmr->fmr->rkey;
768         else
769                 printk(KERN_WARNING "RDS/IB: map_fmr failed (errno=%d)\n", ret);
770
771         ibmr->device = rds_ibdev;
772         rds_ibdev = NULL;
773
774  out:
775         if (ret) {
776                 if (ibmr)
777                         rds_ib_free_mr(ibmr, 0);
778                 ibmr = ERR_PTR(ret);
779         }
780         if (rds_ibdev)
781                 rds_ib_dev_put(rds_ibdev);
782         return ibmr;
783 }
784