Merge branch 'staging-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh...
[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 struct workqueue_struct *rds_ib_fmr_wq;
42
43 static DEFINE_PER_CPU(unsigned long, clean_list_grace);
44 #define CLEAN_LIST_BUSY_BIT 0
45
46 /*
47  * This is stored as mr->r_trans_private.
48  */
49 struct rds_ib_mr {
50         struct rds_ib_device    *device;
51         struct rds_ib_mr_pool   *pool;
52         struct ib_fmr           *fmr;
53
54         struct xlist_head       xlist;
55
56         /* unmap_list is for freeing */
57         struct list_head        unmap_list;
58         unsigned int            remap_count;
59
60         struct scatterlist      *sg;
61         unsigned int            sg_len;
62         u64                     *dma;
63         int                     sg_dma_len;
64 };
65
66 /*
67  * Our own little FMR pool
68  */
69 struct rds_ib_mr_pool {
70         struct mutex            flush_lock;             /* serialize fmr invalidate */
71         struct delayed_work     flush_worker;           /* flush worker */
72
73         atomic_t                item_count;             /* total # of MRs */
74         atomic_t                dirty_count;            /* # dirty of MRs */
75
76         struct xlist_head       drop_list;              /* MRs that have reached their max_maps limit */
77         struct xlist_head       free_list;              /* unused MRs */
78         struct xlist_head       clean_list;             /* global unused & unamapped MRs */
79         wait_queue_head_t       flush_wait;
80
81         atomic_t                free_pinned;            /* memory pinned by free MRs */
82         unsigned long           max_items;
83         unsigned long           max_items_soft;
84         unsigned long           max_free_pinned;
85         struct ib_fmr_attr      fmr_attr;
86 };
87
88 static int rds_ib_flush_mr_pool(struct rds_ib_mr_pool *pool, int free_all, struct rds_ib_mr **);
89 static void rds_ib_teardown_mr(struct rds_ib_mr *ibmr);
90 static void rds_ib_mr_pool_flush_worker(struct work_struct *work);
91
92 static struct rds_ib_device *rds_ib_get_device(__be32 ipaddr)
93 {
94         struct rds_ib_device *rds_ibdev;
95         struct rds_ib_ipaddr *i_ipaddr;
96
97         rcu_read_lock();
98         list_for_each_entry_rcu(rds_ibdev, &rds_ib_devices, list) {
99                 list_for_each_entry_rcu(i_ipaddr, &rds_ibdev->ipaddr_list, list) {
100                         if (i_ipaddr->ipaddr == ipaddr) {
101                                 atomic_inc(&rds_ibdev->refcount);
102                                 rcu_read_unlock();
103                                 return rds_ibdev;
104                         }
105                 }
106         }
107         rcu_read_unlock();
108
109         return NULL;
110 }
111
112 static int rds_ib_add_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
113 {
114         struct rds_ib_ipaddr *i_ipaddr;
115
116         i_ipaddr = kmalloc(sizeof *i_ipaddr, GFP_KERNEL);
117         if (!i_ipaddr)
118                 return -ENOMEM;
119
120         i_ipaddr->ipaddr = ipaddr;
121
122         spin_lock_irq(&rds_ibdev->spinlock);
123         list_add_tail_rcu(&i_ipaddr->list, &rds_ibdev->ipaddr_list);
124         spin_unlock_irq(&rds_ibdev->spinlock);
125
126         return 0;
127 }
128
129 static void rds_ib_remove_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
130 {
131         struct rds_ib_ipaddr *i_ipaddr;
132         struct rds_ib_ipaddr *to_free = NULL;
133
134
135         spin_lock_irq(&rds_ibdev->spinlock);
136         list_for_each_entry_rcu(i_ipaddr, &rds_ibdev->ipaddr_list, list) {
137                 if (i_ipaddr->ipaddr == ipaddr) {
138                         list_del_rcu(&i_ipaddr->list);
139                         to_free = i_ipaddr;
140                         break;
141                 }
142         }
143         spin_unlock_irq(&rds_ibdev->spinlock);
144
145         if (to_free) {
146                 synchronize_rcu();
147                 kfree(to_free);
148         }
149 }
150
151 int rds_ib_update_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
152 {
153         struct rds_ib_device *rds_ibdev_old;
154
155         rds_ibdev_old = rds_ib_get_device(ipaddr);
156         if (rds_ibdev_old) {
157                 rds_ib_remove_ipaddr(rds_ibdev_old, ipaddr);
158                 rds_ib_dev_put(rds_ibdev_old);
159         }
160
161         return rds_ib_add_ipaddr(rds_ibdev, ipaddr);
162 }
163
164 void rds_ib_add_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *conn)
165 {
166         struct rds_ib_connection *ic = conn->c_transport_data;
167
168         /* conn was previously on the nodev_conns_list */
169         spin_lock_irq(&ib_nodev_conns_lock);
170         BUG_ON(list_empty(&ib_nodev_conns));
171         BUG_ON(list_empty(&ic->ib_node));
172         list_del(&ic->ib_node);
173
174         spin_lock(&rds_ibdev->spinlock);
175         list_add_tail(&ic->ib_node, &rds_ibdev->conn_list);
176         spin_unlock(&rds_ibdev->spinlock);
177         spin_unlock_irq(&ib_nodev_conns_lock);
178
179         ic->rds_ibdev = rds_ibdev;
180         atomic_inc(&rds_ibdev->refcount);
181 }
182
183 void rds_ib_remove_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *conn)
184 {
185         struct rds_ib_connection *ic = conn->c_transport_data;
186
187         /* place conn on nodev_conns_list */
188         spin_lock(&ib_nodev_conns_lock);
189
190         spin_lock_irq(&rds_ibdev->spinlock);
191         BUG_ON(list_empty(&ic->ib_node));
192         list_del(&ic->ib_node);
193         spin_unlock_irq(&rds_ibdev->spinlock);
194
195         list_add_tail(&ic->ib_node, &ib_nodev_conns);
196
197         spin_unlock(&ib_nodev_conns_lock);
198
199         ic->rds_ibdev = NULL;
200         rds_ib_dev_put(rds_ibdev);
201 }
202
203 void rds_ib_destroy_nodev_conns(void)
204 {
205         struct rds_ib_connection *ic, *_ic;
206         LIST_HEAD(tmp_list);
207
208         /* avoid calling conn_destroy with irqs off */
209         spin_lock_irq(&ib_nodev_conns_lock);
210         list_splice(&ib_nodev_conns, &tmp_list);
211         spin_unlock_irq(&ib_nodev_conns_lock);
212
213         list_for_each_entry_safe(ic, _ic, &tmp_list, ib_node)
214                 rds_conn_destroy(ic->conn);
215 }
216
217 struct rds_ib_mr_pool *rds_ib_create_mr_pool(struct rds_ib_device *rds_ibdev)
218 {
219         struct rds_ib_mr_pool *pool;
220
221         pool = kzalloc(sizeof(*pool), GFP_KERNEL);
222         if (!pool)
223                 return ERR_PTR(-ENOMEM);
224
225         INIT_XLIST_HEAD(&pool->free_list);
226         INIT_XLIST_HEAD(&pool->drop_list);
227         INIT_XLIST_HEAD(&pool->clean_list);
228         mutex_init(&pool->flush_lock);
229         init_waitqueue_head(&pool->flush_wait);
230         INIT_DELAYED_WORK(&pool->flush_worker, rds_ib_mr_pool_flush_worker);
231
232         pool->fmr_attr.max_pages = fmr_message_size;
233         pool->fmr_attr.max_maps = rds_ibdev->fmr_max_remaps;
234         pool->fmr_attr.page_shift = PAGE_SHIFT;
235         pool->max_free_pinned = rds_ibdev->max_fmrs * fmr_message_size / 4;
236
237         /* We never allow more than max_items MRs to be allocated.
238          * When we exceed more than max_items_soft, we start freeing
239          * items more aggressively.
240          * Make sure that max_items > max_items_soft > max_items / 2
241          */
242         pool->max_items_soft = rds_ibdev->max_fmrs * 3 / 4;
243         pool->max_items = rds_ibdev->max_fmrs;
244
245         return pool;
246 }
247
248 void rds_ib_get_mr_info(struct rds_ib_device *rds_ibdev, struct rds_info_rdma_connection *iinfo)
249 {
250         struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
251
252         iinfo->rdma_mr_max = pool->max_items;
253         iinfo->rdma_mr_size = pool->fmr_attr.max_pages;
254 }
255
256 void rds_ib_destroy_mr_pool(struct rds_ib_mr_pool *pool)
257 {
258         cancel_delayed_work_sync(&pool->flush_worker);
259         rds_ib_flush_mr_pool(pool, 1, NULL);
260         WARN_ON(atomic_read(&pool->item_count));
261         WARN_ON(atomic_read(&pool->free_pinned));
262         kfree(pool);
263 }
264
265 static void refill_local(struct rds_ib_mr_pool *pool, struct xlist_head *xl,
266                          struct rds_ib_mr **ibmr_ret)
267 {
268         struct xlist_head *ibmr_xl;
269         ibmr_xl = xlist_del_head_fast(xl);
270         *ibmr_ret = list_entry(ibmr_xl, struct rds_ib_mr, xlist);
271 }
272
273 static inline struct rds_ib_mr *rds_ib_reuse_fmr(struct rds_ib_mr_pool *pool)
274 {
275         struct rds_ib_mr *ibmr = NULL;
276         struct xlist_head *ret;
277         unsigned long *flag;
278
279         preempt_disable();
280         flag = &__get_cpu_var(clean_list_grace);
281         set_bit(CLEAN_LIST_BUSY_BIT, flag);
282         ret = xlist_del_head(&pool->clean_list);
283         if (ret)
284                 ibmr = list_entry(ret, struct rds_ib_mr, xlist);
285
286         clear_bit(CLEAN_LIST_BUSY_BIT, flag);
287         preempt_enable();
288         return ibmr;
289 }
290
291 static inline void wait_clean_list_grace(void)
292 {
293         int cpu;
294         unsigned long *flag;
295
296         for_each_online_cpu(cpu) {
297                 flag = &per_cpu(clean_list_grace, cpu);
298                 while (test_bit(CLEAN_LIST_BUSY_BIT, flag))
299                         cpu_relax();
300         }
301 }
302
303 static struct rds_ib_mr *rds_ib_alloc_fmr(struct rds_ib_device *rds_ibdev)
304 {
305         struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
306         struct rds_ib_mr *ibmr = NULL;
307         int err = 0, iter = 0;
308
309         if (atomic_read(&pool->dirty_count) >= pool->max_items / 10)
310                 queue_delayed_work(rds_ib_fmr_wq, &pool->flush_worker, 10);
311
312         while (1) {
313                 ibmr = rds_ib_reuse_fmr(pool);
314                 if (ibmr)
315                         return ibmr;
316
317                 /* No clean MRs - now we have the choice of either
318                  * allocating a fresh MR up to the limit imposed by the
319                  * driver, or flush any dirty unused MRs.
320                  * We try to avoid stalling in the send path if possible,
321                  * so we allocate as long as we're allowed to.
322                  *
323                  * We're fussy with enforcing the FMR limit, though. If the driver
324                  * tells us we can't use more than N fmrs, we shouldn't start
325                  * arguing with it */
326                 if (atomic_inc_return(&pool->item_count) <= pool->max_items)
327                         break;
328
329                 atomic_dec(&pool->item_count);
330
331                 if (++iter > 2) {
332                         rds_ib_stats_inc(s_ib_rdma_mr_pool_depleted);
333                         return ERR_PTR(-EAGAIN);
334                 }
335
336                 /* We do have some empty MRs. Flush them out. */
337                 rds_ib_stats_inc(s_ib_rdma_mr_pool_wait);
338                 rds_ib_flush_mr_pool(pool, 0, &ibmr);
339                 if (ibmr)
340                         return ibmr;
341         }
342
343         ibmr = kzalloc_node(sizeof(*ibmr), GFP_KERNEL, rdsibdev_to_node(rds_ibdev));
344         if (!ibmr) {
345                 err = -ENOMEM;
346                 goto out_no_cigar;
347         }
348
349         memset(ibmr, 0, sizeof(*ibmr));
350
351         ibmr->fmr = ib_alloc_fmr(rds_ibdev->pd,
352                         (IB_ACCESS_LOCAL_WRITE |
353                          IB_ACCESS_REMOTE_READ |
354                          IB_ACCESS_REMOTE_WRITE|
355                          IB_ACCESS_REMOTE_ATOMIC),
356                         &pool->fmr_attr);
357         if (IS_ERR(ibmr->fmr)) {
358                 err = PTR_ERR(ibmr->fmr);
359                 ibmr->fmr = NULL;
360                 printk(KERN_WARNING "RDS/IB: ib_alloc_fmr failed (err=%d)\n", err);
361                 goto out_no_cigar;
362         }
363
364         rds_ib_stats_inc(s_ib_rdma_mr_alloc);
365         return ibmr;
366
367 out_no_cigar:
368         if (ibmr) {
369                 if (ibmr->fmr)
370                         ib_dealloc_fmr(ibmr->fmr);
371                 kfree(ibmr);
372         }
373         atomic_dec(&pool->item_count);
374         return ERR_PTR(err);
375 }
376
377 static int rds_ib_map_fmr(struct rds_ib_device *rds_ibdev, struct rds_ib_mr *ibmr,
378                struct scatterlist *sg, unsigned int nents)
379 {
380         struct ib_device *dev = rds_ibdev->dev;
381         struct scatterlist *scat = sg;
382         u64 io_addr = 0;
383         u64 *dma_pages;
384         u32 len;
385         int page_cnt, sg_dma_len;
386         int i, j;
387         int ret;
388
389         sg_dma_len = ib_dma_map_sg(dev, sg, nents,
390                                  DMA_BIDIRECTIONAL);
391         if (unlikely(!sg_dma_len)) {
392                 printk(KERN_WARNING "RDS/IB: dma_map_sg failed!\n");
393                 return -EBUSY;
394         }
395
396         len = 0;
397         page_cnt = 0;
398
399         for (i = 0; i < sg_dma_len; ++i) {
400                 unsigned int dma_len = ib_sg_dma_len(dev, &scat[i]);
401                 u64 dma_addr = ib_sg_dma_address(dev, &scat[i]);
402
403                 if (dma_addr & ~PAGE_MASK) {
404                         if (i > 0)
405                                 return -EINVAL;
406                         else
407                                 ++page_cnt;
408                 }
409                 if ((dma_addr + dma_len) & ~PAGE_MASK) {
410                         if (i < sg_dma_len - 1)
411                                 return -EINVAL;
412                         else
413                                 ++page_cnt;
414                 }
415
416                 len += dma_len;
417         }
418
419         page_cnt += len >> PAGE_SHIFT;
420         if (page_cnt > fmr_message_size)
421                 return -EINVAL;
422
423         dma_pages = kmalloc_node(sizeof(u64) * page_cnt, GFP_ATOMIC,
424                                  rdsibdev_to_node(rds_ibdev));
425         if (!dma_pages)
426                 return -ENOMEM;
427
428         page_cnt = 0;
429         for (i = 0; i < sg_dma_len; ++i) {
430                 unsigned int dma_len = ib_sg_dma_len(dev, &scat[i]);
431                 u64 dma_addr = ib_sg_dma_address(dev, &scat[i]);
432
433                 for (j = 0; j < dma_len; j += PAGE_SIZE)
434                         dma_pages[page_cnt++] =
435                                 (dma_addr & PAGE_MASK) + j;
436         }
437
438         ret = ib_map_phys_fmr(ibmr->fmr,
439                                    dma_pages, page_cnt, io_addr);
440         if (ret)
441                 goto out;
442
443         /* Success - we successfully remapped the MR, so we can
444          * safely tear down the old mapping. */
445         rds_ib_teardown_mr(ibmr);
446
447         ibmr->sg = scat;
448         ibmr->sg_len = nents;
449         ibmr->sg_dma_len = sg_dma_len;
450         ibmr->remap_count++;
451
452         rds_ib_stats_inc(s_ib_rdma_mr_used);
453         ret = 0;
454
455 out:
456         kfree(dma_pages);
457
458         return ret;
459 }
460
461 void rds_ib_sync_mr(void *trans_private, int direction)
462 {
463         struct rds_ib_mr *ibmr = trans_private;
464         struct rds_ib_device *rds_ibdev = ibmr->device;
465
466         switch (direction) {
467         case DMA_FROM_DEVICE:
468                 ib_dma_sync_sg_for_cpu(rds_ibdev->dev, ibmr->sg,
469                         ibmr->sg_dma_len, DMA_BIDIRECTIONAL);
470                 break;
471         case DMA_TO_DEVICE:
472                 ib_dma_sync_sg_for_device(rds_ibdev->dev, ibmr->sg,
473                         ibmr->sg_dma_len, DMA_BIDIRECTIONAL);
474                 break;
475         }
476 }
477
478 static void __rds_ib_teardown_mr(struct rds_ib_mr *ibmr)
479 {
480         struct rds_ib_device *rds_ibdev = ibmr->device;
481
482         if (ibmr->sg_dma_len) {
483                 ib_dma_unmap_sg(rds_ibdev->dev,
484                                 ibmr->sg, ibmr->sg_len,
485                                 DMA_BIDIRECTIONAL);
486                 ibmr->sg_dma_len = 0;
487         }
488
489         /* Release the s/g list */
490         if (ibmr->sg_len) {
491                 unsigned int i;
492
493                 for (i = 0; i < ibmr->sg_len; ++i) {
494                         struct page *page = sg_page(&ibmr->sg[i]);
495
496                         /* FIXME we need a way to tell a r/w MR
497                          * from a r/o MR */
498                         BUG_ON(irqs_disabled());
499                         set_page_dirty(page);
500                         put_page(page);
501                 }
502                 kfree(ibmr->sg);
503
504                 ibmr->sg = NULL;
505                 ibmr->sg_len = 0;
506         }
507 }
508
509 static void rds_ib_teardown_mr(struct rds_ib_mr *ibmr)
510 {
511         unsigned int pinned = ibmr->sg_len;
512
513         __rds_ib_teardown_mr(ibmr);
514         if (pinned) {
515                 struct rds_ib_device *rds_ibdev = ibmr->device;
516                 struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
517
518                 atomic_sub(pinned, &pool->free_pinned);
519         }
520 }
521
522 static inline unsigned int rds_ib_flush_goal(struct rds_ib_mr_pool *pool, int free_all)
523 {
524         unsigned int item_count;
525
526         item_count = atomic_read(&pool->item_count);
527         if (free_all)
528                 return item_count;
529
530         return 0;
531 }
532
533 /*
534  * given an xlist of mrs, put them all into the list_head for more processing
535  */
536 static void xlist_append_to_list(struct xlist_head *xlist, struct list_head *list)
537 {
538         struct rds_ib_mr *ibmr;
539         struct xlist_head splice;
540         struct xlist_head *cur;
541         struct xlist_head *next;
542
543         splice.next = NULL;
544         xlist_splice(xlist, &splice);
545         cur = splice.next;
546         while (cur) {
547                 next = cur->next;
548                 ibmr = list_entry(cur, struct rds_ib_mr, xlist);
549                 list_add_tail(&ibmr->unmap_list, list);
550                 cur = next;
551         }
552 }
553
554 /*
555  * this takes a list head of mrs and turns it into an xlist of clusters.
556  * each cluster has an xlist of MR_CLUSTER_SIZE mrs that are ready for
557  * reuse.
558  */
559 static void list_append_to_xlist(struct rds_ib_mr_pool *pool,
560                                 struct list_head *list, struct xlist_head *xlist,
561                                 struct xlist_head **tail_ret)
562 {
563         struct rds_ib_mr *ibmr;
564         struct xlist_head *cur_mr = xlist;
565         struct xlist_head *tail_mr = NULL;
566
567         list_for_each_entry(ibmr, list, unmap_list) {
568                 tail_mr = &ibmr->xlist;
569                 tail_mr->next = NULL;
570                 cur_mr->next = tail_mr;
571                 cur_mr = tail_mr;
572         }
573         *tail_ret = tail_mr;
574 }
575
576 /*
577  * Flush our pool of MRs.
578  * At a minimum, all currently unused MRs are unmapped.
579  * If the number of MRs allocated exceeds the limit, we also try
580  * to free as many MRs as needed to get back to this limit.
581  */
582 static int rds_ib_flush_mr_pool(struct rds_ib_mr_pool *pool,
583                                 int free_all, struct rds_ib_mr **ibmr_ret)
584 {
585         struct rds_ib_mr *ibmr, *next;
586         struct xlist_head clean_xlist;
587         struct xlist_head *clean_tail;
588         LIST_HEAD(unmap_list);
589         LIST_HEAD(fmr_list);
590         unsigned long unpinned = 0;
591         unsigned int nfreed = 0, ncleaned = 0, free_goal;
592         int ret = 0;
593
594         rds_ib_stats_inc(s_ib_rdma_mr_pool_flush);
595
596         if (ibmr_ret) {
597                 DEFINE_WAIT(wait);
598                 while(!mutex_trylock(&pool->flush_lock)) {
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                         prepare_to_wait(&pool->flush_wait, &wait,
607                                         TASK_UNINTERRUPTIBLE);
608                         if (xlist_empty(&pool->clean_list))
609                                 schedule();
610
611                         ibmr = rds_ib_reuse_fmr(pool);
612                         if (ibmr) {
613                                 *ibmr_ret = ibmr;
614                                 finish_wait(&pool->flush_wait, &wait);
615                                 goto out_nolock;
616                         }
617                 }
618                 finish_wait(&pool->flush_wait, &wait);
619         } else
620                 mutex_lock(&pool->flush_lock);
621
622         if (ibmr_ret) {
623                 ibmr = rds_ib_reuse_fmr(pool);
624                 if (ibmr) {
625                         *ibmr_ret = ibmr;
626                         goto out;
627                 }
628         }
629
630         /* Get the list of all MRs to be dropped. Ordering matters -
631          * we want to put drop_list ahead of free_list.
632          */
633         xlist_append_to_list(&pool->drop_list, &unmap_list);
634         xlist_append_to_list(&pool->free_list, &unmap_list);
635         if (free_all)
636                 xlist_append_to_list(&pool->clean_list, &unmap_list);
637
638         free_goal = rds_ib_flush_goal(pool, free_all);
639
640         if (list_empty(&unmap_list))
641                 goto out;
642
643         /* String all ib_mr's onto one list and hand them to ib_unmap_fmr */
644         list_for_each_entry(ibmr, &unmap_list, unmap_list)
645                 list_add(&ibmr->fmr->list, &fmr_list);
646
647         ret = ib_unmap_fmr(&fmr_list);
648         if (ret)
649                 printk(KERN_WARNING "RDS/IB: ib_unmap_fmr failed (err=%d)\n", ret);
650
651         /* Now we can destroy the DMA mapping and unpin any pages */
652         list_for_each_entry_safe(ibmr, next, &unmap_list, unmap_list) {
653                 unpinned += ibmr->sg_len;
654                 __rds_ib_teardown_mr(ibmr);
655                 if (nfreed < free_goal || ibmr->remap_count >= pool->fmr_attr.max_maps) {
656                         rds_ib_stats_inc(s_ib_rdma_mr_free);
657                         list_del(&ibmr->unmap_list);
658                         ib_dealloc_fmr(ibmr->fmr);
659                         kfree(ibmr);
660                         nfreed++;
661                 }
662                 ncleaned++;
663         }
664
665         if (!list_empty(&unmap_list)) {
666                 /* we have to make sure that none of the things we're about
667                  * to put on the clean list would race with other cpus trying
668                  * to pull items off.  The xlist would explode if we managed to
669                  * remove something from the clean list and then add it back again
670                  * while another CPU was spinning on that same item in xlist_del_head.
671                  *
672                  * This is pretty unlikely, but just in case  wait for an xlist grace period
673                  * here before adding anything back into the clean list.
674                  */
675                 wait_clean_list_grace();
676
677                 list_append_to_xlist(pool, &unmap_list, &clean_xlist, &clean_tail);
678                 if (ibmr_ret)
679                         refill_local(pool, &clean_xlist, ibmr_ret);
680
681                 /* refill_local may have emptied our list */
682                 if (!xlist_empty(&clean_xlist))
683                         xlist_add(clean_xlist.next, clean_tail, &pool->clean_list);
684
685         }
686
687         atomic_sub(unpinned, &pool->free_pinned);
688         atomic_sub(ncleaned, &pool->dirty_count);
689         atomic_sub(nfreed, &pool->item_count);
690
691 out:
692         mutex_unlock(&pool->flush_lock);
693         if (waitqueue_active(&pool->flush_wait))
694                 wake_up(&pool->flush_wait);
695 out_nolock:
696         return ret;
697 }
698
699 int rds_ib_fmr_init(void)
700 {
701         rds_ib_fmr_wq = create_workqueue("rds_fmr_flushd");
702         if (!rds_ib_fmr_wq)
703                 return -ENOMEM;
704         return 0;
705 }
706
707 /*
708  * By the time this is called all the IB devices should have been torn down and
709  * had their pools freed.  As each pool is freed its work struct is waited on,
710  * so the pool flushing work queue should be idle by the time we get here.
711  */
712 void rds_ib_fmr_exit(void)
713 {
714         destroy_workqueue(rds_ib_fmr_wq);
715 }
716
717 static void rds_ib_mr_pool_flush_worker(struct work_struct *work)
718 {
719         struct rds_ib_mr_pool *pool = container_of(work, struct rds_ib_mr_pool, flush_worker.work);
720
721         rds_ib_flush_mr_pool(pool, 0, NULL);
722 }
723
724 void rds_ib_free_mr(void *trans_private, int invalidate)
725 {
726         struct rds_ib_mr *ibmr = trans_private;
727         struct rds_ib_device *rds_ibdev = ibmr->device;
728         struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
729
730         rdsdebug("RDS/IB: free_mr nents %u\n", ibmr->sg_len);
731
732         /* Return it to the pool's free list */
733         if (ibmr->remap_count >= pool->fmr_attr.max_maps)
734                 xlist_add(&ibmr->xlist, &ibmr->xlist, &pool->drop_list);
735         else
736                 xlist_add(&ibmr->xlist, &ibmr->xlist, &pool->free_list);
737
738         atomic_add(ibmr->sg_len, &pool->free_pinned);
739         atomic_inc(&pool->dirty_count);
740
741         /* If we've pinned too many pages, request a flush */
742         if (atomic_read(&pool->free_pinned) >= pool->max_free_pinned ||
743             atomic_read(&pool->dirty_count) >= pool->max_items / 10)
744                 queue_delayed_work(rds_ib_fmr_wq, &pool->flush_worker, 10);
745
746         if (invalidate) {
747                 if (likely(!in_interrupt())) {
748                         rds_ib_flush_mr_pool(pool, 0, NULL);
749                 } else {
750                         /* We get here if the user created a MR marked
751                          * as use_once and invalidate at the same time. */
752                         queue_delayed_work(rds_ib_fmr_wq,
753                                            &pool->flush_worker, 10);
754                 }
755         }
756
757         rds_ib_dev_put(rds_ibdev);
758 }
759
760 void rds_ib_flush_mrs(void)
761 {
762         struct rds_ib_device *rds_ibdev;
763
764         down_read(&rds_ib_devices_lock);
765         list_for_each_entry(rds_ibdev, &rds_ib_devices, list) {
766                 struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
767
768                 if (pool)
769                         rds_ib_flush_mr_pool(pool, 0, NULL);
770         }
771         up_read(&rds_ib_devices_lock);
772 }
773
774 void *rds_ib_get_mr(struct scatterlist *sg, unsigned long nents,
775                     struct rds_sock *rs, u32 *key_ret)
776 {
777         struct rds_ib_device *rds_ibdev;
778         struct rds_ib_mr *ibmr = NULL;
779         int ret;
780
781         rds_ibdev = rds_ib_get_device(rs->rs_bound_addr);
782         if (!rds_ibdev) {
783                 ret = -ENODEV;
784                 goto out;
785         }
786
787         if (!rds_ibdev->mr_pool) {
788                 ret = -ENODEV;
789                 goto out;
790         }
791
792         ibmr = rds_ib_alloc_fmr(rds_ibdev);
793         if (IS_ERR(ibmr))
794                 return ibmr;
795
796         ret = rds_ib_map_fmr(rds_ibdev, ibmr, sg, nents);
797         if (ret == 0)
798                 *key_ret = ibmr->fmr->rkey;
799         else
800                 printk(KERN_WARNING "RDS/IB: map_fmr failed (errno=%d)\n", ret);
801
802         ibmr->device = rds_ibdev;
803         rds_ibdev = NULL;
804
805  out:
806         if (ret) {
807                 if (ibmr)
808                         rds_ib_free_mr(ibmr, 0);
809                 ibmr = ERR_PTR(ret);
810         }
811         if (rds_ibdev)
812                 rds_ib_dev_put(rds_ibdev);
813         return ibmr;
814 }
815