RDS/IB: Always use PAGE_SIZE for FMR page size
[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
35 #include "rds.h"
36 #include "rdma.h"
37 #include "ib.h"
38
39
40 /*
41  * This is stored as mr->r_trans_private.
42  */
43 struct rds_ib_mr {
44         struct rds_ib_device    *device;
45         struct rds_ib_mr_pool   *pool;
46         struct ib_fmr           *fmr;
47         struct list_head        list;
48         unsigned int            remap_count;
49
50         struct scatterlist      *sg;
51         unsigned int            sg_len;
52         u64                     *dma;
53         int                     sg_dma_len;
54 };
55
56 /*
57  * Our own little FMR pool
58  */
59 struct rds_ib_mr_pool {
60         struct mutex            flush_lock;             /* serialize fmr invalidate */
61         struct work_struct      flush_worker;           /* flush worker */
62
63         spinlock_t              list_lock;              /* protect variables below */
64         atomic_t                item_count;             /* total # of MRs */
65         atomic_t                dirty_count;            /* # dirty of MRs */
66         struct list_head        drop_list;              /* MRs that have reached their max_maps limit */
67         struct list_head        free_list;              /* unused MRs */
68         struct list_head        clean_list;             /* unused & unamapped MRs */
69         atomic_t                free_pinned;            /* memory pinned by free MRs */
70         unsigned long           max_items;
71         unsigned long           max_items_soft;
72         unsigned long           max_free_pinned;
73         struct ib_fmr_attr      fmr_attr;
74 };
75
76 static int rds_ib_flush_mr_pool(struct rds_ib_mr_pool *pool, int free_all);
77 static void rds_ib_teardown_mr(struct rds_ib_mr *ibmr);
78 static void rds_ib_mr_pool_flush_worker(struct work_struct *work);
79
80 static struct rds_ib_device *rds_ib_get_device(__be32 ipaddr)
81 {
82         struct rds_ib_device *rds_ibdev;
83         struct rds_ib_ipaddr *i_ipaddr;
84
85         list_for_each_entry(rds_ibdev, &rds_ib_devices, list) {
86                 spin_lock_irq(&rds_ibdev->spinlock);
87                 list_for_each_entry(i_ipaddr, &rds_ibdev->ipaddr_list, list) {
88                         if (i_ipaddr->ipaddr == ipaddr) {
89                                 spin_unlock_irq(&rds_ibdev->spinlock);
90                                 return rds_ibdev;
91                         }
92                 }
93                 spin_unlock_irq(&rds_ibdev->spinlock);
94         }
95
96         return NULL;
97 }
98
99 static int rds_ib_add_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
100 {
101         struct rds_ib_ipaddr *i_ipaddr;
102
103         i_ipaddr = kmalloc(sizeof *i_ipaddr, GFP_KERNEL);
104         if (!i_ipaddr)
105                 return -ENOMEM;
106
107         i_ipaddr->ipaddr = ipaddr;
108
109         spin_lock_irq(&rds_ibdev->spinlock);
110         list_add_tail(&i_ipaddr->list, &rds_ibdev->ipaddr_list);
111         spin_unlock_irq(&rds_ibdev->spinlock);
112
113         return 0;
114 }
115
116 static void rds_ib_remove_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
117 {
118         struct rds_ib_ipaddr *i_ipaddr, *next;
119
120         spin_lock_irq(&rds_ibdev->spinlock);
121         list_for_each_entry_safe(i_ipaddr, next, &rds_ibdev->ipaddr_list, list) {
122                 if (i_ipaddr->ipaddr == ipaddr) {
123                         list_del(&i_ipaddr->list);
124                         kfree(i_ipaddr);
125                         break;
126                 }
127         }
128         spin_unlock_irq(&rds_ibdev->spinlock);
129 }
130
131 int rds_ib_update_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
132 {
133         struct rds_ib_device *rds_ibdev_old;
134
135         rds_ibdev_old = rds_ib_get_device(ipaddr);
136         if (rds_ibdev_old)
137                 rds_ib_remove_ipaddr(rds_ibdev_old, ipaddr);
138
139         return rds_ib_add_ipaddr(rds_ibdev, ipaddr);
140 }
141
142 void rds_ib_add_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *conn)
143 {
144         struct rds_ib_connection *ic = conn->c_transport_data;
145
146         /* conn was previously on the nodev_conns_list */
147         spin_lock_irq(&ib_nodev_conns_lock);
148         BUG_ON(list_empty(&ib_nodev_conns));
149         BUG_ON(list_empty(&ic->ib_node));
150         list_del(&ic->ib_node);
151
152         spin_lock_irq(&rds_ibdev->spinlock);
153         list_add_tail(&ic->ib_node, &rds_ibdev->conn_list);
154         spin_unlock_irq(&rds_ibdev->spinlock);
155         spin_unlock_irq(&ib_nodev_conns_lock);
156
157         ic->rds_ibdev = rds_ibdev;
158 }
159
160 void rds_ib_remove_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *conn)
161 {
162         struct rds_ib_connection *ic = conn->c_transport_data;
163
164         /* place conn on nodev_conns_list */
165         spin_lock(&ib_nodev_conns_lock);
166
167         spin_lock_irq(&rds_ibdev->spinlock);
168         BUG_ON(list_empty(&ic->ib_node));
169         list_del(&ic->ib_node);
170         spin_unlock_irq(&rds_ibdev->spinlock);
171
172         list_add_tail(&ic->ib_node, &ib_nodev_conns);
173
174         spin_unlock(&ib_nodev_conns_lock);
175
176         ic->rds_ibdev = NULL;
177 }
178
179 void __rds_ib_destroy_conns(struct list_head *list, spinlock_t *list_lock)
180 {
181         struct rds_ib_connection *ic, *_ic;
182         LIST_HEAD(tmp_list);
183
184         /* avoid calling conn_destroy with irqs off */
185         spin_lock_irq(list_lock);
186         list_splice(list, &tmp_list);
187         INIT_LIST_HEAD(list);
188         spin_unlock_irq(list_lock);
189
190         list_for_each_entry_safe(ic, _ic, &tmp_list, ib_node) {
191                 if (ic->conn->c_passive)
192                         rds_conn_destroy(ic->conn->c_passive);
193                 rds_conn_destroy(ic->conn);
194         }
195 }
196
197 struct rds_ib_mr_pool *rds_ib_create_mr_pool(struct rds_ib_device *rds_ibdev)
198 {
199         struct rds_ib_mr_pool *pool;
200
201         pool = kzalloc(sizeof(*pool), GFP_KERNEL);
202         if (!pool)
203                 return ERR_PTR(-ENOMEM);
204
205         INIT_LIST_HEAD(&pool->free_list);
206         INIT_LIST_HEAD(&pool->drop_list);
207         INIT_LIST_HEAD(&pool->clean_list);
208         mutex_init(&pool->flush_lock);
209         spin_lock_init(&pool->list_lock);
210         INIT_WORK(&pool->flush_worker, rds_ib_mr_pool_flush_worker);
211
212         pool->fmr_attr.max_pages = fmr_message_size;
213         pool->fmr_attr.max_maps = rds_ibdev->fmr_max_remaps;
214         pool->fmr_attr.page_shift = PAGE_SHIFT;
215         pool->max_free_pinned = rds_ibdev->max_fmrs * fmr_message_size / 4;
216
217         /* We never allow more than max_items MRs to be allocated.
218          * When we exceed more than max_items_soft, we start freeing
219          * items more aggressively.
220          * Make sure that max_items > max_items_soft > max_items / 2
221          */
222         pool->max_items_soft = rds_ibdev->max_fmrs * 3 / 4;
223         pool->max_items = rds_ibdev->max_fmrs;
224
225         return pool;
226 }
227
228 void rds_ib_get_mr_info(struct rds_ib_device *rds_ibdev, struct rds_info_rdma_connection *iinfo)
229 {
230         struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
231
232         iinfo->rdma_mr_max = pool->max_items;
233         iinfo->rdma_mr_size = pool->fmr_attr.max_pages;
234 }
235
236 void rds_ib_destroy_mr_pool(struct rds_ib_mr_pool *pool)
237 {
238         flush_workqueue(rds_wq);
239         rds_ib_flush_mr_pool(pool, 1);
240         BUG_ON(atomic_read(&pool->item_count));
241         BUG_ON(atomic_read(&pool->free_pinned));
242         kfree(pool);
243 }
244
245 static inline struct rds_ib_mr *rds_ib_reuse_fmr(struct rds_ib_mr_pool *pool)
246 {
247         struct rds_ib_mr *ibmr = NULL;
248         unsigned long flags;
249
250         spin_lock_irqsave(&pool->list_lock, flags);
251         if (!list_empty(&pool->clean_list)) {
252                 ibmr = list_entry(pool->clean_list.next, struct rds_ib_mr, list);
253                 list_del_init(&ibmr->list);
254         }
255         spin_unlock_irqrestore(&pool->list_lock, flags);
256
257         return ibmr;
258 }
259
260 static struct rds_ib_mr *rds_ib_alloc_fmr(struct rds_ib_device *rds_ibdev)
261 {
262         struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
263         struct rds_ib_mr *ibmr = NULL;
264         int err = 0, iter = 0;
265
266         while (1) {
267                 ibmr = rds_ib_reuse_fmr(pool);
268                 if (ibmr)
269                         return ibmr;
270
271                 /* No clean MRs - now we have the choice of either
272                  * allocating a fresh MR up to the limit imposed by the
273                  * driver, or flush any dirty unused MRs.
274                  * We try to avoid stalling in the send path if possible,
275                  * so we allocate as long as we're allowed to.
276                  *
277                  * We're fussy with enforcing the FMR limit, though. If the driver
278                  * tells us we can't use more than N fmrs, we shouldn't start
279                  * arguing with it */
280                 if (atomic_inc_return(&pool->item_count) <= pool->max_items)
281                         break;
282
283                 atomic_dec(&pool->item_count);
284
285                 if (++iter > 2) {
286                         rds_ib_stats_inc(s_ib_rdma_mr_pool_depleted);
287                         return ERR_PTR(-EAGAIN);
288                 }
289
290                 /* We do have some empty MRs. Flush them out. */
291                 rds_ib_stats_inc(s_ib_rdma_mr_pool_wait);
292                 rds_ib_flush_mr_pool(pool, 0);
293         }
294
295         ibmr = kzalloc(sizeof(*ibmr), GFP_KERNEL);
296         if (!ibmr) {
297                 err = -ENOMEM;
298                 goto out_no_cigar;
299         }
300
301         ibmr->fmr = ib_alloc_fmr(rds_ibdev->pd,
302                         (IB_ACCESS_LOCAL_WRITE |
303                          IB_ACCESS_REMOTE_READ |
304                          IB_ACCESS_REMOTE_WRITE),
305                         &pool->fmr_attr);
306         if (IS_ERR(ibmr->fmr)) {
307                 err = PTR_ERR(ibmr->fmr);
308                 ibmr->fmr = NULL;
309                 printk(KERN_WARNING "RDS/IB: ib_alloc_fmr failed (err=%d)\n", err);
310                 goto out_no_cigar;
311         }
312
313         rds_ib_stats_inc(s_ib_rdma_mr_alloc);
314         return ibmr;
315
316 out_no_cigar:
317         if (ibmr) {
318                 if (ibmr->fmr)
319                         ib_dealloc_fmr(ibmr->fmr);
320                 kfree(ibmr);
321         }
322         atomic_dec(&pool->item_count);
323         return ERR_PTR(err);
324 }
325
326 static int rds_ib_map_fmr(struct rds_ib_device *rds_ibdev, struct rds_ib_mr *ibmr,
327                struct scatterlist *sg, unsigned int nents)
328 {
329         struct ib_device *dev = rds_ibdev->dev;
330         struct scatterlist *scat = sg;
331         u64 io_addr = 0;
332         u64 *dma_pages;
333         u32 len;
334         int page_cnt, sg_dma_len;
335         int i, j;
336         int ret;
337
338         sg_dma_len = ib_dma_map_sg(dev, sg, nents,
339                                  DMA_BIDIRECTIONAL);
340         if (unlikely(!sg_dma_len)) {
341                 printk(KERN_WARNING "RDS/IB: dma_map_sg failed!\n");
342                 return -EBUSY;
343         }
344
345         len = 0;
346         page_cnt = 0;
347
348         for (i = 0; i < sg_dma_len; ++i) {
349                 unsigned int dma_len = ib_sg_dma_len(dev, &scat[i]);
350                 u64 dma_addr = ib_sg_dma_address(dev, &scat[i]);
351
352                 if (dma_addr & ~PAGE_MASK) {
353                         if (i > 0)
354                                 return -EINVAL;
355                         else
356                                 ++page_cnt;
357                 }
358                 if ((dma_addr + dma_len) & ~PAGE_MASK) {
359                         if (i < sg_dma_len - 1)
360                                 return -EINVAL;
361                         else
362                                 ++page_cnt;
363                 }
364
365                 len += dma_len;
366         }
367
368         page_cnt += len >> PAGE_SHIFT;
369         if (page_cnt > fmr_message_size)
370                 return -EINVAL;
371
372         dma_pages = kmalloc(sizeof(u64) * page_cnt, GFP_ATOMIC);
373         if (!dma_pages)
374                 return -ENOMEM;
375
376         page_cnt = 0;
377         for (i = 0; i < sg_dma_len; ++i) {
378                 unsigned int dma_len = ib_sg_dma_len(dev, &scat[i]);
379                 u64 dma_addr = ib_sg_dma_address(dev, &scat[i]);
380
381                 for (j = 0; j < dma_len; j += PAGE_SIZE)
382                         dma_pages[page_cnt++] =
383                                 (dma_addr & PAGE_MASK) + j;
384         }
385
386         ret = ib_map_phys_fmr(ibmr->fmr,
387                                    dma_pages, page_cnt, io_addr);
388         if (ret)
389                 goto out;
390
391         /* Success - we successfully remapped the MR, so we can
392          * safely tear down the old mapping. */
393         rds_ib_teardown_mr(ibmr);
394
395         ibmr->sg = scat;
396         ibmr->sg_len = nents;
397         ibmr->sg_dma_len = sg_dma_len;
398         ibmr->remap_count++;
399
400         rds_ib_stats_inc(s_ib_rdma_mr_used);
401         ret = 0;
402
403 out:
404         kfree(dma_pages);
405
406         return ret;
407 }
408
409 void rds_ib_sync_mr(void *trans_private, int direction)
410 {
411         struct rds_ib_mr *ibmr = trans_private;
412         struct rds_ib_device *rds_ibdev = ibmr->device;
413
414         switch (direction) {
415         case DMA_FROM_DEVICE:
416                 ib_dma_sync_sg_for_cpu(rds_ibdev->dev, ibmr->sg,
417                         ibmr->sg_dma_len, DMA_BIDIRECTIONAL);
418                 break;
419         case DMA_TO_DEVICE:
420                 ib_dma_sync_sg_for_device(rds_ibdev->dev, ibmr->sg,
421                         ibmr->sg_dma_len, DMA_BIDIRECTIONAL);
422                 break;
423         }
424 }
425
426 static void __rds_ib_teardown_mr(struct rds_ib_mr *ibmr)
427 {
428         struct rds_ib_device *rds_ibdev = ibmr->device;
429
430         if (ibmr->sg_dma_len) {
431                 ib_dma_unmap_sg(rds_ibdev->dev,
432                                 ibmr->sg, ibmr->sg_len,
433                                 DMA_BIDIRECTIONAL);
434                 ibmr->sg_dma_len = 0;
435         }
436
437         /* Release the s/g list */
438         if (ibmr->sg_len) {
439                 unsigned int i;
440
441                 for (i = 0; i < ibmr->sg_len; ++i) {
442                         struct page *page = sg_page(&ibmr->sg[i]);
443
444                         /* FIXME we need a way to tell a r/w MR
445                          * from a r/o MR */
446                         set_page_dirty(page);
447                         put_page(page);
448                 }
449                 kfree(ibmr->sg);
450
451                 ibmr->sg = NULL;
452                 ibmr->sg_len = 0;
453         }
454 }
455
456 static void rds_ib_teardown_mr(struct rds_ib_mr *ibmr)
457 {
458         unsigned int pinned = ibmr->sg_len;
459
460         __rds_ib_teardown_mr(ibmr);
461         if (pinned) {
462                 struct rds_ib_device *rds_ibdev = ibmr->device;
463                 struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
464
465                 atomic_sub(pinned, &pool->free_pinned);
466         }
467 }
468
469 static inline unsigned int rds_ib_flush_goal(struct rds_ib_mr_pool *pool, int free_all)
470 {
471         unsigned int item_count;
472
473         item_count = atomic_read(&pool->item_count);
474         if (free_all)
475                 return item_count;
476
477         return 0;
478 }
479
480 /*
481  * Flush our pool of MRs.
482  * At a minimum, all currently unused MRs are unmapped.
483  * If the number of MRs allocated exceeds the limit, we also try
484  * to free as many MRs as needed to get back to this limit.
485  */
486 static int rds_ib_flush_mr_pool(struct rds_ib_mr_pool *pool, int free_all)
487 {
488         struct rds_ib_mr *ibmr, *next;
489         LIST_HEAD(unmap_list);
490         LIST_HEAD(fmr_list);
491         unsigned long unpinned = 0;
492         unsigned long flags;
493         unsigned int nfreed = 0, ncleaned = 0, free_goal;
494         int ret = 0;
495
496         rds_ib_stats_inc(s_ib_rdma_mr_pool_flush);
497
498         mutex_lock(&pool->flush_lock);
499
500         spin_lock_irqsave(&pool->list_lock, flags);
501         /* Get the list of all MRs to be dropped. Ordering matters -
502          * we want to put drop_list ahead of free_list. */
503         list_splice_init(&pool->free_list, &unmap_list);
504         list_splice_init(&pool->drop_list, &unmap_list);
505         if (free_all)
506                 list_splice_init(&pool->clean_list, &unmap_list);
507         spin_unlock_irqrestore(&pool->list_lock, flags);
508
509         free_goal = rds_ib_flush_goal(pool, free_all);
510
511         if (list_empty(&unmap_list))
512                 goto out;
513
514         /* String all ib_mr's onto one list and hand them to ib_unmap_fmr */
515         list_for_each_entry(ibmr, &unmap_list, list)
516                 list_add(&ibmr->fmr->list, &fmr_list);
517         ret = ib_unmap_fmr(&fmr_list);
518         if (ret)
519                 printk(KERN_WARNING "RDS/IB: ib_unmap_fmr failed (err=%d)\n", ret);
520
521         /* Now we can destroy the DMA mapping and unpin any pages */
522         list_for_each_entry_safe(ibmr, next, &unmap_list, list) {
523                 unpinned += ibmr->sg_len;
524                 __rds_ib_teardown_mr(ibmr);
525                 if (nfreed < free_goal || ibmr->remap_count >= pool->fmr_attr.max_maps) {
526                         rds_ib_stats_inc(s_ib_rdma_mr_free);
527                         list_del(&ibmr->list);
528                         ib_dealloc_fmr(ibmr->fmr);
529                         kfree(ibmr);
530                         nfreed++;
531                 }
532                 ncleaned++;
533         }
534
535         spin_lock_irqsave(&pool->list_lock, flags);
536         list_splice(&unmap_list, &pool->clean_list);
537         spin_unlock_irqrestore(&pool->list_lock, flags);
538
539         atomic_sub(unpinned, &pool->free_pinned);
540         atomic_sub(ncleaned, &pool->dirty_count);
541         atomic_sub(nfreed, &pool->item_count);
542
543 out:
544         mutex_unlock(&pool->flush_lock);
545         return ret;
546 }
547
548 static void rds_ib_mr_pool_flush_worker(struct work_struct *work)
549 {
550         struct rds_ib_mr_pool *pool = container_of(work, struct rds_ib_mr_pool, flush_worker);
551
552         rds_ib_flush_mr_pool(pool, 0);
553 }
554
555 void rds_ib_free_mr(void *trans_private, int invalidate)
556 {
557         struct rds_ib_mr *ibmr = trans_private;
558         struct rds_ib_device *rds_ibdev = ibmr->device;
559         struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
560         unsigned long flags;
561
562         rdsdebug("RDS/IB: free_mr nents %u\n", ibmr->sg_len);
563
564         /* Return it to the pool's free list */
565         spin_lock_irqsave(&pool->list_lock, flags);
566         if (ibmr->remap_count >= pool->fmr_attr.max_maps)
567                 list_add(&ibmr->list, &pool->drop_list);
568         else
569                 list_add(&ibmr->list, &pool->free_list);
570
571         atomic_add(ibmr->sg_len, &pool->free_pinned);
572         atomic_inc(&pool->dirty_count);
573         spin_unlock_irqrestore(&pool->list_lock, flags);
574
575         /* If we've pinned too many pages, request a flush */
576         if (atomic_read(&pool->free_pinned) >= pool->max_free_pinned
577          || atomic_read(&pool->dirty_count) >= pool->max_items / 10)
578                 queue_work(rds_wq, &pool->flush_worker);
579
580         if (invalidate) {
581                 if (likely(!in_interrupt())) {
582                         rds_ib_flush_mr_pool(pool, 0);
583                 } else {
584                         /* We get here if the user created a MR marked
585                          * as use_once and invalidate at the same time. */
586                         queue_work(rds_wq, &pool->flush_worker);
587                 }
588         }
589 }
590
591 void rds_ib_flush_mrs(void)
592 {
593         struct rds_ib_device *rds_ibdev;
594
595         list_for_each_entry(rds_ibdev, &rds_ib_devices, list) {
596                 struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool;
597
598                 if (pool)
599                         rds_ib_flush_mr_pool(pool, 0);
600         }
601 }
602
603 void *rds_ib_get_mr(struct scatterlist *sg, unsigned long nents,
604                     struct rds_sock *rs, u32 *key_ret)
605 {
606         struct rds_ib_device *rds_ibdev;
607         struct rds_ib_mr *ibmr = NULL;
608         int ret;
609
610         rds_ibdev = rds_ib_get_device(rs->rs_bound_addr);
611         if (!rds_ibdev) {
612                 ret = -ENODEV;
613                 goto out;
614         }
615
616         if (!rds_ibdev->mr_pool) {
617                 ret = -ENODEV;
618                 goto out;
619         }
620
621         ibmr = rds_ib_alloc_fmr(rds_ibdev);
622         if (IS_ERR(ibmr))
623                 return ibmr;
624
625         ret = rds_ib_map_fmr(rds_ibdev, ibmr, sg, nents);
626         if (ret == 0)
627                 *key_ret = ibmr->fmr->rkey;
628         else
629                 printk(KERN_WARNING "RDS/IB: map_fmr failed (errno=%d)\n", ret);
630
631         ibmr->device = rds_ibdev;
632
633  out:
634         if (ret) {
635                 if (ibmr)
636                         rds_ib_free_mr(ibmr, 0);
637                 ibmr = ERR_PTR(ret);
638         }
639         return ibmr;
640 }