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RDS: Remove some unused iWARP code
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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/ratelimit.h>
36
37 #include "rds.h"
38 #include "iw.h"
39
40
41 /*
42  * This is stored as mr->r_trans_private.
43  */
44 struct rds_iw_mr {
45         struct rds_iw_device    *device;
46         struct rds_iw_mr_pool   *pool;
47         struct rdma_cm_id       *cm_id;
48
49         struct ib_mr    *mr;
50         struct ib_fast_reg_page_list *page_list;
51
52         struct rds_iw_mapping   mapping;
53         unsigned char           remap_count;
54 };
55
56 /*
57  * Our own little MR pool
58  */
59 struct rds_iw_mr_pool {
60         struct rds_iw_device    *device;                /* back ptr to the device that owns us */
61
62         struct mutex            flush_lock;             /* serialize fmr invalidate */
63         struct work_struct      flush_worker;           /* flush worker */
64
65         spinlock_t              list_lock;              /* protect variables below */
66         atomic_t                item_count;             /* total # of MRs */
67         atomic_t                dirty_count;            /* # dirty of MRs */
68         struct list_head        dirty_list;             /* dirty mappings */
69         struct list_head        clean_list;             /* unused & unamapped MRs */
70         atomic_t                free_pinned;            /* memory pinned by free MRs */
71         unsigned long           max_message_size;       /* in pages */
72         unsigned long           max_items;
73         unsigned long           max_items_soft;
74         unsigned long           max_free_pinned;
75         int                     max_pages;
76 };
77
78 static int rds_iw_flush_mr_pool(struct rds_iw_mr_pool *pool, int free_all);
79 static void rds_iw_mr_pool_flush_worker(struct work_struct *work);
80 static int rds_iw_init_fastreg(struct rds_iw_mr_pool *pool, struct rds_iw_mr *ibmr);
81 static int rds_iw_map_fastreg(struct rds_iw_mr_pool *pool,
82                           struct rds_iw_mr *ibmr,
83                           struct scatterlist *sg, unsigned int nents);
84 static void rds_iw_free_fastreg(struct rds_iw_mr_pool *pool, struct rds_iw_mr *ibmr);
85 static unsigned int rds_iw_unmap_fastreg_list(struct rds_iw_mr_pool *pool,
86                         struct list_head *unmap_list,
87                         struct list_head *kill_list,
88                         int *unpinned);
89 static void rds_iw_destroy_fastreg(struct rds_iw_mr_pool *pool, struct rds_iw_mr *ibmr);
90
91 static int rds_iw_get_device(struct rds_sock *rs, struct rds_iw_device **rds_iwdev, struct rdma_cm_id **cm_id)
92 {
93         struct rds_iw_device *iwdev;
94         struct rds_iw_cm_id *i_cm_id;
95
96         *rds_iwdev = NULL;
97         *cm_id = NULL;
98
99         list_for_each_entry(iwdev, &rds_iw_devices, list) {
100                 spin_lock_irq(&iwdev->spinlock);
101                 list_for_each_entry(i_cm_id, &iwdev->cm_id_list, list) {
102                         struct sockaddr_in *src_addr, *dst_addr;
103
104                         src_addr = (struct sockaddr_in *)&i_cm_id->cm_id->route.addr.src_addr;
105                         dst_addr = (struct sockaddr_in *)&i_cm_id->cm_id->route.addr.dst_addr;
106
107                         rdsdebug("local ipaddr = %x port %d, "
108                                  "remote ipaddr = %x port %d"
109                                  "..looking for %x port %d, "
110                                  "remote ipaddr = %x port %d\n",
111                                 src_addr->sin_addr.s_addr,
112                                 src_addr->sin_port,
113                                 dst_addr->sin_addr.s_addr,
114                                 dst_addr->sin_port,
115                                 rs->rs_bound_addr,
116                                 rs->rs_bound_port,
117                                 rs->rs_conn_addr,
118                                 rs->rs_conn_port);
119 #ifdef WORKING_TUPLE_DETECTION
120                         if (src_addr->sin_addr.s_addr == rs->rs_bound_addr &&
121                             src_addr->sin_port == rs->rs_bound_port &&
122                             dst_addr->sin_addr.s_addr == rs->rs_conn_addr &&
123                             dst_addr->sin_port == rs->rs_conn_port) {
124 #else
125                         /* FIXME - needs to compare the local and remote
126                          * ipaddr/port tuple, but the ipaddr is the only
127                          * available information in the rds_sock (as the rest are
128                          * zero'ed.  It doesn't appear to be properly populated
129                          * during connection setup...
130                          */
131                         if (src_addr->sin_addr.s_addr == rs->rs_bound_addr) {
132 #endif
133                                 spin_unlock_irq(&iwdev->spinlock);
134                                 *rds_iwdev = iwdev;
135                                 *cm_id = i_cm_id->cm_id;
136                                 return 0;
137                         }
138                 }
139                 spin_unlock_irq(&iwdev->spinlock);
140         }
141
142         return 1;
143 }
144
145 static int rds_iw_add_cm_id(struct rds_iw_device *rds_iwdev, struct rdma_cm_id *cm_id)
146 {
147         struct rds_iw_cm_id *i_cm_id;
148
149         i_cm_id = kmalloc(sizeof *i_cm_id, GFP_KERNEL);
150         if (!i_cm_id)
151                 return -ENOMEM;
152
153         i_cm_id->cm_id = cm_id;
154
155         spin_lock_irq(&rds_iwdev->spinlock);
156         list_add_tail(&i_cm_id->list, &rds_iwdev->cm_id_list);
157         spin_unlock_irq(&rds_iwdev->spinlock);
158
159         return 0;
160 }
161
162 static void rds_iw_remove_cm_id(struct rds_iw_device *rds_iwdev,
163                                 struct rdma_cm_id *cm_id)
164 {
165         struct rds_iw_cm_id *i_cm_id;
166
167         spin_lock_irq(&rds_iwdev->spinlock);
168         list_for_each_entry(i_cm_id, &rds_iwdev->cm_id_list, list) {
169                 if (i_cm_id->cm_id == cm_id) {
170                         list_del(&i_cm_id->list);
171                         kfree(i_cm_id);
172                         break;
173                 }
174         }
175         spin_unlock_irq(&rds_iwdev->spinlock);
176 }
177
178
179 int rds_iw_update_cm_id(struct rds_iw_device *rds_iwdev, struct rdma_cm_id *cm_id)
180 {
181         struct sockaddr_in *src_addr, *dst_addr;
182         struct rds_iw_device *rds_iwdev_old;
183         struct rds_sock rs;
184         struct rdma_cm_id *pcm_id;
185         int rc;
186
187         src_addr = (struct sockaddr_in *)&cm_id->route.addr.src_addr;
188         dst_addr = (struct sockaddr_in *)&cm_id->route.addr.dst_addr;
189
190         rs.rs_bound_addr = src_addr->sin_addr.s_addr;
191         rs.rs_bound_port = src_addr->sin_port;
192         rs.rs_conn_addr = dst_addr->sin_addr.s_addr;
193         rs.rs_conn_port = dst_addr->sin_port;
194
195         rc = rds_iw_get_device(&rs, &rds_iwdev_old, &pcm_id);
196         if (rc)
197                 rds_iw_remove_cm_id(rds_iwdev, cm_id);
198
199         return rds_iw_add_cm_id(rds_iwdev, cm_id);
200 }
201
202 void rds_iw_add_conn(struct rds_iw_device *rds_iwdev, struct rds_connection *conn)
203 {
204         struct rds_iw_connection *ic = conn->c_transport_data;
205
206         /* conn was previously on the nodev_conns_list */
207         spin_lock_irq(&iw_nodev_conns_lock);
208         BUG_ON(list_empty(&iw_nodev_conns));
209         BUG_ON(list_empty(&ic->iw_node));
210         list_del(&ic->iw_node);
211
212         spin_lock(&rds_iwdev->spinlock);
213         list_add_tail(&ic->iw_node, &rds_iwdev->conn_list);
214         spin_unlock(&rds_iwdev->spinlock);
215         spin_unlock_irq(&iw_nodev_conns_lock);
216
217         ic->rds_iwdev = rds_iwdev;
218 }
219
220 void rds_iw_remove_conn(struct rds_iw_device *rds_iwdev, struct rds_connection *conn)
221 {
222         struct rds_iw_connection *ic = conn->c_transport_data;
223
224         /* place conn on nodev_conns_list */
225         spin_lock(&iw_nodev_conns_lock);
226
227         spin_lock_irq(&rds_iwdev->spinlock);
228         BUG_ON(list_empty(&ic->iw_node));
229         list_del(&ic->iw_node);
230         spin_unlock_irq(&rds_iwdev->spinlock);
231
232         list_add_tail(&ic->iw_node, &iw_nodev_conns);
233
234         spin_unlock(&iw_nodev_conns_lock);
235
236         rds_iw_remove_cm_id(ic->rds_iwdev, ic->i_cm_id);
237         ic->rds_iwdev = NULL;
238 }
239
240 void __rds_iw_destroy_conns(struct list_head *list, spinlock_t *list_lock)
241 {
242         struct rds_iw_connection *ic, *_ic;
243         LIST_HEAD(tmp_list);
244
245         /* avoid calling conn_destroy with irqs off */
246         spin_lock_irq(list_lock);
247         list_splice(list, &tmp_list);
248         INIT_LIST_HEAD(list);
249         spin_unlock_irq(list_lock);
250
251         list_for_each_entry_safe(ic, _ic, &tmp_list, iw_node)
252                 rds_conn_destroy(ic->conn);
253 }
254
255 static void rds_iw_set_scatterlist(struct rds_iw_scatterlist *sg,
256                 struct scatterlist *list, unsigned int sg_len)
257 {
258         sg->list = list;
259         sg->len = sg_len;
260         sg->dma_len = 0;
261         sg->dma_npages = 0;
262         sg->bytes = 0;
263 }
264
265 static u64 *rds_iw_map_scatterlist(struct rds_iw_device *rds_iwdev,
266                         struct rds_iw_scatterlist *sg)
267 {
268         struct ib_device *dev = rds_iwdev->dev;
269         u64 *dma_pages = NULL;
270         int i, j, ret;
271
272         WARN_ON(sg->dma_len);
273
274         sg->dma_len = ib_dma_map_sg(dev, sg->list, sg->len, DMA_BIDIRECTIONAL);
275         if (unlikely(!sg->dma_len)) {
276                 printk(KERN_WARNING "RDS/IW: dma_map_sg failed!\n");
277                 return ERR_PTR(-EBUSY);
278         }
279
280         sg->bytes = 0;
281         sg->dma_npages = 0;
282
283         ret = -EINVAL;
284         for (i = 0; i < sg->dma_len; ++i) {
285                 unsigned int dma_len = ib_sg_dma_len(dev, &sg->list[i]);
286                 u64 dma_addr = ib_sg_dma_address(dev, &sg->list[i]);
287                 u64 end_addr;
288
289                 sg->bytes += dma_len;
290
291                 end_addr = dma_addr + dma_len;
292                 if (dma_addr & PAGE_MASK) {
293                         if (i > 0)
294                                 goto out_unmap;
295                         dma_addr &= ~PAGE_MASK;
296                 }
297                 if (end_addr & PAGE_MASK) {
298                         if (i < sg->dma_len - 1)
299                                 goto out_unmap;
300                         end_addr = (end_addr + PAGE_MASK) & ~PAGE_MASK;
301                 }
302
303                 sg->dma_npages += (end_addr - dma_addr) >> PAGE_SHIFT;
304         }
305
306         /* Now gather the dma addrs into one list */
307         if (sg->dma_npages > fastreg_message_size)
308                 goto out_unmap;
309
310         dma_pages = kmalloc(sizeof(u64) * sg->dma_npages, GFP_ATOMIC);
311         if (!dma_pages) {
312                 ret = -ENOMEM;
313                 goto out_unmap;
314         }
315
316         for (i = j = 0; i < sg->dma_len; ++i) {
317                 unsigned int dma_len = ib_sg_dma_len(dev, &sg->list[i]);
318                 u64 dma_addr = ib_sg_dma_address(dev, &sg->list[i]);
319                 u64 end_addr;
320
321                 end_addr = dma_addr + dma_len;
322                 dma_addr &= ~PAGE_MASK;
323                 for (; dma_addr < end_addr; dma_addr += PAGE_SIZE)
324                         dma_pages[j++] = dma_addr;
325                 BUG_ON(j > sg->dma_npages);
326         }
327
328         return dma_pages;
329
330 out_unmap:
331         ib_dma_unmap_sg(rds_iwdev->dev, sg->list, sg->len, DMA_BIDIRECTIONAL);
332         sg->dma_len = 0;
333         kfree(dma_pages);
334         return ERR_PTR(ret);
335 }
336
337
338 struct rds_iw_mr_pool *rds_iw_create_mr_pool(struct rds_iw_device *rds_iwdev)
339 {
340         struct rds_iw_mr_pool *pool;
341
342         pool = kzalloc(sizeof(*pool), GFP_KERNEL);
343         if (!pool) {
344                 printk(KERN_WARNING "RDS/IW: rds_iw_create_mr_pool alloc error\n");
345                 return ERR_PTR(-ENOMEM);
346         }
347
348         pool->device = rds_iwdev;
349         INIT_LIST_HEAD(&pool->dirty_list);
350         INIT_LIST_HEAD(&pool->clean_list);
351         mutex_init(&pool->flush_lock);
352         spin_lock_init(&pool->list_lock);
353         INIT_WORK(&pool->flush_worker, rds_iw_mr_pool_flush_worker);
354
355         pool->max_message_size = fastreg_message_size;
356         pool->max_items = fastreg_pool_size;
357         pool->max_free_pinned = pool->max_items * pool->max_message_size / 4;
358         pool->max_pages = fastreg_message_size;
359
360         /* We never allow more than max_items MRs to be allocated.
361          * When we exceed more than max_items_soft, we start freeing
362          * items more aggressively.
363          * Make sure that max_items > max_items_soft > max_items / 2
364          */
365         pool->max_items_soft = pool->max_items * 3 / 4;
366
367         return pool;
368 }
369
370 void rds_iw_get_mr_info(struct rds_iw_device *rds_iwdev, struct rds_info_rdma_connection *iinfo)
371 {
372         struct rds_iw_mr_pool *pool = rds_iwdev->mr_pool;
373
374         iinfo->rdma_mr_max = pool->max_items;
375         iinfo->rdma_mr_size = pool->max_pages;
376 }
377
378 void rds_iw_destroy_mr_pool(struct rds_iw_mr_pool *pool)
379 {
380         flush_workqueue(rds_wq);
381         rds_iw_flush_mr_pool(pool, 1);
382         BUG_ON(atomic_read(&pool->item_count));
383         BUG_ON(atomic_read(&pool->free_pinned));
384         kfree(pool);
385 }
386
387 static inline struct rds_iw_mr *rds_iw_reuse_fmr(struct rds_iw_mr_pool *pool)
388 {
389         struct rds_iw_mr *ibmr = NULL;
390         unsigned long flags;
391
392         spin_lock_irqsave(&pool->list_lock, flags);
393         if (!list_empty(&pool->clean_list)) {
394                 ibmr = list_entry(pool->clean_list.next, struct rds_iw_mr, mapping.m_list);
395                 list_del_init(&ibmr->mapping.m_list);
396         }
397         spin_unlock_irqrestore(&pool->list_lock, flags);
398
399         return ibmr;
400 }
401
402 static struct rds_iw_mr *rds_iw_alloc_mr(struct rds_iw_device *rds_iwdev)
403 {
404         struct rds_iw_mr_pool *pool = rds_iwdev->mr_pool;
405         struct rds_iw_mr *ibmr = NULL;
406         int err = 0, iter = 0;
407
408         while (1) {
409                 ibmr = rds_iw_reuse_fmr(pool);
410                 if (ibmr)
411                         return ibmr;
412
413                 /* No clean MRs - now we have the choice of either
414                  * allocating a fresh MR up to the limit imposed by the
415                  * driver, or flush any dirty unused MRs.
416                  * We try to avoid stalling in the send path if possible,
417                  * so we allocate as long as we're allowed to.
418                  *
419                  * We're fussy with enforcing the FMR limit, though. If the driver
420                  * tells us we can't use more than N fmrs, we shouldn't start
421                  * arguing with it */
422                 if (atomic_inc_return(&pool->item_count) <= pool->max_items)
423                         break;
424
425                 atomic_dec(&pool->item_count);
426
427                 if (++iter > 2) {
428                         rds_iw_stats_inc(s_iw_rdma_mr_pool_depleted);
429                         return ERR_PTR(-EAGAIN);
430                 }
431
432                 /* We do have some empty MRs. Flush them out. */
433                 rds_iw_stats_inc(s_iw_rdma_mr_pool_wait);
434                 rds_iw_flush_mr_pool(pool, 0);
435         }
436
437         ibmr = kzalloc(sizeof(*ibmr), GFP_KERNEL);
438         if (!ibmr) {
439                 err = -ENOMEM;
440                 goto out_no_cigar;
441         }
442
443         spin_lock_init(&ibmr->mapping.m_lock);
444         INIT_LIST_HEAD(&ibmr->mapping.m_list);
445         ibmr->mapping.m_mr = ibmr;
446
447         err = rds_iw_init_fastreg(pool, ibmr);
448         if (err)
449                 goto out_no_cigar;
450
451         rds_iw_stats_inc(s_iw_rdma_mr_alloc);
452         return ibmr;
453
454 out_no_cigar:
455         if (ibmr) {
456                 rds_iw_destroy_fastreg(pool, ibmr);
457                 kfree(ibmr);
458         }
459         atomic_dec(&pool->item_count);
460         return ERR_PTR(err);
461 }
462
463 void rds_iw_sync_mr(void *trans_private, int direction)
464 {
465         struct rds_iw_mr *ibmr = trans_private;
466         struct rds_iw_device *rds_iwdev = ibmr->device;
467
468         switch (direction) {
469         case DMA_FROM_DEVICE:
470                 ib_dma_sync_sg_for_cpu(rds_iwdev->dev, ibmr->mapping.m_sg.list,
471                         ibmr->mapping.m_sg.dma_len, DMA_BIDIRECTIONAL);
472                 break;
473         case DMA_TO_DEVICE:
474                 ib_dma_sync_sg_for_device(rds_iwdev->dev, ibmr->mapping.m_sg.list,
475                         ibmr->mapping.m_sg.dma_len, DMA_BIDIRECTIONAL);
476                 break;
477         }
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_iw_flush_mr_pool(struct rds_iw_mr_pool *pool, int free_all)
487 {
488         struct rds_iw_mr *ibmr, *next;
489         LIST_HEAD(unmap_list);
490         LIST_HEAD(kill_list);
491         unsigned long flags;
492         unsigned int nfreed = 0, ncleaned = 0, unpinned = 0;
493         int ret = 0;
494
495         rds_iw_stats_inc(s_iw_rdma_mr_pool_flush);
496
497         mutex_lock(&pool->flush_lock);
498
499         spin_lock_irqsave(&pool->list_lock, flags);
500         /* Get the list of all mappings to be destroyed */
501         list_splice_init(&pool->dirty_list, &unmap_list);
502         if (free_all)
503                 list_splice_init(&pool->clean_list, &kill_list);
504         spin_unlock_irqrestore(&pool->list_lock, flags);
505
506         /* Batched invalidate of dirty MRs.
507          * For FMR based MRs, the mappings on the unmap list are
508          * actually members of an ibmr (ibmr->mapping). They either
509          * migrate to the kill_list, or have been cleaned and should be
510          * moved to the clean_list.
511          * For fastregs, they will be dynamically allocated, and
512          * will be destroyed by the unmap function.
513          */
514         if (!list_empty(&unmap_list)) {
515                 ncleaned = rds_iw_unmap_fastreg_list(pool, &unmap_list,
516                                                      &kill_list, &unpinned);
517                 /* If we've been asked to destroy all MRs, move those
518                  * that were simply cleaned to the kill list */
519                 if (free_all)
520                         list_splice_init(&unmap_list, &kill_list);
521         }
522
523         /* Destroy any MRs that are past their best before date */
524         list_for_each_entry_safe(ibmr, next, &kill_list, mapping.m_list) {
525                 rds_iw_stats_inc(s_iw_rdma_mr_free);
526                 list_del(&ibmr->mapping.m_list);
527                 rds_iw_destroy_fastreg(pool, ibmr);
528                 kfree(ibmr);
529                 nfreed++;
530         }
531
532         /* Anything that remains are laundered ibmrs, which we can add
533          * back to the clean list. */
534         if (!list_empty(&unmap_list)) {
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
540         atomic_sub(unpinned, &pool->free_pinned);
541         atomic_sub(ncleaned, &pool->dirty_count);
542         atomic_sub(nfreed, &pool->item_count);
543
544         mutex_unlock(&pool->flush_lock);
545         return ret;
546 }
547
548 static void rds_iw_mr_pool_flush_worker(struct work_struct *work)
549 {
550         struct rds_iw_mr_pool *pool = container_of(work, struct rds_iw_mr_pool, flush_worker);
551
552         rds_iw_flush_mr_pool(pool, 0);
553 }
554
555 void rds_iw_free_mr(void *trans_private, int invalidate)
556 {
557         struct rds_iw_mr *ibmr = trans_private;
558         struct rds_iw_mr_pool *pool = ibmr->device->mr_pool;
559
560         rdsdebug("RDS/IW: free_mr nents %u\n", ibmr->mapping.m_sg.len);
561         if (!pool)
562                 return;
563
564         /* Return it to the pool's free list */
565         rds_iw_free_fastreg(pool, ibmr);
566
567         /* If we've pinned too many pages, request a flush */
568         if (atomic_read(&pool->free_pinned) >= pool->max_free_pinned ||
569             atomic_read(&pool->dirty_count) >= pool->max_items / 10)
570                 queue_work(rds_wq, &pool->flush_worker);
571
572         if (invalidate) {
573                 if (likely(!in_interrupt())) {
574                         rds_iw_flush_mr_pool(pool, 0);
575                 } else {
576                         /* We get here if the user created a MR marked
577                          * as use_once and invalidate at the same time. */
578                         queue_work(rds_wq, &pool->flush_worker);
579                 }
580         }
581 }
582
583 void rds_iw_flush_mrs(void)
584 {
585         struct rds_iw_device *rds_iwdev;
586
587         list_for_each_entry(rds_iwdev, &rds_iw_devices, list) {
588                 struct rds_iw_mr_pool *pool = rds_iwdev->mr_pool;
589
590                 if (pool)
591                         rds_iw_flush_mr_pool(pool, 0);
592         }
593 }
594
595 void *rds_iw_get_mr(struct scatterlist *sg, unsigned long nents,
596                     struct rds_sock *rs, u32 *key_ret)
597 {
598         struct rds_iw_device *rds_iwdev;
599         struct rds_iw_mr *ibmr = NULL;
600         struct rdma_cm_id *cm_id;
601         int ret;
602
603         ret = rds_iw_get_device(rs, &rds_iwdev, &cm_id);
604         if (ret || !cm_id) {
605                 ret = -ENODEV;
606                 goto out;
607         }
608
609         if (!rds_iwdev->mr_pool) {
610                 ret = -ENODEV;
611                 goto out;
612         }
613
614         ibmr = rds_iw_alloc_mr(rds_iwdev);
615         if (IS_ERR(ibmr))
616                 return ibmr;
617
618         ibmr->cm_id = cm_id;
619         ibmr->device = rds_iwdev;
620
621         ret = rds_iw_map_fastreg(rds_iwdev->mr_pool, ibmr, sg, nents);
622         if (ret == 0)
623                 *key_ret = ibmr->mr->rkey;
624         else
625                 printk(KERN_WARNING "RDS/IW: failed to map mr (errno=%d)\n", ret);
626
627 out:
628         if (ret) {
629                 if (ibmr)
630                         rds_iw_free_mr(ibmr, 0);
631                 ibmr = ERR_PTR(ret);
632         }
633         return ibmr;
634 }
635
636 /*
637  * iWARP fastreg handling
638  *
639  * The life cycle of a fastreg registration is a bit different from
640  * FMRs.
641  * The idea behind fastreg is to have one MR, to which we bind different
642  * mappings over time. To avoid stalling on the expensive map and invalidate
643  * operations, these operations are pipelined on the same send queue on
644  * which we want to send the message containing the r_key.
645  *
646  * This creates a bit of a problem for us, as we do not have the destination
647  * IP in GET_MR, so the connection must be setup prior to the GET_MR call for
648  * RDMA to be correctly setup.  If a fastreg request is present, rds_iw_xmit
649  * will try to queue a LOCAL_INV (if needed) and a FAST_REG_MR work request
650  * before queuing the SEND. When completions for these arrive, they are
651  * dispatched to the MR has a bit set showing that RDMa can be performed.
652  *
653  * There is another interesting aspect that's related to invalidation.
654  * The application can request that a mapping is invalidated in FREE_MR.
655  * The expectation there is that this invalidation step includes ALL
656  * PREVIOUSLY FREED MRs.
657  */
658 static int rds_iw_init_fastreg(struct rds_iw_mr_pool *pool,
659                                 struct rds_iw_mr *ibmr)
660 {
661         struct rds_iw_device *rds_iwdev = pool->device;
662         struct ib_fast_reg_page_list *page_list = NULL;
663         struct ib_mr *mr;
664         int err;
665
666         mr = ib_alloc_fast_reg_mr(rds_iwdev->pd, pool->max_message_size);
667         if (IS_ERR(mr)) {
668                 err = PTR_ERR(mr);
669
670                 printk(KERN_WARNING "RDS/IW: ib_alloc_fast_reg_mr failed (err=%d)\n", err);
671                 return err;
672         }
673
674         /* FIXME - this is overkill, but mapping->m_sg.dma_len/mapping->m_sg.dma_npages
675          * is not filled in.
676          */
677         page_list = ib_alloc_fast_reg_page_list(rds_iwdev->dev, pool->max_message_size);
678         if (IS_ERR(page_list)) {
679                 err = PTR_ERR(page_list);
680
681                 printk(KERN_WARNING "RDS/IW: ib_alloc_fast_reg_page_list failed (err=%d)\n", err);
682                 ib_dereg_mr(mr);
683                 return err;
684         }
685
686         ibmr->page_list = page_list;
687         ibmr->mr = mr;
688         return 0;
689 }
690
691 static int rds_iw_rdma_build_fastreg(struct rds_iw_mapping *mapping)
692 {
693         struct rds_iw_mr *ibmr = mapping->m_mr;
694         struct ib_send_wr f_wr, *failed_wr;
695         int ret;
696
697         /*
698          * Perform a WR for the fast_reg_mr. Each individual page
699          * in the sg list is added to the fast reg page list and placed
700          * inside the fast_reg_mr WR.  The key used is a rolling 8bit
701          * counter, which should guarantee uniqueness.
702          */
703         ib_update_fast_reg_key(ibmr->mr, ibmr->remap_count++);
704         mapping->m_rkey = ibmr->mr->rkey;
705
706         memset(&f_wr, 0, sizeof(f_wr));
707         f_wr.wr_id = RDS_IW_FAST_REG_WR_ID;
708         f_wr.opcode = IB_WR_FAST_REG_MR;
709         f_wr.wr.fast_reg.length = mapping->m_sg.bytes;
710         f_wr.wr.fast_reg.rkey = mapping->m_rkey;
711         f_wr.wr.fast_reg.page_list = ibmr->page_list;
712         f_wr.wr.fast_reg.page_list_len = mapping->m_sg.dma_len;
713         f_wr.wr.fast_reg.page_shift = PAGE_SHIFT;
714         f_wr.wr.fast_reg.access_flags = IB_ACCESS_LOCAL_WRITE |
715                                 IB_ACCESS_REMOTE_READ |
716                                 IB_ACCESS_REMOTE_WRITE;
717         f_wr.wr.fast_reg.iova_start = 0;
718         f_wr.send_flags = IB_SEND_SIGNALED;
719
720         failed_wr = &f_wr;
721         ret = ib_post_send(ibmr->cm_id->qp, &f_wr, &failed_wr);
722         BUG_ON(failed_wr != &f_wr);
723         if (ret)
724                 printk_ratelimited(KERN_WARNING "RDS/IW: %s:%d ib_post_send returned %d\n",
725                         __func__, __LINE__, ret);
726         return ret;
727 }
728
729 static int rds_iw_rdma_fastreg_inv(struct rds_iw_mr *ibmr)
730 {
731         struct ib_send_wr s_wr, *failed_wr;
732         int ret = 0;
733
734         if (!ibmr->cm_id->qp || !ibmr->mr)
735                 goto out;
736
737         memset(&s_wr, 0, sizeof(s_wr));
738         s_wr.wr_id = RDS_IW_LOCAL_INV_WR_ID;
739         s_wr.opcode = IB_WR_LOCAL_INV;
740         s_wr.ex.invalidate_rkey = ibmr->mr->rkey;
741         s_wr.send_flags = IB_SEND_SIGNALED;
742
743         failed_wr = &s_wr;
744         ret = ib_post_send(ibmr->cm_id->qp, &s_wr, &failed_wr);
745         if (ret) {
746                 printk_ratelimited(KERN_WARNING "RDS/IW: %s:%d ib_post_send returned %d\n",
747                         __func__, __LINE__, ret);
748                 goto out;
749         }
750 out:
751         return ret;
752 }
753
754 static int rds_iw_map_fastreg(struct rds_iw_mr_pool *pool,
755                         struct rds_iw_mr *ibmr,
756                         struct scatterlist *sg,
757                         unsigned int sg_len)
758 {
759         struct rds_iw_device *rds_iwdev = pool->device;
760         struct rds_iw_mapping *mapping = &ibmr->mapping;
761         u64 *dma_pages;
762         int i, ret = 0;
763
764         rds_iw_set_scatterlist(&mapping->m_sg, sg, sg_len);
765
766         dma_pages = rds_iw_map_scatterlist(rds_iwdev, &mapping->m_sg);
767         if (IS_ERR(dma_pages)) {
768                 ret = PTR_ERR(dma_pages);
769                 dma_pages = NULL;
770                 goto out;
771         }
772
773         if (mapping->m_sg.dma_len > pool->max_message_size) {
774                 ret = -EMSGSIZE;
775                 goto out;
776         }
777
778         for (i = 0; i < mapping->m_sg.dma_npages; ++i)
779                 ibmr->page_list->page_list[i] = dma_pages[i];
780
781         ret = rds_iw_rdma_build_fastreg(mapping);
782         if (ret)
783                 goto out;
784
785         rds_iw_stats_inc(s_iw_rdma_mr_used);
786
787 out:
788         kfree(dma_pages);
789
790         return ret;
791 }
792
793 /*
794  * "Free" a fastreg MR.
795  */
796 static void rds_iw_free_fastreg(struct rds_iw_mr_pool *pool,
797                 struct rds_iw_mr *ibmr)
798 {
799         unsigned long flags;
800         int ret;
801
802         if (!ibmr->mapping.m_sg.dma_len)
803                 return;
804
805         ret = rds_iw_rdma_fastreg_inv(ibmr);
806         if (ret)
807                 return;
808
809         /* Try to post the LOCAL_INV WR to the queue. */
810         spin_lock_irqsave(&pool->list_lock, flags);
811
812         list_add_tail(&ibmr->mapping.m_list, &pool->dirty_list);
813         atomic_add(ibmr->mapping.m_sg.len, &pool->free_pinned);
814         atomic_inc(&pool->dirty_count);
815
816         spin_unlock_irqrestore(&pool->list_lock, flags);
817 }
818
819 static unsigned int rds_iw_unmap_fastreg_list(struct rds_iw_mr_pool *pool,
820                                 struct list_head *unmap_list,
821                                 struct list_head *kill_list,
822                                 int *unpinned)
823 {
824         struct rds_iw_mapping *mapping, *next;
825         unsigned int ncleaned = 0;
826         LIST_HEAD(laundered);
827
828         /* Batched invalidation of fastreg MRs.
829          * Why do we do it this way, even though we could pipeline unmap
830          * and remap? The reason is the application semantics - when the
831          * application requests an invalidation of MRs, it expects all
832          * previously released R_Keys to become invalid.
833          *
834          * If we implement MR reuse naively, we risk memory corruption
835          * (this has actually been observed). So the default behavior
836          * requires that a MR goes through an explicit unmap operation before
837          * we can reuse it again.
838          *
839          * We could probably improve on this a little, by allowing immediate
840          * reuse of a MR on the same socket (eg you could add small
841          * cache of unused MRs to strct rds_socket - GET_MR could grab one
842          * of these without requiring an explicit invalidate).
843          */
844         while (!list_empty(unmap_list)) {
845                 unsigned long flags;
846
847                 spin_lock_irqsave(&pool->list_lock, flags);
848                 list_for_each_entry_safe(mapping, next, unmap_list, m_list) {
849                         *unpinned += mapping->m_sg.len;
850                         list_move(&mapping->m_list, &laundered);
851                         ncleaned++;
852                 }
853                 spin_unlock_irqrestore(&pool->list_lock, flags);
854         }
855
856         /* Move all laundered mappings back to the unmap list.
857          * We do not kill any WRs right now - it doesn't seem the
858          * fastreg API has a max_remap limit. */
859         list_splice_init(&laundered, unmap_list);
860
861         return ncleaned;
862 }
863
864 static void rds_iw_destroy_fastreg(struct rds_iw_mr_pool *pool,
865                 struct rds_iw_mr *ibmr)
866 {
867         if (ibmr->page_list)
868                 ib_free_fast_reg_page_list(ibmr->page_list);
869         if (ibmr->mr)
870                 ib_dereg_mr(ibmr->mr);
871 }