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Linux/net/rds/iw_rdma.c

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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 sockaddr_in *src, struct sockaddr_in *dst,
 92                              struct rds_iw_device **rds_iwdev,
 93                              struct rdma_cm_id **cm_id)
 94 {
 95         struct rds_iw_device *iwdev;
 96         struct rds_iw_cm_id *i_cm_id;
 97 
 98         *rds_iwdev = NULL;
 99         *cm_id = NULL;
100 
101         list_for_each_entry(iwdev, &rds_iw_devices, list) {
102                 spin_lock_irq(&iwdev->spinlock);
103                 list_for_each_entry(i_cm_id, &iwdev->cm_id_list, list) {
104                         struct sockaddr_in *src_addr, *dst_addr;
105 
106                         src_addr = (struct sockaddr_in *)&i_cm_id->cm_id->route.addr.src_addr;
107                         dst_addr = (struct sockaddr_in *)&i_cm_id->cm_id->route.addr.dst_addr;
108 
109                         rdsdebug("local ipaddr = %x port %d, "
110                                  "remote ipaddr = %x port %d"
111                                  "..looking for %x port %d, "
112                                  "remote ipaddr = %x port %d\n",
113                                 src_addr->sin_addr.s_addr,
114                                 src_addr->sin_port,
115                                 dst_addr->sin_addr.s_addr,
116                                 dst_addr->sin_port,
117                                 src->sin_addr.s_addr,
118                                 src->sin_port,
119                                 dst->sin_addr.s_addr,
120                                 dst->sin_port);
121 #ifdef WORKING_TUPLE_DETECTION
122                         if (src_addr->sin_addr.s_addr == src->sin_addr.s_addr &&
123                             src_addr->sin_port == src->sin_port &&
124                             dst_addr->sin_addr.s_addr == dst->sin_addr.s_addr &&
125                             dst_addr->sin_port == dst->sin_port) {
126 #else
127                         /* FIXME - needs to compare the local and remote
128                          * ipaddr/port tuple, but the ipaddr is the only
129                          * available information in the rds_sock (as the rest are
130                          * zero'ed.  It doesn't appear to be properly populated
131                          * during connection setup...
132                          */
133                         if (src_addr->sin_addr.s_addr == src->sin_addr.s_addr) {
134 #endif
135                                 spin_unlock_irq(&iwdev->spinlock);
136                                 *rds_iwdev = iwdev;
137                                 *cm_id = i_cm_id->cm_id;
138                                 return 0;
139                         }
140                 }
141                 spin_unlock_irq(&iwdev->spinlock);
142         }
143 
144         return 1;
145 }
146 
147 static int rds_iw_add_cm_id(struct rds_iw_device *rds_iwdev, struct rdma_cm_id *cm_id)
148 {
149         struct rds_iw_cm_id *i_cm_id;
150 
151         i_cm_id = kmalloc(sizeof *i_cm_id, GFP_KERNEL);
152         if (!i_cm_id)
153                 return -ENOMEM;
154 
155         i_cm_id->cm_id = cm_id;
156 
157         spin_lock_irq(&rds_iwdev->spinlock);
158         list_add_tail(&i_cm_id->list, &rds_iwdev->cm_id_list);
159         spin_unlock_irq(&rds_iwdev->spinlock);
160 
161         return 0;
162 }
163 
164 static void rds_iw_remove_cm_id(struct rds_iw_device *rds_iwdev,
165                                 struct rdma_cm_id *cm_id)
166 {
167         struct rds_iw_cm_id *i_cm_id;
168 
169         spin_lock_irq(&rds_iwdev->spinlock);
170         list_for_each_entry(i_cm_id, &rds_iwdev->cm_id_list, list) {
171                 if (i_cm_id->cm_id == cm_id) {
172                         list_del(&i_cm_id->list);
173                         kfree(i_cm_id);
174                         break;
175                 }
176         }
177         spin_unlock_irq(&rds_iwdev->spinlock);
178 }
179 
180 
181 int rds_iw_update_cm_id(struct rds_iw_device *rds_iwdev, struct rdma_cm_id *cm_id)
182 {
183         struct sockaddr_in *src_addr, *dst_addr;
184         struct rds_iw_device *rds_iwdev_old;
185         struct rdma_cm_id *pcm_id;
186         int rc;
187 
188         src_addr = (struct sockaddr_in *)&cm_id->route.addr.src_addr;
189         dst_addr = (struct sockaddr_in *)&cm_id->route.addr.dst_addr;
190 
191         rc = rds_iw_get_device(src_addr, dst_addr, &rds_iwdev_old, &pcm_id);
192         if (rc)
193                 rds_iw_remove_cm_id(rds_iwdev, cm_id);
194 
195         return rds_iw_add_cm_id(rds_iwdev, cm_id);
196 }
197 
198 void rds_iw_add_conn(struct rds_iw_device *rds_iwdev, struct rds_connection *conn)
199 {
200         struct rds_iw_connection *ic = conn->c_transport_data;
201 
202         /* conn was previously on the nodev_conns_list */
203         spin_lock_irq(&iw_nodev_conns_lock);
204         BUG_ON(list_empty(&iw_nodev_conns));
205         BUG_ON(list_empty(&ic->iw_node));
206         list_del(&ic->iw_node);
207 
208         spin_lock(&rds_iwdev->spinlock);
209         list_add_tail(&ic->iw_node, &rds_iwdev->conn_list);
210         spin_unlock(&rds_iwdev->spinlock);
211         spin_unlock_irq(&iw_nodev_conns_lock);
212 
213         ic->rds_iwdev = rds_iwdev;
214 }
215 
216 void rds_iw_remove_conn(struct rds_iw_device *rds_iwdev, struct rds_connection *conn)
217 {
218         struct rds_iw_connection *ic = conn->c_transport_data;
219 
220         /* place conn on nodev_conns_list */
221         spin_lock(&iw_nodev_conns_lock);
222 
223         spin_lock_irq(&rds_iwdev->spinlock);
224         BUG_ON(list_empty(&ic->iw_node));
225         list_del(&ic->iw_node);
226         spin_unlock_irq(&rds_iwdev->spinlock);
227 
228         list_add_tail(&ic->iw_node, &iw_nodev_conns);
229 
230         spin_unlock(&iw_nodev_conns_lock);
231 
232         rds_iw_remove_cm_id(ic->rds_iwdev, ic->i_cm_id);
233         ic->rds_iwdev = NULL;
234 }
235 
236 void __rds_iw_destroy_conns(struct list_head *list, spinlock_t *list_lock)
237 {
238         struct rds_iw_connection *ic, *_ic;
239         LIST_HEAD(tmp_list);
240 
241         /* avoid calling conn_destroy with irqs off */
242         spin_lock_irq(list_lock);
243         list_splice(list, &tmp_list);
244         INIT_LIST_HEAD(list);
245         spin_unlock_irq(list_lock);
246 
247         list_for_each_entry_safe(ic, _ic, &tmp_list, iw_node)
248                 rds_conn_destroy(ic->conn);
249 }
250 
251 static void rds_iw_set_scatterlist(struct rds_iw_scatterlist *sg,
252                 struct scatterlist *list, unsigned int sg_len)
253 {
254         sg->list = list;
255         sg->len = sg_len;
256         sg->dma_len = 0;
257         sg->dma_npages = 0;
258         sg->bytes = 0;
259 }
260 
261 static u64 *rds_iw_map_scatterlist(struct rds_iw_device *rds_iwdev,
262                         struct rds_iw_scatterlist *sg)
263 {
264         struct ib_device *dev = rds_iwdev->dev;
265         u64 *dma_pages = NULL;
266         int i, j, ret;
267 
268         WARN_ON(sg->dma_len);
269 
270         sg->dma_len = ib_dma_map_sg(dev, sg->list, sg->len, DMA_BIDIRECTIONAL);
271         if (unlikely(!sg->dma_len)) {
272                 printk(KERN_WARNING "RDS/IW: dma_map_sg failed!\n");
273                 return ERR_PTR(-EBUSY);
274         }
275 
276         sg->bytes = 0;
277         sg->dma_npages = 0;
278 
279         ret = -EINVAL;
280         for (i = 0; i < sg->dma_len; ++i) {
281                 unsigned int dma_len = ib_sg_dma_len(dev, &sg->list[i]);
282                 u64 dma_addr = ib_sg_dma_address(dev, &sg->list[i]);
283                 u64 end_addr;
284 
285                 sg->bytes += dma_len;
286 
287                 end_addr = dma_addr + dma_len;
288                 if (dma_addr & PAGE_MASK) {
289                         if (i > 0)
290                                 goto out_unmap;
291                         dma_addr &= ~PAGE_MASK;
292                 }
293                 if (end_addr & PAGE_MASK) {
294                         if (i < sg->dma_len - 1)
295                                 goto out_unmap;
296                         end_addr = (end_addr + PAGE_MASK) & ~PAGE_MASK;
297                 }
298 
299                 sg->dma_npages += (end_addr - dma_addr) >> PAGE_SHIFT;
300         }
301 
302         /* Now gather the dma addrs into one list */
303         if (sg->dma_npages > fastreg_message_size)
304                 goto out_unmap;
305 
306         dma_pages = kmalloc(sizeof(u64) * sg->dma_npages, GFP_ATOMIC);
307         if (!dma_pages) {
308                 ret = -ENOMEM;
309                 goto out_unmap;
310         }
311 
312         for (i = j = 0; i < sg->dma_len; ++i) {
313                 unsigned int dma_len = ib_sg_dma_len(dev, &sg->list[i]);
314                 u64 dma_addr = ib_sg_dma_address(dev, &sg->list[i]);
315                 u64 end_addr;
316 
317                 end_addr = dma_addr + dma_len;
318                 dma_addr &= ~PAGE_MASK;
319                 for (; dma_addr < end_addr; dma_addr += PAGE_SIZE)
320                         dma_pages[j++] = dma_addr;
321                 BUG_ON(j > sg->dma_npages);
322         }
323 
324         return dma_pages;
325 
326 out_unmap:
327         ib_dma_unmap_sg(rds_iwdev->dev, sg->list, sg->len, DMA_BIDIRECTIONAL);
328         sg->dma_len = 0;
329         kfree(dma_pages);
330         return ERR_PTR(ret);
331 }
332 
333 
334 struct rds_iw_mr_pool *rds_iw_create_mr_pool(struct rds_iw_device *rds_iwdev)
335 {
336         struct rds_iw_mr_pool *pool;
337 
338         pool = kzalloc(sizeof(*pool), GFP_KERNEL);
339         if (!pool) {
340                 printk(KERN_WARNING "RDS/IW: rds_iw_create_mr_pool alloc error\n");
341                 return ERR_PTR(-ENOMEM);
342         }
343 
344         pool->device = rds_iwdev;
345         INIT_LIST_HEAD(&pool->dirty_list);
346         INIT_LIST_HEAD(&pool->clean_list);
347         mutex_init(&pool->flush_lock);
348         spin_lock_init(&pool->list_lock);
349         INIT_WORK(&pool->flush_worker, rds_iw_mr_pool_flush_worker);
350 
351         pool->max_message_size = fastreg_message_size;
352         pool->max_items = fastreg_pool_size;
353         pool->max_free_pinned = pool->max_items * pool->max_message_size / 4;
354         pool->max_pages = fastreg_message_size;
355 
356         /* We never allow more than max_items MRs to be allocated.
357          * When we exceed more than max_items_soft, we start freeing
358          * items more aggressively.
359          * Make sure that max_items > max_items_soft > max_items / 2
360          */
361         pool->max_items_soft = pool->max_items * 3 / 4;
362 
363         return pool;
364 }
365 
366 void rds_iw_get_mr_info(struct rds_iw_device *rds_iwdev, struct rds_info_rdma_connection *iinfo)
367 {
368         struct rds_iw_mr_pool *pool = rds_iwdev->mr_pool;
369 
370         iinfo->rdma_mr_max = pool->max_items;
371         iinfo->rdma_mr_size = pool->max_pages;
372 }
373 
374 void rds_iw_destroy_mr_pool(struct rds_iw_mr_pool *pool)
375 {
376         flush_workqueue(rds_wq);
377         rds_iw_flush_mr_pool(pool, 1);
378         BUG_ON(atomic_read(&pool->item_count));
379         BUG_ON(atomic_read(&pool->free_pinned));
380         kfree(pool);
381 }
382 
383 static inline struct rds_iw_mr *rds_iw_reuse_fmr(struct rds_iw_mr_pool *pool)
384 {
385         struct rds_iw_mr *ibmr = NULL;
386         unsigned long flags;
387 
388         spin_lock_irqsave(&pool->list_lock, flags);
389         if (!list_empty(&pool->clean_list)) {
390                 ibmr = list_entry(pool->clean_list.next, struct rds_iw_mr, mapping.m_list);
391                 list_del_init(&ibmr->mapping.m_list);
392         }
393         spin_unlock_irqrestore(&pool->list_lock, flags);
394 
395         return ibmr;
396 }
397 
398 static struct rds_iw_mr *rds_iw_alloc_mr(struct rds_iw_device *rds_iwdev)
399 {
400         struct rds_iw_mr_pool *pool = rds_iwdev->mr_pool;
401         struct rds_iw_mr *ibmr = NULL;
402         int err = 0, iter = 0;
403 
404         while (1) {
405                 ibmr = rds_iw_reuse_fmr(pool);
406                 if (ibmr)
407                         return ibmr;
408 
409                 /* No clean MRs - now we have the choice of either
410                  * allocating a fresh MR up to the limit imposed by the
411                  * driver, or flush any dirty unused MRs.
412                  * We try to avoid stalling in the send path if possible,
413                  * so we allocate as long as we're allowed to.
414                  *
415                  * We're fussy with enforcing the FMR limit, though. If the driver
416                  * tells us we can't use more than N fmrs, we shouldn't start
417                  * arguing with it */
418                 if (atomic_inc_return(&pool->item_count) <= pool->max_items)
419                         break;
420 
421                 atomic_dec(&pool->item_count);
422 
423                 if (++iter > 2) {
424                         rds_iw_stats_inc(s_iw_rdma_mr_pool_depleted);
425                         return ERR_PTR(-EAGAIN);
426                 }
427 
428                 /* We do have some empty MRs. Flush them out. */
429                 rds_iw_stats_inc(s_iw_rdma_mr_pool_wait);
430                 rds_iw_flush_mr_pool(pool, 0);
431         }
432 
433         ibmr = kzalloc(sizeof(*ibmr), GFP_KERNEL);
434         if (!ibmr) {
435                 err = -ENOMEM;
436                 goto out_no_cigar;
437         }
438 
439         spin_lock_init(&ibmr->mapping.m_lock);
440         INIT_LIST_HEAD(&ibmr->mapping.m_list);
441         ibmr->mapping.m_mr = ibmr;
442 
443         err = rds_iw_init_fastreg(pool, ibmr);
444         if (err)
445                 goto out_no_cigar;
446 
447         rds_iw_stats_inc(s_iw_rdma_mr_alloc);
448         return ibmr;
449 
450 out_no_cigar:
451         if (ibmr) {
452                 rds_iw_destroy_fastreg(pool, ibmr);
453                 kfree(ibmr);
454         }
455         atomic_dec(&pool->item_count);
456         return ERR_PTR(err);
457 }
458 
459 void rds_iw_sync_mr(void *trans_private, int direction)
460 {
461         struct rds_iw_mr *ibmr = trans_private;
462         struct rds_iw_device *rds_iwdev = ibmr->device;
463 
464         switch (direction) {
465         case DMA_FROM_DEVICE:
466                 ib_dma_sync_sg_for_cpu(rds_iwdev->dev, ibmr->mapping.m_sg.list,
467                         ibmr->mapping.m_sg.dma_len, DMA_BIDIRECTIONAL);
468                 break;
469         case DMA_TO_DEVICE:
470                 ib_dma_sync_sg_for_device(rds_iwdev->dev, ibmr->mapping.m_sg.list,
471                         ibmr->mapping.m_sg.dma_len, DMA_BIDIRECTIONAL);
472                 break;
473         }
474 }
475 
476 /*
477  * Flush our pool of MRs.
478  * At a minimum, all currently unused MRs are unmapped.
479  * If the number of MRs allocated exceeds the limit, we also try
480  * to free as many MRs as needed to get back to this limit.
481  */
482 static int rds_iw_flush_mr_pool(struct rds_iw_mr_pool *pool, int free_all)
483 {
484         struct rds_iw_mr *ibmr, *next;
485         LIST_HEAD(unmap_list);
486         LIST_HEAD(kill_list);
487         unsigned long flags;
488         unsigned int nfreed = 0, ncleaned = 0, unpinned = 0;
489         int ret = 0;
490 
491         rds_iw_stats_inc(s_iw_rdma_mr_pool_flush);
492 
493         mutex_lock(&pool->flush_lock);
494 
495         spin_lock_irqsave(&pool->list_lock, flags);
496         /* Get the list of all mappings to be destroyed */
497         list_splice_init(&pool->dirty_list, &unmap_list);
498         if (free_all)
499                 list_splice_init(&pool->clean_list, &kill_list);
500         spin_unlock_irqrestore(&pool->list_lock, flags);
501 
502         /* Batched invalidate of dirty MRs.
503          * For FMR based MRs, the mappings on the unmap list are
504          * actually members of an ibmr (ibmr->mapping). They either
505          * migrate to the kill_list, or have been cleaned and should be
506          * moved to the clean_list.
507          * For fastregs, they will be dynamically allocated, and
508          * will be destroyed by the unmap function.
509          */
510         if (!list_empty(&unmap_list)) {
511                 ncleaned = rds_iw_unmap_fastreg_list(pool, &unmap_list,
512                                                      &kill_list, &unpinned);
513                 /* If we've been asked to destroy all MRs, move those
514                  * that were simply cleaned to the kill list */
515                 if (free_all)
516                         list_splice_init(&unmap_list, &kill_list);
517         }
518 
519         /* Destroy any MRs that are past their best before date */
520         list_for_each_entry_safe(ibmr, next, &kill_list, mapping.m_list) {
521                 rds_iw_stats_inc(s_iw_rdma_mr_free);
522                 list_del(&ibmr->mapping.m_list);
523                 rds_iw_destroy_fastreg(pool, ibmr);
524                 kfree(ibmr);
525                 nfreed++;
526         }
527 
528         /* Anything that remains are laundered ibmrs, which we can add
529          * back to the clean list. */
530         if (!list_empty(&unmap_list)) {
531                 spin_lock_irqsave(&pool->list_lock, flags);
532                 list_splice(&unmap_list, &pool->clean_list);
533                 spin_unlock_irqrestore(&pool->list_lock, flags);
534         }
535 
536         atomic_sub(unpinned, &pool->free_pinned);
537         atomic_sub(ncleaned, &pool->dirty_count);
538         atomic_sub(nfreed, &pool->item_count);
539 
540         mutex_unlock(&pool->flush_lock);
541         return ret;
542 }
543 
544 static void rds_iw_mr_pool_flush_worker(struct work_struct *work)
545 {
546         struct rds_iw_mr_pool *pool = container_of(work, struct rds_iw_mr_pool, flush_worker);
547 
548         rds_iw_flush_mr_pool(pool, 0);
549 }
550 
551 void rds_iw_free_mr(void *trans_private, int invalidate)
552 {
553         struct rds_iw_mr *ibmr = trans_private;
554         struct rds_iw_mr_pool *pool = ibmr->device->mr_pool;
555 
556         rdsdebug("RDS/IW: free_mr nents %u\n", ibmr->mapping.m_sg.len);
557         if (!pool)
558                 return;
559 
560         /* Return it to the pool's free list */
561         rds_iw_free_fastreg(pool, ibmr);
562 
563         /* If we've pinned too many pages, request a flush */
564         if (atomic_read(&pool->free_pinned) >= pool->max_free_pinned ||
565             atomic_read(&pool->dirty_count) >= pool->max_items / 10)
566                 queue_work(rds_wq, &pool->flush_worker);
567 
568         if (invalidate) {
569                 if (likely(!in_interrupt())) {
570                         rds_iw_flush_mr_pool(pool, 0);
571                 } else {
572                         /* We get here if the user created a MR marked
573                          * as use_once and invalidate at the same time. */
574                         queue_work(rds_wq, &pool->flush_worker);
575                 }
576         }
577 }
578 
579 void rds_iw_flush_mrs(void)
580 {
581         struct rds_iw_device *rds_iwdev;
582 
583         list_for_each_entry(rds_iwdev, &rds_iw_devices, list) {
584                 struct rds_iw_mr_pool *pool = rds_iwdev->mr_pool;
585 
586                 if (pool)
587                         rds_iw_flush_mr_pool(pool, 0);
588         }
589 }
590 
591 void *rds_iw_get_mr(struct scatterlist *sg, unsigned long nents,
592                     struct rds_sock *rs, u32 *key_ret)
593 {
594         struct rds_iw_device *rds_iwdev;
595         struct rds_iw_mr *ibmr = NULL;
596         struct rdma_cm_id *cm_id;
597         struct sockaddr_in src = {
598                 .sin_addr.s_addr = rs->rs_bound_addr,
599                 .sin_port = rs->rs_bound_port,
600         };
601         struct sockaddr_in dst = {
602                 .sin_addr.s_addr = rs->rs_conn_addr,
603                 .sin_port = rs->rs_conn_port,
604         };
605         int ret;
606 
607         ret = rds_iw_get_device(&src, &dst, &rds_iwdev, &cm_id);
608         if (ret || !cm_id) {
609                 ret = -ENODEV;
610                 goto out;
611         }
612 
613         if (!rds_iwdev->mr_pool) {
614                 ret = -ENODEV;
615                 goto out;
616         }
617 
618         ibmr = rds_iw_alloc_mr(rds_iwdev);
619         if (IS_ERR(ibmr))
620                 return ibmr;
621 
622         ibmr->cm_id = cm_id;
623         ibmr->device = rds_iwdev;
624 
625         ret = rds_iw_map_fastreg(rds_iwdev->mr_pool, ibmr, sg, nents);
626         if (ret == 0)
627                 *key_ret = ibmr->mr->rkey;
628         else
629                 printk(KERN_WARNING "RDS/IW: failed to map mr (errno=%d)\n", ret);
630 
631 out:
632         if (ret) {
633                 if (ibmr)
634                         rds_iw_free_mr(ibmr, 0);
635                 ibmr = ERR_PTR(ret);
636         }
637         return ibmr;
638 }
639 
640 /*
641  * iWARP fastreg handling
642  *
643  * The life cycle of a fastreg registration is a bit different from
644  * FMRs.
645  * The idea behind fastreg is to have one MR, to which we bind different
646  * mappings over time. To avoid stalling on the expensive map and invalidate
647  * operations, these operations are pipelined on the same send queue on
648  * which we want to send the message containing the r_key.
649  *
650  * This creates a bit of a problem for us, as we do not have the destination
651  * IP in GET_MR, so the connection must be setup prior to the GET_MR call for
652  * RDMA to be correctly setup.  If a fastreg request is present, rds_iw_xmit
653  * will try to queue a LOCAL_INV (if needed) and a FAST_REG_MR work request
654  * before queuing the SEND. When completions for these arrive, they are
655  * dispatched to the MR has a bit set showing that RDMa can be performed.
656  *
657  * There is another interesting aspect that's related to invalidation.
658  * The application can request that a mapping is invalidated in FREE_MR.
659  * The expectation there is that this invalidation step includes ALL
660  * PREVIOUSLY FREED MRs.
661  */
662 static int rds_iw_init_fastreg(struct rds_iw_mr_pool *pool,
663                                 struct rds_iw_mr *ibmr)
664 {
665         struct rds_iw_device *rds_iwdev = pool->device;
666         struct ib_fast_reg_page_list *page_list = NULL;
667         struct ib_mr *mr;
668         int err;
669 
670         mr = ib_alloc_fast_reg_mr(rds_iwdev->pd, pool->max_message_size);
671         if (IS_ERR(mr)) {
672                 err = PTR_ERR(mr);
673 
674                 printk(KERN_WARNING "RDS/IW: ib_alloc_fast_reg_mr failed (err=%d)\n", err);
675                 return err;
676         }
677 
678         /* FIXME - this is overkill, but mapping->m_sg.dma_len/mapping->m_sg.dma_npages
679          * is not filled in.
680          */
681         page_list = ib_alloc_fast_reg_page_list(rds_iwdev->dev, pool->max_message_size);
682         if (IS_ERR(page_list)) {
683                 err = PTR_ERR(page_list);
684 
685                 printk(KERN_WARNING "RDS/IW: ib_alloc_fast_reg_page_list failed (err=%d)\n", err);
686                 ib_dereg_mr(mr);
687                 return err;
688         }
689 
690         ibmr->page_list = page_list;
691         ibmr->mr = mr;
692         return 0;
693 }
694 
695 static int rds_iw_rdma_build_fastreg(struct rds_iw_mapping *mapping)
696 {
697         struct rds_iw_mr *ibmr = mapping->m_mr;
698         struct ib_send_wr f_wr, *failed_wr;
699         int ret;
700 
701         /*
702          * Perform a WR for the fast_reg_mr. Each individual page
703          * in the sg list is added to the fast reg page list and placed
704          * inside the fast_reg_mr WR.  The key used is a rolling 8bit
705          * counter, which should guarantee uniqueness.
706          */
707         ib_update_fast_reg_key(ibmr->mr, ibmr->remap_count++);
708         mapping->m_rkey = ibmr->mr->rkey;
709 
710         memset(&f_wr, 0, sizeof(f_wr));
711         f_wr.wr_id = RDS_IW_FAST_REG_WR_ID;
712         f_wr.opcode = IB_WR_FAST_REG_MR;
713         f_wr.wr.fast_reg.length = mapping->m_sg.bytes;
714         f_wr.wr.fast_reg.rkey = mapping->m_rkey;
715         f_wr.wr.fast_reg.page_list = ibmr->page_list;
716         f_wr.wr.fast_reg.page_list_len = mapping->m_sg.dma_len;
717         f_wr.wr.fast_reg.page_shift = PAGE_SHIFT;
718         f_wr.wr.fast_reg.access_flags = IB_ACCESS_LOCAL_WRITE |
719                                 IB_ACCESS_REMOTE_READ |
720                                 IB_ACCESS_REMOTE_WRITE;
721         f_wr.wr.fast_reg.iova_start = 0;
722         f_wr.send_flags = IB_SEND_SIGNALED;
723 
724         failed_wr = &f_wr;
725         ret = ib_post_send(ibmr->cm_id->qp, &f_wr, &failed_wr);
726         BUG_ON(failed_wr != &f_wr);
727         if (ret)
728                 printk_ratelimited(KERN_WARNING "RDS/IW: %s:%d ib_post_send returned %d\n",
729                         __func__, __LINE__, ret);
730         return ret;
731 }
732 
733 static int rds_iw_rdma_fastreg_inv(struct rds_iw_mr *ibmr)
734 {
735         struct ib_send_wr s_wr, *failed_wr;
736         int ret = 0;
737 
738         if (!ibmr->cm_id->qp || !ibmr->mr)
739                 goto out;
740 
741         memset(&s_wr, 0, sizeof(s_wr));
742         s_wr.wr_id = RDS_IW_LOCAL_INV_WR_ID;
743         s_wr.opcode = IB_WR_LOCAL_INV;
744         s_wr.ex.invalidate_rkey = ibmr->mr->rkey;
745         s_wr.send_flags = IB_SEND_SIGNALED;
746 
747         failed_wr = &s_wr;
748         ret = ib_post_send(ibmr->cm_id->qp, &s_wr, &failed_wr);
749         if (ret) {
750                 printk_ratelimited(KERN_WARNING "RDS/IW: %s:%d ib_post_send returned %d\n",
751                         __func__, __LINE__, ret);
752                 goto out;
753         }
754 out:
755         return ret;
756 }
757 
758 static int rds_iw_map_fastreg(struct rds_iw_mr_pool *pool,
759                         struct rds_iw_mr *ibmr,
760                         struct scatterlist *sg,
761                         unsigned int sg_len)
762 {
763         struct rds_iw_device *rds_iwdev = pool->device;
764         struct rds_iw_mapping *mapping = &ibmr->mapping;
765         u64 *dma_pages;
766         int i, ret = 0;
767 
768         rds_iw_set_scatterlist(&mapping->m_sg, sg, sg_len);
769 
770         dma_pages = rds_iw_map_scatterlist(rds_iwdev, &mapping->m_sg);
771         if (IS_ERR(dma_pages)) {
772                 ret = PTR_ERR(dma_pages);
773                 dma_pages = NULL;
774                 goto out;
775         }
776 
777         if (mapping->m_sg.dma_len > pool->max_message_size) {
778                 ret = -EMSGSIZE;
779                 goto out;
780         }
781 
782         for (i = 0; i < mapping->m_sg.dma_npages; ++i)
783                 ibmr->page_list->page_list[i] = dma_pages[i];
784 
785         ret = rds_iw_rdma_build_fastreg(mapping);
786         if (ret)
787                 goto out;
788 
789         rds_iw_stats_inc(s_iw_rdma_mr_used);
790 
791 out:
792         kfree(dma_pages);
793 
794         return ret;
795 }
796 
797 /*
798  * "Free" a fastreg MR.
799  */
800 static void rds_iw_free_fastreg(struct rds_iw_mr_pool *pool,
801                 struct rds_iw_mr *ibmr)
802 {
803         unsigned long flags;
804         int ret;
805 
806         if (!ibmr->mapping.m_sg.dma_len)
807                 return;
808 
809         ret = rds_iw_rdma_fastreg_inv(ibmr);
810         if (ret)
811                 return;
812 
813         /* Try to post the LOCAL_INV WR to the queue. */
814         spin_lock_irqsave(&pool->list_lock, flags);
815 
816         list_add_tail(&ibmr->mapping.m_list, &pool->dirty_list);
817         atomic_add(ibmr->mapping.m_sg.len, &pool->free_pinned);
818         atomic_inc(&pool->dirty_count);
819 
820         spin_unlock_irqrestore(&pool->list_lock, flags);
821 }
822 
823 static unsigned int rds_iw_unmap_fastreg_list(struct rds_iw_mr_pool *pool,
824                                 struct list_head *unmap_list,
825                                 struct list_head *kill_list,
826                                 int *unpinned)
827 {
828         struct rds_iw_mapping *mapping, *next;
829         unsigned int ncleaned = 0;
830         LIST_HEAD(laundered);
831 
832         /* Batched invalidation of fastreg MRs.
833          * Why do we do it this way, even though we could pipeline unmap
834          * and remap? The reason is the application semantics - when the
835          * application requests an invalidation of MRs, it expects all
836          * previously released R_Keys to become invalid.
837          *
838          * If we implement MR reuse naively, we risk memory corruption
839          * (this has actually been observed). So the default behavior
840          * requires that a MR goes through an explicit unmap operation before
841          * we can reuse it again.
842          *
843          * We could probably improve on this a little, by allowing immediate
844          * reuse of a MR on the same socket (eg you could add small
845          * cache of unused MRs to strct rds_socket - GET_MR could grab one
846          * of these without requiring an explicit invalidate).
847          */
848         while (!list_empty(unmap_list)) {
849                 unsigned long flags;
850 
851                 spin_lock_irqsave(&pool->list_lock, flags);
852                 list_for_each_entry_safe(mapping, next, unmap_list, m_list) {
853                         *unpinned += mapping->m_sg.len;
854                         list_move(&mapping->m_list, &laundered);
855                         ncleaned++;
856                 }
857                 spin_unlock_irqrestore(&pool->list_lock, flags);
858         }
859 
860         /* Move all laundered mappings back to the unmap list.
861          * We do not kill any WRs right now - it doesn't seem the
862          * fastreg API has a max_remap limit. */
863         list_splice_init(&laundered, unmap_list);
864 
865         return ncleaned;
866 }
867 
868 static void rds_iw_destroy_fastreg(struct rds_iw_mr_pool *pool,
869                 struct rds_iw_mr *ibmr)
870 {
871         if (ibmr->page_list)
872                 ib_free_fast_reg_page_list(ibmr->page_list);
873         if (ibmr->mr)
874                 ib_dereg_mr(ibmr->mr);
875 }
876 

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