Root/net/rds/iw_rdma.c

1/*
2 * Copyright (c) 2006 Oracle. All rights reserved.
3 *
4 * This software is available to you under a choice of one of two
5 * licenses. You may choose to be licensed under the terms of the GNU
6 * General Public License (GPL) Version 2, available from the file
7 * COPYING in the main directory of this source tree, or the
8 * OpenIB.org BSD license below:
9 *
10 * Redistribution and use in source and binary forms, with or
11 * without modification, are permitted provided that the following
12 * conditions are met:
13 *
14 * - Redistributions of source code must retain the above
15 * copyright notice, this list of conditions and the following
16 * disclaimer.
17 *
18 * - Redistributions in binary form must reproduce the above
19 * copyright notice, this list of conditions and the following
20 * disclaimer in the documentation and/or other materials
21 * provided with the distribution.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30 * SOFTWARE.
31 *
32 */
33#include <linux/kernel.h>
34#include <linux/slab.h>
35
36#include "rds.h"
37#include "rdma.h"
38#include "iw.h"
39
40
41/*
42 * This is stored as mr->r_trans_private.
43 */
44struct 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 */
59struct 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
78static int rds_iw_flush_mr_pool(struct rds_iw_mr_pool *pool, int free_all);
79static void rds_iw_mr_pool_flush_worker(struct work_struct *work);
80static int rds_iw_init_fastreg(struct rds_iw_mr_pool *pool, struct rds_iw_mr *ibmr);
81static int rds_iw_map_fastreg(struct rds_iw_mr_pool *pool,
82              struct rds_iw_mr *ibmr,
83              struct scatterlist *sg, unsigned int nents);
84static void rds_iw_free_fastreg(struct rds_iw_mr_pool *pool, struct rds_iw_mr *ibmr);
85static 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);
88static void rds_iw_destroy_fastreg(struct rds_iw_mr_pool *pool, struct rds_iw_mr *ibmr);
89
90static int rds_iw_get_device(struct rds_sock *rs, struct rds_iw_device **rds_iwdev, struct rdma_cm_id **cm_id)
91{
92    struct rds_iw_device *iwdev;
93    struct rds_iw_cm_id *i_cm_id;
94
95    *rds_iwdev = NULL;
96    *cm_id = NULL;
97
98    list_for_each_entry(iwdev, &rds_iw_devices, list) {
99        spin_lock_irq(&iwdev->spinlock);
100        list_for_each_entry(i_cm_id, &iwdev->cm_id_list, list) {
101            struct sockaddr_in *src_addr, *dst_addr;
102
103            src_addr = (struct sockaddr_in *)&i_cm_id->cm_id->route.addr.src_addr;
104            dst_addr = (struct sockaddr_in *)&i_cm_id->cm_id->route.addr.dst_addr;
105
106            rdsdebug("local ipaddr = %x port %d, "
107                 "remote ipaddr = %x port %d"
108                 "..looking for %x port %d, "
109                 "remote ipaddr = %x port %d\n",
110                src_addr->sin_addr.s_addr,
111                src_addr->sin_port,
112                dst_addr->sin_addr.s_addr,
113                dst_addr->sin_port,
114                rs->rs_bound_addr,
115                rs->rs_bound_port,
116                rs->rs_conn_addr,
117                rs->rs_conn_port);
118#ifdef WORKING_TUPLE_DETECTION
119            if (src_addr->sin_addr.s_addr == rs->rs_bound_addr &&
120                src_addr->sin_port == rs->rs_bound_port &&
121                dst_addr->sin_addr.s_addr == rs->rs_conn_addr &&
122                dst_addr->sin_port == rs->rs_conn_port) {
123#else
124            /* FIXME - needs to compare the local and remote
125             * ipaddr/port tuple, but the ipaddr is the only
126             * available infomation in the rds_sock (as the rest are
127             * zero'ed. It doesn't appear to be properly populated
128             * during connection setup...
129             */
130            if (src_addr->sin_addr.s_addr == rs->rs_bound_addr) {
131#endif
132                spin_unlock_irq(&iwdev->spinlock);
133                *rds_iwdev = iwdev;
134                *cm_id = i_cm_id->cm_id;
135                return 0;
136            }
137        }
138        spin_unlock_irq(&iwdev->spinlock);
139    }
140
141    return 1;
142}
143
144static int rds_iw_add_cm_id(struct rds_iw_device *rds_iwdev, struct rdma_cm_id *cm_id)
145{
146    struct rds_iw_cm_id *i_cm_id;
147
148    i_cm_id = kmalloc(sizeof *i_cm_id, GFP_KERNEL);
149    if (!i_cm_id)
150        return -ENOMEM;
151
152    i_cm_id->cm_id = cm_id;
153
154    spin_lock_irq(&rds_iwdev->spinlock);
155    list_add_tail(&i_cm_id->list, &rds_iwdev->cm_id_list);
156    spin_unlock_irq(&rds_iwdev->spinlock);
157
158    return 0;
159}
160
161void rds_iw_remove_cm_id(struct rds_iw_device *rds_iwdev, struct rdma_cm_id *cm_id)
162{
163    struct rds_iw_cm_id *i_cm_id;
164
165    spin_lock_irq(&rds_iwdev->spinlock);
166    list_for_each_entry(i_cm_id, &rds_iwdev->cm_id_list, list) {
167        if (i_cm_id->cm_id == cm_id) {
168            list_del(&i_cm_id->list);
169            kfree(i_cm_id);
170            break;
171        }
172    }
173    spin_unlock_irq(&rds_iwdev->spinlock);
174}
175
176
177int rds_iw_update_cm_id(struct rds_iw_device *rds_iwdev, struct rdma_cm_id *cm_id)
178{
179    struct sockaddr_in *src_addr, *dst_addr;
180    struct rds_iw_device *rds_iwdev_old;
181    struct rds_sock rs;
182    struct rdma_cm_id *pcm_id;
183    int rc;
184
185    src_addr = (struct sockaddr_in *)&cm_id->route.addr.src_addr;
186    dst_addr = (struct sockaddr_in *)&cm_id->route.addr.dst_addr;
187
188    rs.rs_bound_addr = src_addr->sin_addr.s_addr;
189    rs.rs_bound_port = src_addr->sin_port;
190    rs.rs_conn_addr = dst_addr->sin_addr.s_addr;
191    rs.rs_conn_port = dst_addr->sin_port;
192
193    rc = rds_iw_get_device(&rs, &rds_iwdev_old, &pcm_id);
194    if (rc)
195        rds_iw_remove_cm_id(rds_iwdev, cm_id);
196
197    return rds_iw_add_cm_id(rds_iwdev, cm_id);
198}
199
200void rds_iw_add_conn(struct rds_iw_device *rds_iwdev, struct rds_connection *conn)
201{
202    struct rds_iw_connection *ic = conn->c_transport_data;
203
204    /* conn was previously on the nodev_conns_list */
205    spin_lock_irq(&iw_nodev_conns_lock);
206    BUG_ON(list_empty(&iw_nodev_conns));
207    BUG_ON(list_empty(&ic->iw_node));
208    list_del(&ic->iw_node);
209
210    spin_lock_irq(&rds_iwdev->spinlock);
211    list_add_tail(&ic->iw_node, &rds_iwdev->conn_list);
212    spin_unlock_irq(&rds_iwdev->spinlock);
213    spin_unlock_irq(&iw_nodev_conns_lock);
214
215    ic->rds_iwdev = rds_iwdev;
216}
217
218void rds_iw_remove_conn(struct rds_iw_device *rds_iwdev, struct rds_connection *conn)
219{
220    struct rds_iw_connection *ic = conn->c_transport_data;
221
222    /* place conn on nodev_conns_list */
223    spin_lock(&iw_nodev_conns_lock);
224
225    spin_lock_irq(&rds_iwdev->spinlock);
226    BUG_ON(list_empty(&ic->iw_node));
227    list_del(&ic->iw_node);
228    spin_unlock_irq(&rds_iwdev->spinlock);
229
230    list_add_tail(&ic->iw_node, &iw_nodev_conns);
231
232    spin_unlock(&iw_nodev_conns_lock);
233
234    rds_iw_remove_cm_id(ic->rds_iwdev, ic->i_cm_id);
235    ic->rds_iwdev = NULL;
236}
237
238void __rds_iw_destroy_conns(struct list_head *list, spinlock_t *list_lock)
239{
240    struct rds_iw_connection *ic, *_ic;
241    LIST_HEAD(tmp_list);
242
243    /* avoid calling conn_destroy with irqs off */
244    spin_lock_irq(list_lock);
245    list_splice(list, &tmp_list);
246    INIT_LIST_HEAD(list);
247    spin_unlock_irq(list_lock);
248
249    list_for_each_entry_safe(ic, _ic, &tmp_list, iw_node)
250        rds_conn_destroy(ic->conn);
251}
252
253static void rds_iw_set_scatterlist(struct rds_iw_scatterlist *sg,
254        struct scatterlist *list, unsigned int sg_len)
255{
256    sg->list = list;
257    sg->len = sg_len;
258    sg->dma_len = 0;
259    sg->dma_npages = 0;
260    sg->bytes = 0;
261}
262
263static u64 *rds_iw_map_scatterlist(struct rds_iw_device *rds_iwdev,
264            struct rds_iw_scatterlist *sg)
265{
266    struct ib_device *dev = rds_iwdev->dev;
267    u64 *dma_pages = NULL;
268    int i, j, ret;
269
270    WARN_ON(sg->dma_len);
271
272    sg->dma_len = ib_dma_map_sg(dev, sg->list, sg->len, DMA_BIDIRECTIONAL);
273    if (unlikely(!sg->dma_len)) {
274        printk(KERN_WARNING "RDS/IW: dma_map_sg failed!\n");
275        return ERR_PTR(-EBUSY);
276    }
277
278    sg->bytes = 0;
279    sg->dma_npages = 0;
280
281    ret = -EINVAL;
282    for (i = 0; i < sg->dma_len; ++i) {
283        unsigned int dma_len = ib_sg_dma_len(dev, &sg->list[i]);
284        u64 dma_addr = ib_sg_dma_address(dev, &sg->list[i]);
285        u64 end_addr;
286
287        sg->bytes += dma_len;
288
289        end_addr = dma_addr + dma_len;
290        if (dma_addr & PAGE_MASK) {
291            if (i > 0)
292                goto out_unmap;
293            dma_addr &= ~PAGE_MASK;
294        }
295        if (end_addr & PAGE_MASK) {
296            if (i < sg->dma_len - 1)
297                goto out_unmap;
298            end_addr = (end_addr + PAGE_MASK) & ~PAGE_MASK;
299        }
300
301        sg->dma_npages += (end_addr - dma_addr) >> PAGE_SHIFT;
302    }
303
304    /* Now gather the dma addrs into one list */
305    if (sg->dma_npages > fastreg_message_size)
306        goto out_unmap;
307
308    dma_pages = kmalloc(sizeof(u64) * sg->dma_npages, GFP_ATOMIC);
309    if (!dma_pages) {
310        ret = -ENOMEM;
311        goto out_unmap;
312    }
313
314    for (i = j = 0; i < sg->dma_len; ++i) {
315        unsigned int dma_len = ib_sg_dma_len(dev, &sg->list[i]);
316        u64 dma_addr = ib_sg_dma_address(dev, &sg->list[i]);
317        u64 end_addr;
318
319        end_addr = dma_addr + dma_len;
320        dma_addr &= ~PAGE_MASK;
321        for (; dma_addr < end_addr; dma_addr += PAGE_SIZE)
322            dma_pages[j++] = dma_addr;
323        BUG_ON(j > sg->dma_npages);
324    }
325
326    return dma_pages;
327
328out_unmap:
329    ib_dma_unmap_sg(rds_iwdev->dev, sg->list, sg->len, DMA_BIDIRECTIONAL);
330    sg->dma_len = 0;
331    kfree(dma_pages);
332    return ERR_PTR(ret);
333}
334
335
336struct rds_iw_mr_pool *rds_iw_create_mr_pool(struct rds_iw_device *rds_iwdev)
337{
338    struct rds_iw_mr_pool *pool;
339
340    pool = kzalloc(sizeof(*pool), GFP_KERNEL);
341    if (!pool) {
342        printk(KERN_WARNING "RDS/IW: rds_iw_create_mr_pool alloc error\n");
343        return ERR_PTR(-ENOMEM);
344    }
345
346    pool->device = rds_iwdev;
347    INIT_LIST_HEAD(&pool->dirty_list);
348    INIT_LIST_HEAD(&pool->clean_list);
349    mutex_init(&pool->flush_lock);
350    spin_lock_init(&pool->list_lock);
351    INIT_WORK(&pool->flush_worker, rds_iw_mr_pool_flush_worker);
352
353    pool->max_message_size = fastreg_message_size;
354    pool->max_items = fastreg_pool_size;
355    pool->max_free_pinned = pool->max_items * pool->max_message_size / 4;
356    pool->max_pages = fastreg_message_size;
357
358    /* We never allow more than max_items MRs to be allocated.
359     * When we exceed more than max_items_soft, we start freeing
360     * items more aggressively.
361     * Make sure that max_items > max_items_soft > max_items / 2
362     */
363    pool->max_items_soft = pool->max_items * 3 / 4;
364
365    return pool;
366}
367
368void rds_iw_get_mr_info(struct rds_iw_device *rds_iwdev, struct rds_info_rdma_connection *iinfo)
369{
370    struct rds_iw_mr_pool *pool = rds_iwdev->mr_pool;
371
372    iinfo->rdma_mr_max = pool->max_items;
373    iinfo->rdma_mr_size = pool->max_pages;
374}
375
376void rds_iw_destroy_mr_pool(struct rds_iw_mr_pool *pool)
377{
378    flush_workqueue(rds_wq);
379    rds_iw_flush_mr_pool(pool, 1);
380    BUG_ON(atomic_read(&pool->item_count));
381    BUG_ON(atomic_read(&pool->free_pinned));
382    kfree(pool);
383}
384
385static inline struct rds_iw_mr *rds_iw_reuse_fmr(struct rds_iw_mr_pool *pool)
386{
387    struct rds_iw_mr *ibmr = NULL;
388    unsigned long flags;
389
390    spin_lock_irqsave(&pool->list_lock, flags);
391    if (!list_empty(&pool->clean_list)) {
392        ibmr = list_entry(pool->clean_list.next, struct rds_iw_mr, mapping.m_list);
393        list_del_init(&ibmr->mapping.m_list);
394    }
395    spin_unlock_irqrestore(&pool->list_lock, flags);
396
397    return ibmr;
398}
399
400static struct rds_iw_mr *rds_iw_alloc_mr(struct rds_iw_device *rds_iwdev)
401{
402    struct rds_iw_mr_pool *pool = rds_iwdev->mr_pool;
403    struct rds_iw_mr *ibmr = NULL;
404    int err = 0, iter = 0;
405
406    while (1) {
407        ibmr = rds_iw_reuse_fmr(pool);
408        if (ibmr)
409            return ibmr;
410
411        /* No clean MRs - now we have the choice of either
412         * allocating a fresh MR up to the limit imposed by the
413         * driver, or flush any dirty unused MRs.
414         * We try to avoid stalling in the send path if possible,
415         * so we allocate as long as we're allowed to.
416         *
417         * We're fussy with enforcing the FMR limit, though. If the driver
418         * tells us we can't use more than N fmrs, we shouldn't start
419         * arguing with it */
420        if (atomic_inc_return(&pool->item_count) <= pool->max_items)
421            break;
422
423        atomic_dec(&pool->item_count);
424
425        if (++iter > 2) {
426            rds_iw_stats_inc(s_iw_rdma_mr_pool_depleted);
427            return ERR_PTR(-EAGAIN);
428        }
429
430        /* We do have some empty MRs. Flush them out. */
431        rds_iw_stats_inc(s_iw_rdma_mr_pool_wait);
432        rds_iw_flush_mr_pool(pool, 0);
433    }
434
435    ibmr = kzalloc(sizeof(*ibmr), GFP_KERNEL);
436    if (!ibmr) {
437        err = -ENOMEM;
438        goto out_no_cigar;
439    }
440
441    spin_lock_init(&ibmr->mapping.m_lock);
442    INIT_LIST_HEAD(&ibmr->mapping.m_list);
443    ibmr->mapping.m_mr = ibmr;
444
445    err = rds_iw_init_fastreg(pool, ibmr);
446    if (err)
447        goto out_no_cigar;
448
449    rds_iw_stats_inc(s_iw_rdma_mr_alloc);
450    return ibmr;
451
452out_no_cigar:
453    if (ibmr) {
454        rds_iw_destroy_fastreg(pool, ibmr);
455        kfree(ibmr);
456    }
457    atomic_dec(&pool->item_count);
458    return ERR_PTR(err);
459}
460
461void rds_iw_sync_mr(void *trans_private, int direction)
462{
463    struct rds_iw_mr *ibmr = trans_private;
464    struct rds_iw_device *rds_iwdev = ibmr->device;
465
466    switch (direction) {
467    case DMA_FROM_DEVICE:
468        ib_dma_sync_sg_for_cpu(rds_iwdev->dev, ibmr->mapping.m_sg.list,
469            ibmr->mapping.m_sg.dma_len, DMA_BIDIRECTIONAL);
470        break;
471    case DMA_TO_DEVICE:
472        ib_dma_sync_sg_for_device(rds_iwdev->dev, ibmr->mapping.m_sg.list,
473            ibmr->mapping.m_sg.dma_len, DMA_BIDIRECTIONAL);
474        break;
475    }
476}
477
478static inline unsigned int rds_iw_flush_goal(struct rds_iw_mr_pool *pool, int free_all)
479{
480    unsigned int item_count;
481
482    item_count = atomic_read(&pool->item_count);
483    if (free_all)
484        return item_count;
485
486    return 0;
487}
488
489/*
490 * Flush our pool of MRs.
491 * At a minimum, all currently unused MRs are unmapped.
492 * If the number of MRs allocated exceeds the limit, we also try
493 * to free as many MRs as needed to get back to this limit.
494 */
495static int rds_iw_flush_mr_pool(struct rds_iw_mr_pool *pool, int free_all)
496{
497    struct rds_iw_mr *ibmr, *next;
498    LIST_HEAD(unmap_list);
499    LIST_HEAD(kill_list);
500    unsigned long flags;
501    unsigned int nfreed = 0, ncleaned = 0, free_goal;
502    int ret = 0;
503
504    rds_iw_stats_inc(s_iw_rdma_mr_pool_flush);
505
506    mutex_lock(&pool->flush_lock);
507
508    spin_lock_irqsave(&pool->list_lock, flags);
509    /* Get the list of all mappings to be destroyed */
510    list_splice_init(&pool->dirty_list, &unmap_list);
511    if (free_all)
512        list_splice_init(&pool->clean_list, &kill_list);
513    spin_unlock_irqrestore(&pool->list_lock, flags);
514
515    free_goal = rds_iw_flush_goal(pool, free_all);
516
517    /* Batched invalidate of dirty MRs.
518     * For FMR based MRs, the mappings on the unmap list are
519     * actually members of an ibmr (ibmr->mapping). They either
520     * migrate to the kill_list, or have been cleaned and should be
521     * moved to the clean_list.
522     * For fastregs, they will be dynamically allocated, and
523     * will be destroyed by the unmap function.
524     */
525    if (!list_empty(&unmap_list)) {
526        ncleaned = rds_iw_unmap_fastreg_list(pool, &unmap_list, &kill_list);
527        /* If we've been asked to destroy all MRs, move those
528         * that were simply cleaned to the kill list */
529        if (free_all)
530            list_splice_init(&unmap_list, &kill_list);
531    }
532
533    /* Destroy any MRs that are past their best before date */
534    list_for_each_entry_safe(ibmr, next, &kill_list, mapping.m_list) {
535        rds_iw_stats_inc(s_iw_rdma_mr_free);
536        list_del(&ibmr->mapping.m_list);
537        rds_iw_destroy_fastreg(pool, ibmr);
538        kfree(ibmr);
539        nfreed++;
540    }
541
542    /* Anything that remains are laundered ibmrs, which we can add
543     * back to the clean list. */
544    if (!list_empty(&unmap_list)) {
545        spin_lock_irqsave(&pool->list_lock, flags);
546        list_splice(&unmap_list, &pool->clean_list);
547        spin_unlock_irqrestore(&pool->list_lock, flags);
548    }
549
550    atomic_sub(ncleaned, &pool->dirty_count);
551    atomic_sub(nfreed, &pool->item_count);
552
553    mutex_unlock(&pool->flush_lock);
554    return ret;
555}
556
557static void rds_iw_mr_pool_flush_worker(struct work_struct *work)
558{
559    struct rds_iw_mr_pool *pool = container_of(work, struct rds_iw_mr_pool, flush_worker);
560
561    rds_iw_flush_mr_pool(pool, 0);
562}
563
564void rds_iw_free_mr(void *trans_private, int invalidate)
565{
566    struct rds_iw_mr *ibmr = trans_private;
567    struct rds_iw_mr_pool *pool = ibmr->device->mr_pool;
568
569    rdsdebug("RDS/IW: free_mr nents %u\n", ibmr->mapping.m_sg.len);
570    if (!pool)
571        return;
572
573    /* Return it to the pool's free list */
574    rds_iw_free_fastreg(pool, ibmr);
575
576    /* If we've pinned too many pages, request a flush */
577    if (atomic_read(&pool->free_pinned) >= pool->max_free_pinned ||
578        atomic_read(&pool->dirty_count) >= pool->max_items / 10)
579        queue_work(rds_wq, &pool->flush_worker);
580
581    if (invalidate) {
582        if (likely(!in_interrupt())) {
583            rds_iw_flush_mr_pool(pool, 0);
584        } else {
585            /* We get here if the user created a MR marked
586             * as use_once and invalidate at the same time. */
587            queue_work(rds_wq, &pool->flush_worker);
588        }
589    }
590}
591
592void rds_iw_flush_mrs(void)
593{
594    struct rds_iw_device *rds_iwdev;
595
596    list_for_each_entry(rds_iwdev, &rds_iw_devices, list) {
597        struct rds_iw_mr_pool *pool = rds_iwdev->mr_pool;
598
599        if (pool)
600            rds_iw_flush_mr_pool(pool, 0);
601    }
602}
603
604void *rds_iw_get_mr(struct scatterlist *sg, unsigned long nents,
605            struct rds_sock *rs, u32 *key_ret)
606{
607    struct rds_iw_device *rds_iwdev;
608    struct rds_iw_mr *ibmr = NULL;
609    struct rdma_cm_id *cm_id;
610    int ret;
611
612    ret = rds_iw_get_device(rs, &rds_iwdev, &cm_id);
613    if (ret || !cm_id) {
614        ret = -ENODEV;
615        goto out;
616    }
617
618    if (!rds_iwdev->mr_pool) {
619        ret = -ENODEV;
620        goto out;
621    }
622
623    ibmr = rds_iw_alloc_mr(rds_iwdev);
624    if (IS_ERR(ibmr))
625        return ibmr;
626
627    ibmr->cm_id = cm_id;
628    ibmr->device = rds_iwdev;
629
630    ret = rds_iw_map_fastreg(rds_iwdev->mr_pool, ibmr, sg, nents);
631    if (ret == 0)
632        *key_ret = ibmr->mr->rkey;
633    else
634        printk(KERN_WARNING "RDS/IW: failed to map mr (errno=%d)\n", ret);
635
636out:
637    if (ret) {
638        if (ibmr)
639            rds_iw_free_mr(ibmr, 0);
640        ibmr = ERR_PTR(ret);
641    }
642    return ibmr;
643}
644
645/*
646 * iWARP fastreg handling
647 *
648 * The life cycle of a fastreg registration is a bit different from
649 * FMRs.
650 * The idea behind fastreg is to have one MR, to which we bind different
651 * mappings over time. To avoid stalling on the expensive map and invalidate
652 * operations, these operations are pipelined on the same send queue on
653 * which we want to send the message containing the r_key.
654 *
655 * This creates a bit of a problem for us, as we do not have the destination
656 * IP in GET_MR, so the connection must be setup prior to the GET_MR call for
657 * RDMA to be correctly setup. If a fastreg request is present, rds_iw_xmit
658 * will try to queue a LOCAL_INV (if needed) and a FAST_REG_MR work request
659 * before queuing the SEND. When completions for these arrive, they are
660 * dispatched to the MR has a bit set showing that RDMa can be performed.
661 *
662 * There is another interesting aspect that's related to invalidation.
663 * The application can request that a mapping is invalidated in FREE_MR.
664 * The expectation there is that this invalidation step includes ALL
665 * PREVIOUSLY FREED MRs.
666 */
667static int rds_iw_init_fastreg(struct rds_iw_mr_pool *pool,
668                struct rds_iw_mr *ibmr)
669{
670    struct rds_iw_device *rds_iwdev = pool->device;
671    struct ib_fast_reg_page_list *page_list = NULL;
672    struct ib_mr *mr;
673    int err;
674
675    mr = ib_alloc_fast_reg_mr(rds_iwdev->pd, pool->max_message_size);
676    if (IS_ERR(mr)) {
677        err = PTR_ERR(mr);
678
679        printk(KERN_WARNING "RDS/IW: ib_alloc_fast_reg_mr failed (err=%d)\n", err);
680        return err;
681    }
682
683    /* FIXME - this is overkill, but mapping->m_sg.dma_len/mapping->m_sg.dma_npages
684     * is not filled in.
685     */
686    page_list = ib_alloc_fast_reg_page_list(rds_iwdev->dev, pool->max_message_size);
687    if (IS_ERR(page_list)) {
688        err = PTR_ERR(page_list);
689
690        printk(KERN_WARNING "RDS/IW: ib_alloc_fast_reg_page_list failed (err=%d)\n", err);
691        ib_dereg_mr(mr);
692        return err;
693    }
694
695    ibmr->page_list = page_list;
696    ibmr->mr = mr;
697    return 0;
698}
699
700static int rds_iw_rdma_build_fastreg(struct rds_iw_mapping *mapping)
701{
702    struct rds_iw_mr *ibmr = mapping->m_mr;
703    struct ib_send_wr f_wr, *failed_wr;
704    int ret;
705
706    /*
707     * Perform a WR for the fast_reg_mr. Each individual page
708     * in the sg list is added to the fast reg page list and placed
709     * inside the fast_reg_mr WR. The key used is a rolling 8bit
710     * counter, which should guarantee uniqueness.
711     */
712    ib_update_fast_reg_key(ibmr->mr, ibmr->remap_count++);
713    mapping->m_rkey = ibmr->mr->rkey;
714
715    memset(&f_wr, 0, sizeof(f_wr));
716    f_wr.wr_id = RDS_IW_FAST_REG_WR_ID;
717    f_wr.opcode = IB_WR_FAST_REG_MR;
718    f_wr.wr.fast_reg.length = mapping->m_sg.bytes;
719    f_wr.wr.fast_reg.rkey = mapping->m_rkey;
720    f_wr.wr.fast_reg.page_list = ibmr->page_list;
721    f_wr.wr.fast_reg.page_list_len = mapping->m_sg.dma_len;
722    f_wr.wr.fast_reg.page_shift = PAGE_SHIFT;
723    f_wr.wr.fast_reg.access_flags = IB_ACCESS_LOCAL_WRITE |
724                IB_ACCESS_REMOTE_READ |
725                IB_ACCESS_REMOTE_WRITE;
726    f_wr.wr.fast_reg.iova_start = 0;
727    f_wr.send_flags = IB_SEND_SIGNALED;
728
729    failed_wr = &f_wr;
730    ret = ib_post_send(ibmr->cm_id->qp, &f_wr, &failed_wr);
731    BUG_ON(failed_wr != &f_wr);
732    if (ret && printk_ratelimit())
733        printk(KERN_WARNING "RDS/IW: %s:%d ib_post_send returned %d\n",
734            __func__, __LINE__, ret);
735    return ret;
736}
737
738static int rds_iw_rdma_fastreg_inv(struct rds_iw_mr *ibmr)
739{
740    struct ib_send_wr s_wr, *failed_wr;
741    int ret = 0;
742
743    if (!ibmr->cm_id->qp || !ibmr->mr)
744        goto out;
745
746    memset(&s_wr, 0, sizeof(s_wr));
747    s_wr.wr_id = RDS_IW_LOCAL_INV_WR_ID;
748    s_wr.opcode = IB_WR_LOCAL_INV;
749    s_wr.ex.invalidate_rkey = ibmr->mr->rkey;
750    s_wr.send_flags = IB_SEND_SIGNALED;
751
752    failed_wr = &s_wr;
753    ret = ib_post_send(ibmr->cm_id->qp, &s_wr, &failed_wr);
754    if (ret && printk_ratelimit()) {
755        printk(KERN_WARNING "RDS/IW: %s:%d ib_post_send returned %d\n",
756            __func__, __LINE__, ret);
757        goto out;
758    }
759out:
760    return ret;
761}
762
763static int rds_iw_map_fastreg(struct rds_iw_mr_pool *pool,
764            struct rds_iw_mr *ibmr,
765            struct scatterlist *sg,
766            unsigned int sg_len)
767{
768    struct rds_iw_device *rds_iwdev = pool->device;
769    struct rds_iw_mapping *mapping = &ibmr->mapping;
770    u64 *dma_pages;
771    int i, ret = 0;
772
773    rds_iw_set_scatterlist(&mapping->m_sg, sg, sg_len);
774
775    dma_pages = rds_iw_map_scatterlist(rds_iwdev, &mapping->m_sg);
776    if (IS_ERR(dma_pages)) {
777        ret = PTR_ERR(dma_pages);
778        dma_pages = NULL;
779        goto out;
780    }
781
782    if (mapping->m_sg.dma_len > pool->max_message_size) {
783        ret = -EMSGSIZE;
784        goto out;
785    }
786
787    for (i = 0; i < mapping->m_sg.dma_npages; ++i)
788        ibmr->page_list->page_list[i] = dma_pages[i];
789
790    ret = rds_iw_rdma_build_fastreg(mapping);
791    if (ret)
792        goto out;
793
794    rds_iw_stats_inc(s_iw_rdma_mr_used);
795
796out:
797    kfree(dma_pages);
798
799    return ret;
800}
801
802/*
803 * "Free" a fastreg MR.
804 */
805static void rds_iw_free_fastreg(struct rds_iw_mr_pool *pool,
806        struct rds_iw_mr *ibmr)
807{
808    unsigned long flags;
809    int ret;
810
811    if (!ibmr->mapping.m_sg.dma_len)
812        return;
813
814    ret = rds_iw_rdma_fastreg_inv(ibmr);
815    if (ret)
816        return;
817
818    /* Try to post the LOCAL_INV WR to the queue. */
819    spin_lock_irqsave(&pool->list_lock, flags);
820
821    list_add_tail(&ibmr->mapping.m_list, &pool->dirty_list);
822    atomic_add(ibmr->mapping.m_sg.len, &pool->free_pinned);
823    atomic_inc(&pool->dirty_count);
824
825    spin_unlock_irqrestore(&pool->list_lock, flags);
826}
827
828static unsigned int rds_iw_unmap_fastreg_list(struct rds_iw_mr_pool *pool,
829                struct list_head *unmap_list,
830                struct list_head *kill_list)
831{
832    struct rds_iw_mapping *mapping, *next;
833    unsigned int ncleaned = 0;
834    LIST_HEAD(laundered);
835
836    /* Batched invalidation of fastreg MRs.
837     * Why do we do it this way, even though we could pipeline unmap
838     * and remap? The reason is the application semantics - when the
839     * application requests an invalidation of MRs, it expects all
840     * previously released R_Keys to become invalid.
841     *
842     * If we implement MR reuse naively, we risk memory corruption
843     * (this has actually been observed). So the default behavior
844     * requires that a MR goes through an explicit unmap operation before
845     * we can reuse it again.
846     *
847     * We could probably improve on this a little, by allowing immediate
848     * reuse of a MR on the same socket (eg you could add small
849     * cache of unused MRs to strct rds_socket - GET_MR could grab one
850     * of these without requiring an explicit invalidate).
851     */
852    while (!list_empty(unmap_list)) {
853        unsigned long flags;
854
855        spin_lock_irqsave(&pool->list_lock, flags);
856        list_for_each_entry_safe(mapping, next, unmap_list, m_list) {
857            list_move(&mapping->m_list, &laundered);
858            ncleaned++;
859        }
860        spin_unlock_irqrestore(&pool->list_lock, flags);
861    }
862
863    /* Move all laundered mappings back to the unmap list.
864     * We do not kill any WRs right now - it doesn't seem the
865     * fastreg API has a max_remap limit. */
866    list_splice_init(&laundered, unmap_list);
867
868    return ncleaned;
869}
870
871static void rds_iw_destroy_fastreg(struct rds_iw_mr_pool *pool,
872        struct rds_iw_mr *ibmr)
873{
874    if (ibmr->page_list)
875        ib_free_fast_reg_page_list(ibmr->page_list);
876    if (ibmr->mr)
877        ib_dereg_mr(ibmr->mr);
878}
879

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