GNU Linux-libre 6.6.31-gnu
[releases.git] / net / rds / ib_frmr.c
1 /*
2  * Copyright (c) 2016 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 "ib_mr.h"
34
35 static inline void
36 rds_transition_frwr_state(struct rds_ib_mr *ibmr,
37                           enum rds_ib_fr_state old_state,
38                           enum rds_ib_fr_state new_state)
39 {
40         if (cmpxchg(&ibmr->u.frmr.fr_state,
41                     old_state, new_state) == old_state &&
42             old_state == FRMR_IS_INUSE) {
43                 /* enforce order of ibmr->u.frmr.fr_state update
44                  * before decrementing i_fastreg_inuse_count
45                  */
46                 smp_mb__before_atomic();
47                 atomic_dec(&ibmr->ic->i_fastreg_inuse_count);
48                 if (waitqueue_active(&rds_ib_ring_empty_wait))
49                         wake_up(&rds_ib_ring_empty_wait);
50         }
51 }
52
53 static struct rds_ib_mr *rds_ib_alloc_frmr(struct rds_ib_device *rds_ibdev,
54                                            int npages)
55 {
56         struct rds_ib_mr_pool *pool;
57         struct rds_ib_mr *ibmr = NULL;
58         struct rds_ib_frmr *frmr;
59         int err = 0;
60
61         if (npages <= RDS_MR_8K_MSG_SIZE)
62                 pool = rds_ibdev->mr_8k_pool;
63         else
64                 pool = rds_ibdev->mr_1m_pool;
65
66         ibmr = rds_ib_try_reuse_ibmr(pool);
67         if (ibmr)
68                 return ibmr;
69
70         ibmr = kzalloc_node(sizeof(*ibmr), GFP_KERNEL,
71                             rdsibdev_to_node(rds_ibdev));
72         if (!ibmr) {
73                 err = -ENOMEM;
74                 goto out_no_cigar;
75         }
76
77         frmr = &ibmr->u.frmr;
78         frmr->mr = ib_alloc_mr(rds_ibdev->pd, IB_MR_TYPE_MEM_REG,
79                          pool->max_pages);
80         if (IS_ERR(frmr->mr)) {
81                 pr_warn("RDS/IB: %s failed to allocate MR", __func__);
82                 err = PTR_ERR(frmr->mr);
83                 goto out_no_cigar;
84         }
85
86         ibmr->pool = pool;
87         if (pool->pool_type == RDS_IB_MR_8K_POOL)
88                 rds_ib_stats_inc(s_ib_rdma_mr_8k_alloc);
89         else
90                 rds_ib_stats_inc(s_ib_rdma_mr_1m_alloc);
91
92         if (atomic_read(&pool->item_count) > pool->max_items_soft)
93                 pool->max_items_soft = pool->max_items;
94
95         frmr->fr_state = FRMR_IS_FREE;
96         init_waitqueue_head(&frmr->fr_inv_done);
97         init_waitqueue_head(&frmr->fr_reg_done);
98         return ibmr;
99
100 out_no_cigar:
101         kfree(ibmr);
102         atomic_dec(&pool->item_count);
103         return ERR_PTR(err);
104 }
105
106 static void rds_ib_free_frmr(struct rds_ib_mr *ibmr, bool drop)
107 {
108         struct rds_ib_mr_pool *pool = ibmr->pool;
109
110         if (drop)
111                 llist_add(&ibmr->llnode, &pool->drop_list);
112         else
113                 llist_add(&ibmr->llnode, &pool->free_list);
114         atomic_add(ibmr->sg_len, &pool->free_pinned);
115         atomic_inc(&pool->dirty_count);
116
117         /* If we've pinned too many pages, request a flush */
118         if (atomic_read(&pool->free_pinned) >= pool->max_free_pinned ||
119             atomic_read(&pool->dirty_count) >= pool->max_items / 5)
120                 queue_delayed_work(rds_ib_mr_wq, &pool->flush_worker, 10);
121 }
122
123 static int rds_ib_post_reg_frmr(struct rds_ib_mr *ibmr)
124 {
125         struct rds_ib_frmr *frmr = &ibmr->u.frmr;
126         struct ib_reg_wr reg_wr;
127         int ret, off = 0;
128
129         while (atomic_dec_return(&ibmr->ic->i_fastreg_wrs) <= 0) {
130                 atomic_inc(&ibmr->ic->i_fastreg_wrs);
131                 cpu_relax();
132         }
133
134         ret = ib_map_mr_sg_zbva(frmr->mr, ibmr->sg, ibmr->sg_dma_len,
135                                 &off, PAGE_SIZE);
136         if (unlikely(ret != ibmr->sg_dma_len))
137                 return ret < 0 ? ret : -EINVAL;
138
139         if (cmpxchg(&frmr->fr_state,
140                     FRMR_IS_FREE, FRMR_IS_INUSE) != FRMR_IS_FREE)
141                 return -EBUSY;
142
143         atomic_inc(&ibmr->ic->i_fastreg_inuse_count);
144
145         /* Perform a WR for the fast_reg_mr. Each individual page
146          * in the sg list is added to the fast reg page list and placed
147          * inside the fast_reg_mr WR.  The key used is a rolling 8bit
148          * counter, which should guarantee uniqueness.
149          */
150         ib_update_fast_reg_key(frmr->mr, ibmr->remap_count++);
151         frmr->fr_reg = true;
152
153         memset(&reg_wr, 0, sizeof(reg_wr));
154         reg_wr.wr.wr_id = (unsigned long)(void *)ibmr;
155         reg_wr.wr.opcode = IB_WR_REG_MR;
156         reg_wr.wr.num_sge = 0;
157         reg_wr.mr = frmr->mr;
158         reg_wr.key = frmr->mr->rkey;
159         reg_wr.access = IB_ACCESS_LOCAL_WRITE |
160                         IB_ACCESS_REMOTE_READ |
161                         IB_ACCESS_REMOTE_WRITE;
162         reg_wr.wr.send_flags = IB_SEND_SIGNALED;
163
164         ret = ib_post_send(ibmr->ic->i_cm_id->qp, &reg_wr.wr, NULL);
165         if (unlikely(ret)) {
166                 /* Failure here can be because of -ENOMEM as well */
167                 rds_transition_frwr_state(ibmr, FRMR_IS_INUSE, FRMR_IS_STALE);
168
169                 atomic_inc(&ibmr->ic->i_fastreg_wrs);
170                 if (printk_ratelimit())
171                         pr_warn("RDS/IB: %s returned error(%d)\n",
172                                 __func__, ret);
173                 goto out;
174         }
175
176         /* Wait for the registration to complete in order to prevent an invalid
177          * access error resulting from a race between the memory region already
178          * being accessed while registration is still pending.
179          */
180         wait_event(frmr->fr_reg_done, !frmr->fr_reg);
181
182 out:
183
184         return ret;
185 }
186
187 static int rds_ib_map_frmr(struct rds_ib_device *rds_ibdev,
188                            struct rds_ib_mr_pool *pool,
189                            struct rds_ib_mr *ibmr,
190                            struct scatterlist *sg, unsigned int sg_len)
191 {
192         struct ib_device *dev = rds_ibdev->dev;
193         struct rds_ib_frmr *frmr = &ibmr->u.frmr;
194         int i;
195         u32 len;
196         int ret = 0;
197
198         /* We want to teardown old ibmr values here and fill it up with
199          * new sg values
200          */
201         rds_ib_teardown_mr(ibmr);
202
203         ibmr->sg = sg;
204         ibmr->sg_len = sg_len;
205         ibmr->sg_dma_len = 0;
206         frmr->sg_byte_len = 0;
207         WARN_ON(ibmr->sg_dma_len);
208         ibmr->sg_dma_len = ib_dma_map_sg(dev, ibmr->sg, ibmr->sg_len,
209                                          DMA_BIDIRECTIONAL);
210         if (unlikely(!ibmr->sg_dma_len)) {
211                 pr_warn("RDS/IB: %s failed!\n", __func__);
212                 return -EBUSY;
213         }
214
215         frmr->sg_byte_len = 0;
216         frmr->dma_npages = 0;
217         len = 0;
218
219         ret = -EINVAL;
220         for (i = 0; i < ibmr->sg_dma_len; ++i) {
221                 unsigned int dma_len = sg_dma_len(&ibmr->sg[i]);
222                 u64 dma_addr = sg_dma_address(&ibmr->sg[i]);
223
224                 frmr->sg_byte_len += dma_len;
225                 if (dma_addr & ~PAGE_MASK) {
226                         if (i > 0)
227                                 goto out_unmap;
228                         else
229                                 ++frmr->dma_npages;
230                 }
231
232                 if ((dma_addr + dma_len) & ~PAGE_MASK) {
233                         if (i < ibmr->sg_dma_len - 1)
234                                 goto out_unmap;
235                         else
236                                 ++frmr->dma_npages;
237                 }
238
239                 len += dma_len;
240         }
241         frmr->dma_npages += len >> PAGE_SHIFT;
242
243         if (frmr->dma_npages > ibmr->pool->max_pages) {
244                 ret = -EMSGSIZE;
245                 goto out_unmap;
246         }
247
248         ret = rds_ib_post_reg_frmr(ibmr);
249         if (ret)
250                 goto out_unmap;
251
252         if (ibmr->pool->pool_type == RDS_IB_MR_8K_POOL)
253                 rds_ib_stats_inc(s_ib_rdma_mr_8k_used);
254         else
255                 rds_ib_stats_inc(s_ib_rdma_mr_1m_used);
256
257         return ret;
258
259 out_unmap:
260         ib_dma_unmap_sg(rds_ibdev->dev, ibmr->sg, ibmr->sg_len,
261                         DMA_BIDIRECTIONAL);
262         ibmr->sg_dma_len = 0;
263         return ret;
264 }
265
266 static int rds_ib_post_inv(struct rds_ib_mr *ibmr)
267 {
268         struct ib_send_wr *s_wr;
269         struct rds_ib_frmr *frmr = &ibmr->u.frmr;
270         struct rdma_cm_id *i_cm_id = ibmr->ic->i_cm_id;
271         int ret = -EINVAL;
272
273         if (!i_cm_id || !i_cm_id->qp || !frmr->mr)
274                 goto out;
275
276         if (frmr->fr_state != FRMR_IS_INUSE)
277                 goto out;
278
279         while (atomic_dec_return(&ibmr->ic->i_fastreg_wrs) <= 0) {
280                 atomic_inc(&ibmr->ic->i_fastreg_wrs);
281                 cpu_relax();
282         }
283
284         frmr->fr_inv = true;
285         s_wr = &frmr->fr_wr;
286
287         memset(s_wr, 0, sizeof(*s_wr));
288         s_wr->wr_id = (unsigned long)(void *)ibmr;
289         s_wr->opcode = IB_WR_LOCAL_INV;
290         s_wr->ex.invalidate_rkey = frmr->mr->rkey;
291         s_wr->send_flags = IB_SEND_SIGNALED;
292
293         ret = ib_post_send(i_cm_id->qp, s_wr, NULL);
294         if (unlikely(ret)) {
295                 rds_transition_frwr_state(ibmr, FRMR_IS_INUSE, FRMR_IS_STALE);
296                 frmr->fr_inv = false;
297                 /* enforce order of frmr->fr_inv update
298                  * before incrementing i_fastreg_wrs
299                  */
300                 smp_mb__before_atomic();
301                 atomic_inc(&ibmr->ic->i_fastreg_wrs);
302                 pr_err("RDS/IB: %s returned error(%d)\n", __func__, ret);
303                 goto out;
304         }
305
306         /* Wait for the FRMR_IS_FREE (or FRMR_IS_STALE) transition in order to
307          * 1) avoid a silly bouncing between "clean_list" and "drop_list"
308          *    triggered by function "rds_ib_reg_frmr" as it is releases frmr
309          *    regions whose state is not "FRMR_IS_FREE" right away.
310          * 2) prevents an invalid access error in a race
311          *    from a pending "IB_WR_LOCAL_INV" operation
312          *    with a teardown ("dma_unmap_sg", "put_page")
313          *    and de-registration ("ib_dereg_mr") of the corresponding
314          *    memory region.
315          */
316         wait_event(frmr->fr_inv_done, frmr->fr_state != FRMR_IS_INUSE);
317
318 out:
319         return ret;
320 }
321
322 void rds_ib_mr_cqe_handler(struct rds_ib_connection *ic, struct ib_wc *wc)
323 {
324         struct rds_ib_mr *ibmr = (void *)(unsigned long)wc->wr_id;
325         struct rds_ib_frmr *frmr = &ibmr->u.frmr;
326
327         if (wc->status != IB_WC_SUCCESS) {
328                 rds_transition_frwr_state(ibmr, FRMR_IS_INUSE, FRMR_IS_STALE);
329                 if (rds_conn_up(ic->conn))
330                         rds_ib_conn_error(ic->conn,
331                                           "frmr completion <%pI4,%pI4> status %u(%s), vendor_err 0x%x, disconnecting and reconnecting\n",
332                                           &ic->conn->c_laddr,
333                                           &ic->conn->c_faddr,
334                                           wc->status,
335                                           ib_wc_status_msg(wc->status),
336                                           wc->vendor_err);
337         }
338
339         if (frmr->fr_inv) {
340                 rds_transition_frwr_state(ibmr, FRMR_IS_INUSE, FRMR_IS_FREE);
341                 frmr->fr_inv = false;
342                 wake_up(&frmr->fr_inv_done);
343         }
344
345         if (frmr->fr_reg) {
346                 frmr->fr_reg = false;
347                 wake_up(&frmr->fr_reg_done);
348         }
349
350         /* enforce order of frmr->{fr_reg,fr_inv} update
351          * before incrementing i_fastreg_wrs
352          */
353         smp_mb__before_atomic();
354         atomic_inc(&ic->i_fastreg_wrs);
355 }
356
357 void rds_ib_unreg_frmr(struct list_head *list, unsigned int *nfreed,
358                        unsigned long *unpinned, unsigned int goal)
359 {
360         struct rds_ib_mr *ibmr, *next;
361         struct rds_ib_frmr *frmr;
362         int ret = 0, ret2;
363         unsigned int freed = *nfreed;
364
365         /* String all ib_mr's onto one list and hand them to ib_unmap_fmr */
366         list_for_each_entry(ibmr, list, unmap_list) {
367                 if (ibmr->sg_dma_len) {
368                         ret2 = rds_ib_post_inv(ibmr);
369                         if (ret2 && !ret)
370                                 ret = ret2;
371                 }
372         }
373
374         if (ret)
375                 pr_warn("RDS/IB: %s failed (err=%d)\n", __func__, ret);
376
377         /* Now we can destroy the DMA mapping and unpin any pages */
378         list_for_each_entry_safe(ibmr, next, list, unmap_list) {
379                 *unpinned += ibmr->sg_len;
380                 frmr = &ibmr->u.frmr;
381                 __rds_ib_teardown_mr(ibmr);
382                 if (freed < goal || frmr->fr_state == FRMR_IS_STALE) {
383                         /* Don't de-allocate if the MR is not free yet */
384                         if (frmr->fr_state == FRMR_IS_INUSE)
385                                 continue;
386
387                         if (ibmr->pool->pool_type == RDS_IB_MR_8K_POOL)
388                                 rds_ib_stats_inc(s_ib_rdma_mr_8k_free);
389                         else
390                                 rds_ib_stats_inc(s_ib_rdma_mr_1m_free);
391                         list_del(&ibmr->unmap_list);
392                         if (frmr->mr)
393                                 ib_dereg_mr(frmr->mr);
394                         kfree(ibmr);
395                         freed++;
396                 }
397         }
398         *nfreed = freed;
399 }
400
401 struct rds_ib_mr *rds_ib_reg_frmr(struct rds_ib_device *rds_ibdev,
402                                   struct rds_ib_connection *ic,
403                                   struct scatterlist *sg,
404                                   unsigned long nents, u32 *key)
405 {
406         struct rds_ib_mr *ibmr = NULL;
407         struct rds_ib_frmr *frmr;
408         int ret;
409
410         if (!ic) {
411                 /* TODO: Add FRWR support for RDS_GET_MR using proxy qp*/
412                 return ERR_PTR(-EOPNOTSUPP);
413         }
414
415         do {
416                 if (ibmr)
417                         rds_ib_free_frmr(ibmr, true);
418                 ibmr = rds_ib_alloc_frmr(rds_ibdev, nents);
419                 if (IS_ERR(ibmr))
420                         return ibmr;
421                 frmr = &ibmr->u.frmr;
422         } while (frmr->fr_state != FRMR_IS_FREE);
423
424         ibmr->ic = ic;
425         ibmr->device = rds_ibdev;
426         ret = rds_ib_map_frmr(rds_ibdev, ibmr->pool, ibmr, sg, nents);
427         if (ret == 0) {
428                 *key = frmr->mr->rkey;
429         } else {
430                 rds_ib_free_frmr(ibmr, false);
431                 ibmr = ERR_PTR(ret);
432         }
433
434         return ibmr;
435 }
436
437 void rds_ib_free_frmr_list(struct rds_ib_mr *ibmr)
438 {
439         struct rds_ib_mr_pool *pool = ibmr->pool;
440         struct rds_ib_frmr *frmr = &ibmr->u.frmr;
441
442         if (frmr->fr_state == FRMR_IS_STALE)
443                 llist_add(&ibmr->llnode, &pool->drop_list);
444         else
445                 llist_add(&ibmr->llnode, &pool->free_list);
446 }