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1/*
2 * Copyright (c) 2015 Oracle. All rights reserved.
3 * Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
4 */
5
6/* Lightweight memory registration using Fast Memory Regions (FMR).
7 * Referred to sometimes as MTHCAFMR mode.
8 *
9 * FMR uses synchronous memory registration and deregistration.
10 * FMR registration is known to be fast, but FMR deregistration
11 * can take tens of usecs to complete.
12 */
13
14/* Normal operation
15 *
16 * A Memory Region is prepared for RDMA READ or WRITE using the
17 * ib_map_phys_fmr verb (fmr_op_map). When the RDMA operation is
18 * finished, the Memory Region is unmapped using the ib_unmap_fmr
19 * verb (fmr_op_unmap).
20 */
21
22/* Transport recovery
23 *
24 * After a transport reconnect, fmr_op_map re-uses the MR already
25 * allocated for the RPC, but generates a fresh rkey then maps the
26 * MR again. This process is synchronous.
27 */
28
29#include "xprt_rdma.h"
30
31#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
32# define RPCDBG_FACILITY RPCDBG_TRANS
33#endif
34
35/* Maximum scatter/gather per FMR */
36#define RPCRDMA_MAX_FMR_SGES (64)
37
38static int
39fmr_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep,
40 struct rpcrdma_create_data_internal *cdata)
41{
42 return 0;
43}
44
45/* FMR mode conveys up to 64 pages of payload per chunk segment.
46 */
47static size_t
48fmr_op_maxpages(struct rpcrdma_xprt *r_xprt)
49{
50 return min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS,
51 rpcrdma_max_segments(r_xprt) * RPCRDMA_MAX_FMR_SGES);
52}
53
54static int
55fmr_op_init(struct rpcrdma_xprt *r_xprt)
56{
57 struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
58 int mr_access_flags = IB_ACCESS_REMOTE_WRITE | IB_ACCESS_REMOTE_READ;
59 struct ib_fmr_attr fmr_attr = {
60 .max_pages = RPCRDMA_MAX_FMR_SGES,
61 .max_maps = 1,
62 .page_shift = PAGE_SHIFT
63 };
64 struct ib_pd *pd = r_xprt->rx_ia.ri_pd;
65 struct rpcrdma_mw *r;
66 int i, rc;
67
68 spin_lock_init(&buf->rb_mwlock);
69 INIT_LIST_HEAD(&buf->rb_mws);
70 INIT_LIST_HEAD(&buf->rb_all);
71
72 i = max_t(int, RPCRDMA_MAX_DATA_SEGS / RPCRDMA_MAX_FMR_SGES, 1);
73 i += 2; /* head + tail */
74 i *= buf->rb_max_requests; /* one set for each RPC slot */
75 dprintk("RPC: %s: initalizing %d FMRs\n", __func__, i);
76
77 rc = -ENOMEM;
78 while (i--) {
79 r = kzalloc(sizeof(*r), GFP_KERNEL);
80 if (!r)
81 goto out;
82
83 r->fmr.physaddrs = kmalloc(RPCRDMA_MAX_FMR_SGES *
84 sizeof(u64), GFP_KERNEL);
85 if (!r->fmr.physaddrs)
86 goto out_free;
87
88 r->fmr.fmr = ib_alloc_fmr(pd, mr_access_flags, &fmr_attr);
89 if (IS_ERR(r->fmr.fmr))
90 goto out_fmr_err;
91
92 list_add(&r->mw_list, &buf->rb_mws);
93 list_add(&r->mw_all, &buf->rb_all);
94 }
95 return 0;
96
97out_fmr_err:
98 rc = PTR_ERR(r->fmr.fmr);
99 dprintk("RPC: %s: ib_alloc_fmr status %i\n", __func__, rc);
100 kfree(r->fmr.physaddrs);
101out_free:
102 kfree(r);
103out:
104 return rc;
105}
106
107static int
108__fmr_unmap(struct rpcrdma_mw *r)
109{
110 LIST_HEAD(l);
111
112 list_add(&r->fmr.fmr->list, &l);
113 return ib_unmap_fmr(&l);
114}
115
116/* Use the ib_map_phys_fmr() verb to register a memory region
117 * for remote access via RDMA READ or RDMA WRITE.
118 */
119static int
120fmr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
121 int nsegs, bool writing)
122{
123 struct rpcrdma_ia *ia = &r_xprt->rx_ia;
124 struct ib_device *device = ia->ri_device;
125 enum dma_data_direction direction = rpcrdma_data_dir(writing);
126 struct rpcrdma_mr_seg *seg1 = seg;
127 int len, pageoff, i, rc;
128 struct rpcrdma_mw *mw;
129
130 mw = seg1->rl_mw;
131 seg1->rl_mw = NULL;
132 if (!mw) {
133 mw = rpcrdma_get_mw(r_xprt);
134 if (!mw)
135 return -ENOMEM;
136 } else {
137 /* this is a retransmit; generate a fresh rkey */
138 rc = __fmr_unmap(mw);
139 if (rc)
140 return rc;
141 }
142
143 pageoff = offset_in_page(seg1->mr_offset);
144 seg1->mr_offset -= pageoff; /* start of page */
145 seg1->mr_len += pageoff;
146 len = -pageoff;
147 if (nsegs > RPCRDMA_MAX_FMR_SGES)
148 nsegs = RPCRDMA_MAX_FMR_SGES;
149 for (i = 0; i < nsegs;) {
150 rpcrdma_map_one(device, seg, direction);
151 mw->fmr.physaddrs[i] = seg->mr_dma;
152 len += seg->mr_len;
153 ++seg;
154 ++i;
155 /* Check for holes */
156 if ((i < nsegs && offset_in_page(seg->mr_offset)) ||
157 offset_in_page((seg-1)->mr_offset + (seg-1)->mr_len))
158 break;
159 }
160
161 rc = ib_map_phys_fmr(mw->fmr.fmr, mw->fmr.physaddrs,
162 i, seg1->mr_dma);
163 if (rc)
164 goto out_maperr;
165
166 seg1->rl_mw = mw;
167 seg1->mr_rkey = mw->fmr.fmr->rkey;
168 seg1->mr_base = seg1->mr_dma + pageoff;
169 seg1->mr_nsegs = i;
170 seg1->mr_len = len;
171 return i;
172
173out_maperr:
174 dprintk("RPC: %s: ib_map_phys_fmr %u@0x%llx+%i (%d) status %i\n",
175 __func__, len, (unsigned long long)seg1->mr_dma,
176 pageoff, i, rc);
177 while (i--)
178 rpcrdma_unmap_one(device, --seg);
179 return rc;
180}
181
182static void
183__fmr_dma_unmap(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg)
184{
185 struct ib_device *device = r_xprt->rx_ia.ri_device;
186 struct rpcrdma_mw *mw = seg->rl_mw;
187 int nsegs = seg->mr_nsegs;
188
189 seg->rl_mw = NULL;
190
191 while (nsegs--)
192 rpcrdma_unmap_one(device, seg++);
193
194 rpcrdma_put_mw(r_xprt, mw);
195}
196
197/* Invalidate all memory regions that were registered for "req".
198 *
199 * Sleeps until it is safe for the host CPU to access the
200 * previously mapped memory regions.
201 */
202static void
203fmr_op_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req)
204{
205 struct rpcrdma_mr_seg *seg;
206 unsigned int i, nchunks;
207 struct rpcrdma_mw *mw;
208 LIST_HEAD(unmap_list);
209 int rc;
210
211 dprintk("RPC: %s: req %p\n", __func__, req);
212
213 /* ORDER: Invalidate all of the req's MRs first
214 *
215 * ib_unmap_fmr() is slow, so use a single call instead
216 * of one call per mapped MR.
217 */
218 for (i = 0, nchunks = req->rl_nchunks; nchunks; nchunks--) {
219 seg = &req->rl_segments[i];
220 mw = seg->rl_mw;
221
222 list_add(&mw->fmr.fmr->list, &unmap_list);
223
224 i += seg->mr_nsegs;
225 }
226 rc = ib_unmap_fmr(&unmap_list);
227 if (rc)
228 pr_warn("%s: ib_unmap_fmr failed (%i)\n", __func__, rc);
229
230 /* ORDER: Now DMA unmap all of the req's MRs, and return
231 * them to the free MW list.
232 */
233 for (i = 0, nchunks = req->rl_nchunks; nchunks; nchunks--) {
234 seg = &req->rl_segments[i];
235
236 __fmr_dma_unmap(r_xprt, seg);
237
238 i += seg->mr_nsegs;
239 seg->mr_nsegs = 0;
240 }
241
242 req->rl_nchunks = 0;
243}
244
245/* Use the ib_unmap_fmr() verb to prevent further remote
246 * access via RDMA READ or RDMA WRITE.
247 */
248static int
249fmr_op_unmap(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg)
250{
251 struct rpcrdma_ia *ia = &r_xprt->rx_ia;
252 struct rpcrdma_mr_seg *seg1 = seg;
253 struct rpcrdma_mw *mw = seg1->rl_mw;
254 int rc, nsegs = seg->mr_nsegs;
255
256 dprintk("RPC: %s: FMR %p\n", __func__, mw);
257
258 seg1->rl_mw = NULL;
259 while (seg1->mr_nsegs--)
260 rpcrdma_unmap_one(ia->ri_device, seg++);
261 rc = __fmr_unmap(mw);
262 if (rc)
263 goto out_err;
264 rpcrdma_put_mw(r_xprt, mw);
265 return nsegs;
266
267out_err:
268 /* The FMR is abandoned, but remains in rb_all. fmr_op_destroy
269 * will attempt to release it when the transport is destroyed.
270 */
271 dprintk("RPC: %s: ib_unmap_fmr status %i\n", __func__, rc);
272 return nsegs;
273}
274
275static void
276fmr_op_destroy(struct rpcrdma_buffer *buf)
277{
278 struct rpcrdma_mw *r;
279 int rc;
280
281 while (!list_empty(&buf->rb_all)) {
282 r = list_entry(buf->rb_all.next, struct rpcrdma_mw, mw_all);
283 list_del(&r->mw_all);
284 kfree(r->fmr.physaddrs);
285
286 rc = ib_dealloc_fmr(r->fmr.fmr);
287 if (rc)
288 dprintk("RPC: %s: ib_dealloc_fmr failed %i\n",
289 __func__, rc);
290
291 kfree(r);
292 }
293}
294
295const struct rpcrdma_memreg_ops rpcrdma_fmr_memreg_ops = {
296 .ro_map = fmr_op_map,
297 .ro_unmap_sync = fmr_op_unmap_sync,
298 .ro_unmap = fmr_op_unmap,
299 .ro_open = fmr_op_open,
300 .ro_maxpages = fmr_op_maxpages,
301 .ro_init = fmr_op_init,
302 .ro_destroy = fmr_op_destroy,
303 .ro_displayname = "fmr",
304};
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2015, 2017 Oracle. All rights reserved.
4 * Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
5 */
6
7/* Lightweight memory registration using Fast Memory Regions (FMR).
8 * Referred to sometimes as MTHCAFMR mode.
9 *
10 * FMR uses synchronous memory registration and deregistration.
11 * FMR registration is known to be fast, but FMR deregistration
12 * can take tens of usecs to complete.
13 */
14
15/* Normal operation
16 *
17 * A Memory Region is prepared for RDMA READ or WRITE using the
18 * ib_map_phys_fmr verb (fmr_op_map). When the RDMA operation is
19 * finished, the Memory Region is unmapped using the ib_unmap_fmr
20 * verb (fmr_op_unmap).
21 */
22
23#include "xprt_rdma.h"
24
25#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
26# define RPCDBG_FACILITY RPCDBG_TRANS
27#endif
28
29/* Maximum scatter/gather per FMR */
30#define RPCRDMA_MAX_FMR_SGES (64)
31
32/* Access mode of externally registered pages */
33enum {
34 RPCRDMA_FMR_ACCESS_FLAGS = IB_ACCESS_REMOTE_WRITE |
35 IB_ACCESS_REMOTE_READ,
36};
37
38bool
39fmr_is_supported(struct rpcrdma_ia *ia)
40{
41 if (!ia->ri_device->alloc_fmr) {
42 pr_info("rpcrdma: 'fmr' mode is not supported by device %s\n",
43 ia->ri_device->name);
44 return false;
45 }
46 return true;
47}
48
49static int
50fmr_op_init_mr(struct rpcrdma_ia *ia, struct rpcrdma_mr *mr)
51{
52 static struct ib_fmr_attr fmr_attr = {
53 .max_pages = RPCRDMA_MAX_FMR_SGES,
54 .max_maps = 1,
55 .page_shift = PAGE_SHIFT
56 };
57
58 mr->fmr.fm_physaddrs = kcalloc(RPCRDMA_MAX_FMR_SGES,
59 sizeof(u64), GFP_KERNEL);
60 if (!mr->fmr.fm_physaddrs)
61 goto out_free;
62
63 mr->mr_sg = kcalloc(RPCRDMA_MAX_FMR_SGES,
64 sizeof(*mr->mr_sg), GFP_KERNEL);
65 if (!mr->mr_sg)
66 goto out_free;
67
68 sg_init_table(mr->mr_sg, RPCRDMA_MAX_FMR_SGES);
69
70 mr->fmr.fm_mr = ib_alloc_fmr(ia->ri_pd, RPCRDMA_FMR_ACCESS_FLAGS,
71 &fmr_attr);
72 if (IS_ERR(mr->fmr.fm_mr))
73 goto out_fmr_err;
74
75 INIT_LIST_HEAD(&mr->mr_list);
76 return 0;
77
78out_fmr_err:
79 dprintk("RPC: %s: ib_alloc_fmr returned %ld\n", __func__,
80 PTR_ERR(mr->fmr.fm_mr));
81
82out_free:
83 kfree(mr->mr_sg);
84 kfree(mr->fmr.fm_physaddrs);
85 return -ENOMEM;
86}
87
88static int
89__fmr_unmap(struct rpcrdma_mr *mr)
90{
91 LIST_HEAD(l);
92 int rc;
93
94 list_add(&mr->fmr.fm_mr->list, &l);
95 rc = ib_unmap_fmr(&l);
96 list_del(&mr->fmr.fm_mr->list);
97 return rc;
98}
99
100static void
101fmr_op_release_mr(struct rpcrdma_mr *mr)
102{
103 LIST_HEAD(unmap_list);
104 int rc;
105
106 kfree(mr->fmr.fm_physaddrs);
107 kfree(mr->mr_sg);
108
109 /* In case this one was left mapped, try to unmap it
110 * to prevent dealloc_fmr from failing with EBUSY
111 */
112 rc = __fmr_unmap(mr);
113 if (rc)
114 pr_err("rpcrdma: final ib_unmap_fmr for %p failed %i\n",
115 mr, rc);
116
117 rc = ib_dealloc_fmr(mr->fmr.fm_mr);
118 if (rc)
119 pr_err("rpcrdma: final ib_dealloc_fmr for %p returned %i\n",
120 mr, rc);
121
122 kfree(mr);
123}
124
125/* Reset of a single FMR.
126 */
127static void
128fmr_op_recover_mr(struct rpcrdma_mr *mr)
129{
130 struct rpcrdma_xprt *r_xprt = mr->mr_xprt;
131 int rc;
132
133 /* ORDER: invalidate first */
134 rc = __fmr_unmap(mr);
135 if (rc)
136 goto out_release;
137
138 /* ORDER: then DMA unmap */
139 rpcrdma_mr_unmap_and_put(mr);
140
141 r_xprt->rx_stats.mrs_recovered++;
142 return;
143
144out_release:
145 pr_err("rpcrdma: FMR reset failed (%d), %p released\n", rc, mr);
146 r_xprt->rx_stats.mrs_orphaned++;
147
148 trace_xprtrdma_dma_unmap(mr);
149 ib_dma_unmap_sg(r_xprt->rx_ia.ri_device,
150 mr->mr_sg, mr->mr_nents, mr->mr_dir);
151
152 spin_lock(&r_xprt->rx_buf.rb_mrlock);
153 list_del(&mr->mr_all);
154 spin_unlock(&r_xprt->rx_buf.rb_mrlock);
155
156 fmr_op_release_mr(mr);
157}
158
159static int
160fmr_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep,
161 struct rpcrdma_create_data_internal *cdata)
162{
163 ia->ri_max_segs = max_t(unsigned int, 1, RPCRDMA_MAX_DATA_SEGS /
164 RPCRDMA_MAX_FMR_SGES);
165 return 0;
166}
167
168/* FMR mode conveys up to 64 pages of payload per chunk segment.
169 */
170static size_t
171fmr_op_maxpages(struct rpcrdma_xprt *r_xprt)
172{
173 return min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS,
174 RPCRDMA_MAX_HDR_SEGS * RPCRDMA_MAX_FMR_SGES);
175}
176
177/* Use the ib_map_phys_fmr() verb to register a memory region
178 * for remote access via RDMA READ or RDMA WRITE.
179 */
180static struct rpcrdma_mr_seg *
181fmr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
182 int nsegs, bool writing, struct rpcrdma_mr **out)
183{
184 struct rpcrdma_mr_seg *seg1 = seg;
185 int len, pageoff, i, rc;
186 struct rpcrdma_mr *mr;
187 u64 *dma_pages;
188
189 mr = rpcrdma_mr_get(r_xprt);
190 if (!mr)
191 return ERR_PTR(-EAGAIN);
192
193 pageoff = offset_in_page(seg1->mr_offset);
194 seg1->mr_offset -= pageoff; /* start of page */
195 seg1->mr_len += pageoff;
196 len = -pageoff;
197 if (nsegs > RPCRDMA_MAX_FMR_SGES)
198 nsegs = RPCRDMA_MAX_FMR_SGES;
199 for (i = 0; i < nsegs;) {
200 if (seg->mr_page)
201 sg_set_page(&mr->mr_sg[i],
202 seg->mr_page,
203 seg->mr_len,
204 offset_in_page(seg->mr_offset));
205 else
206 sg_set_buf(&mr->mr_sg[i], seg->mr_offset,
207 seg->mr_len);
208 len += seg->mr_len;
209 ++seg;
210 ++i;
211 /* Check for holes */
212 if ((i < nsegs && offset_in_page(seg->mr_offset)) ||
213 offset_in_page((seg-1)->mr_offset + (seg-1)->mr_len))
214 break;
215 }
216 mr->mr_dir = rpcrdma_data_dir(writing);
217
218 mr->mr_nents = ib_dma_map_sg(r_xprt->rx_ia.ri_device,
219 mr->mr_sg, i, mr->mr_dir);
220 if (!mr->mr_nents)
221 goto out_dmamap_err;
222
223 for (i = 0, dma_pages = mr->fmr.fm_physaddrs; i < mr->mr_nents; i++)
224 dma_pages[i] = sg_dma_address(&mr->mr_sg[i]);
225 rc = ib_map_phys_fmr(mr->fmr.fm_mr, dma_pages, mr->mr_nents,
226 dma_pages[0]);
227 if (rc)
228 goto out_maperr;
229
230 mr->mr_handle = mr->fmr.fm_mr->rkey;
231 mr->mr_length = len;
232 mr->mr_offset = dma_pages[0] + pageoff;
233
234 *out = mr;
235 return seg;
236
237out_dmamap_err:
238 pr_err("rpcrdma: failed to DMA map sg %p sg_nents %d\n",
239 mr->mr_sg, i);
240 rpcrdma_mr_put(mr);
241 return ERR_PTR(-EIO);
242
243out_maperr:
244 pr_err("rpcrdma: ib_map_phys_fmr %u@0x%llx+%i (%d) status %i\n",
245 len, (unsigned long long)dma_pages[0],
246 pageoff, mr->mr_nents, rc);
247 rpcrdma_mr_unmap_and_put(mr);
248 return ERR_PTR(-EIO);
249}
250
251/* Post Send WR containing the RPC Call message.
252 */
253static int
254fmr_op_send(struct rpcrdma_ia *ia, struct rpcrdma_req *req)
255{
256 struct ib_send_wr *bad_wr;
257
258 return ib_post_send(ia->ri_id->qp, &req->rl_sendctx->sc_wr, &bad_wr);
259}
260
261/* Invalidate all memory regions that were registered for "req".
262 *
263 * Sleeps until it is safe for the host CPU to access the
264 * previously mapped memory regions.
265 *
266 * Caller ensures that @mrs is not empty before the call. This
267 * function empties the list.
268 */
269static void
270fmr_op_unmap_sync(struct rpcrdma_xprt *r_xprt, struct list_head *mrs)
271{
272 struct rpcrdma_mr *mr;
273 LIST_HEAD(unmap_list);
274 int rc;
275
276 /* ORDER: Invalidate all of the req's MRs first
277 *
278 * ib_unmap_fmr() is slow, so use a single call instead
279 * of one call per mapped FMR.
280 */
281 list_for_each_entry(mr, mrs, mr_list) {
282 dprintk("RPC: %s: unmapping fmr %p\n",
283 __func__, &mr->fmr);
284 trace_xprtrdma_localinv(mr);
285 list_add_tail(&mr->fmr.fm_mr->list, &unmap_list);
286 }
287 r_xprt->rx_stats.local_inv_needed++;
288 rc = ib_unmap_fmr(&unmap_list);
289 if (rc)
290 goto out_reset;
291
292 /* ORDER: Now DMA unmap all of the req's MRs, and return
293 * them to the free MW list.
294 */
295 while (!list_empty(mrs)) {
296 mr = rpcrdma_mr_pop(mrs);
297 list_del(&mr->fmr.fm_mr->list);
298 rpcrdma_mr_unmap_and_put(mr);
299 }
300
301 return;
302
303out_reset:
304 pr_err("rpcrdma: ib_unmap_fmr failed (%i)\n", rc);
305
306 while (!list_empty(mrs)) {
307 mr = rpcrdma_mr_pop(mrs);
308 list_del(&mr->fmr.fm_mr->list);
309 fmr_op_recover_mr(mr);
310 }
311}
312
313const struct rpcrdma_memreg_ops rpcrdma_fmr_memreg_ops = {
314 .ro_map = fmr_op_map,
315 .ro_send = fmr_op_send,
316 .ro_unmap_sync = fmr_op_unmap_sync,
317 .ro_recover_mr = fmr_op_recover_mr,
318 .ro_open = fmr_op_open,
319 .ro_maxpages = fmr_op_maxpages,
320 .ro_init_mr = fmr_op_init_mr,
321 .ro_release_mr = fmr_op_release_mr,
322 .ro_displayname = "fmr",
323 .ro_send_w_inv_ok = 0,
324};