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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#include "xprt_rdma.h"
23
24#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
25# define RPCDBG_FACILITY RPCDBG_TRANS
26#endif
27
28/* Maximum scatter/gather per FMR */
29#define RPCRDMA_MAX_FMR_SGES (64)
30
31/* Access mode of externally registered pages */
32enum {
33 RPCRDMA_FMR_ACCESS_FLAGS = IB_ACCESS_REMOTE_WRITE |
34 IB_ACCESS_REMOTE_READ,
35};
36
37bool
38fmr_is_supported(struct rpcrdma_ia *ia)
39{
40 if (!ia->ri_device->alloc_fmr) {
41 pr_info("rpcrdma: 'fmr' mode is not supported by device %s\n",
42 ia->ri_device->name);
43 return false;
44 }
45 return true;
46}
47
48static int
49fmr_op_init_mr(struct rpcrdma_ia *ia, struct rpcrdma_mw *mw)
50{
51 static struct ib_fmr_attr fmr_attr = {
52 .max_pages = RPCRDMA_MAX_FMR_SGES,
53 .max_maps = 1,
54 .page_shift = PAGE_SHIFT
55 };
56
57 mw->fmr.fm_physaddrs = kcalloc(RPCRDMA_MAX_FMR_SGES,
58 sizeof(u64), GFP_KERNEL);
59 if (!mw->fmr.fm_physaddrs)
60 goto out_free;
61
62 mw->mw_sg = kcalloc(RPCRDMA_MAX_FMR_SGES,
63 sizeof(*mw->mw_sg), GFP_KERNEL);
64 if (!mw->mw_sg)
65 goto out_free;
66
67 sg_init_table(mw->mw_sg, RPCRDMA_MAX_FMR_SGES);
68
69 mw->fmr.fm_mr = ib_alloc_fmr(ia->ri_pd, RPCRDMA_FMR_ACCESS_FLAGS,
70 &fmr_attr);
71 if (IS_ERR(mw->fmr.fm_mr))
72 goto out_fmr_err;
73
74 return 0;
75
76out_fmr_err:
77 dprintk("RPC: %s: ib_alloc_fmr returned %ld\n", __func__,
78 PTR_ERR(mw->fmr.fm_mr));
79
80out_free:
81 kfree(mw->mw_sg);
82 kfree(mw->fmr.fm_physaddrs);
83 return -ENOMEM;
84}
85
86static int
87__fmr_unmap(struct rpcrdma_mw *mw)
88{
89 LIST_HEAD(l);
90 int rc;
91
92 list_add(&mw->fmr.fm_mr->list, &l);
93 rc = ib_unmap_fmr(&l);
94 list_del_init(&mw->fmr.fm_mr->list);
95 return rc;
96}
97
98static void
99fmr_op_release_mr(struct rpcrdma_mw *r)
100{
101 LIST_HEAD(unmap_list);
102 int rc;
103
104 /* Ensure MW is not on any rl_registered list */
105 if (!list_empty(&r->mw_list))
106 list_del(&r->mw_list);
107
108 kfree(r->fmr.fm_physaddrs);
109 kfree(r->mw_sg);
110
111 /* In case this one was left mapped, try to unmap it
112 * to prevent dealloc_fmr from failing with EBUSY
113 */
114 rc = __fmr_unmap(r);
115 if (rc)
116 pr_err("rpcrdma: final ib_unmap_fmr for %p failed %i\n",
117 r, rc);
118
119 rc = ib_dealloc_fmr(r->fmr.fm_mr);
120 if (rc)
121 pr_err("rpcrdma: final ib_dealloc_fmr for %p returned %i\n",
122 r, rc);
123
124 kfree(r);
125}
126
127/* Reset of a single FMR.
128 */
129static void
130fmr_op_recover_mr(struct rpcrdma_mw *mw)
131{
132 struct rpcrdma_xprt *r_xprt = mw->mw_xprt;
133 int rc;
134
135 /* ORDER: invalidate first */
136 rc = __fmr_unmap(mw);
137
138 /* ORDER: then DMA unmap */
139 ib_dma_unmap_sg(r_xprt->rx_ia.ri_device,
140 mw->mw_sg, mw->mw_nents, mw->mw_dir);
141 if (rc)
142 goto out_release;
143
144 rpcrdma_put_mw(r_xprt, mw);
145 r_xprt->rx_stats.mrs_recovered++;
146 return;
147
148out_release:
149 pr_err("rpcrdma: FMR reset failed (%d), %p released\n", rc, mw);
150 r_xprt->rx_stats.mrs_orphaned++;
151
152 spin_lock(&r_xprt->rx_buf.rb_mwlock);
153 list_del(&mw->mw_all);
154 spin_unlock(&r_xprt->rx_buf.rb_mwlock);
155
156 fmr_op_release_mr(mw);
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 int
181fmr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
182 int nsegs, bool writing, struct rpcrdma_mw **out)
183{
184 struct rpcrdma_mr_seg *seg1 = seg;
185 int len, pageoff, i, rc;
186 struct rpcrdma_mw *mw;
187 u64 *dma_pages;
188
189 mw = rpcrdma_get_mw(r_xprt);
190 if (!mw)
191 return -ENOBUFS;
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(&mw->mw_sg[i],
202 seg->mr_page,
203 seg->mr_len,
204 offset_in_page(seg->mr_offset));
205 else
206 sg_set_buf(&mw->mw_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 mw->mw_nents = i;
217 mw->mw_dir = rpcrdma_data_dir(writing);
218 if (i == 0)
219 goto out_dmamap_err;
220
221 if (!ib_dma_map_sg(r_xprt->rx_ia.ri_device,
222 mw->mw_sg, mw->mw_nents, mw->mw_dir))
223 goto out_dmamap_err;
224
225 for (i = 0, dma_pages = mw->fmr.fm_physaddrs; i < mw->mw_nents; i++)
226 dma_pages[i] = sg_dma_address(&mw->mw_sg[i]);
227 rc = ib_map_phys_fmr(mw->fmr.fm_mr, dma_pages, mw->mw_nents,
228 dma_pages[0]);
229 if (rc)
230 goto out_maperr;
231
232 mw->mw_handle = mw->fmr.fm_mr->rkey;
233 mw->mw_length = len;
234 mw->mw_offset = dma_pages[0] + pageoff;
235
236 *out = mw;
237 return mw->mw_nents;
238
239out_dmamap_err:
240 pr_err("rpcrdma: failed to dma map sg %p sg_nents %u\n",
241 mw->mw_sg, mw->mw_nents);
242 rpcrdma_defer_mr_recovery(mw);
243 return -EIO;
244
245out_maperr:
246 pr_err("rpcrdma: ib_map_phys_fmr %u@0x%llx+%i (%d) status %i\n",
247 len, (unsigned long long)dma_pages[0],
248 pageoff, mw->mw_nents, rc);
249 rpcrdma_defer_mr_recovery(mw);
250 return -EIO;
251}
252
253/* Invalidate all memory regions that were registered for "req".
254 *
255 * Sleeps until it is safe for the host CPU to access the
256 * previously mapped memory regions.
257 *
258 * Caller ensures that req->rl_registered is not empty.
259 */
260static void
261fmr_op_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req)
262{
263 struct rpcrdma_mw *mw, *tmp;
264 LIST_HEAD(unmap_list);
265 int rc;
266
267 dprintk("RPC: %s: req %p\n", __func__, req);
268
269 /* ORDER: Invalidate all of the req's MRs first
270 *
271 * ib_unmap_fmr() is slow, so use a single call instead
272 * of one call per mapped FMR.
273 */
274 list_for_each_entry(mw, &req->rl_registered, mw_list)
275 list_add_tail(&mw->fmr.fm_mr->list, &unmap_list);
276 r_xprt->rx_stats.local_inv_needed++;
277 rc = ib_unmap_fmr(&unmap_list);
278 if (rc)
279 goto out_reset;
280
281 /* ORDER: Now DMA unmap all of the req's MRs, and return
282 * them to the free MW list.
283 */
284 list_for_each_entry_safe(mw, tmp, &req->rl_registered, mw_list) {
285 list_del_init(&mw->mw_list);
286 list_del_init(&mw->fmr.fm_mr->list);
287 ib_dma_unmap_sg(r_xprt->rx_ia.ri_device,
288 mw->mw_sg, mw->mw_nents, mw->mw_dir);
289 rpcrdma_put_mw(r_xprt, mw);
290 }
291
292 return;
293
294out_reset:
295 pr_err("rpcrdma: ib_unmap_fmr failed (%i)\n", rc);
296
297 list_for_each_entry_safe(mw, tmp, &req->rl_registered, mw_list) {
298 list_del_init(&mw->fmr.fm_mr->list);
299 fmr_op_recover_mr(mw);
300 }
301}
302
303/* Use a slow, safe mechanism to invalidate all memory regions
304 * that were registered for "req".
305 */
306static void
307fmr_op_unmap_safe(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req,
308 bool sync)
309{
310 struct rpcrdma_mw *mw;
311
312 while (!list_empty(&req->rl_registered)) {
313 mw = list_first_entry(&req->rl_registered,
314 struct rpcrdma_mw, mw_list);
315 list_del_init(&mw->mw_list);
316
317 if (sync)
318 fmr_op_recover_mr(mw);
319 else
320 rpcrdma_defer_mr_recovery(mw);
321 }
322}
323
324const struct rpcrdma_memreg_ops rpcrdma_fmr_memreg_ops = {
325 .ro_map = fmr_op_map,
326 .ro_unmap_sync = fmr_op_unmap_sync,
327 .ro_unmap_safe = fmr_op_unmap_safe,
328 .ro_recover_mr = fmr_op_recover_mr,
329 .ro_open = fmr_op_open,
330 .ro_maxpages = fmr_op_maxpages,
331 .ro_init_mr = fmr_op_init_mr,
332 .ro_release_mr = fmr_op_release_mr,
333 .ro_displayname = "fmr",
334 .ro_send_w_inv_ok = 0,
335};
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};