Commit | Line | Data |
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a0ce85f5 CL |
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 | ||
fc7fbb59 CL |
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 | ||
a0ce85f5 CL |
29 | #include "xprt_rdma.h" |
30 | ||
31 | #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) | |
32 | # define RPCDBG_FACILITY RPCDBG_TRANS | |
33 | #endif | |
34 | ||
1c9351ee CL |
35 | /* Maximum scatter/gather per FMR */ |
36 | #define RPCRDMA_MAX_FMR_SGES (64) | |
37 | ||
3968cb58 CL |
38 | static int |
39 | fmr_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep, | |
40 | struct rpcrdma_create_data_internal *cdata) | |
41 | { | |
42 | return 0; | |
43 | } | |
44 | ||
1c9351ee CL |
45 | /* FMR mode conveys up to 64 pages of payload per chunk segment. |
46 | */ | |
47 | static size_t | |
48 | fmr_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 | ||
91e70e70 CL |
54 | static int |
55 | fmr_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 | ||
58d1dcf5 | 68 | spin_lock_init(&buf->rb_mwlock); |
91e70e70 CL |
69 | INIT_LIST_HEAD(&buf->rb_mws); |
70 | INIT_LIST_HEAD(&buf->rb_all); | |
71 | ||
40c6ed0c CL |
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); | |
91e70e70 | 76 | |
acb9da7a | 77 | rc = -ENOMEM; |
91e70e70 CL |
78 | while (i--) { |
79 | r = kzalloc(sizeof(*r), GFP_KERNEL); | |
80 | if (!r) | |
acb9da7a CL |
81 | goto out; |
82 | ||
c882a655 CL |
83 | r->fmr.physaddrs = kmalloc(RPCRDMA_MAX_FMR_SGES * |
84 | sizeof(u64), GFP_KERNEL); | |
85 | if (!r->fmr.physaddrs) | |
acb9da7a | 86 | goto out_free; |
91e70e70 | 87 | |
c882a655 CL |
88 | r->fmr.fmr = ib_alloc_fmr(pd, mr_access_flags, &fmr_attr); |
89 | if (IS_ERR(r->fmr.fmr)) | |
91e70e70 CL |
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 | ||
97 | out_fmr_err: | |
c882a655 | 98 | rc = PTR_ERR(r->fmr.fmr); |
91e70e70 | 99 | dprintk("RPC: %s: ib_alloc_fmr status %i\n", __func__, rc); |
c882a655 | 100 | kfree(r->fmr.physaddrs); |
acb9da7a | 101 | out_free: |
91e70e70 | 102 | kfree(r); |
acb9da7a | 103 | out: |
91e70e70 CL |
104 | return rc; |
105 | } | |
106 | ||
fc7fbb59 CL |
107 | static int |
108 | __fmr_unmap(struct rpcrdma_mw *r) | |
109 | { | |
110 | LIST_HEAD(l); | |
111 | ||
c882a655 | 112 | list_add(&r->fmr.fmr->list, &l); |
fc7fbb59 CL |
113 | return ib_unmap_fmr(&l); |
114 | } | |
115 | ||
9c1b4d77 CL |
116 | /* Use the ib_map_phys_fmr() verb to register a memory region |
117 | * for remote access via RDMA READ or RDMA WRITE. | |
118 | */ | |
119 | static int | |
120 | fmr_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; | |
89e0d112 | 124 | struct ib_device *device = ia->ri_device; |
d654788e | 125 | enum dma_data_direction direction = rpcrdma_data_dir(writing); |
9c1b4d77 | 126 | struct rpcrdma_mr_seg *seg1 = seg; |
9c1b4d77 | 127 | int len, pageoff, i, rc; |
fc7fbb59 CL |
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 | } | |
9c1b4d77 CL |
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;) { | |
d654788e | 150 | rpcrdma_map_one(device, seg, direction); |
c882a655 | 151 | mw->fmr.physaddrs[i] = seg->mr_dma; |
9c1b4d77 CL |
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 | ||
c882a655 | 161 | rc = ib_map_phys_fmr(mw->fmr.fmr, mw->fmr.physaddrs, |
acb9da7a | 162 | i, seg1->mr_dma); |
9c1b4d77 CL |
163 | if (rc) |
164 | goto out_maperr; | |
165 | ||
fc7fbb59 | 166 | seg1->rl_mw = mw; |
c882a655 | 167 | seg1->mr_rkey = mw->fmr.fmr->rkey; |
9c1b4d77 CL |
168 | seg1->mr_base = seg1->mr_dma + pageoff; |
169 | seg1->mr_nsegs = i; | |
170 | seg1->mr_len = len; | |
171 | return i; | |
172 | ||
173 | out_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--) | |
d654788e | 178 | rpcrdma_unmap_one(device, --seg); |
9c1b4d77 CL |
179 | return rc; |
180 | } | |
181 | ||
7c7a5390 CL |
182 | static 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 | */ | |
202 | static void | |
203 | fmr_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 | ||
c882a655 | 222 | list_add(&mw->fmr.fmr->list, &unmap_list); |
7c7a5390 CL |
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 | ||
6814baea CL |
245 | /* Use the ib_unmap_fmr() verb to prevent further remote |
246 | * access via RDMA READ or RDMA WRITE. | |
247 | */ | |
248 | static int | |
249 | fmr_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; | |
fc7fbb59 | 253 | struct rpcrdma_mw *mw = seg1->rl_mw; |
6814baea | 254 | int rc, nsegs = seg->mr_nsegs; |
6814baea | 255 | |
fc7fbb59 CL |
256 | dprintk("RPC: %s: FMR %p\n", __func__, mw); |
257 | ||
258 | seg1->rl_mw = NULL; | |
6814baea | 259 | while (seg1->mr_nsegs--) |
89e0d112 | 260 | rpcrdma_unmap_one(ia->ri_device, seg++); |
fc7fbb59 | 261 | rc = __fmr_unmap(mw); |
6814baea CL |
262 | if (rc) |
263 | goto out_err; | |
fc7fbb59 | 264 | rpcrdma_put_mw(r_xprt, mw); |
6814baea CL |
265 | return nsegs; |
266 | ||
267 | out_err: | |
fc7fbb59 CL |
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 | */ | |
6814baea CL |
271 | dprintk("RPC: %s: ib_unmap_fmr status %i\n", __func__, rc); |
272 | return nsegs; | |
273 | } | |
274 | ||
4561f347 CL |
275 | static void |
276 | fmr_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); | |
c882a655 | 284 | kfree(r->fmr.physaddrs); |
acb9da7a | 285 | |
c882a655 | 286 | rc = ib_dealloc_fmr(r->fmr.fmr); |
4561f347 CL |
287 | if (rc) |
288 | dprintk("RPC: %s: ib_dealloc_fmr failed %i\n", | |
289 | __func__, rc); | |
acb9da7a | 290 | |
4561f347 CL |
291 | kfree(r); |
292 | } | |
293 | } | |
294 | ||
a0ce85f5 | 295 | const struct rpcrdma_memreg_ops rpcrdma_fmr_memreg_ops = { |
9c1b4d77 | 296 | .ro_map = fmr_op_map, |
7c7a5390 | 297 | .ro_unmap_sync = fmr_op_unmap_sync, |
6814baea | 298 | .ro_unmap = fmr_op_unmap, |
3968cb58 | 299 | .ro_open = fmr_op_open, |
1c9351ee | 300 | .ro_maxpages = fmr_op_maxpages, |
91e70e70 | 301 | .ro_init = fmr_op_init, |
4561f347 | 302 | .ro_destroy = fmr_op_destroy, |
a0ce85f5 CL |
303 | .ro_displayname = "fmr", |
304 | }; |