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 Registration Work 7 * Requests (FRWR). Also referred to sometimes as FRMR mode. 8 * 9 * FRWR features ordered asynchronous registration and deregistration 10 * of arbitrarily sized memory regions. This is the fastest and safest 11 * but most complex memory registration mode. 12 */ 13 14 #include "xprt_rdma.h" 15 16 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) 17 # define RPCDBG_FACILITY RPCDBG_TRANS 18 #endif 19 20 static int 21 __frwr_init(struct rpcrdma_mw *r, struct ib_pd *pd, struct ib_device *device, 22 unsigned int depth) 23 { 24 struct rpcrdma_frmr *f = &r->r.frmr; 25 int rc; 26 27 f->fr_mr = ib_alloc_fast_reg_mr(pd, depth); 28 if (IS_ERR(f->fr_mr)) 29 goto out_mr_err; 30 f->fr_pgl = ib_alloc_fast_reg_page_list(device, depth); 31 if (IS_ERR(f->fr_pgl)) 32 goto out_list_err; 33 return 0; 34 35 out_mr_err: 36 rc = PTR_ERR(f->fr_mr); 37 dprintk("RPC: %s: ib_alloc_fast_reg_mr status %i\n", 38 __func__, rc); 39 return rc; 40 41 out_list_err: 42 rc = PTR_ERR(f->fr_pgl); 43 dprintk("RPC: %s: ib_alloc_fast_reg_page_list status %i\n", 44 __func__, rc); 45 ib_dereg_mr(f->fr_mr); 46 return rc; 47 } 48 49 static void 50 __frwr_release(struct rpcrdma_mw *r) 51 { 52 int rc; 53 54 rc = ib_dereg_mr(r->r.frmr.fr_mr); 55 if (rc) 56 dprintk("RPC: %s: ib_dereg_mr status %i\n", 57 __func__, rc); 58 ib_free_fast_reg_page_list(r->r.frmr.fr_pgl); 59 } 60 61 static int 62 frwr_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep, 63 struct rpcrdma_create_data_internal *cdata) 64 { 65 struct ib_device_attr *devattr = &ia->ri_devattr; 66 int depth, delta; 67 68 ia->ri_max_frmr_depth = 69 min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS, 70 devattr->max_fast_reg_page_list_len); 71 dprintk("RPC: %s: device's max FR page list len = %u\n", 72 __func__, ia->ri_max_frmr_depth); 73 74 /* Add room for frmr register and invalidate WRs. 75 * 1. FRMR reg WR for head 76 * 2. FRMR invalidate WR for head 77 * 3. N FRMR reg WRs for pagelist 78 * 4. N FRMR invalidate WRs for pagelist 79 * 5. FRMR reg WR for tail 80 * 6. FRMR invalidate WR for tail 81 * 7. The RDMA_SEND WR 82 */ 83 depth = 7; 84 85 /* Calculate N if the device max FRMR depth is smaller than 86 * RPCRDMA_MAX_DATA_SEGS. 87 */ 88 if (ia->ri_max_frmr_depth < RPCRDMA_MAX_DATA_SEGS) { 89 delta = RPCRDMA_MAX_DATA_SEGS - ia->ri_max_frmr_depth; 90 do { 91 depth += 2; /* FRMR reg + invalidate */ 92 delta -= ia->ri_max_frmr_depth; 93 } while (delta > 0); 94 } 95 96 ep->rep_attr.cap.max_send_wr *= depth; 97 if (ep->rep_attr.cap.max_send_wr > devattr->max_qp_wr) { 98 cdata->max_requests = devattr->max_qp_wr / depth; 99 if (!cdata->max_requests) 100 return -EINVAL; 101 ep->rep_attr.cap.max_send_wr = cdata->max_requests * 102 depth; 103 } 104 105 return 0; 106 } 107 108 /* FRWR mode conveys a list of pages per chunk segment. The 109 * maximum length of that list is the FRWR page list depth. 110 */ 111 static size_t 112 frwr_op_maxpages(struct rpcrdma_xprt *r_xprt) 113 { 114 struct rpcrdma_ia *ia = &r_xprt->rx_ia; 115 116 return min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS, 117 rpcrdma_max_segments(r_xprt) * ia->ri_max_frmr_depth); 118 } 119 120 /* If FAST_REG or LOCAL_INV failed, indicate the frmr needs to be reset. */ 121 static void 122 frwr_sendcompletion(struct ib_wc *wc) 123 { 124 struct rpcrdma_mw *r; 125 126 if (likely(wc->status == IB_WC_SUCCESS)) 127 return; 128 129 /* WARNING: Only wr_id and status are reliable at this point */ 130 r = (struct rpcrdma_mw *)(unsigned long)wc->wr_id; 131 dprintk("RPC: %s: frmr %p (stale), status %d\n", 132 __func__, r, wc->status); 133 r->r.frmr.fr_state = FRMR_IS_STALE; 134 } 135 136 static int 137 frwr_op_init(struct rpcrdma_xprt *r_xprt) 138 { 139 struct rpcrdma_buffer *buf = &r_xprt->rx_buf; 140 struct ib_device *device = r_xprt->rx_ia.ri_id->device; 141 unsigned int depth = r_xprt->rx_ia.ri_max_frmr_depth; 142 struct ib_pd *pd = r_xprt->rx_ia.ri_pd; 143 int i; 144 145 INIT_LIST_HEAD(&buf->rb_mws); 146 INIT_LIST_HEAD(&buf->rb_all); 147 148 i = (buf->rb_max_requests + 1) * RPCRDMA_MAX_SEGS; 149 dprintk("RPC: %s: initializing %d FRMRs\n", __func__, i); 150 151 while (i--) { 152 struct rpcrdma_mw *r; 153 int rc; 154 155 r = kzalloc(sizeof(*r), GFP_KERNEL); 156 if (!r) 157 return -ENOMEM; 158 159 rc = __frwr_init(r, pd, device, depth); 160 if (rc) { 161 kfree(r); 162 return rc; 163 } 164 165 list_add(&r->mw_list, &buf->rb_mws); 166 list_add(&r->mw_all, &buf->rb_all); 167 r->mw_sendcompletion = frwr_sendcompletion; 168 } 169 170 return 0; 171 } 172 173 /* Post a FAST_REG Work Request to register a memory region 174 * for remote access via RDMA READ or RDMA WRITE. 175 */ 176 static int 177 frwr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg, 178 int nsegs, bool writing) 179 { 180 struct rpcrdma_ia *ia = &r_xprt->rx_ia; 181 struct ib_device *device = ia->ri_id->device; 182 enum dma_data_direction direction = rpcrdma_data_dir(writing); 183 struct rpcrdma_mr_seg *seg1 = seg; 184 struct rpcrdma_mw *mw = seg1->rl_mw; 185 struct rpcrdma_frmr *frmr = &mw->r.frmr; 186 struct ib_mr *mr = frmr->fr_mr; 187 struct ib_send_wr fastreg_wr, *bad_wr; 188 u8 key; 189 int len, pageoff; 190 int i, rc; 191 int seg_len; 192 u64 pa; 193 int page_no; 194 195 pageoff = offset_in_page(seg1->mr_offset); 196 seg1->mr_offset -= pageoff; /* start of page */ 197 seg1->mr_len += pageoff; 198 len = -pageoff; 199 if (nsegs > ia->ri_max_frmr_depth) 200 nsegs = ia->ri_max_frmr_depth; 201 for (page_no = i = 0; i < nsegs;) { 202 rpcrdma_map_one(device, seg, direction); 203 pa = seg->mr_dma; 204 for (seg_len = seg->mr_len; seg_len > 0; seg_len -= PAGE_SIZE) { 205 frmr->fr_pgl->page_list[page_no++] = pa; 206 pa += PAGE_SIZE; 207 } 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 dprintk("RPC: %s: Using frmr %p to map %d segments (%d bytes)\n", 217 __func__, mw, i, len); 218 219 frmr->fr_state = FRMR_IS_VALID; 220 221 memset(&fastreg_wr, 0, sizeof(fastreg_wr)); 222 fastreg_wr.wr_id = (unsigned long)(void *)mw; 223 fastreg_wr.opcode = IB_WR_FAST_REG_MR; 224 fastreg_wr.wr.fast_reg.iova_start = seg1->mr_dma + pageoff; 225 fastreg_wr.wr.fast_reg.page_list = frmr->fr_pgl; 226 fastreg_wr.wr.fast_reg.page_shift = PAGE_SHIFT; 227 fastreg_wr.wr.fast_reg.page_list_len = page_no; 228 fastreg_wr.wr.fast_reg.length = len; 229 fastreg_wr.wr.fast_reg.access_flags = writing ? 230 IB_ACCESS_REMOTE_WRITE | IB_ACCESS_LOCAL_WRITE : 231 IB_ACCESS_REMOTE_READ; 232 key = (u8)(mr->rkey & 0x000000FF); 233 ib_update_fast_reg_key(mr, ++key); 234 fastreg_wr.wr.fast_reg.rkey = mr->rkey; 235 236 DECR_CQCOUNT(&r_xprt->rx_ep); 237 rc = ib_post_send(ia->ri_id->qp, &fastreg_wr, &bad_wr); 238 if (rc) 239 goto out_senderr; 240 241 seg1->mr_rkey = mr->rkey; 242 seg1->mr_base = seg1->mr_dma + pageoff; 243 seg1->mr_nsegs = i; 244 seg1->mr_len = len; 245 return i; 246 247 out_senderr: 248 dprintk("RPC: %s: ib_post_send status %i\n", __func__, rc); 249 ib_update_fast_reg_key(mr, --key); 250 frmr->fr_state = FRMR_IS_INVALID; 251 while (i--) 252 rpcrdma_unmap_one(device, --seg); 253 return rc; 254 } 255 256 /* Post a LOCAL_INV Work Request to prevent further remote access 257 * via RDMA READ or RDMA WRITE. 258 */ 259 static int 260 frwr_op_unmap(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg) 261 { 262 struct rpcrdma_mr_seg *seg1 = seg; 263 struct rpcrdma_ia *ia = &r_xprt->rx_ia; 264 struct ib_send_wr invalidate_wr, *bad_wr; 265 int rc, nsegs = seg->mr_nsegs; 266 struct ib_device *device; 267 268 seg1->rl_mw->r.frmr.fr_state = FRMR_IS_INVALID; 269 270 memset(&invalidate_wr, 0, sizeof(invalidate_wr)); 271 invalidate_wr.wr_id = (unsigned long)(void *)seg1->rl_mw; 272 invalidate_wr.opcode = IB_WR_LOCAL_INV; 273 invalidate_wr.ex.invalidate_rkey = seg1->rl_mw->r.frmr.fr_mr->rkey; 274 DECR_CQCOUNT(&r_xprt->rx_ep); 275 276 read_lock(&ia->ri_qplock); 277 device = ia->ri_id->device; 278 while (seg1->mr_nsegs--) 279 rpcrdma_unmap_one(device, seg++); 280 rc = ib_post_send(ia->ri_id->qp, &invalidate_wr, &bad_wr); 281 read_unlock(&ia->ri_qplock); 282 if (rc) 283 goto out_err; 284 return nsegs; 285 286 out_err: 287 /* Force rpcrdma_buffer_get() to retry */ 288 seg1->rl_mw->r.frmr.fr_state = FRMR_IS_STALE; 289 dprintk("RPC: %s: ib_post_send status %i\n", __func__, rc); 290 return nsegs; 291 } 292 293 /* After a disconnect, a flushed FAST_REG_MR can leave an FRMR in 294 * an unusable state. Find FRMRs in this state and dereg / reg 295 * each. FRMRs that are VALID and attached to an rpcrdma_req are 296 * also torn down. 297 * 298 * This gives all in-use FRMRs a fresh rkey and leaves them INVALID. 299 * 300 * This is invoked only in the transport connect worker in order 301 * to serialize with rpcrdma_register_frmr_external(). 302 */ 303 static void 304 frwr_op_reset(struct rpcrdma_xprt *r_xprt) 305 { 306 struct rpcrdma_buffer *buf = &r_xprt->rx_buf; 307 struct ib_device *device = r_xprt->rx_ia.ri_id->device; 308 unsigned int depth = r_xprt->rx_ia.ri_max_frmr_depth; 309 struct ib_pd *pd = r_xprt->rx_ia.ri_pd; 310 struct rpcrdma_mw *r; 311 int rc; 312 313 list_for_each_entry(r, &buf->rb_all, mw_all) { 314 if (r->r.frmr.fr_state == FRMR_IS_INVALID) 315 continue; 316 317 __frwr_release(r); 318 rc = __frwr_init(r, pd, device, depth); 319 if (rc) { 320 dprintk("RPC: %s: mw %p left %s\n", 321 __func__, r, 322 (r->r.frmr.fr_state == FRMR_IS_STALE ? 323 "stale" : "valid")); 324 continue; 325 } 326 327 r->r.frmr.fr_state = FRMR_IS_INVALID; 328 } 329 } 330 331 static void 332 frwr_op_destroy(struct rpcrdma_buffer *buf) 333 { 334 struct rpcrdma_mw *r; 335 336 while (!list_empty(&buf->rb_all)) { 337 r = list_entry(buf->rb_all.next, struct rpcrdma_mw, mw_all); 338 list_del(&r->mw_all); 339 __frwr_release(r); 340 kfree(r); 341 } 342 } 343 344 const struct rpcrdma_memreg_ops rpcrdma_frwr_memreg_ops = { 345 .ro_map = frwr_op_map, 346 .ro_unmap = frwr_op_unmap, 347 .ro_open = frwr_op_open, 348 .ro_maxpages = frwr_op_maxpages, 349 .ro_init = frwr_op_init, 350 .ro_reset = frwr_op_reset, 351 .ro_destroy = frwr_op_destroy, 352 .ro_displayname = "frwr", 353 }; 354