summaryrefslogtreecommitdiff
path: root/net/sunrpc/xprtrdma/frwr_ops.c
blob: d234521320a4bb45a9bbecd40e5e58bbb42d77d8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
/*
 * Copyright (c) 2015 Oracle.  All rights reserved.
 * Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
 */

/* Lightweight memory registration using Fast Registration Work
 * Requests (FRWR). Also referred to sometimes as FRMR mode.
 *
 * FRWR features ordered asynchronous registration and deregistration
 * of arbitrarily sized memory regions. This is the fastest and safest
 * but most complex memory registration mode.
 */

#include "xprt_rdma.h"

#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
# define RPCDBG_FACILITY	RPCDBG_TRANS
#endif

static int
__frwr_init(struct rpcrdma_mw *r, struct ib_pd *pd, struct ib_device *device,
	    unsigned int depth)
{
	struct rpcrdma_frmr *f = &r->r.frmr;
	int rc;

	f->fr_mr = ib_alloc_fast_reg_mr(pd, depth);
	if (IS_ERR(f->fr_mr))
		goto out_mr_err;
	f->fr_pgl = ib_alloc_fast_reg_page_list(device, depth);
	if (IS_ERR(f->fr_pgl))
		goto out_list_err;
	return 0;

out_mr_err:
	rc = PTR_ERR(f->fr_mr);
	dprintk("RPC:       %s: ib_alloc_fast_reg_mr status %i\n",
		__func__, rc);
	return rc;

out_list_err:
	rc = PTR_ERR(f->fr_pgl);
	dprintk("RPC:       %s: ib_alloc_fast_reg_page_list status %i\n",
		__func__, rc);
	ib_dereg_mr(f->fr_mr);
	return rc;
}

static void
__frwr_release(struct rpcrdma_mw *r)
{
	int rc;

	rc = ib_dereg_mr(r->r.frmr.fr_mr);
	if (rc)
		dprintk("RPC:       %s: ib_dereg_mr status %i\n",
			__func__, rc);
	ib_free_fast_reg_page_list(r->r.frmr.fr_pgl);
}

static int
frwr_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep,
	     struct rpcrdma_create_data_internal *cdata)
{
	struct ib_device_attr *devattr = &ia->ri_devattr;
	int depth, delta;

	ia->ri_max_frmr_depth =
			min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS,
			      devattr->max_fast_reg_page_list_len);
	dprintk("RPC:       %s: device's max FR page list len = %u\n",
		__func__, ia->ri_max_frmr_depth);

	/* Add room for frmr register and invalidate WRs.
	 * 1. FRMR reg WR for head
	 * 2. FRMR invalidate WR for head
	 * 3. N FRMR reg WRs for pagelist
	 * 4. N FRMR invalidate WRs for pagelist
	 * 5. FRMR reg WR for tail
	 * 6. FRMR invalidate WR for tail
	 * 7. The RDMA_SEND WR
	 */
	depth = 7;

	/* Calculate N if the device max FRMR depth is smaller than
	 * RPCRDMA_MAX_DATA_SEGS.
	 */
	if (ia->ri_max_frmr_depth < RPCRDMA_MAX_DATA_SEGS) {
		delta = RPCRDMA_MAX_DATA_SEGS - ia->ri_max_frmr_depth;
		do {
			depth += 2; /* FRMR reg + invalidate */
			delta -= ia->ri_max_frmr_depth;
		} while (delta > 0);
	}

	ep->rep_attr.cap.max_send_wr *= depth;
	if (ep->rep_attr.cap.max_send_wr > devattr->max_qp_wr) {
		cdata->max_requests = devattr->max_qp_wr / depth;
		if (!cdata->max_requests)
			return -EINVAL;
		ep->rep_attr.cap.max_send_wr = cdata->max_requests *
					       depth;
	}

	return 0;
}

/* FRWR mode conveys a list of pages per chunk segment. The
 * maximum length of that list is the FRWR page list depth.
 */
static size_t
frwr_op_maxpages(struct rpcrdma_xprt *r_xprt)
{
	struct rpcrdma_ia *ia = &r_xprt->rx_ia;

	return min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS,
		     rpcrdma_max_segments(r_xprt) * ia->ri_max_frmr_depth);
}

/* If FAST_REG or LOCAL_INV failed, indicate the frmr needs to be reset. */
static void
frwr_sendcompletion(struct ib_wc *wc)
{
	struct rpcrdma_mw *r;

	if (likely(wc->status == IB_WC_SUCCESS))
		return;

	/* WARNING: Only wr_id and status are reliable at this point */
	r = (struct rpcrdma_mw *)(unsigned long)wc->wr_id;
	dprintk("RPC:       %s: frmr %p (stale), status %s (%d)\n",
		__func__, r, ib_wc_status_msg(wc->status), wc->status);
	r->r.frmr.fr_state = FRMR_IS_STALE;
}

static int
frwr_op_init(struct rpcrdma_xprt *r_xprt)
{
	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
	struct ib_device *device = r_xprt->rx_ia.ri_id->device;
	unsigned int depth = r_xprt->rx_ia.ri_max_frmr_depth;
	struct ib_pd *pd = r_xprt->rx_ia.ri_pd;
	int i;

	INIT_LIST_HEAD(&buf->rb_mws);
	INIT_LIST_HEAD(&buf->rb_all);

	i = (buf->rb_max_requests + 1) * RPCRDMA_MAX_SEGS;
	dprintk("RPC:       %s: initializing %d FRMRs\n", __func__, i);

	while (i--) {
		struct rpcrdma_mw *r;
		int rc;

		r = kzalloc(sizeof(*r), GFP_KERNEL);
		if (!r)
			return -ENOMEM;

		rc = __frwr_init(r, pd, device, depth);
		if (rc) {
			kfree(r);
			return rc;
		}

		list_add(&r->mw_list, &buf->rb_mws);
		list_add(&r->mw_all, &buf->rb_all);
		r->mw_sendcompletion = frwr_sendcompletion;
	}

	return 0;
}

/* Post a FAST_REG Work Request to register a memory region
 * for remote access via RDMA READ or RDMA WRITE.
 */
static int
frwr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
	    int nsegs, bool writing)
{
	struct rpcrdma_ia *ia = &r_xprt->rx_ia;
	struct ib_device *device = ia->ri_id->device;
	enum dma_data_direction direction = rpcrdma_data_dir(writing);
	struct rpcrdma_mr_seg *seg1 = seg;
	struct rpcrdma_mw *mw = seg1->rl_mw;
	struct rpcrdma_frmr *frmr = &mw->r.frmr;
	struct ib_mr *mr = frmr->fr_mr;
	struct ib_send_wr fastreg_wr, *bad_wr;
	u8 key;
	int len, pageoff;
	int i, rc;
	int seg_len;
	u64 pa;
	int page_no;

	pageoff = offset_in_page(seg1->mr_offset);
	seg1->mr_offset -= pageoff;	/* start of page */
	seg1->mr_len += pageoff;
	len = -pageoff;
	if (nsegs > ia->ri_max_frmr_depth)
		nsegs = ia->ri_max_frmr_depth;
	for (page_no = i = 0; i < nsegs;) {
		rpcrdma_map_one(device, seg, direction);
		pa = seg->mr_dma;
		for (seg_len = seg->mr_len; seg_len > 0; seg_len -= PAGE_SIZE) {
			frmr->fr_pgl->page_list[page_no++] = pa;
			pa += PAGE_SIZE;
		}
		len += seg->mr_len;
		++seg;
		++i;
		/* Check for holes */
		if ((i < nsegs && offset_in_page(seg->mr_offset)) ||
		    offset_in_page((seg-1)->mr_offset + (seg-1)->mr_len))
			break;
	}
	dprintk("RPC:       %s: Using frmr %p to map %d segments (%d bytes)\n",
		__func__, mw, i, len);

	frmr->fr_state = FRMR_IS_VALID;

	memset(&fastreg_wr, 0, sizeof(fastreg_wr));
	fastreg_wr.wr_id = (unsigned long)(void *)mw;
	fastreg_wr.opcode = IB_WR_FAST_REG_MR;
	fastreg_wr.wr.fast_reg.iova_start = seg1->mr_dma + pageoff;
	fastreg_wr.wr.fast_reg.page_list = frmr->fr_pgl;
	fastreg_wr.wr.fast_reg.page_shift = PAGE_SHIFT;
	fastreg_wr.wr.fast_reg.page_list_len = page_no;
	fastreg_wr.wr.fast_reg.length = len;
	fastreg_wr.wr.fast_reg.access_flags = writing ?
				IB_ACCESS_REMOTE_WRITE | IB_ACCESS_LOCAL_WRITE :
				IB_ACCESS_REMOTE_READ;
	key = (u8)(mr->rkey & 0x000000FF);
	ib_update_fast_reg_key(mr, ++key);
	fastreg_wr.wr.fast_reg.rkey = mr->rkey;

	DECR_CQCOUNT(&r_xprt->rx_ep);
	rc = ib_post_send(ia->ri_id->qp, &fastreg_wr, &bad_wr);
	if (rc)
		goto out_senderr;

	seg1->mr_rkey = mr->rkey;
	seg1->mr_base = seg1->mr_dma + pageoff;
	seg1->mr_nsegs = i;
	seg1->mr_len = len;
	return i;

out_senderr:
	dprintk("RPC:       %s: ib_post_send status %i\n", __func__, rc);
	ib_update_fast_reg_key(mr, --key);
	frmr->fr_state = FRMR_IS_INVALID;
	while (i--)
		rpcrdma_unmap_one(device, --seg);
	return rc;
}

/* Post a LOCAL_INV Work Request to prevent further remote access
 * via RDMA READ or RDMA WRITE.
 */
static int
frwr_op_unmap(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg)
{
	struct rpcrdma_mr_seg *seg1 = seg;
	struct rpcrdma_ia *ia = &r_xprt->rx_ia;
	struct ib_send_wr invalidate_wr, *bad_wr;
	int rc, nsegs = seg->mr_nsegs;
	struct ib_device *device;

	seg1->rl_mw->r.frmr.fr_state = FRMR_IS_INVALID;

	memset(&invalidate_wr, 0, sizeof(invalidate_wr));
	invalidate_wr.wr_id = (unsigned long)(void *)seg1->rl_mw;
	invalidate_wr.opcode = IB_WR_LOCAL_INV;
	invalidate_wr.ex.invalidate_rkey = seg1->rl_mw->r.frmr.fr_mr->rkey;
	DECR_CQCOUNT(&r_xprt->rx_ep);

	read_lock(&ia->ri_qplock);
	device = ia->ri_id->device;
	while (seg1->mr_nsegs--)
		rpcrdma_unmap_one(device, seg++);
	rc = ib_post_send(ia->ri_id->qp, &invalidate_wr, &bad_wr);
	read_unlock(&ia->ri_qplock);
	if (rc)
		goto out_err;
	return nsegs;

out_err:
	/* Force rpcrdma_buffer_get() to retry */
	seg1->rl_mw->r.frmr.fr_state = FRMR_IS_STALE;
	dprintk("RPC:       %s: ib_post_send status %i\n", __func__, rc);
	return nsegs;
}

/* After a disconnect, a flushed FAST_REG_MR can leave an FRMR in
 * an unusable state. Find FRMRs in this state and dereg / reg
 * each.  FRMRs that are VALID and attached to an rpcrdma_req are
 * also torn down.
 *
 * This gives all in-use FRMRs a fresh rkey and leaves them INVALID.
 *
 * This is invoked only in the transport connect worker in order
 * to serialize with rpcrdma_register_frmr_external().
 */
static void
frwr_op_reset(struct rpcrdma_xprt *r_xprt)
{
	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
	struct ib_device *device = r_xprt->rx_ia.ri_id->device;
	unsigned int depth = r_xprt->rx_ia.ri_max_frmr_depth;
	struct ib_pd *pd = r_xprt->rx_ia.ri_pd;
	struct rpcrdma_mw *r;
	int rc;

	list_for_each_entry(r, &buf->rb_all, mw_all) {
		if (r->r.frmr.fr_state == FRMR_IS_INVALID)
			continue;

		__frwr_release(r);
		rc = __frwr_init(r, pd, device, depth);
		if (rc) {
			dprintk("RPC:       %s: mw %p left %s\n",
				__func__, r,
				(r->r.frmr.fr_state == FRMR_IS_STALE ?
					"stale" : "valid"));
			continue;
		}

		r->r.frmr.fr_state = FRMR_IS_INVALID;
	}
}

static void
frwr_op_destroy(struct rpcrdma_buffer *buf)
{
	struct rpcrdma_mw *r;

	while (!list_empty(&buf->rb_all)) {
		r = list_entry(buf->rb_all.next, struct rpcrdma_mw, mw_all);
		list_del(&r->mw_all);
		__frwr_release(r);
		kfree(r);
	}
}

const struct rpcrdma_memreg_ops rpcrdma_frwr_memreg_ops = {
	.ro_map				= frwr_op_map,
	.ro_unmap			= frwr_op_unmap,
	.ro_open			= frwr_op_open,
	.ro_maxpages			= frwr_op_maxpages,
	.ro_init			= frwr_op_init,
	.ro_reset			= frwr_op_reset,
	.ro_destroy			= frwr_op_destroy,
	.ro_displayname			= "frwr",
};