summaryrefslogtreecommitdiff
path: root/net/smc/smc_cdc.h
blob: 271e2524dc8f988706f021cbaf2129b4e3823f02 (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
/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Shared Memory Communications over RDMA (SMC-R) and RoCE
 *
 * Connection Data Control (CDC)
 *
 * Copyright IBM Corp. 2016
 *
 * Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
 */

#ifndef SMC_CDC_H
#define SMC_CDC_H

#include <linux/kernel.h> /* max_t */
#include <linux/atomic.h>
#include <linux/in.h>
#include <linux/compiler.h>

#include "smc.h"
#include "smc_core.h"
#include "smc_wr.h"

#define	SMC_CDC_MSG_TYPE		0xFE

/* in network byte order */
union smc_cdc_cursor {		/* SMC cursor */
	struct {
		__be16	reserved;
		__be16	wrap;
		__be32	count;
	};
#ifdef KERNEL_HAS_ATOMIC64
	atomic64_t	acurs;		/* for atomic processing */
#else
	u64		acurs;		/* for atomic processing */
#endif
} __aligned(8);

/* in network byte order */
struct smc_cdc_msg {
	struct smc_wr_rx_hdr		common; /* .type = 0xFE */
	u8				len;	/* 44 */
	__be16				seqno;
	__be32				token;
	union smc_cdc_cursor		prod;
	union smc_cdc_cursor		cons;	/* piggy backed "ack" */
	struct smc_cdc_producer_flags	prod_flags;
	struct smc_cdc_conn_state_flags	conn_state_flags;
	u8				reserved[18];
};

/* SMC-D cursor format */
union smcd_cdc_cursor {
	struct {
		u16	wrap;
		u32	count;
		struct smc_cdc_producer_flags	prod_flags;
		struct smc_cdc_conn_state_flags	conn_state_flags;
	} __packed;
#ifdef KERNEL_HAS_ATOMIC64
	atomic64_t		acurs;		/* for atomic processing */
#else
	u64			acurs;		/* for atomic processing */
#endif
} __aligned(8);

/* CDC message for SMC-D */
struct smcd_cdc_msg {
	struct smc_wr_rx_hdr common;	/* Type = 0xFE */
	u8 res1[7];
	union smcd_cdc_cursor	prod;
	union smcd_cdc_cursor	cons;
	u8 res3[8];
} __aligned(8);

static inline bool smc_cdc_rxed_any_close(struct smc_connection *conn)
{
	return conn->local_rx_ctrl.conn_state_flags.peer_conn_abort ||
	       conn->local_rx_ctrl.conn_state_flags.peer_conn_closed;
}

static inline bool smc_cdc_rxed_any_close_or_senddone(
	struct smc_connection *conn)
{
	return smc_cdc_rxed_any_close(conn) ||
	       conn->local_rx_ctrl.conn_state_flags.peer_done_writing;
}

static inline void smc_curs_add(int size, union smc_host_cursor *curs,
				int value)
{
	curs->count += value;
	if (curs->count >= size) {
		curs->wrap++;
		curs->count -= size;
	}
}

/* SMC cursors are 8 bytes long and require atomic reading and writing */
static inline u64 smc_curs_read(union smc_host_cursor *curs,
				struct smc_connection *conn)
{
#ifndef KERNEL_HAS_ATOMIC64
	unsigned long flags;
	u64 ret;

	spin_lock_irqsave(&conn->acurs_lock, flags);
	ret = curs->acurs;
	spin_unlock_irqrestore(&conn->acurs_lock, flags);
	return ret;
#else
	return atomic64_read(&curs->acurs);
#endif
}

/* Copy cursor src into tgt */
static inline void smc_curs_copy(union smc_host_cursor *tgt,
				 union smc_host_cursor *src,
				 struct smc_connection *conn)
{
#ifndef KERNEL_HAS_ATOMIC64
	unsigned long flags;

	spin_lock_irqsave(&conn->acurs_lock, flags);
	tgt->acurs = src->acurs;
	spin_unlock_irqrestore(&conn->acurs_lock, flags);
#else
	atomic64_set(&tgt->acurs, atomic64_read(&src->acurs));
#endif
}

static inline void smc_curs_copy_net(union smc_cdc_cursor *tgt,
				     union smc_cdc_cursor *src,
				     struct smc_connection *conn)
{
#ifndef KERNEL_HAS_ATOMIC64
	unsigned long flags;

	spin_lock_irqsave(&conn->acurs_lock, flags);
	tgt->acurs = src->acurs;
	spin_unlock_irqrestore(&conn->acurs_lock, flags);
#else
	atomic64_set(&tgt->acurs, atomic64_read(&src->acurs));
#endif
}

static inline void smcd_curs_copy(union smcd_cdc_cursor *tgt,
				  union smcd_cdc_cursor *src,
				  struct smc_connection *conn)
{
#ifndef KERNEL_HAS_ATOMIC64
	unsigned long flags;

	spin_lock_irqsave(&conn->acurs_lock, flags);
	tgt->acurs = src->acurs;
	spin_unlock_irqrestore(&conn->acurs_lock, flags);
#else
	atomic64_set(&tgt->acurs, atomic64_read(&src->acurs));
#endif
}

/* calculate cursor difference between old and new, where old <= new and
 * difference cannot exceed size
 */
static inline int smc_curs_diff(unsigned int size,
				union smc_host_cursor *old,
				union smc_host_cursor *new)
{
	if (old->wrap != new->wrap)
		return max_t(int, 0,
			     ((size - old->count) + new->count));

	return max_t(int, 0, (new->count - old->count));
}

/* calculate cursor difference between old and new - returns negative
 * value in case old > new
 */
static inline int smc_curs_comp(unsigned int size,
				union smc_host_cursor *old,
				union smc_host_cursor *new)
{
	if (old->wrap > new->wrap ||
	    (old->wrap == new->wrap && old->count > new->count))
		return -smc_curs_diff(size, new, old);
	return smc_curs_diff(size, old, new);
}

/* calculate cursor difference between old and new, where old <= new and
 * difference may exceed size
 */
static inline int smc_curs_diff_large(unsigned int size,
				      union smc_host_cursor *old,
				      union smc_host_cursor *new)
{
	if (old->wrap < new->wrap)
		return min_t(int,
			     (size - old->count) + new->count +
			     (new->wrap - old->wrap - 1) * size,
			     size);

	if (old->wrap > new->wrap) /* wrap has switched from 0xffff to 0x0000 */
		return min_t(int,
			     (size - old->count) + new->count +
			     (new->wrap + 0xffff - old->wrap) * size,
			     size);

	return max_t(int, 0, (new->count - old->count));
}

static inline void smc_host_cursor_to_cdc(union smc_cdc_cursor *peer,
					  union smc_host_cursor *local,
					  struct smc_connection *conn)
{
	union smc_host_cursor temp;

	smc_curs_copy(&temp, local, conn);
	peer->count = htonl(temp.count);
	peer->wrap = htons(temp.wrap);
	/* peer->reserved = htons(0); must be ensured by caller */
}

static inline void smc_host_msg_to_cdc(struct smc_cdc_msg *peer,
				       struct smc_host_cdc_msg *local,
				       struct smc_connection *conn)
{
	peer->common.type = local->common.type;
	peer->len = local->len;
	peer->seqno = htons(local->seqno);
	peer->token = htonl(local->token);
	smc_host_cursor_to_cdc(&peer->prod, &local->prod, conn);
	smc_host_cursor_to_cdc(&peer->cons, &local->cons, conn);
	peer->prod_flags = local->prod_flags;
	peer->conn_state_flags = local->conn_state_flags;
}

static inline void smc_cdc_cursor_to_host(union smc_host_cursor *local,
					  union smc_cdc_cursor *peer,
					  struct smc_connection *conn)
{
	union smc_host_cursor temp, old;
	union smc_cdc_cursor net;

	smc_curs_copy(&old, local, conn);
	smc_curs_copy_net(&net, peer, conn);
	temp.count = ntohl(net.count);
	temp.wrap = ntohs(net.wrap);
	if ((old.wrap > temp.wrap) && temp.wrap)
		return;
	if ((old.wrap == temp.wrap) &&
	    (old.count > temp.count))
		return;
	smc_curs_copy(local, &temp, conn);
}

static inline void smcr_cdc_msg_to_host(struct smc_host_cdc_msg *local,
					struct smc_cdc_msg *peer,
					struct smc_connection *conn)
{
	local->common.type = peer->common.type;
	local->len = peer->len;
	local->seqno = ntohs(peer->seqno);
	local->token = ntohl(peer->token);
	smc_cdc_cursor_to_host(&local->prod, &peer->prod, conn);
	smc_cdc_cursor_to_host(&local->cons, &peer->cons, conn);
	local->prod_flags = peer->prod_flags;
	local->conn_state_flags = peer->conn_state_flags;
}

static inline void smcd_cdc_msg_to_host(struct smc_host_cdc_msg *local,
					struct smcd_cdc_msg *peer)
{
	union smc_host_cursor temp;

	temp.wrap = peer->prod.wrap;
	temp.count = peer->prod.count;
	atomic64_set(&local->prod.acurs, atomic64_read(&temp.acurs));

	temp.wrap = peer->cons.wrap;
	temp.count = peer->cons.count;
	atomic64_set(&local->cons.acurs, atomic64_read(&temp.acurs));
	local->prod_flags = peer->cons.prod_flags;
	local->conn_state_flags = peer->cons.conn_state_flags;
}

static inline void smc_cdc_msg_to_host(struct smc_host_cdc_msg *local,
				       struct smc_cdc_msg *peer,
				       struct smc_connection *conn)
{
	if (conn->lgr->is_smcd)
		smcd_cdc_msg_to_host(local, (struct smcd_cdc_msg *)peer);
	else
		smcr_cdc_msg_to_host(local, peer, conn);
}

struct smc_cdc_tx_pend {
	struct smc_connection	*conn;		/* socket connection */
	union smc_host_cursor	cursor;		/* tx sndbuf cursor sent */
	union smc_host_cursor	p_cursor;	/* rx RMBE cursor produced */
	u16			ctrl_seq;	/* conn. tx sequence # */
};

int smc_cdc_get_free_slot(struct smc_connection *conn,
			  struct smc_wr_buf **wr_buf,
			  struct smc_rdma_wr **wr_rdma_buf,
			  struct smc_cdc_tx_pend **pend);
void smc_cdc_tx_dismiss_slots(struct smc_connection *conn);
int smc_cdc_msg_send(struct smc_connection *conn, struct smc_wr_buf *wr_buf,
		     struct smc_cdc_tx_pend *pend);
int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn);
int smcd_cdc_msg_send(struct smc_connection *conn);
int smc_cdc_init(void) __init;
void smcd_cdc_rx_init(struct smc_connection *conn);

#endif /* SMC_CDC_H */