xref: /linux/net/smc/smc_cdc.h (revision 03ab8e6297acd1bc0eedaa050e2a1635c576fd11)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * Shared Memory Communications over RDMA (SMC-R) and RoCE
4  *
5  * Connection Data Control (CDC)
6  *
7  * Copyright IBM Corp. 2016
8  *
9  * Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
10  */
11 
12 #ifndef SMC_CDC_H
13 #define SMC_CDC_H
14 
15 #include <linux/kernel.h> /* max_t */
16 #include <linux/atomic.h>
17 #include <linux/in.h>
18 #include <linux/compiler.h>
19 
20 #include "smc.h"
21 #include "smc_core.h"
22 #include "smc_wr.h"
23 
24 #define	SMC_CDC_MSG_TYPE		0xFE
25 
26 /* in network byte order */
27 union smc_cdc_cursor {		/* SMC cursor */
28 	struct {
29 		__be16	reserved;
30 		__be16	wrap;
31 		__be32	count;
32 	};
33 #ifdef KERNEL_HAS_ATOMIC64
34 	atomic64_t	acurs;		/* for atomic processing */
35 #else
36 	u64		acurs;		/* for atomic processing */
37 #endif
38 } __aligned(8);
39 
40 /* in network byte order */
41 struct smc_cdc_msg {
42 	struct smc_wr_rx_hdr		common; /* .type = 0xFE */
43 	u8				len;	/* 44 */
44 	__be16				seqno;
45 	__be32				token;
46 	union smc_cdc_cursor		prod;
47 	union smc_cdc_cursor		cons;	/* piggy backed "ack" */
48 	struct smc_cdc_producer_flags	prod_flags;
49 	struct smc_cdc_conn_state_flags	conn_state_flags;
50 	u8				reserved[18];
51 };
52 
53 /* SMC-D cursor format */
54 union smcd_cdc_cursor {
55 	struct {
56 		u16	wrap;
57 		u32	count;
58 		struct smc_cdc_producer_flags	prod_flags;
59 		struct smc_cdc_conn_state_flags	conn_state_flags;
60 	} __packed;
61 #ifdef KERNEL_HAS_ATOMIC64
62 	atomic64_t		acurs;		/* for atomic processing */
63 #else
64 	u64			acurs;		/* for atomic processing */
65 #endif
66 } __aligned(8);
67 
68 /* CDC message for SMC-D */
69 struct smcd_cdc_msg {
70 	struct smc_wr_rx_hdr common;	/* Type = 0xFE */
71 	u8 res1[7];
72 	union smcd_cdc_cursor	prod;
73 	union smcd_cdc_cursor	cons;
74 	u8 res3[8];
75 } __aligned(8);
76 
smc_cdc_rxed_any_close(struct smc_connection * conn)77 static inline bool smc_cdc_rxed_any_close(struct smc_connection *conn)
78 {
79 	return conn->local_rx_ctrl.conn_state_flags.peer_conn_abort ||
80 	       conn->local_rx_ctrl.conn_state_flags.peer_conn_closed;
81 }
82 
smc_cdc_rxed_any_close_or_senddone(struct smc_connection * conn)83 static inline bool smc_cdc_rxed_any_close_or_senddone(
84 	struct smc_connection *conn)
85 {
86 	return smc_cdc_rxed_any_close(conn) ||
87 	       conn->local_rx_ctrl.conn_state_flags.peer_done_writing;
88 }
89 
smc_curs_add(int size,union smc_host_cursor * curs,int value)90 static inline void smc_curs_add(int size, union smc_host_cursor *curs,
91 				int value)
92 {
93 	curs->count += value;
94 	if (curs->count >= size) {
95 		curs->wrap++;
96 		curs->count -= size;
97 	}
98 }
99 
100 /* Copy cursor src into tgt */
smc_curs_copy(union smc_host_cursor * tgt,union smc_host_cursor * src,struct smc_connection * conn)101 static inline void smc_curs_copy(union smc_host_cursor *tgt,
102 				 union smc_host_cursor *src,
103 				 struct smc_connection *conn)
104 {
105 #ifndef KERNEL_HAS_ATOMIC64
106 	unsigned long flags;
107 
108 	spin_lock_irqsave(&conn->acurs_lock, flags);
109 	tgt->acurs = src->acurs;
110 	spin_unlock_irqrestore(&conn->acurs_lock, flags);
111 #else
112 	atomic64_set(&tgt->acurs, atomic64_read(&src->acurs));
113 #endif
114 }
115 
smc_curs_copy_net(union smc_cdc_cursor * tgt,union smc_cdc_cursor * src,struct smc_connection * conn)116 static inline void smc_curs_copy_net(union smc_cdc_cursor *tgt,
117 				     union smc_cdc_cursor *src,
118 				     struct smc_connection *conn)
119 {
120 #ifndef KERNEL_HAS_ATOMIC64
121 	unsigned long flags;
122 
123 	spin_lock_irqsave(&conn->acurs_lock, flags);
124 	tgt->acurs = src->acurs;
125 	spin_unlock_irqrestore(&conn->acurs_lock, flags);
126 #else
127 	atomic64_set(&tgt->acurs, atomic64_read(&src->acurs));
128 #endif
129 }
130 
smcd_curs_copy(union smcd_cdc_cursor * tgt,union smcd_cdc_cursor * src,struct smc_connection * conn)131 static inline void smcd_curs_copy(union smcd_cdc_cursor *tgt,
132 				  union smcd_cdc_cursor *src,
133 				  struct smc_connection *conn)
134 {
135 #ifndef KERNEL_HAS_ATOMIC64
136 	unsigned long flags;
137 
138 	spin_lock_irqsave(&conn->acurs_lock, flags);
139 	tgt->acurs = src->acurs;
140 	spin_unlock_irqrestore(&conn->acurs_lock, flags);
141 #else
142 	atomic64_set(&tgt->acurs, atomic64_read(&src->acurs));
143 #endif
144 }
145 
146 /* calculate cursor difference between old and new, where old <= new and
147  * difference cannot exceed size
148  */
smc_curs_diff(unsigned int size,union smc_host_cursor * old,union smc_host_cursor * new)149 static inline int smc_curs_diff(unsigned int size,
150 				union smc_host_cursor *old,
151 				union smc_host_cursor *new)
152 {
153 	if (old->wrap != new->wrap)
154 		return max_t(int, 0,
155 			     ((size - old->count) + new->count));
156 
157 	return max_t(int, 0, (new->count - old->count));
158 }
159 
160 /* calculate cursor difference between old and new - returns negative
161  * value in case old > new
162  */
smc_curs_comp(unsigned int size,union smc_host_cursor * old,union smc_host_cursor * new)163 static inline int smc_curs_comp(unsigned int size,
164 				union smc_host_cursor *old,
165 				union smc_host_cursor *new)
166 {
167 	if (old->wrap > new->wrap ||
168 	    (old->wrap == new->wrap && old->count > new->count))
169 		return -smc_curs_diff(size, new, old);
170 	return smc_curs_diff(size, old, new);
171 }
172 
173 /* calculate cursor difference between old and new, where old <= new and
174  * difference may exceed size
175  */
smc_curs_diff_large(unsigned int size,union smc_host_cursor * old,union smc_host_cursor * new)176 static inline int smc_curs_diff_large(unsigned int size,
177 				      union smc_host_cursor *old,
178 				      union smc_host_cursor *new)
179 {
180 	if (old->wrap < new->wrap)
181 		return min_t(int,
182 			     (size - old->count) + new->count +
183 			     (new->wrap - old->wrap - 1) * size,
184 			     size);
185 
186 	if (old->wrap > new->wrap) /* wrap has switched from 0xffff to 0x0000 */
187 		return min_t(int,
188 			     (size - old->count) + new->count +
189 			     (new->wrap + 0xffff - old->wrap) * size,
190 			     size);
191 
192 	return max_t(int, 0, (new->count - old->count));
193 }
194 
smc_host_cursor_to_cdc(union smc_cdc_cursor * peer,union smc_host_cursor * local,union smc_host_cursor * save,struct smc_connection * conn)195 static inline void smc_host_cursor_to_cdc(union smc_cdc_cursor *peer,
196 					  union smc_host_cursor *local,
197 					  union smc_host_cursor *save,
198 					  struct smc_connection *conn)
199 {
200 	smc_curs_copy(save, local, conn);
201 	peer->count = htonl(save->count);
202 	peer->wrap = htons(save->wrap);
203 	/* peer->reserved = htons(0); must be ensured by caller */
204 }
205 
smc_host_msg_to_cdc(struct smc_cdc_msg * peer,struct smc_connection * conn,union smc_host_cursor * save)206 static inline void smc_host_msg_to_cdc(struct smc_cdc_msg *peer,
207 				       struct smc_connection *conn,
208 				       union smc_host_cursor *save)
209 {
210 	struct smc_host_cdc_msg *local = &conn->local_tx_ctrl;
211 
212 	peer->common.type = local->common.type;
213 	peer->len = local->len;
214 	peer->seqno = htons(local->seqno);
215 	peer->token = htonl(local->token);
216 	smc_host_cursor_to_cdc(&peer->prod, &local->prod, save, conn);
217 	smc_host_cursor_to_cdc(&peer->cons, &local->cons, save, conn);
218 	peer->prod_flags = local->prod_flags;
219 	peer->conn_state_flags = local->conn_state_flags;
220 }
221 
smc_cdc_cursor_to_host(union smc_host_cursor * local,union smc_cdc_cursor * peer,struct smc_connection * conn)222 static inline void smc_cdc_cursor_to_host(union smc_host_cursor *local,
223 					  union smc_cdc_cursor *peer,
224 					  struct smc_connection *conn)
225 {
226 	union smc_host_cursor temp, old;
227 	union smc_cdc_cursor net;
228 
229 	smc_curs_copy(&old, local, conn);
230 	smc_curs_copy_net(&net, peer, conn);
231 	temp.count = ntohl(net.count);
232 	temp.wrap = ntohs(net.wrap);
233 	if ((old.wrap > temp.wrap) && temp.wrap)
234 		return;
235 	if ((old.wrap == temp.wrap) &&
236 	    (old.count > temp.count))
237 		return;
238 	smc_curs_copy(local, &temp, conn);
239 }
240 
smcr_cdc_msg_to_host(struct smc_host_cdc_msg * local,struct smc_cdc_msg * peer,struct smc_connection * conn)241 static inline void smcr_cdc_msg_to_host(struct smc_host_cdc_msg *local,
242 					struct smc_cdc_msg *peer,
243 					struct smc_connection *conn)
244 {
245 	local->common.type = peer->common.type;
246 	local->len = peer->len;
247 	local->seqno = ntohs(peer->seqno);
248 	local->token = ntohl(peer->token);
249 	smc_cdc_cursor_to_host(&local->prod, &peer->prod, conn);
250 	smc_cdc_cursor_to_host(&local->cons, &peer->cons, conn);
251 	local->prod_flags = peer->prod_flags;
252 	local->conn_state_flags = peer->conn_state_flags;
253 }
254 
smcd_cdc_msg_to_host(struct smc_host_cdc_msg * local,struct smcd_cdc_msg * peer,struct smc_connection * conn)255 static inline void smcd_cdc_msg_to_host(struct smc_host_cdc_msg *local,
256 					struct smcd_cdc_msg *peer,
257 					struct smc_connection *conn)
258 {
259 	union smc_host_cursor temp;
260 
261 	temp.wrap = peer->prod.wrap;
262 	temp.count = peer->prod.count;
263 	smc_curs_copy(&local->prod, &temp, conn);
264 
265 	temp.wrap = peer->cons.wrap;
266 	temp.count = peer->cons.count;
267 	smc_curs_copy(&local->cons, &temp, conn);
268 	local->prod_flags = peer->cons.prod_flags;
269 	local->conn_state_flags = peer->cons.conn_state_flags;
270 }
271 
smc_cdc_msg_to_host(struct smc_host_cdc_msg * local,struct smc_cdc_msg * peer,struct smc_connection * conn)272 static inline void smc_cdc_msg_to_host(struct smc_host_cdc_msg *local,
273 				       struct smc_cdc_msg *peer,
274 				       struct smc_connection *conn)
275 {
276 	if (conn->lgr->is_smcd)
277 		smcd_cdc_msg_to_host(local, (struct smcd_cdc_msg *)peer, conn);
278 	else
279 		smcr_cdc_msg_to_host(local, peer, conn);
280 }
281 
282 struct smc_cdc_tx_pend {
283 	struct smc_connection	*conn;		/* socket connection */
284 	union smc_host_cursor	cursor;		/* tx sndbuf cursor sent */
285 	union smc_host_cursor	p_cursor;	/* rx RMBE cursor produced */
286 	u16			ctrl_seq;	/* conn. tx sequence # */
287 };
288 
289 int smc_cdc_get_free_slot(struct smc_connection *conn,
290 			  struct smc_link *link,
291 			  struct smc_wr_buf **wr_buf,
292 			  struct smc_rdma_wr **wr_rdma_buf,
293 			  struct smc_cdc_tx_pend **pend);
294 void smc_cdc_wait_pend_tx_wr(struct smc_connection *conn);
295 int smc_cdc_msg_send(struct smc_connection *conn, struct smc_wr_buf *wr_buf,
296 		     struct smc_cdc_tx_pend *pend);
297 int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn);
298 int smcd_cdc_msg_send(struct smc_connection *conn);
299 int smcr_cdc_msg_send_validation(struct smc_connection *conn,
300 				 struct smc_cdc_tx_pend *pend,
301 				 struct smc_wr_buf *wr_buf);
302 int smc_cdc_init(void) __init;
303 void smcd_cdc_rx_init(struct smc_connection *conn);
304 
305 #endif /* SMC_CDC_H */
306