934df4473a7cebc4f2cb4fa654d7189201745ac2
[sfrench/cifs-2.6.git] / net / smc / smc_cdc.h
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 } __packed;                                     /* format defined in RFC7609 */
52
53 /* CDC message for SMC-D */
54 struct smcd_cdc_msg {
55         struct smc_wr_rx_hdr common;    /* Type = 0xFE */
56         u8 res1[7];
57         u16 prod_wrap;
58         u32 prod_count;
59         u8 res2[2];
60         u16 cons_wrap;
61         u32 cons_count;
62         struct smc_cdc_producer_flags   prod_flags;
63         struct smc_cdc_conn_state_flags conn_state_flags;
64         u8 res3[8];
65 } __packed;
66
67 static inline bool smc_cdc_rxed_any_close(struct smc_connection *conn)
68 {
69         return conn->local_rx_ctrl.conn_state_flags.peer_conn_abort ||
70                conn->local_rx_ctrl.conn_state_flags.peer_conn_closed;
71 }
72
73 static inline bool smc_cdc_rxed_any_close_or_senddone(
74         struct smc_connection *conn)
75 {
76         return smc_cdc_rxed_any_close(conn) ||
77                conn->local_rx_ctrl.conn_state_flags.peer_done_writing;
78 }
79
80 static inline void smc_curs_add(int size, union smc_host_cursor *curs,
81                                 int value)
82 {
83         curs->count += value;
84         if (curs->count >= size) {
85                 curs->wrap++;
86                 curs->count -= size;
87         }
88 }
89
90 /* SMC cursors are 8 bytes long and require atomic reading and writing */
91 static inline u64 smc_curs_read(union smc_host_cursor *curs,
92                                 struct smc_connection *conn)
93 {
94 #ifndef KERNEL_HAS_ATOMIC64
95         unsigned long flags;
96         u64 ret;
97
98         spin_lock_irqsave(&conn->acurs_lock, flags);
99         ret = curs->acurs;
100         spin_unlock_irqrestore(&conn->acurs_lock, flags);
101         return ret;
102 #else
103         return atomic64_read(&curs->acurs);
104 #endif
105 }
106
107 /* Copy cursor src into tgt */
108 static inline void smc_curs_copy(union smc_host_cursor *tgt,
109                                  union smc_host_cursor *src,
110                                  struct smc_connection *conn)
111 {
112 #ifndef KERNEL_HAS_ATOMIC64
113         unsigned long flags;
114
115         spin_lock_irqsave(&conn->acurs_lock, flags);
116         tgt->acurs = src->acurs;
117         spin_unlock_irqrestore(&conn->acurs_lock, flags);
118 #else
119         atomic64_set(&tgt->acurs, atomic64_read(&src->acurs));
120 #endif
121 }
122
123 static inline void smc_curs_copy_net(union smc_cdc_cursor *tgt,
124                                      union smc_cdc_cursor *src,
125                                      struct smc_connection *conn)
126 {
127 #ifndef KERNEL_HAS_ATOMIC64
128         unsigned long flags;
129
130         spin_lock_irqsave(&conn->acurs_lock, flags);
131         tgt->acurs = src->acurs;
132         spin_unlock_irqrestore(&conn->acurs_lock, flags);
133 #else
134         atomic64_set(&tgt->acurs, atomic64_read(&src->acurs));
135 #endif
136 }
137
138 /* calculate cursor difference between old and new, where old <= new */
139 static inline int smc_curs_diff(unsigned int size,
140                                 union smc_host_cursor *old,
141                                 union smc_host_cursor *new)
142 {
143         if (old->wrap != new->wrap)
144                 return max_t(int, 0,
145                              ((size - old->count) + new->count));
146
147         return max_t(int, 0, (new->count - old->count));
148 }
149
150 /* calculate cursor difference between old and new - returns negative
151  * value in case old > new
152  */
153 static inline int smc_curs_comp(unsigned int size,
154                                 union smc_host_cursor *old,
155                                 union smc_host_cursor *new)
156 {
157         if (old->wrap > new->wrap ||
158             (old->wrap == new->wrap && old->count > new->count))
159                 return -smc_curs_diff(size, new, old);
160         return smc_curs_diff(size, old, new);
161 }
162
163 static inline void smc_host_cursor_to_cdc(union smc_cdc_cursor *peer,
164                                           union smc_host_cursor *local,
165                                           struct smc_connection *conn)
166 {
167         union smc_host_cursor temp;
168
169         smc_curs_copy(&temp, local, conn);
170         peer->count = htonl(temp.count);
171         peer->wrap = htons(temp.wrap);
172         /* peer->reserved = htons(0); must be ensured by caller */
173 }
174
175 static inline void smc_host_msg_to_cdc(struct smc_cdc_msg *peer,
176                                        struct smc_host_cdc_msg *local,
177                                        struct smc_connection *conn)
178 {
179         peer->common.type = local->common.type;
180         peer->len = local->len;
181         peer->seqno = htons(local->seqno);
182         peer->token = htonl(local->token);
183         smc_host_cursor_to_cdc(&peer->prod, &local->prod, conn);
184         smc_host_cursor_to_cdc(&peer->cons, &local->cons, conn);
185         peer->prod_flags = local->prod_flags;
186         peer->conn_state_flags = local->conn_state_flags;
187 }
188
189 static inline void smc_cdc_cursor_to_host(union smc_host_cursor *local,
190                                           union smc_cdc_cursor *peer,
191                                           struct smc_connection *conn)
192 {
193         union smc_host_cursor temp, old;
194         union smc_cdc_cursor net;
195
196         smc_curs_copy(&old, local, conn);
197         smc_curs_copy_net(&net, peer, conn);
198         temp.count = ntohl(net.count);
199         temp.wrap = ntohs(net.wrap);
200         if ((old.wrap > temp.wrap) && temp.wrap)
201                 return;
202         if ((old.wrap == temp.wrap) &&
203             (old.count > temp.count))
204                 return;
205         smc_curs_copy(local, &temp, conn);
206 }
207
208 static inline void smcr_cdc_msg_to_host(struct smc_host_cdc_msg *local,
209                                         struct smc_cdc_msg *peer,
210                                         struct smc_connection *conn)
211 {
212         local->common.type = peer->common.type;
213         local->len = peer->len;
214         local->seqno = ntohs(peer->seqno);
215         local->token = ntohl(peer->token);
216         smc_cdc_cursor_to_host(&local->prod, &peer->prod, conn);
217         smc_cdc_cursor_to_host(&local->cons, &peer->cons, conn);
218         local->prod_flags = peer->prod_flags;
219         local->conn_state_flags = peer->conn_state_flags;
220 }
221
222 static inline void smcd_cdc_msg_to_host(struct smc_host_cdc_msg *local,
223                                         struct smcd_cdc_msg *peer)
224 {
225         local->prod.wrap = peer->prod_wrap;
226         local->prod.count = peer->prod_count;
227         local->cons.wrap = peer->cons_wrap;
228         local->cons.count = peer->cons_count;
229         local->prod_flags = peer->prod_flags;
230         local->conn_state_flags = peer->conn_state_flags;
231 }
232
233 static inline void smc_cdc_msg_to_host(struct smc_host_cdc_msg *local,
234                                        struct smc_cdc_msg *peer,
235                                        struct smc_connection *conn)
236 {
237         if (conn->lgr->is_smcd)
238                 smcd_cdc_msg_to_host(local, (struct smcd_cdc_msg *)peer);
239         else
240                 smcr_cdc_msg_to_host(local, peer, conn);
241 }
242
243 struct smc_cdc_tx_pend;
244
245 int smc_cdc_get_free_slot(struct smc_connection *conn,
246                           struct smc_wr_buf **wr_buf,
247                           struct smc_cdc_tx_pend **pend);
248 void smc_cdc_tx_dismiss_slots(struct smc_connection *conn);
249 int smc_cdc_msg_send(struct smc_connection *conn, struct smc_wr_buf *wr_buf,
250                      struct smc_cdc_tx_pend *pend);
251 int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn);
252 int smcd_cdc_msg_send(struct smc_connection *conn);
253 int smc_cdc_init(void) __init;
254 void smcd_cdc_rx_init(struct smc_connection *conn);
255
256 #endif /* SMC_CDC_H */