xref: /openbmc/linux/drivers/block/rnbd/rnbd-proto.h (revision d6e94913)
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * RDMA Network Block Driver
4  *
5  * Copyright (c) 2014 - 2018 ProfitBricks GmbH. All rights reserved.
6  * Copyright (c) 2018 - 2019 1&1 IONOS Cloud GmbH. All rights reserved.
7  * Copyright (c) 2019 - 2020 1&1 IONOS SE. All rights reserved.
8  */
9 #ifndef RNBD_PROTO_H
10 #define RNBD_PROTO_H
11 
12 #include <linux/types.h>
13 #include <linux/blk-mq.h>
14 #include <linux/limits.h>
15 #include <linux/inet.h>
16 #include <linux/in.h>
17 #include <linux/in6.h>
18 #include <rdma/ib.h>
19 
20 #define RNBD_PROTO_VER_MAJOR 2
21 #define RNBD_PROTO_VER_MINOR 0
22 
23 /* The default port number the RTRS server is listening on. */
24 #define RTRS_PORT 1234
25 
26 /**
27  * enum rnbd_msg_types - RNBD message types
28  * @RNBD_MSG_SESS_INFO:	initial session info from client to server
29  * @RNBD_MSG_SESS_INFO_RSP:	initial session info from server to client
30  * @RNBD_MSG_OPEN:		open (map) device request
31  * @RNBD_MSG_OPEN_RSP:		response to an @RNBD_MSG_OPEN
32  * @RNBD_MSG_IO:		block IO request operation
33  * @RNBD_MSG_CLOSE:		close (unmap) device request
34  */
35 enum rnbd_msg_type {
36 	RNBD_MSG_SESS_INFO,
37 	RNBD_MSG_SESS_INFO_RSP,
38 	RNBD_MSG_OPEN,
39 	RNBD_MSG_OPEN_RSP,
40 	RNBD_MSG_IO,
41 	RNBD_MSG_CLOSE,
42 };
43 
44 /**
45  * struct rnbd_msg_hdr - header of RNBD messages
46  * @type:	Message type, valid values see: enum rnbd_msg_types
47  */
48 struct rnbd_msg_hdr {
49 	__le16		type;
50 	__le16		__padding;
51 };
52 
53 /**
54  * We allow to map RO many times and RW only once. We allow to map yet another
55  * time RW, if MIGRATION is provided (second RW export can be required for
56  * example for VM migration)
57  */
58 enum rnbd_access_mode {
59 	RNBD_ACCESS_RO,
60 	RNBD_ACCESS_RW,
61 	RNBD_ACCESS_MIGRATION,
62 };
63 
64 static const __maybe_unused struct {
65 	enum rnbd_access_mode mode;
66 	const char *str;
67 } rnbd_access_modes[] = {
68 	[RNBD_ACCESS_RO] = {RNBD_ACCESS_RO, "ro"},
69 	[RNBD_ACCESS_RW] = {RNBD_ACCESS_RW, "rw"},
70 	[RNBD_ACCESS_MIGRATION] = {RNBD_ACCESS_MIGRATION, "migration"},
71 };
72 
73 /**
74  * struct rnbd_msg_sess_info - initial session info from client to server
75  * @hdr:		message header
76  * @ver:		RNBD protocol version
77  */
78 struct rnbd_msg_sess_info {
79 	struct rnbd_msg_hdr hdr;
80 	u8		ver;
81 	u8		reserved[31];
82 };
83 
84 /**
85  * struct rnbd_msg_sess_info_rsp - initial session info from server to client
86  * @hdr:		message header
87  * @ver:		RNBD protocol version
88  */
89 struct rnbd_msg_sess_info_rsp {
90 	struct rnbd_msg_hdr hdr;
91 	u8		ver;
92 	u8		reserved[31];
93 };
94 
95 /**
96  * struct rnbd_msg_open - request to open a remote device.
97  * @hdr:		message header
98  * @access_mode:	the mode to open remote device, valid values see:
99  *			enum rnbd_access_mode
100  * @device_name:	device path on remote side
101  */
102 struct rnbd_msg_open {
103 	struct rnbd_msg_hdr hdr;
104 	u8		access_mode;
105 	u8		resv1;
106 	s8		dev_name[NAME_MAX];
107 	u8		reserved[3];
108 };
109 
110 /**
111  * struct rnbd_msg_close - request to close a remote device.
112  * @hdr:	message header
113  * @device_id:	device_id on server side to identify the device
114  */
115 struct rnbd_msg_close {
116 	struct rnbd_msg_hdr hdr;
117 	__le32		device_id;
118 };
119 
120 enum rnbd_cache_policy {
121 	RNBD_FUA = 1 << 0,
122 	RNBD_WRITEBACK = 1 << 1,
123 };
124 
125 /**
126  * struct rnbd_msg_open_rsp - response message to RNBD_MSG_OPEN
127  * @hdr:		message header
128  * @device_id:		device_id on server side to identify the device
129  * @nsectors:		number of sectors in the usual 512b unit
130  * @max_hw_sectors:	max hardware sectors in the usual 512b unit
131  * @max_write_same_sectors: max sectors for WRITE SAME in the 512b unit
132  * @max_discard_sectors: max. sectors that can be discarded at once in 512b
133  * unit.
134  * @discard_granularity: size of the internal discard allocation unit in bytes
135  * @discard_alignment: offset from internal allocation assignment in bytes
136  * @physical_block_size: physical block size device supports in bytes
137  * @logical_block_size: logical block size device supports in bytes
138  * @max_segments:	max segments hardware support in one transfer
139  * @secure_discard:	supports secure discard
140  * @obsolete_rotational: obsolete, not in used.
141  * @cache_policy: 	support write-back caching or FUA?
142  */
143 struct rnbd_msg_open_rsp {
144 	struct rnbd_msg_hdr	hdr;
145 	__le32			device_id;
146 	__le64			nsectors;
147 	__le32			max_hw_sectors;
148 	__le32			max_write_same_sectors;
149 	__le32			max_discard_sectors;
150 	__le32			discard_granularity;
151 	__le32			discard_alignment;
152 	__le16			physical_block_size;
153 	__le16			logical_block_size;
154 	__le16			max_segments;
155 	__le16			secure_discard;
156 	u8			obsolete_rotational;
157 	u8			cache_policy;
158 	u8			reserved[10];
159 };
160 
161 /**
162  * struct rnbd_msg_io - message for I/O read/write
163  * @hdr:	message header
164  * @device_id:	device_id on server side to find the right device
165  * @sector:	bi_sector attribute from struct bio
166  * @rw:		valid values are defined in enum rnbd_io_flags
167  * @bi_size:    number of bytes for I/O read/write
168  * @prio:       priority
169  */
170 struct rnbd_msg_io {
171 	struct rnbd_msg_hdr hdr;
172 	__le32		device_id;
173 	__le64		sector;
174 	__le32		rw;
175 	__le32		bi_size;
176 	__le16		prio;
177 };
178 
179 #define RNBD_OP_BITS  8
180 #define RNBD_OP_MASK  ((1 << RNBD_OP_BITS) - 1)
181 
182 /**
183  * enum rnbd_io_flags - RNBD request types from rq_flag_bits
184  * @RNBD_OP_READ:	     read sectors from the device
185  * @RNBD_OP_WRITE:	     write sectors to the device
186  * @RNBD_OP_FLUSH:	     flush the volatile write cache
187  * @RNBD_OP_DISCARD:        discard sectors
188  * @RNBD_OP_SECURE_ERASE:   securely erase sectors
189  * @RNBD_OP_WRITE_SAME:     write the same sectors many times
190 
191  * @RNBD_F_SYNC:	     request is sync (sync write or read)
192  * @RNBD_F_FUA:             forced unit access
193  */
194 enum rnbd_io_flags {
195 
196 	/* Operations */
197 	RNBD_OP_READ		= 0,
198 	RNBD_OP_WRITE		= 1,
199 	RNBD_OP_FLUSH		= 2,
200 	RNBD_OP_DISCARD	= 3,
201 	RNBD_OP_SECURE_ERASE	= 4,
202 	RNBD_OP_WRITE_SAME	= 5,
203 
204 	/* Flags */
205 	RNBD_F_SYNC  = 1<<(RNBD_OP_BITS + 0),
206 	RNBD_F_FUA   = 1<<(RNBD_OP_BITS + 1),
207 };
208 
rnbd_op(u32 flags)209 static inline u32 rnbd_op(u32 flags)
210 {
211 	return flags & RNBD_OP_MASK;
212 }
213 
rnbd_flags(u32 flags)214 static inline u32 rnbd_flags(u32 flags)
215 {
216 	return flags & ~RNBD_OP_MASK;
217 }
218 
rnbd_to_bio_flags(u32 rnbd_opf)219 static inline blk_opf_t rnbd_to_bio_flags(u32 rnbd_opf)
220 {
221 	blk_opf_t bio_opf;
222 
223 	switch (rnbd_op(rnbd_opf)) {
224 	case RNBD_OP_READ:
225 		bio_opf = REQ_OP_READ;
226 		break;
227 	case RNBD_OP_WRITE:
228 		bio_opf = REQ_OP_WRITE;
229 		break;
230 	case RNBD_OP_FLUSH:
231 		bio_opf = REQ_OP_WRITE | REQ_PREFLUSH;
232 		break;
233 	case RNBD_OP_DISCARD:
234 		bio_opf = REQ_OP_DISCARD;
235 		break;
236 	case RNBD_OP_SECURE_ERASE:
237 		bio_opf = REQ_OP_SECURE_ERASE;
238 		break;
239 	default:
240 		WARN(1, "Unknown RNBD type: %d (flags %d)\n",
241 		     rnbd_op(rnbd_opf), rnbd_opf);
242 		bio_opf = 0;
243 	}
244 
245 	if (rnbd_opf & RNBD_F_SYNC)
246 		bio_opf |= REQ_SYNC;
247 
248 	if (rnbd_opf & RNBD_F_FUA)
249 		bio_opf |= REQ_FUA;
250 
251 	return bio_opf;
252 }
253 
rq_to_rnbd_flags(struct request * rq)254 static inline u32 rq_to_rnbd_flags(struct request *rq)
255 {
256 	u32 rnbd_opf;
257 
258 	switch (req_op(rq)) {
259 	case REQ_OP_READ:
260 		rnbd_opf = RNBD_OP_READ;
261 		break;
262 	case REQ_OP_WRITE:
263 		rnbd_opf = RNBD_OP_WRITE;
264 		break;
265 	case REQ_OP_DISCARD:
266 		rnbd_opf = RNBD_OP_DISCARD;
267 		break;
268 	case REQ_OP_SECURE_ERASE:
269 		rnbd_opf = RNBD_OP_SECURE_ERASE;
270 		break;
271 	case REQ_OP_FLUSH:
272 		rnbd_opf = RNBD_OP_FLUSH;
273 		break;
274 	default:
275 		WARN(1, "Unknown request type %d (flags %llu)\n",
276 		     (__force u32)req_op(rq),
277 		     (__force unsigned long long)rq->cmd_flags);
278 		rnbd_opf = 0;
279 	}
280 
281 	if (op_is_sync(rq->cmd_flags))
282 		rnbd_opf |= RNBD_F_SYNC;
283 
284 	if (op_is_flush(rq->cmd_flags))
285 		rnbd_opf |= RNBD_F_FUA;
286 
287 	return rnbd_opf;
288 }
289 
290 const char *rnbd_access_mode_str(enum rnbd_access_mode mode);
291 
292 #endif /* RNBD_PROTO_H */
293