1 /*
2  * iSCSI transport class definitions
3  *
4  * Copyright (C) IBM Corporation, 2004
5  * Copyright (C) Mike Christie, 2004 - 2006
6  * Copyright (C) Dmitry Yusupov, 2004 - 2005
7  * Copyright (C) Alex Aizman, 2004 - 2005
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  * GNU General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License
20  * along with this program; if not, write to the Free Software
21  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
22  */
23 #ifndef SCSI_TRANSPORT_ISCSI_H
24 #define SCSI_TRANSPORT_ISCSI_H
25 
26 #include <linux/device.h>
27 #include <linux/list.h>
28 #include <linux/mutex.h>
29 #include <scsi/iscsi_if.h>
30 
31 struct scsi_transport_template;
32 struct iscsi_transport;
33 struct iscsi_endpoint;
34 struct Scsi_Host;
35 struct scsi_cmnd;
36 struct iscsi_cls_conn;
37 struct iscsi_conn;
38 struct iscsi_task;
39 struct sockaddr;
40 
41 /**
42  * struct iscsi_transport - iSCSI Transport template
43  *
44  * @name:		transport name
45  * @caps:		iSCSI Data-Path capabilities
46  * @create_session:	create new iSCSI session object
47  * @destroy_session:	destroy existing iSCSI session object
48  * @create_conn:	create new iSCSI connection
49  * @bind_conn:		associate this connection with existing iSCSI session
50  *			and specified transport descriptor
51  * @destroy_conn:	destroy inactive iSCSI connection
52  * @set_param:		set iSCSI parameter. Return 0 on success, -ENODATA
53  *			when param is not supported, and a -Exx value on other
54  *			error.
55  * @get_param		get iSCSI parameter. Must return number of bytes
56  *			copied to buffer on success, -ENODATA when param
57  *			is not supported, and a -Exx value on other error
58  * @start_conn:		set connection to be operational
59  * @stop_conn:		suspend/recover/terminate connection
60  * @send_pdu:		send iSCSI PDU, Login, Logout, NOP-Out, Reject, Text.
61  * @session_recovery_timedout: notify LLD a block during recovery timed out
62  * @init_task:		Initialize a iscsi_task and any internal structs.
63  *			When offloading the data path, this is called from
64  *			queuecommand with the session lock, or from the
65  *			iscsi_conn_send_pdu context with the session lock.
66  *			When not offloading the data path, this is called
67  *			from the scsi work queue without the session lock.
68  * @xmit_task		Requests LLD to transfer cmd task. Returns 0 or the
69  *			the number of bytes transferred on success, and -Exyz
70  *			value on error. When offloading the data path, this
71  *			is called from queuecommand with the session lock, or
72  *			from the iscsi_conn_send_pdu context with the session
73  *			lock. When not offloading the data path, this is called
74  *			from the scsi work queue without the session lock.
75  * @cleanup_task:	requests LLD to fail task. Called with session lock
76  *			and after the connection has been suspended and
77  *			terminated during recovery. If called
78  *			from abort task then connection is not suspended
79  *			or terminated but sk_callback_lock is held
80  *
81  * Template API provided by iSCSI Transport
82  */
83 struct iscsi_transport {
84 	struct module *owner;
85 	char *name;
86 	unsigned int caps;
87 	/* LLD sets this to indicate what values it can export to sysfs */
88 	uint64_t param_mask;
89 	uint64_t host_param_mask;
90 	struct iscsi_cls_session *(*create_session) (struct iscsi_endpoint *ep,
91 					uint16_t cmds_max, uint16_t qdepth,
92 					uint32_t sn);
93 	void (*destroy_session) (struct iscsi_cls_session *session);
94 	struct iscsi_cls_conn *(*create_conn) (struct iscsi_cls_session *sess,
95 				uint32_t cid);
96 	int (*bind_conn) (struct iscsi_cls_session *session,
97 			  struct iscsi_cls_conn *cls_conn,
98 			  uint64_t transport_eph, int is_leading);
99 	int (*start_conn) (struct iscsi_cls_conn *conn);
100 	void (*stop_conn) (struct iscsi_cls_conn *conn, int flag);
101 	void (*destroy_conn) (struct iscsi_cls_conn *conn);
102 	int (*set_param) (struct iscsi_cls_conn *conn, enum iscsi_param param,
103 			  char *buf, int buflen);
104 	int (*get_ep_param) (struct iscsi_endpoint *ep, enum iscsi_param param,
105 			     char *buf);
106 	int (*get_conn_param) (struct iscsi_cls_conn *conn,
107 			       enum iscsi_param param, char *buf);
108 	int (*get_session_param) (struct iscsi_cls_session *session,
109 				  enum iscsi_param param, char *buf);
110 	int (*get_host_param) (struct Scsi_Host *shost,
111 				enum iscsi_host_param param, char *buf);
112 	int (*set_host_param) (struct Scsi_Host *shost,
113 			       enum iscsi_host_param param, char *buf,
114 			       int buflen);
115 	int (*send_pdu) (struct iscsi_cls_conn *conn, struct iscsi_hdr *hdr,
116 			 char *data, uint32_t data_size);
117 	void (*get_stats) (struct iscsi_cls_conn *conn,
118 			   struct iscsi_stats *stats);
119 
120 	int (*init_task) (struct iscsi_task *task);
121 	int (*xmit_task) (struct iscsi_task *task);
122 	void (*cleanup_task) (struct iscsi_task *task);
123 
124 	int (*alloc_pdu) (struct iscsi_task *task, uint8_t opcode);
125 	int (*xmit_pdu) (struct iscsi_task *task);
126 	int (*init_pdu) (struct iscsi_task *task, unsigned int offset,
127 			 unsigned int count);
128 	void (*parse_pdu_itt) (struct iscsi_conn *conn, itt_t itt,
129 			       int *index, int *age);
130 
131 	void (*session_recovery_timedout) (struct iscsi_cls_session *session);
132 	struct iscsi_endpoint *(*ep_connect) (struct Scsi_Host *shost,
133 					      struct sockaddr *dst_addr,
134 					      int non_blocking);
135 	int (*ep_poll) (struct iscsi_endpoint *ep, int timeout_ms);
136 	void (*ep_disconnect) (struct iscsi_endpoint *ep);
137 	int (*tgt_dscvr) (struct Scsi_Host *shost, enum iscsi_tgt_dscvr type,
138 			  uint32_t enable, struct sockaddr *dst_addr);
139 	int (*set_path) (struct Scsi_Host *shost, struct iscsi_path *params);
140 };
141 
142 /*
143  * transport registration upcalls
144  */
145 extern struct scsi_transport_template *iscsi_register_transport(struct iscsi_transport *tt);
146 extern int iscsi_unregister_transport(struct iscsi_transport *tt);
147 
148 /*
149  * control plane upcalls
150  */
151 extern void iscsi_conn_error_event(struct iscsi_cls_conn *conn,
152 				   enum iscsi_err error);
153 extern int iscsi_recv_pdu(struct iscsi_cls_conn *conn, struct iscsi_hdr *hdr,
154 			  char *data, uint32_t data_size);
155 
156 extern int iscsi_offload_mesg(struct Scsi_Host *shost,
157 			      struct iscsi_transport *transport, uint32_t type,
158 			      char *data, uint16_t data_size);
159 
160 struct iscsi_cls_conn {
161 	struct list_head conn_list;	/* item in connlist */
162 	void *dd_data;			/* LLD private data */
163 	struct iscsi_transport *transport;
164 	uint32_t cid;			/* connection id */
165 	struct mutex ep_mutex;
166 	struct iscsi_endpoint *ep;
167 
168 	struct device dev;		/* sysfs transport/container device */
169 };
170 
171 #define iscsi_dev_to_conn(_dev) \
172 	container_of(_dev, struct iscsi_cls_conn, dev)
173 
174 #define iscsi_conn_to_session(_conn) \
175 	iscsi_dev_to_session(_conn->dev.parent)
176 
177 /* iscsi class session state */
178 enum {
179 	ISCSI_SESSION_LOGGED_IN,
180 	ISCSI_SESSION_FAILED,
181 	ISCSI_SESSION_FREE,
182 };
183 
184 #define ISCSI_MAX_TARGET -1
185 
186 struct iscsi_cls_session {
187 	struct list_head sess_list;		/* item in session_list */
188 	struct iscsi_transport *transport;
189 	spinlock_t lock;
190 	struct work_struct block_work;
191 	struct work_struct unblock_work;
192 	struct work_struct scan_work;
193 	struct work_struct unbind_work;
194 
195 	/* recovery fields */
196 	int recovery_tmo;
197 	struct delayed_work recovery_work;
198 
199 	unsigned int target_id;
200 
201 	int state;
202 	int sid;				/* session id */
203 	void *dd_data;				/* LLD private data */
204 	struct device dev;	/* sysfs transport/container device */
205 };
206 
207 #define iscsi_dev_to_session(_dev) \
208 	container_of(_dev, struct iscsi_cls_session, dev)
209 
210 #define iscsi_session_to_shost(_session) \
211 	dev_to_shost(_session->dev.parent)
212 
213 #define starget_to_session(_stgt) \
214 	iscsi_dev_to_session(_stgt->dev.parent)
215 
216 struct iscsi_cls_host {
217 	atomic_t nr_scans;
218 	struct mutex mutex;
219 };
220 
221 extern void iscsi_host_for_each_session(struct Scsi_Host *shost,
222 				void (*fn)(struct iscsi_cls_session *));
223 
224 struct iscsi_endpoint {
225 	void *dd_data;			/* LLD private data */
226 	struct device dev;
227 	uint64_t id;
228 	struct iscsi_cls_conn *conn;
229 };
230 
231 /*
232  * session and connection functions that can be used by HW iSCSI LLDs
233  */
234 #define iscsi_cls_session_printk(prefix, _cls_session, fmt, a...) \
235 	dev_printk(prefix, &(_cls_session)->dev, fmt, ##a)
236 
237 #define iscsi_cls_conn_printk(prefix, _cls_conn, fmt, a...) \
238 	dev_printk(prefix, &(_cls_conn)->dev, fmt, ##a)
239 
240 extern int iscsi_session_chkready(struct iscsi_cls_session *session);
241 extern struct iscsi_cls_session *iscsi_alloc_session(struct Scsi_Host *shost,
242 				struct iscsi_transport *transport, int dd_size);
243 extern int iscsi_add_session(struct iscsi_cls_session *session,
244 			     unsigned int target_id);
245 extern int iscsi_session_event(struct iscsi_cls_session *session,
246 			       enum iscsi_uevent_e event);
247 extern struct iscsi_cls_session *iscsi_create_session(struct Scsi_Host *shost,
248 						struct iscsi_transport *t,
249 						int dd_size,
250 						unsigned int target_id);
251 extern void iscsi_remove_session(struct iscsi_cls_session *session);
252 extern void iscsi_free_session(struct iscsi_cls_session *session);
253 extern int iscsi_destroy_session(struct iscsi_cls_session *session);
254 extern struct iscsi_cls_conn *iscsi_create_conn(struct iscsi_cls_session *sess,
255 						int dd_size, uint32_t cid);
256 extern int iscsi_destroy_conn(struct iscsi_cls_conn *conn);
257 extern void iscsi_unblock_session(struct iscsi_cls_session *session);
258 extern void iscsi_block_session(struct iscsi_cls_session *session);
259 extern int iscsi_scan_finished(struct Scsi_Host *shost, unsigned long time);
260 extern struct iscsi_endpoint *iscsi_create_endpoint(int dd_size);
261 extern void iscsi_destroy_endpoint(struct iscsi_endpoint *ep);
262 extern struct iscsi_endpoint *iscsi_lookup_endpoint(u64 handle);
263 extern int iscsi_block_scsi_eh(struct scsi_cmnd *cmd);
264 
265 #endif
266