1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef SCSI_TRANSPORT_SRP_H
3#define SCSI_TRANSPORT_SRP_H
4
5#include <linux/transport_class.h>
6#include <linux/types.h>
7#include <linux/mutex.h>
8
9#define SRP_RPORT_ROLE_INITIATOR 0
10#define SRP_RPORT_ROLE_TARGET 1
11
12struct srp_rport_identifiers {
13	u8 port_id[16];
14	u8 roles;
15};
16
17/**
18 * enum srp_rport_state - SRP transport layer state
19 * @SRP_RPORT_RUNNING:   Transport layer operational.
20 * @SRP_RPORT_BLOCKED:   Transport layer not operational; fast I/O fail timer
21 *                       is running and I/O has been blocked.
22 * @SRP_RPORT_FAIL_FAST: Fast I/O fail timer has expired; fail I/O fast.
23 * @SRP_RPORT_LOST:      Port is being removed.
24 */
25enum srp_rport_state {
26	SRP_RPORT_RUNNING,
27	SRP_RPORT_BLOCKED,
28	SRP_RPORT_FAIL_FAST,
29	SRP_RPORT_LOST,
30};
31
32/**
33 * struct srp_rport - SRP initiator or target port
34 *
35 * Fields that are relevant for SRP initiator and SRP target drivers:
36 * @dev:               Device associated with this rport.
37 * @port_id:           16-byte port identifier.
38 * @roles:             Role of this port - initiator or target.
39 *
40 * Fields that are only relevant for SRP initiator drivers:
41 * @lld_data:          LLD private data.
42 * @mutex:             Protects against concurrent rport reconnect /
43 *                     fast_io_fail / dev_loss_tmo activity.
44 * @state:             rport state.
45 * @reconnect_delay:   Reconnect delay in seconds.
46 * @failed_reconnects: Number of failed reconnect attempts.
47 * @reconnect_work:    Work structure used for scheduling reconnect attempts.
48 * @fast_io_fail_tmo:  Fast I/O fail timeout in seconds.
49 * @dev_loss_tmo:      Device loss timeout in seconds.
50 * @fast_io_fail_work: Work structure used for scheduling fast I/O fail work.
51 * @dev_loss_work:     Work structure used for scheduling device loss work.
52 */
53struct srp_rport {
54	/* for initiator and target drivers */
55
56	struct device dev;
57
58	u8 port_id[16];
59	u8 roles;
60
61	/* for initiator drivers */
62
63	void			*lld_data;
64
65	struct mutex		mutex;
66	enum srp_rport_state	state;
67	int			reconnect_delay;
68	int			failed_reconnects;
69	struct delayed_work	reconnect_work;
70	int			fast_io_fail_tmo;
71	int			dev_loss_tmo;
72	struct delayed_work	fast_io_fail_work;
73	struct delayed_work	dev_loss_work;
74};
75
76/**
77 * struct srp_function_template
78 *
79 * Fields that are only relevant for SRP initiator drivers:
80 * @has_rport_state: Whether or not to create the state, fast_io_fail_tmo and
81 *     dev_loss_tmo sysfs attribute for an rport.
82 * @reset_timer_if_blocked: Whether or srp_timed_out() should reset the command
83 *     timer if the device on which it has been queued is blocked.
84 * @reconnect_delay: If not NULL, points to the default reconnect_delay value.
85 * @fast_io_fail_tmo: If not NULL, points to the default fast_io_fail_tmo value.
86 * @dev_loss_tmo: If not NULL, points to the default dev_loss_tmo value.
87 * @reconnect: Callback function for reconnecting to the target. See also
88 *     srp_reconnect_rport().
89 * @terminate_rport_io: Callback function for terminating all outstanding I/O
90 *     requests for an rport.
91 * @rport_delete: Callback function that deletes an rport.
92 */
93struct srp_function_template {
94	/* for initiator drivers */
95	bool has_rport_state;
96	bool reset_timer_if_blocked;
97	int *reconnect_delay;
98	int *fast_io_fail_tmo;
99	int *dev_loss_tmo;
100	int (*reconnect)(struct srp_rport *rport);
101	void (*terminate_rport_io)(struct srp_rport *rport);
102	void (*rport_delete)(struct srp_rport *rport);
103};
104
105extern struct scsi_transport_template *
106srp_attach_transport(struct srp_function_template *);
107extern void srp_release_transport(struct scsi_transport_template *);
108
109extern void srp_rport_get(struct srp_rport *rport);
110extern void srp_rport_put(struct srp_rport *rport);
111extern struct srp_rport *srp_rport_add(struct Scsi_Host *,
112				       struct srp_rport_identifiers *);
113extern void srp_rport_del(struct srp_rport *);
114extern int srp_tmo_valid(int reconnect_delay, int fast_io_fail_tmo,
115			 long dev_loss_tmo);
116int srp_parse_tmo(int *tmo, const char *buf);
117extern int srp_reconnect_rport(struct srp_rport *rport);
118extern void srp_start_tl_fail_timers(struct srp_rport *rport);
119extern void srp_remove_host(struct Scsi_Host *);
120extern void srp_stop_rport_timers(struct srp_rport *rport);
121enum scsi_timeout_action srp_timed_out(struct scsi_cmnd *scmd);
122
123/**
124 * srp_chkready() - evaluate the transport layer state before I/O
125 * @rport: SRP target port pointer.
126 *
127 * Returns a SCSI result code that can be returned by the LLD queuecommand()
128 * implementation. The role of this function is similar to that of
129 * fc_remote_port_chkready().
130 */
131static inline int srp_chkready(struct srp_rport *rport)
132{
133	switch (rport->state) {
134	case SRP_RPORT_RUNNING:
135	case SRP_RPORT_BLOCKED:
136	default:
137		return 0;
138	case SRP_RPORT_FAIL_FAST:
139		return DID_TRANSPORT_FAILFAST << 16;
140	case SRP_RPORT_LOST:
141		return DID_NO_CONNECT << 16;
142	}
143}
144
145#endif
146