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 
12 struct 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  */
25 enum 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  */
53 struct 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  */
93 struct 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 
105 extern struct scsi_transport_template *
106 srp_attach_transport(struct srp_function_template *);
107 extern void srp_release_transport(struct scsi_transport_template *);
108 
109 extern void srp_rport_get(struct srp_rport *rport);
110 extern void srp_rport_put(struct srp_rport *rport);
111 extern struct srp_rport *srp_rport_add(struct Scsi_Host *,
112 				       struct srp_rport_identifiers *);
113 extern void srp_rport_del(struct srp_rport *);
114 extern int srp_tmo_valid(int reconnect_delay, int fast_io_fail_tmo,
115 			 long dev_loss_tmo);
116 int srp_parse_tmo(int *tmo, const char *buf);
117 extern int srp_reconnect_rport(struct srp_rport *rport);
118 extern void srp_start_tl_fail_timers(struct srp_rport *rport);
119 extern void srp_remove_host(struct Scsi_Host *);
120 extern void srp_stop_rport_timers(struct srp_rport *rport);
121 enum blk_eh_timer_return 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  */
srp_chkready(struct srp_rport * rport)131 static 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