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 */
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