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