include/scsi/scsi_transport_srp.h

   1 #ifndef SCSI_TRANSPORT_SRP_H
   2 #define SCSI_TRANSPORT_SRP_H
   3
   4 #include <linux/transport_class.h>
   5 #include <linux/types.h>
   6 #include <linux/mutex.h>
   7
   8 #define SRP_RPORT_ROLE_INITIATOR 0
   9 #define SRP_RPORT_ROLE_TARGET 1
  10
  11 struct srp_rport_identifiers {
  12         u8 port_id[16];
  13         u8 roles;
  14 };
  15
  16 /**
  17  * enum srp_rport_state - SRP transport layer state
  18  * @SRP_RPORT_RUNNING:   Transport layer operational.
  19  * @SRP_RPORT_BLOCKED:   Transport layer not operational; fast I/O fail timer
  20  *                       is running and I/O has been blocked.
  21  * @SRP_RPORT_FAIL_FAST: Fast I/O fail timer has expired; fail I/O fast.
  22  * @SRP_RPORT_LOST:      Port is being removed.
  23  */
  24 enum srp_rport_state {
  25         SRP_RPORT_RUNNING,
  26         SRP_RPORT_BLOCKED,
  27         SRP_RPORT_FAIL_FAST,
  28         SRP_RPORT_LOST,
  29 };
  30
  31 /**
  32  * struct srp_rport - SRP initiator or target port
  33  *
  34  * Fields that are relevant for SRP initiator and SRP target drivers:
  35  * @dev:               Device associated with this rport.
  36  * @port_id:           16-byte port identifier.
  37  * @roles:             Role of this port - initiator or target.
  38  *
  39  * Fields that are only relevant for SRP initiator drivers:
  40  * @lld_data:          LLD private data.
  41  * @mutex:             Protects against concurrent rport reconnect /
  42  *                     fast_io_fail / dev_loss_tmo activity.
  43  * @state:             rport state.
  44  * @deleted:           Whether or not srp_rport_del() has already been invoked.
  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  * Fields that are only relevant for SRP target drivers:
  94  * @tsk_mgmt_response: Callback function for sending a task management response.
  95  * @it_nexus_response: Callback function for processing an IT nexus response.
  96  */
  97 struct srp_function_template {
  98         /* for initiator drivers */
  99         bool has_rport_state;
 100         bool reset_timer_if_blocked;
 101         int *reconnect_delay;
 102         int *fast_io_fail_tmo;
 103         int *dev_loss_tmo;
 104         int (*reconnect)(struct srp_rport *rport);
 105         void (*terminate_rport_io)(struct srp_rport *rport);
 106         void (*rport_delete)(struct srp_rport *rport);
 107         /* for target drivers */
 108         int (* tsk_mgmt_response)(struct Scsi_Host *, u64, u64, int);
 109         int (* it_nexus_response)(struct Scsi_Host *, u64, int);
 110 };
 111
 112 extern struct scsi_transport_template *
 113 srp_attach_transport(struct srp_function_template *);
 114 extern void srp_release_transport(struct scsi_transport_template *);
 115
 116 extern void srp_rport_get(struct srp_rport *rport);
 117 extern void srp_rport_put(struct srp_rport *rport);
 118 extern struct srp_rport *srp_rport_add(struct Scsi_Host *,
 119                                        struct srp_rport_identifiers *);
 120 extern void srp_rport_del(struct srp_rport *);
 121 extern int srp_tmo_valid(int reconnect_delay, int fast_io_fail_tmo,
 122                          int dev_loss_tmo);
 123 extern int srp_reconnect_rport(struct srp_rport *rport);
 124 extern void srp_start_tl_fail_timers(struct srp_rport *rport);
 125 extern void srp_remove_host(struct Scsi_Host *);
 126 extern void srp_stop_rport_timers(struct srp_rport *rport);
 127
 128 /**
 129  * srp_chkready() - evaluate the transport layer state before I/O
 130  * @rport: SRP target port pointer.
 131  *
 132  * Returns a SCSI result code that can be returned by the LLD queuecommand()
 133  * implementation. The role of this function is similar to that of
 134  * fc_remote_port_chkready().
 135  */
 136 static inline int srp_chkready(struct srp_rport *rport)
 137 {
 138         switch (rport->state) {
 139         case SRP_RPORT_RUNNING:
 140         case SRP_RPORT_BLOCKED:
 141         default:
 142                 return 0;
 143         case SRP_RPORT_FAIL_FAST:
 144                 return DID_TRANSPORT_FAILFAST << 16;
 145         case SRP_RPORT_LOST:
 146                 return DID_NO_CONNECT << 16;
 147         }
 148 }
 149
 150 #endif