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8c64e4531c
Add support for periodically reconnecting to an SRP target until the dev_loss timer expires. After the tenth reconnection attempt, gradually slow down subsequent reconnect attempts. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Acked-by: David Dillow <dillowda@ornl.gov> Signed-off-by: Roland Dreier <roland@purestorage.com>
127 lines
3.8 KiB
C
127 lines
3.8 KiB
C
#ifndef SCSI_TRANSPORT_SRP_H
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#define SCSI_TRANSPORT_SRP_H
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#include <linux/transport_class.h>
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#include <linux/types.h>
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#include <linux/mutex.h>
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#define SRP_RPORT_ROLE_INITIATOR 0
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#define SRP_RPORT_ROLE_TARGET 1
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struct srp_rport_identifiers {
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u8 port_id[16];
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u8 roles;
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};
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/**
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* enum srp_rport_state - SRP transport layer state
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* @SRP_RPORT_RUNNING: Transport layer operational.
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* @SRP_RPORT_BLOCKED: Transport layer not operational; fast I/O fail timer
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* is running and I/O has been blocked.
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* @SRP_RPORT_FAIL_FAST: Fast I/O fail timer has expired; fail I/O fast.
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* @SRP_RPORT_LOST: Device loss timer has expired; port is being removed.
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*/
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enum srp_rport_state {
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SRP_RPORT_RUNNING,
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SRP_RPORT_BLOCKED,
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SRP_RPORT_FAIL_FAST,
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SRP_RPORT_LOST,
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};
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/**
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* struct srp_rport
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* @lld_data: LLD private data.
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* @mutex: Protects against concurrent rport reconnect / fast_io_fail /
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* dev_loss_tmo activity.
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*/
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struct srp_rport {
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/* for initiator and target drivers */
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struct device dev;
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u8 port_id[16];
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u8 roles;
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/* for initiator drivers */
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void *lld_data;
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struct mutex mutex;
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enum srp_rport_state state;
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bool deleted;
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int reconnect_delay;
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int failed_reconnects;
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struct delayed_work reconnect_work;
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int fast_io_fail_tmo;
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int dev_loss_tmo;
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struct delayed_work fast_io_fail_work;
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struct delayed_work dev_loss_work;
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};
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/**
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* struct srp_function_template
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* @has_rport_state: Whether or not to create the state, fast_io_fail_tmo and
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* dev_loss_tmo sysfs attribute for an rport.
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* @reset_timer_if_blocked: Whether or srp_timed_out() should reset the command
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* timer if the device on which it has been queued is blocked.
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* @reconnect_delay: If not NULL, points to the default reconnect_delay value.
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* @fast_io_fail_tmo: If not NULL, points to the default fast_io_fail_tmo value.
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* @dev_loss_tmo: If not NULL, points to the default dev_loss_tmo value.
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* @reconnect: Callback function for reconnecting to the target. See also
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* srp_reconnect_rport().
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* @terminate_rport_io: Callback function for terminating all outstanding I/O
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* requests for an rport.
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*/
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struct srp_function_template {
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/* for initiator drivers */
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bool has_rport_state;
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bool reset_timer_if_blocked;
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int *reconnect_delay;
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int *fast_io_fail_tmo;
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int *dev_loss_tmo;
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int (*reconnect)(struct srp_rport *rport);
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void (*terminate_rport_io)(struct srp_rport *rport);
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void (*rport_delete)(struct srp_rport *rport);
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/* for target drivers */
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int (* tsk_mgmt_response)(struct Scsi_Host *, u64, u64, int);
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int (* it_nexus_response)(struct Scsi_Host *, u64, int);
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};
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extern struct scsi_transport_template *
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srp_attach_transport(struct srp_function_template *);
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extern void srp_release_transport(struct scsi_transport_template *);
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extern void srp_rport_get(struct srp_rport *rport);
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extern void srp_rport_put(struct srp_rport *rport);
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extern struct srp_rport *srp_rport_add(struct Scsi_Host *,
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struct srp_rport_identifiers *);
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extern void srp_rport_del(struct srp_rport *);
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extern int srp_tmo_valid(int reconnect_delay, int fast_io_fail_tmo,
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int dev_loss_tmo);
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extern int srp_reconnect_rport(struct srp_rport *rport);
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extern void srp_start_tl_fail_timers(struct srp_rport *rport);
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extern void srp_remove_host(struct Scsi_Host *);
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/**
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* srp_chkready() - evaluate the transport layer state before I/O
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*
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* Returns a SCSI result code that can be returned by the LLD queuecommand()
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* implementation. The role of this function is similar to that of
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* fc_remote_port_chkready().
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*/
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static inline int srp_chkready(struct srp_rport *rport)
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{
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switch (rport->state) {
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case SRP_RPORT_RUNNING:
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case SRP_RPORT_BLOCKED:
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default:
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return 0;
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case SRP_RPORT_FAIL_FAST:
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return DID_TRANSPORT_FAILFAST << 16;
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case SRP_RPORT_LOST:
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return DID_NO_CONNECT << 16;
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}
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}
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#endif
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