[SCSI] FC transport: Add dev_loss_tmo callbacks, and new fast_io_fail_tmo w/ callback

This patch adds the following functionality to the FC transport:

- dev_loss_tmo LLDD callback :
  Called to essentially confirm the deletion of an rport. Thus, it is
  called whenever the dev_loss_tmo fires, or when the rport is deleted
  due to other circumstances (module unload, etc).  It is expected that
  the callback will initiate the termination of any outstanding i/o on
  the rport.

- fast_io_fail_tmo and LLD callback:
  There are some cases where it may take a long while to truly determine
  device loss, but the system is in a multipathing configuration that if
  the i/o was failed quickly (faster than dev_loss_tmo), it could be
  redirected to a different path and completed sooner.

Many thanks to Mike Reed who cleaned up the initial RFC in support
of this post.

The original RFC is at:
http://marc.theaimsgroup.com/?l=linux-scsi&m=115505981027246&w=2

Signed-off-by: James Smart <James.Smart@emulex.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/scsi/scsi_transport_fc.h b/include/scsi/scsi_transport_fc.h
index 0b11eff989e..fd352323378 100644
--- a/include/scsi/scsi_transport_fc.h
+++ b/include/scsi/scsi_transport_fc.h
@@ -195,6 +195,7 @@ struct fc_rport {	/* aka fc_starget_attrs */
 	u32 roles;
 	enum fc_port_state port_state;	/* Will only be ONLINE or UNKNOWN */
 	u32 scsi_target_id;
+	u32 fast_io_fail_tmo;
 
 	/* exported data */
 	void *dd_data;			/* Used for driver-specific storage */
@@ -207,6 +208,7 @@ struct fc_rport {	/* aka fc_starget_attrs */
 	struct device dev;
  	struct work_struct dev_loss_work;
  	struct work_struct scan_work;
+ 	struct work_struct fail_io_work;
  	struct work_struct stgt_delete_work;
 	struct work_struct rport_delete_work;
 } __attribute__((aligned(sizeof(unsigned long))));
@@ -445,6 +447,9 @@ struct fc_function_template {
 
 	int	(*issue_fc_host_lip)(struct Scsi_Host *);
 
+	void    (*dev_loss_tmo_callbk)(struct fc_rport *);
+	void	(*terminate_rport_io)(struct fc_rport *);
+
 	/* allocation lengths for host-specific data */
 	u32	 			dd_fcrport_size;