[SCSI] FC Pass Thru support

Attached is the ELS/CT pass-thru patch for the FC Transport. The patch
creates a generic framework that lays on top of bsg and the SGIO v4 ioctl
in order to pass transaction requests to LLDD's.

The interface supports the following operations:
  On an fc_host basis:
    Request login to the specified N_Port_ID, creating an fc_rport.
    Request logout of the specified N_Port_ID, deleting an fc_rport
    Send ELS request to specified N_Port_ID w/o requiring a login, and
      wait for ELS response.
    Send CT request to specified N_Port_ID and wait for CT response.
      Login is required, but LLDD is allowed to manage login and decide
      whether it stays in place after the request is satisfied.
    Vendor-Unique request. Allows a LLDD-specific request to be passed
      to the LLDD, and the passing of a response back to the application.
  On an fc_rport basis:
    Send ELS request to nport and wait for ELS response.
    Send CT request to nport and wait for CT response.

The patch also exports several headers from include/scsi such that
they can be available to user-space applications:
  include/scsi/scsi.h
  include/scsi/scsi_netlink.h
  include/scsi/scsi_netlink_fc.h
  include/scsi/scsi_bsg_fc.h

For further information, refer to the last RFC:
http://marc.info/?l=linux-scsi&m=123436574018579&w=2

Note: Documentation is still spotty and will be added later.

[[email protected]: update for new block API]
Signed-off-by: James Smart <[email protected]>
Signed-off-by: James Bottomley <[email protected]>

Documentation/scsi/scsi_fc_transport.txt

@@ -1,10 +1,11 @@
                              SCSI FC Tansport
                  =============================================
 
-Date:  4/12/2007
+Date:  11/18/2008
 Kernel Revisions for features:
   rports : <<TBS>>
-  vports : 2.6.22 (? TBD)
+  vports : 2.6.22
+  bsg support : 2.6.30 (?TBD?)
 
 
 Introduction
@@ -15,6 +16,7 @@ The FC transport can be found at:
   drivers/scsi/scsi_transport_fc.c
   include/scsi/scsi_transport_fc.h
   include/scsi/scsi_netlink_fc.h
+  include/scsi/scsi_bsg_fc.h
 
 This file is found at Documentation/scsi/scsi_fc_transport.txt
 
@@ -472,6 +474,14 @@ int
 fc_vport_terminate(struct fc_vport *vport)
 
 
+FC BSG support (CT & ELS passthru, and more)
+========================================================================
+<< To Be Supplied >>
+
+
+
+
+
 Credits
 =======
 The following people have contributed to this document:

Documentation/scsi/scsi_mid_low_api.txt

@@ -1271,6 +1271,11 @@ of interest:
     hostdata[0]  - area reserved for LLD at end of struct Scsi_Host. Size
                    is set by the second argument (named 'xtr_bytes') to
                    scsi_host_alloc() or scsi_register().
+    vendor_id    - a unique value that identifies the vendor supplying
+                   the LLD for the Scsi_Host.  Used most often in validating
+                   vendor-specific message requests.  Value consists of an
+                   identifier type and a vendor-specific value.
+                   See scsi_netlink.h for a description of valid formats.
 
 The scsi_host structure is defined in include/scsi/scsi_host.h