[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.

[bharrosh@panasas.com: update for new block API]
Signed-off-by: James Smart <james.smart@emulex.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/Documentation/scsi/scsi_mid_low_api.txt b/Documentation/scsi/scsi_mid_low_api.txt
index a6d5354639b2..de67229251d8 100644
--- a/Documentation/scsi/scsi_mid_low_api.txt
+++ b/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