[SCSI] add support for variable length extended commands

Add support for variable-length, extended, and vendor specific
CDBs to scsi-ml. It is now possible for initiators and ULD's
to issue these types of commands. LLDs need not change much.
All they need is to raise the .max_cmd_len to the longest command
they support (see iscsi patch).

- clean-up some code paths that did not expect commands to be
  larger than 16, and change cmd_len members' type to short as
  char is not enough.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 3 insertions, 5 deletions

diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index d967d6dc7a28..1834fdfe82a7 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -573,13 +573,11 @@ struct Scsi_Host {
         /*
          * The maximum length of SCSI commands that this host can accept.
          * Probably 12 for most host adapters, but could be 16 for others.
+         * or 260 if the driver supports variable length cdbs.
          * For drivers that don't set this field, a value of 12 is
-         * assumed.  I am leaving this as a number rather than a bit
-         * because you never know what subsequent SCSI standards might do
-         * (i.e. could there be a 20 byte or a 24-byte command a few years
-         * down the road?).  
+         * assumed.
          */
-        unsigned char max_cmd_len;
+        unsigned short max_cmd_len;
 
         int this_id;
         int can_queue;