Below is the change to the design doc about the new ioctl:

    The newest SBC-3 spec (sbc3r17) extended READ CAPACITY (16) command to
    not only report the initiator LOGICAL BLOCK LENGTH IN BYTES but also
    report LOGICAL BLOCKS PER PHYSICAL BLOCK EXPONENT which is the 2^n
|   logical blocks per physical block. So the proposal here is to add a new
|   dkio(7I) DKIOCGMEDIAINFOEXT ioctl to report the physical block size.
    Applications and filesystems can decide the physical block size by
    issuing DKIOCGMEDIAINFOEXT and can send I/O requests that are aligned
    with the physical block size to improve the I/O performance.

#define DKIOCGMEDIAINFOEXT             (DKIO|48)

|   The argument of DKIOCGMEDIAINFOEXT

      /*
       * Used for media info with physcial block size 
       */
       struct dk_minfo_ext {
           uint_t        dki_media_type; /* Media type or profile info */
           uint_t        dki_lbsize;     /* Logical blocksize of media */
           diskaddr_t    dki_capacity; /* Capacity as # of dki_lbsize blks */
           uint_t        dki_pbsize;      /* Physical blocksize of media */
     };

Change to the Exported Interface table

	Exported Interface	Classification           Comments
       ====================  =====================  ==========================
 
       --------------------  ---------------------  ---------------------------
|        DKIOCGMEDIAINFOEXT        Committed        Add a new ioctl to dkio(7I) 
|                                                   to report the physical 
|                                                   blocksize of media.
|						    <sys/dkio.h>


The man page update for dkio(7I) is 

     DKIOCGMEDIAINFOEXT The argument to this ioctl() is a pointer
                        to  a dk_minfo_pbs structure. The structure
                        indicates the type of media or  the  com-
                        mand  set  profile  used  by the drive to
                        operate on the media. The dk_minfo_pbs struc-
                        ture  also  indicates  the  logical media
                        blocksize the drive  uses  as  the  basic
                        unit  blocksize  of operation,   the  raw
                        formatted capacity of the media in number
                        of logical blocks and the physical  block
 			size of the media.
			
      /*
       * Used for media info with physcial block size
       */
       struct dk_minfo_ext {
       uint_t           dki_media_type; /* Media type or profile info */
       uint_t        dki_lbsize;     /* Logical blocksize of media */
       diskaddr_t       dki_capacity;  /* Capacity as # of dki_lbsize blks */
       uint_t        dki_pbsize;     /* Physical blocksize of media */
       };