re: Implement mode_select for atapi tape drives - round 4

[matthew green <mrg%eterna.com.au@localhost>]

   > +  u_int select_len;
   > +  struct select {
   > +          struct scsi_mode_parameter_header_6 header;
   > +          struct scsi_general_block_descriptor blk_desc;
   > +          u_char sense_data[MAX_PAGE_0_SIZE];
   > +  } select;
   > +  struct scsipi_periph *periph = st->sc_periph;
   > +
   > +  select_len = sizeof(select.header) + sizeof(select.blk_desc) +
   > +               st->page_0_size;
   > 
   > should select be __packed?
   
   Yes, it should probably be. I know most hardware structures are not
   declared __packed in the scsipi code, we've been luky this didn't cause
   issues for now ...


are these structures used heavily?  __packed will significantly
slow down accesses to and from them.


.mrg.