I'm wondering why no one refer to following fix.

1. change scsi_scsi_cmd(,... SCSI_NOSLEEP) behavior into returning
  EWOULDBLOCK (or something like that), when (*sc_link->adapter->scsi_cmd)()
  returns TRY_AGAIN_LATOR. 
  (if SCSI_NOSLEEP is not specified,
   or if (*sc_link->adapter->scsi_cmd)() doesn't return TRY_AGAIN_LATOR,
   then scsi_scsi_cmd() behaves as it is.)

2. sdstart(), ststart() and cdstart() check return value of
  scsi_scsi_cmd(), and these remove `struct buf' from sc->buf_queue,
  only if scsi_scsi_cmd() does not return EWOULDBLOCK.
  That is, if scsi_scsi_cmd() returns EWOULDBLOCK, we leave
  sc->buf_queue as it is, and immediately returns from xxstart().
  (xxstart() continues to use SCSI_NOSLEEP.)

This fix seems to be easy to implement, and doesn't change traditional
behavior of xxstart(). (xxstart() can be called from interrupt)

Probably I'm overlooking something, but what is that ?
--
soda@sra.co.jp		Software Research Associates, Inc., Japan
(Noriyuki Soda)		   software tools and technology group