strategy(9E)

NAME

     strategy - perform block I/O

SYNOPSIS

     #include <sys/types.h>
     #include <sys/buf.h>
     #include <sys/ddi.h>
     #include <sys/sunddi.h>

     int prefixstrategy(struct buf *bp);

INTERFACE LEVEL

     Architecture independent level 1 (DDI/DKI). This entry point
     is required for block devices.

PARAMETERS

      bp   Pointer to the  buf(9S) structure.

DESCRIPTION

     The   strategy()  routine  is  called  indirectly   (through
     cb_ops(9S))  by  the kernel to read and write blocks of data
     on  the  block  device.    strategy()  may  also  be  called
     directly  or  indirectly to support the raw character inter-
     face of a block device ( read(9E), write(9E) and ioctl(9E)).
     The  strategy()  routine's  responsibility  is to set up and
     initiate the transfer.

RETURN VALUES

     The strategy() routine should always return 0.  On an  error
     condition,  it  should  call  bioerror(9f) to set b_flags to
     the proper error code, and call  biodone(9f).  Note  that  a
     partial transfer is not considered to be an error.

SEE ALSO

     ioctl(9E), read(9E), write(9E),  biodone(9F),  bioerror(9F),
     buf(9S), cb_ops(9S)

     Writing Device Drivers