Manual Pages for UNIX Operating System command usage for man aphysio

Kernel Functions for Drivers                          aphysio(9F)



NAME
     aphysio, aminphys - perform asynchronous physical I/O

SYNOPSIS
     #include 
     #include 
     #include 
     #include 
     #include 
     #include 



     int  aphysio(int (*strat)( struct buf *), int (*cancel)(struct buf *),
          dev_t dev, int rw, void (*mincnt)(struct buf *),
          struct  aio_req *aio_reqp);


PARAMETERS
     strat        Pointer to device strategy routine.


     cancel       Pointer to driver cancel routine.  Used to can-
                  cel  a  submitted request. The driver must pass
                  the  address  of  the  function   anocancel(9F)
                  because cancellation is not supported.


     dev          The device number.


     rw           Read/write flag. This is  either   B_READ  when
                  reading from the device or B_WRITE when writing
                  to the device.


     mincnt       Routine which bounds the maximum transfer  unit
                  size.


     aio_reqp     Pointer to  the   aio_req(9S)  structure  which
                  describes the user I/O request.


INTERFACE LEVEL
     Solaris  DDI specific (Solaris DDI).

DESCRIPTION
     aphysio() performs asynchronous  I/O operations between  the
     device and the address space described by aio_reqp->aio_uio.





SunOS 5.11           Last change: 9 Nov 1994                    1






Kernel Functions for Drivers                          aphysio(9F)



     Prior to the start of the transfer,  aphysio() verifies  the
     requested  operation  is  valid.   It  then  locks the pages
     involved in the  I/O transfer so they can not be paged  out.
     The  device  strategy routine,  strat, is then called one or
     more times to  perform the physical  I/O operations.   aphy-
     sio()  does  not  wait  for  each  transfer to complete, but
     returns as soon as the necessary requests have been made.


     aphysio() calls  mincnt to bound the maximum  transfer  unit
     size  to  a sensible default for the  device and the system.
     Drivers which do not provide their own local mincnt  routine
     should  call  aphysio() with minphys(9F). minphys(9F) is the
     system  mincnt routine.   minphys(9F) ensures  the  transfer
     size does not exceed any system limits.


     If a driver supplies a local  mincnt routine,  this  routine
     should perform the following actions:

         o    If bp->b_bcount exceeds a  device  limit,  physio()
              returns ENOTSUP.

         o    Call aminphys(9F) to ensure that  the  driver  does
              not   circumvent   additional   system  limits.  If
              aminphys(9F) does not return 0, return ENOTSUP.

RETURN VALUES
     aphysio() returns:

     0           Upon success.


     non-zero    Upon failure.


CONTEXT
     aphysio() can be called from user context only.

SEE ALSO
     aread(9E),    awrite(9E),    strategy(9E),    anocancel(9F),
     biodone(9F),     biowait(9F),    minphys(9F),    physio(9F),
     aio_req(9S), buf(9S), uio(9S)


     Writing Device Drivers

WARNINGS
     It is the driver's responsibility to call  biodone(9F)  when
     the transfer is complete.





SunOS 5.11           Last change: 9 Nov 1994                    2






Kernel Functions for Drivers                          aphysio(9F)



BUGS
     Cancellation is not supported in this release.   The address
     of  the  function  anocancel(9F) must be used as the  cancel
     argument.



















































SunOS 5.11           Last change: 9 Nov 1994                    3