linux man page for aphysio

aphysio(9F)						   Kernel Functions for Drivers 					       aphysio(9F)

NAME
       aphysio - perform asynchronous physical I/O

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

       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 cancel 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.

       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.   aphysio() 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, set  bp->b_bcount to a value supported by the device.

	 o  Call minphys(9F) to ensure that the driver does not circumvent additional system limits.

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.

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

SunOS 5.10							    9 Nov 1994							       aphysio(9F)