aphysio(9F) Kernel Functions for Drivers aphysio(9F)NAME
aphysio, aminphys - 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 sub‐
mitted request. The driver must pass the address of the
function anocancel(9F) because cancellation is not sup‐
ported.
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).
DESCRIPTIONaphysio() 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 min‐
phys(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 per‐
form 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 circum‐
vent additional system limits. If aminphys(9F) does not
return 0, return ENOTSUP.
RETURN VALUESaphysio() returns:
0 Upon success.
non-zero Upon failure.
CONTEXTaphysio() can be called from user context only.
SEE ALSOaread(9E), awrite(9E), strategy(9E), anocancel(9F), biodone(9F),
biowait(9F), minphys(9F), physio(9F), aio_req(9S), buf(9S), uio(9S)WARNINGS
It is the driver's responsibility to call biodone(9F) when the trans‐
fer 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)
