uphysio Kernel Service mincnt Routine

Purpose

Tailors a buf data transfer request to device-dependent requirements.

Syntax

#include <sys/types.h> #include <sys/errno.h> #include <sys/buf.h> int mincnt ( bp, minparms) struct buf *bp; void *minparms;

Parameters

Item	Description
bp	Points to the buf structure to be tailored.
minparms	Points to parameters.

Description

Only the following fields in the buf header sent to the routine specified by the uphysio kernel service mincnt parameter can be modified by that routine:

b_bcount
b_work
b_options

The mincnt parameter cannot modify any other fields without the risk of error. If the mincnt parameter determines that the buf header cannot be supported by the target device, the routine should return a nonzero return code. This stops the buf header and any additional buf headers from being sent to the ddstrategy routine.

The uphysio kernel service waits for all buf headers already sent to the strategy routine to complete and then returns with the return code from the mincnt parameter.