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

NAME

bp_mapout - deallocate virtual address space

SYNOPSIS

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


void bp_mapout(struct buf *bp);

INTERFACE LEVEL

Architecture independent level 1 (DDI/DKI).

PARAMETERS

bp
Pointer to the buffer header structure.

DESCRIPTION

bp_mapout() deallocates system virtual address space allocated by a
previous call to bp_mapin(9F).bp_mapout() should only be called on
buffers which have been allocated and are owned by the device driver.
It must not be called on buffers passed to the driver through the
strategy(9E) entry point (for example a filesystem). Because
bp_mapin(9F) does not keep a reference count, bp_mapout() will wipe
out any kernel mapping that a layer above the device driver might
rely on.

CONTEXT

bp_mapout() can be called from user context only.

SEE ALSO

strategy(9E), bp_mapin(9F), buf(9S)


Writing Device Drivers

November 15, 1996 BP_MAPOUT(9F)