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)