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


NAME


bp_mapin - allocate virtual address space

SYNOPSIS


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


void bp_mapin(struct buf *bp);


INTERFACE LEVEL


Architecture independent level 1 (DDI/DKI).

PARAMETERS


bp
Pointer to the buffer header structure.


DESCRIPTION


bp_mapin() is used to map virtual address space to a page list maintained
by the buffer header during a paged- I/O request. bp_mapin() allocates
system virtual address space, maps that space to the page list, and
returns the starting address of the space in the bp->b_un.b_addr field of
the buf(9S) structure. Virtual address space is then deallocated using
the bp_mapout(9F) function.


If a null page list is encountered, bp_mapin() returns without allocating
space and no mapping is performed.

CONTEXT


bp_mapin() can be called from user and kernel contexts.

SEE ALSO


bp_mapout(9F), buf(9S)


Writing Device Drivers


September 13, 1992 BP_MAPIN(9F)