NAME

bp_mapin - allocate virtual address space

SYNOPSIS

#include <sys/types.h>

#include <sys/buf.h>

void bp_mapin(struct buf * bp);

ARGUMENTS

bp

Pointer to the buffer header structure.

INTERFACE LEVEL

Architecture independent level 1 (DDI/DKI).

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 context only.

SEE ALSO

bp_mapout(9F), buf(9S)

Writing Device Drivers