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