Kernel Functions for Drivers                         bpmapin(9F)



NAME
     bpmapin - allocate virtual address space

SYNOPSIS
     #include 
     #include 



     void bpmapin(struct buf *bp);


INTERFACE LEVEL
     Architecture independent level 1 (DI/DKI).

PARAMETERS
     bp     Pointer to the buffer header structure.


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


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

CONTEXT
     bpmapin() can be called from user and kernel contexts.

SEE ALSO
     bpmapout(9F), buf(9S)


     Writing Device Drivers















SunOS 5.11          Last change: 13 Sep 1992                    1