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PMAP_EXTRACT(9)		 BSD Kernel Developer's	Manual	       PMAP_EXTRACT(9)

NAME
     pmap_extract, pmap_extract_and_hold -- map	a virtual address to a physi-
     cal page

SYNOPSIS
     #include <sys/param.h>
     #include <vm/vm.h>
     #include <vm/pmap.h>

     vm_paddr_t
     pmap_extract(pmap_t pmap, vm_offset_t va);

     vm_paddr_t
     pmap_extract_and_hold(pmap_t pmap,	vm_offset_t va,	vm_prot_t prot);

DESCRIPTION
     The pmap_extract()	function maps a	virtual	address	to a physical page.
     In	certain	situations, callers may	use pmap_extract_and_hold() instead,
     to	ensure that the	returned page is held.

     The pmap_extract_and_hold() function maps a virtual address to a physical
     page, and atomically holds	the returned page for use by the caller, only
     if	the mapping permits the	given page protection.

IMPLEMENTATION NOTES
     Currently,	the page protection requested by the caller is not verified.

RETURN VALUES
     The pmap_extract()	function will return the physical page address associ-
     ated with the virtual address va inside the physical map pmap.  If	the
     mapping does not exist, or	if the pmap parameter is NULL, then NULL will
     be	returned.

     The pmap_extract_and_hold() function will return the physical page	ad-
     dress associated with the virtual address va inside the physical map
     pmap.  If the mapping does	not exist, the result is a no-op, and NULL
     will be returned.

SEE ALSO
     mutex(9), pmap(9)

AUTHORS
     The pmap_extract_and_hold() function was implemented by Alan L. Cox
     <alc@imimic.com>.	This manual page was written by	Bruce M	Simpson
     <bms@spc.org>.

BSD				 July 21, 2003				   BSD

NAME | SYNOPSIS | DESCRIPTION | IMPLEMENTATION NOTES | RETURN VALUES | SEE ALSO | AUTHORS

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