To date, unwiring a fictitious page has produced a panic. The reason

being that PHYS_TO_VM_PAGE() returns the wrong vm_page for fictitious
pages but unwiring uses PHYS_TO_VM_PAGE().  The resulting panic
reported an unexpected wired count.  Rather than attempting to fix
PHYS_TO_VM_PAGE(), this fix takes advantage of the properties of
fictitious pages.  Specifically, fictitious pages will never be
completely unwired.  Therefore, we can keep a fictitious page's wired
count forever set to one and thereby avoid the use of
PHYS_TO_VM_PAGE() when we know that we're working with a fictitious
page, just not which one.

In collaboration with: green@, tegge@
PR: kern/29915

1 files changed, 2 insertions, 2 deletions

diff --git a/sys/vm/vm_extern.h b/sys/vm/vm_extern.h
index 7060efb..08169ef 100644
--- a/sys/vm/vm_extern.h
+++ b/sys/vm/vm_extern.h
@@ -69,8 +69,8 @@ void swapout_procs(int);
 int useracc(void *, int, int);
 int vm_fault(vm_map_t, vm_offset_t, vm_prot_t, int);
 void vm_fault_copy_entry(vm_map_t, vm_map_t, vm_map_entry_t, vm_map_entry_t);
-void vm_fault_unwire(vm_map_t, vm_offset_t, vm_offset_t);
-int vm_fault_wire(vm_map_t, vm_offset_t, vm_offset_t, boolean_t);
+void vm_fault_unwire(vm_map_t, vm_offset_t, vm_offset_t, boolean_t);
+int vm_fault_wire(vm_map_t, vm_offset_t, vm_offset_t, boolean_t, boolean_t);
 void vm_forkproc(struct thread *, struct proc *, struct thread *, int);
 void vm_waitproc(struct proc *);
 int vm_mmap(vm_map_t, vm_offset_t *, vm_size_t, vm_prot_t, vm_prot_t, int, void *, vm_ooffset_t);