[src/trunk]: src/sys/uvm Until such time as the swap subsystem can be convert...

[jakllsch <jakllsch%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/605df8ed6b17
branches:  trunk
changeset: 782939:605df8ed6b17
user:      jakllsch <jakllsch%NetBSD.org@localhost>
date:      Tue Nov 27 20:15:55 2012 +0000

description:
Until such time as the swap subsystem can be converted to use The One True
Allocator, prevent panics if (MAXPHYS/PAGE_SIZE) > BLIST_MAX_ALLOC.
>From Wolfgang Stukenbrock in PR#41765.

diffstat:

 sys/uvm/uvm_swap.c |  17 +++++++++++++++--
 1 files changed, 15 insertions(+), 2 deletions(-)

diffs (38 lines):

diff -r 7e30e700b3fb -r 605df8ed6b17 sys/uvm/uvm_swap.c
--- a/sys/uvm/uvm_swap.c        Tue Nov 27 20:06:36 2012 +0000
+++ b/sys/uvm/uvm_swap.c        Tue Nov 27 20:15:55 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_swap.c,v 1.161 2012/02/05 16:08:28 rmind Exp $     */
+/*     $NetBSD: uvm_swap.c,v 1.162 2012/11/27 20:15:55 jakllsch Exp $  */
 
 /*
  * Copyright (c) 1995, 1996, 1997, 2009 Matthew R. Green
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_swap.c,v 1.161 2012/02/05 16:08:28 rmind Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_swap.c,v 1.162 2012/11/27 20:15:55 jakllsch Exp $");
 
 #include "opt_uvmhist.h"
 #include "opt_compat_netbsd.h"
@@ -1535,6 +1535,19 @@
                return 0;
 
        /*
+        * XXXJAK: BEGIN HACK
+        *
+        * blist_alloc() in subr_blist.c will panic if we try to allocate
+        * too many slots.
+        */
+       if (*nslots > BLIST_MAX_ALLOC) {
+               if (__predict_false(lessok == false))
+                       return 0;
+               *nslots = BLIST_MAX_ALLOC;
+       }
+       /* XXXJAK: END HACK */
+
+       /*
         * lock data lock, convert slots into blocks, and enter loop
         */
        mutex_enter(&uvm_swap_data_lock);