Make sure variables are used initialized in amap_wiperange

Uninitialized variables used in an if/else could cause a slower
codepath to be taken, but the end effect of both paths is the same.

Found by jsg@

diff --git a/sys/uvm/uvm_amap.c b/sys/uvm/uvm_amap.c
index f282277..c699421 100644 (file)
--- a/sys/uvm/uvm_amap.c
+++ b/sys/uvm/uvm_amap.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: uvm_amap.c,v 1.73 2016/07/09 17:13:05 stefan Exp $    */
+/*     $OpenBSD: uvm_amap.c,v 1.74 2016/07/11 08:38:49 stefan Exp $    */
 /*     $NetBSD: uvm_amap.c,v 1.27 2000/11/25 06:27:59 chs Exp $        */
 
 /*
@@ -895,6 +895,9 @@ amap_wiperange(struct vm_amap *amap, int slotoff, int slots)
        int bucket, startbucket, endbucket;
        struct vm_amap_chunk *chunk, *nchunk;
 
+       startbucket = UVM_AMAP_BUCKET(amap, slotoff);
+       endbucket = UVM_AMAP_BUCKET(amap, slotoff + slots - 1);
+
        /*
         * we can either traverse the amap by am_chunks or by am_buckets
         * depending on which is cheaper.    decide now.
@@ -913,9 +916,6 @@ amap_wiperange(struct vm_amap *amap, int slotoff, int slots)
                                amap_chunk_free(amap, chunk);
                }
        } else {
-               startbucket = UVM_AMAP_BUCKET(amap, slotoff);
-               endbucket = UVM_AMAP_BUCKET(amap, slotoff + slots - 1);
-
                for (bucket = startbucket; bucket <= endbucket; bucket++) {
                        for (chunk = amap->am_buckets[bucket]; chunk != NULL;
                            chunk = nchunk) {