From 7769be7d2f10cedc653d654b6c9924bcbf5d4480 Mon Sep 17 00:00:00 2001
From: Andrew Gerrand <adg@golang.org>
Date: Wed, 13 Aug 2014 13:38:50 +1000
Subject: [PATCH] [release-branch.go1.3] undo 941ef9ddbada / 125150044

It broke the build across all platforms.
The original change wasn't even reviewed.
Probably should never have been ported to this branch.

LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/128130043
---
 src/pkg/runtime/mgc0.c | 15 ++-------------
 1 file changed, 2 insertions(+), 13 deletions(-)

diff --git a/src/pkg/runtime/mgc0.c b/src/pkg/runtime/mgc0.c
index 9b23c53c21..392da535b1 100644
--- a/src/pkg/runtime/mgc0.c
+++ b/src/pkg/runtime/mgc0.c
@@ -2760,7 +2760,7 @@ runtime·markscan(void *v)
 void
 runtime·markfreed(void *v)
 {
-	uintptr *b, off, shift, xbits;
+	uintptr *b, off, shift;
 
 	if(0)
 		runtime·printf("markfreed %p\n", v);
@@ -2771,18 +2771,7 @@ runtime·markfreed(void *v)
 	off = (uintptr*)v - (uintptr*)runtime·mheap.arena_start;  // word offset
 	b = (uintptr*)runtime·mheap.arena_start - off/wordsPerBitmapWord - 1;
 	shift = off % wordsPerBitmapWord;
-	if(!g->m->gcing || work.nproc == 1) {
-		// During normal operation (not GC), the span bitmap is not updated concurrently,
-		// because either the span is cached or accesses are protected with MCentral lock.
-		*b = (*b & ~(bitMask<<shift)) | (bitAllocated<<shift);
-	} else {
-		// During GC other threads concurrently mark heap.
-		for(;;) {
-			xbits = *b;
-			if(runtime·casp((void**)b, (void*)xbits, (void*)((xbits & ~(bitMask<<shift)) | (bitAllocated<<shift))))
-				break;
-		}
-	}
+	*b = (*b & ~(bitMask<<shift)) | (bitAllocated<<shift);
 }
 
 // check that the block at v of size n is marked freed.
-- 
2.50.0