From: Andrea Arcangeli <aarcange@redhat.com>
Date: Wed, 2 Nov 2011 20:37:11 +0000 (-0700)
Subject: powerpc: gup_hugepte() avoid freeing the head page too many times
X-Git-Tag: firefly_0821_release~7541^2~2377
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=cf2f493ba5c49afe9efd3afa02a505e9b060832d;p=firefly-linux-kernel-4.4.55.git

powerpc: gup_hugepte() avoid freeing the head page too many times

commit 8596468487e2062cae2aad56e973784e03959245 upstream.

We only taken "refs" pins on the head page not "*nr" pins.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index b649c288af90..78b14abded65 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -428,10 +428,9 @@ static noinline int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long add
 
 	if (unlikely(pte_val(pte) != pte_val(*ptep))) {
 		/* Could be optimized better */
-		while (*nr) {
+		*nr -= refs;
+		while (refs--)
 			put_page(head);
-			(*nr)--;
-		}
 	}
 
 	return 1;