From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Date: Wed, 11 Sep 2013 21:21:57 +0000 (-0700)
Subject: mm, hugetlb: grab a page_table_lock after page_cache_release
X-Git-Tag: firefly_0821_release~3680^2~103^2^2~1
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=6f9971e037a3a7d6fc7c97c20d520d3dc01569f9;p=firefly-linux-kernel-4.4.55.git

mm, hugetlb: grab a page_table_lock after page_cache_release

We don't need to grab a page_table_lock when we try to release a page.
So, defer to grab a page_table_lock.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: Davidlohr Bueso <davidlohr@hp.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Hillf Danton <dhillf@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit 8312034f3604bc0339c40545c538116f4ddad152)
Signed-off-by: Mark Brown <broonie@linaro.org>
---

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index f0a9e32c75b4..1265a836ac4f 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2630,10 +2630,11 @@ retry_avoidcopy:
 	}
 	spin_unlock(&mm->page_table_lock);
 	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
-	/* Caller expects lock to be held */
-	spin_lock(&mm->page_table_lock);
 	page_cache_release(new_page);
 	page_cache_release(old_page);
+
+	/* Caller expects lock to be held */
+	spin_lock(&mm->page_table_lock);
 	return 0;
 }