linux-kernel - [PATCH v2] hugetlbfs: correct handling of negative input to /proc/sys/vm/nr

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Message-ID: <4D6419C0.8080804@redhat.com>
Date:	Tue, 22 Feb 2011 21:17:04 +0100
From:	Petr Holasek <pholasek@...hat.com>
To:	linux-kernel@...r.kernel.org
CC:	Petr Holasek <pholasek@...hat.com>,
	Andi Kleen <ak@...ux.intel.com>,
	Naoya Horiguchi <n-horiguchi@...jp.nec.com>,
	Mel Gorman <mel@....ul.ie>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Wu Fengguang <fengguang.wu@...el.com>, linux-mm@...ck.org
Subject: [PATCH v2] hugetlbfs: correct handling of negative input to /proc/sys/vm/nr_hugepages

When user insert negative value into /proc/sys/vm/nr_hugepages it will 
result
in the setting a random number of HugePages in system (can be easily showed
at /proc/meminfo output). This patch fixes the wrong behavior so that the
negative input will result in nr_hugepages value unchanged.

v2: same fix was also done in hugetlb_overcommit_handler function
     as suggested by reviewers.

Signed-off-by: Petr Holasek <pholasek@...hat.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@...jp.nec.com>
---
  mm/hugetlb.c |    6 ++----
  1 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index bb0b7c1..06de5aa 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1872,8 +1872,7 @@ static int hugetlb_sysctl_handler_common(bool 
obey_mempolicy,
      unsigned long tmp;
      int ret;

-    if (!write)
-        tmp = h->max_huge_pages;
+    tmp = h->max_huge_pages;

      if (write && h->order >= MAX_ORDER)
          return -EINVAL;
@@ -1938,8 +1937,7 @@ int hugetlb_overcommit_handler(struct ctl_table 
*table, int write,
      unsigned long tmp;
      int ret;

-    if (!write)
-        tmp = h->nr_overcommit_huge_pages;
+    tmp = h->nr_overcommit_huge_pages;

      if (write && h->order >= MAX_ORDER)
          return -EINVAL;
-- 
1.7.1
--
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