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

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Date:	Thu, 24 Feb 2011 12:02:11 -0500 (EST)
From:	Petr Holasek <pholasek@...hat.com>
To:	linux-kernel@...r.kernel.org
Cc:	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: Re: [PATCH v2] hugetlbfs: correct handling of negative input to
 /proc/sys/vm/nr_hugepages

----- Original Message -----
> 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
> Sent: Tuesday, February 22, 2011 9:17:04 PM
> 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
> --
> To unsubscribe from this list: send the line "unsubscribe
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> Please read the FAQ at http://www.tux.org/lkml/

I am really sorry, but tabs were broken up into spaces during posting,
here is the right version:

thanks,
Petr

---
 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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