linux-kernel - [PATCH] mm: Unsigned 'nr_pages' always larger than zero

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Date:   Wed, 4 Sep 2019 18:26:03 +0800
From:   zhong jiang <zhongjiang@...wei.com>
To:     <akpm@...ux-foundation.org>, <mhocko@...nel.org>
CC:     <anshuman.khandual@....com>, <vbabka@...e.cz>,
        <zhongjiang@...wei.com>, <linux-mm@...ck.org>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH] mm: Unsigned 'nr_pages' always larger than zero

With the help of unsigned_lesser_than_zero.cocci. Unsigned 'nr_pages"'
compare with zero. And __get_user_pages_locked will return an long value.
Hence, Convert the long to compare with zero is feasible.

Signed-off-by: zhong jiang <zhongjiang@...wei.com>
---
 mm/gup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/gup.c b/mm/gup.c
index 23a9f9c..956d5a1 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1508,7 +1508,7 @@ static long check_and_migrate_cma_pages(struct task_struct *tsk,
 						   pages, vmas, NULL,
 						   gup_flags);
 
-		if ((nr_pages > 0) && migrate_allow) {
+		if (((long)nr_pages > 0) && migrate_allow) {
 			drain_allow = true;
 			goto check_again;
 		}
-- 
1.7.12.4