linux-kernel - [PATCH 4/7] nandsim: Don't use PF

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Message-Id: <20091117161843.3DE0.A69D9226@jp.fujitsu.com>
Date:	Tue, 17 Nov 2009 16:19:33 +0900 (JST)
From:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
To:	LKML <linux-kernel@...r.kernel.org>
Cc:	kosaki.motohiro@...fujitsu.com, linux-mm <linux-mm@...ck.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	David Woodhouse <David.Woodhouse@...el.com>,
	Artem Bityutskiy <Artem.Bityutskiy@...ia.com>,
	linux-mtd@...ts.infradead.org
Subject: [PATCH 4/7] nandsim: Don't use PF_MEMALLOC


Non MM subsystem must not use PF_MEMALLOC. Memory reclaim need few
memory, anyone must not prevent it. Otherwise the system cause
mysterious hang-up and/or OOM Killer invokation.

Cc: David Woodhouse <David.Woodhouse@...el.com>
Cc: Artem Bityutskiy <Artem.Bityutskiy@...ia.com>
Cc: linux-mtd@...ts.infradead.org
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
---
 drivers/mtd/nand/nandsim.c |   22 ++--------------------
 1 files changed, 2 insertions(+), 20 deletions(-)

diff --git a/drivers/mtd/nand/nandsim.c b/drivers/mtd/nand/nandsim.c
index cd0711b..97a8bbb 100644
--- a/drivers/mtd/nand/nandsim.c
+++ b/drivers/mtd/nand/nandsim.c
@@ -1322,34 +1322,18 @@ static int get_pages(struct nandsim *ns, struct file *file, size_t count, loff_t
 	return 0;
 }
 
-static int set_memalloc(void)
-{
-	if (current->flags & PF_MEMALLOC)
-		return 0;
-	current->flags |= PF_MEMALLOC;
-	return 1;
-}
-
-static void clear_memalloc(int memalloc)
-{
-	if (memalloc)
-		current->flags &= ~PF_MEMALLOC;
-}
-
 static ssize_t read_file(struct nandsim *ns, struct file *file, void *buf, size_t count, loff_t *pos)
 {
 	mm_segment_t old_fs;
 	ssize_t tx;
-	int err, memalloc;
+	int err;
 
 	err = get_pages(ns, file, count, *pos);
 	if (err)
 		return err;
 	old_fs = get_fs();
 	set_fs(get_ds());
-	memalloc = set_memalloc();
 	tx = vfs_read(file, (char __user *)buf, count, pos);
-	clear_memalloc(memalloc);
 	set_fs(old_fs);
 	put_pages(ns);
 	return tx;
@@ -1359,16 +1343,14 @@ static ssize_t write_file(struct nandsim *ns, struct file *file, void *buf, size
 {
 	mm_segment_t old_fs;
 	ssize_t tx;
-	int err, memalloc;
+	int err;
 
 	err = get_pages(ns, file, count, *pos);
 	if (err)
 		return err;
 	old_fs = get_fs();
 	set_fs(get_ds());
-	memalloc = set_memalloc();
 	tx = vfs_write(file, (char __user *)buf, count, pos);
-	clear_memalloc(memalloc);
 	set_fs(old_fs);
 	put_pages(ns);
 	return tx;
-- 
1.6.2.5



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