linux-kernel - [PATCH] atm: he: Replace GFP_ATOMIC with GFP_KERNEL in he

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Message-Id: <1516955010-31452-1-git-send-email-baijiaju1990@gmail.com>
Date:   Fri, 26 Jan 2018 16:23:30 +0800
From:   Jia-Ju Bai <baijiaju1990@...il.com>
To:     3chas3@...il.com
Cc:     linux-atm-general@...ts.sourceforge.net, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, Jia-Ju Bai <baijiaju1990@...il.com>
Subject: [PATCH] atm: he: Replace GFP_ATOMIC with GFP_KERNEL in he_open

After checking all possible call chains to he_open() here,
my tool finds that he_open() is never called in atomic context.
And this function is assigned to a function pointer "dev->ops->open",
which is only called by __vcc_connect() (net/atm/common.c)
through dev->ops->send(), and __vcc_connect() is only called by
vcc_connect(), which calls mutex_lock(),
so it indicates that he_open() can call functions which may sleep.
Thus GFP_ATOMIC is not necessary, and it can be replaced with GFP_KERNEL.

This is found by a static analysis tool named DCNS written by myself.

Signed-off-by: Jia-Ju Bai <baijiaju1990@...il.com>
---
 drivers/atm/he.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/atm/he.c b/drivers/atm/he.c
index e58538c..fea5bf0 100644
--- a/drivers/atm/he.c
+++ b/drivers/atm/he.c
@@ -2135,7 +2135,7 @@ static int he_start(struct atm_dev *dev)

 	cid = he_mkcid(he_dev, vpi, vci);

-	he_vcc = kmalloc(sizeof(struct he_vcc), GFP_ATOMIC);
+	he_vcc = kmalloc(sizeof(struct he_vcc), GFP_KERNEL);
 	if (he_vcc == NULL) {
 		hprintk("unable to allocate he_vcc during open\n");
 		return -ENOMEM;
-- 
1.7.9.5