linux-kernel - [PATCH 2/2] atm: fore200e: Replace GFP_ATOMIC with GFP_KERNEL in fore200e

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Message-Id: <1516931773-25222-1-git-send-email-baijiaju1990@gmail.com>
Date:   Fri, 26 Jan 2018 09:56:13 +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 2/2] atm: fore200e: Replace GFP_ATOMIC with GFP_KERNEL in fore200e_send

After checking all possible call chains to fore200e_send here,
my tool finds that fore200e_send is never called in atomic context.
And this function is assigned to a function pointer "dev->ops->send",
which is only called by vcc_sendmsg (net/atm/common.c) 
through vcc->dev->ops->send, and vcc_sendmsg calls schedule,
it indicates that fore200e_send 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/fore200e.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/atm/fore200e.c b/drivers/atm/fore200e.c
index 6ebc4e4..f6a5326 100644
--- a/drivers/atm/fore200e.c
+++ b/drivers/atm/fore200e.c
@@ -1611,7 +1611,7 @@ int bsq_audit(int where, struct host_bsq* bsq, int scheme, int magn)
     }

     if (tx_copy) {
-	data = kmalloc(tx_len, GFP_ATOMIC | GFP_DMA);
+	data = kmalloc(tx_len, GFP_KERNEL | GFP_DMA);
 	if (data == NULL) {
 	    if (vcc->pop) {
 		vcc->pop(vcc, skb);
-- 
1.7.9.5