linux-kernel - [PATCH] block: DAC960: Replace GFP_ATOMIC with GFP_KERNEL in DAC960

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Message-Id: <1516962333-2198-1-git-send-email-baijiaju1990@gmail.com>
Date:   Fri, 26 Jan 2018 18:25:33 +0800
From:   Jia-Ju Bai <baijiaju1990@...il.com>
To:     keescook@...omium.org, axboe@...nel.dk, arnd@...db.de
Cc:     linux-kernel@...r.kernel.org, Jia-Ju Bai <baijiaju1990@...il.com>
Subject: [PATCH] block: DAC960: Replace GFP_ATOMIC with GFP_KERNEL in DAC960_DetectController

After checking all possible call chains to DAC960_DetectController(), 
my tool finds that this function is never called in atomic context, 
namely never in an interrupt handler or holding a spinlock.
And DAC960_DetectController() calls pci_enable_device that can sleep, 
so it indicates that DAC960_DetectController() 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/block/DAC960.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/DAC960.c b/drivers/block/DAC960.c
index 442e777..25ee9af 100644
--- a/drivers/block/DAC960.c
+++ b/drivers/block/DAC960.c
@@ -2725,7 +2725,7 @@ static void DAC960_DetectCleanup(DAC960_Controller_T *Controller)
   void __iomem *BaseAddress;
   int i;

-  Controller = kzalloc(sizeof(DAC960_Controller_T), GFP_ATOMIC);
+  Controller = kzalloc(sizeof(DAC960_Controller_T), GFP_KERNEL);
   if (Controller == NULL) {
 	DAC960_Error("Unable to allocate Controller structure for "
                        "Controller at\n", NULL);
-- 
1.7.9.5