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

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Date:   Fri, 26 Jan 2018 22:44:22 +0800
From:   Jia-Ju Bai <baijiaju1990@...il.com>
To:     philipp.reisner@...bit.com, lars.ellenberg@...bit.com
Cc:     drbd-dev@...ts.linbit.com, linux-kernel@...r.kernel.org,
        Jia-Ju Bai <baijiaju1990@...il.com>
Subject: [PATCH] block: drbd: Replace GFP_ATOMIC with GFP_KERNEL in drbd_resync_finished

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

diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 1476cb3..7ea56db 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -883,7 +883,7 @@ int drbd_resync_finished(struct drbd_device *device)
 		 * is not finished by now).   Retry in 100ms. */

 		schedule_timeout_interruptible(HZ / 10);
-		dw = kmalloc(sizeof(struct drbd_device_work), GFP_ATOMIC);
+		dw = kmalloc(sizeof(struct drbd_device_work), GFP_KERNEL);
 		if (dw) {
 			dw->w.cb = w_resync_finished;
 			dw->device = device;
-- 
1.7.9.5