linux-kernel - Re: [PATCH] bluetooth: btmrvl_main: Replace GFP_ATOMIC with GFP_KERNEL in btmrvl_send_sync

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Message-Id: <C39D859D-E8B7-4805-94F7-28FEFCACEEEC@holtmann.org>
Date:   Wed, 7 Feb 2018 09:55:44 +0100
From:   Marcel Holtmann <marcel@...tmann.org>
To:     Jia-Ju Bai <baijiaju1990@...il.com>
Cc:     "Gustavo F. Padovan" <gustavo@...ovan.org>,
        Johan Hedberg <johan.hedberg@...il.com>,
        linux-bluetooth@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] bluetooth: btmrvl_main: Replace GFP_ATOMIC with
 GFP_KERNEL in btmrvl_send_sync_cmd

Hi Jia-Ju,

> After checking all possible call chains to btmrvl_send_sync_cmd(), 
> 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 wait_event_interruptible_timeout() after bt_skb_alloc(), 
> so it indicates that btmrvl_send_sync_cmd() 
> 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/bluetooth/btmrvl_main.c |    2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)

patch has been applied to bluetooth-next tree.

Regards

Marcel