From: "Manoharan, Rajkumar" <rmanohar@qti.qualcomm.com>
To: "greearb@candelatech.com" <greearb@candelatech.com>,
"ath10k@lists.infradead.org" <ath10k@lists.infradead.org>
Cc: "linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>
Subject: Re: [PATCH 2/3] ath10k: Grab rcu_read_lock before the txqs spinlock.
Date: Fri, 19 Aug 2016 03:01:14 +0000 [thread overview]
Message-ID: <1471575674214.65791@qti.qualcomm.com> (raw)
In-Reply-To: <1471569995-10028-2-git-send-email-greearb@candelatech.com>
> diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless=
/ath/ath10k/mac.c=0A=
> index 916119c..d96c06e 100644=0A=
> --- a/drivers/net/wireless/ath/ath10k/mac.c=0A=
> +++ b/drivers/net/wireless/ath/ath10k/mac.c=0A=
> @@ -4307,8 +4307,8 @@ void ath10k_mac_tx_push_pending(struct ath10k *ar)=
=0A=
> int max;=0A=
> int loop_max =3D 2000;=0A=
> =0A=
> - spin_lock_bh(&ar->txqs_lock);=0A=
> rcu_read_lock();=0A=
> + spin_lock_bh(&ar->txqs_lock);=0A=
>=0A=
Ben,=0A=
=0A=
It is quite possible that push_pending can be preempted after acquiring rcu=
_lock which=0A=
may lead to deadlock. no? I assume to prevent that spin_lock is taken first=
. =0A=
=0A=
Could you please explain how this reordering is fixing dead lock?=0A=
=0A=
-Rajkumar=
next prev parent reply other threads:[~2016-08-19 3:02 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-19 1:26 [PATCH 1/3] ath10k: Ensure there are no stale ar->txqs entries greearb
2016-08-19 1:26 ` [PATCH 2/3] ath10k: Grab rcu_read_lock before the txqs spinlock greearb
2016-08-19 3:01 ` Manoharan, Rajkumar [this message]
2016-08-19 3:28 ` Ben Greear
2016-09-09 13:36 ` Valo, Kalle
2016-09-09 14:47 ` Ben Greear
2016-09-12 6:41 ` Johannes Berg
2016-09-12 16:37 ` Ben Greear
2016-08-19 1:26 ` [PATCH 3/3] ath10k: Improve logging message greearb
2016-08-19 6:35 ` Mohammed Shafi Shajakhan
2016-09-09 13:30 ` Valo, Kalle
2016-09-13 12:29 ` [3/3] " Kalle Valo
2016-08-19 6:59 ` [PATCH 1/3] ath10k: Ensure there are no stale ar->txqs entries Michal Kazior
2016-08-19 13:34 ` Ben Greear
2016-12-01 22:52 ` Ben Greear
2016-12-02 0:24 ` Ben Greear
2016-12-05 8:50 ` Michal Kazior
2016-12-05 18:19 ` Ben Greear
2016-09-09 17:25 ` Felix Fietkau
2016-09-09 17:46 ` Ben Greear
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