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Date:   Tue, 30 Aug 2022 14:29:08 +0200
From:   Andrew Lunn <andrew@lunn.ch>
To:     =?iso-8859-1?B?Q3Pza+Fz?= Bence <csokas.bence@prolan.hu>
Cc:     netdev@vger.kernel.org, Richard Cochran <richardcochran@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, qiangqing.zhang@nxp.com,
        kernel@pengutronix.de, Marc Kleine-Budde <mkl@pengutronix.de>
Subject: Re: [PATCH v2] net: fec: Use unlocked timecounter reads for saving
 state
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> -	fec_ptp_gettime(&fep->ptp_caps, &fep->ptp_saved_state.ts_phc);
> +	if (preempt_count_equals(0)) {

~/linux/drivers$ grep -r preempt_count_equals *
~/linux/drivers$ 

No other driver plays games like this.

Why not unconditionally take the lock?

    Andrew