Date:   Mon, 10 Jan 2022 15:10:07 +0000
From:   Mark Brown <broonie@kernel.org>
To:     Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Cc:     Liam Girdwood <lgirdwood@gmail.com>,
        Jaroslav Kysela <perex@perex.cz>,
        Takashi Iwai <tiwai@suse.com>,
        Biju Das <biju.das.jz@bp.renesas.com>,
        Pavel Machek <pavel@denx.de>,
        linux-renesas-soc@vger.kernel.org,
        Prabhakar <prabhakar.csengg@gmail.com>,
        alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 5/5] ASoC: sh: rz-ssi: Add functions to get/set substream
 pointer
Message-ID: <YdxMT02wvvWw85Bn@sirena.org.uk>
References: <20220110094711.8574-1-prabhakar.mahadev-lad.rj@bp.renesas.com>
 <20220110094711.8574-6-prabhakar.mahadev-lad.rj@bp.renesas.com>
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On Mon, Jan 10, 2022 at 09:47:11AM +0000, Lad Prabhakar wrote:

> +static struct snd_pcm_substream *rz_ssi_get_substream(struct rz_ssi_stream *strm)
> +{
> +	struct rz_ssi_priv *ssi = strm->priv;
> +	struct snd_pcm_substream *substream;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&ssi->lock, flags);
> +	substream = strm->substream;
> +	spin_unlock_irqrestore(&ssi->lock, flags);

This locking doesn't seem useful, we just take a copy of the lock and
then immediately return so the lock isn't protecting anything in
particular - the caller can happily continue using the substream after
the variable has been updated.

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