Re: [PATCH 6/7] media: cedrus: Add infra for extra buffers connected to capture buffers

From: Maxime Ripard <maxime.ripard@bootlin.com>
To: "Jernej Škrabec" <jernej.skrabec@siol.net>
Cc: paul.kocialkowski@bootlin.com, wens@csie.org, mchehab@kernel.org,
	gregkh@linuxfoundation.org, linux-media@vger.kernel.org,
	devel@driverdev.osuosl.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 6/7] media: cedrus: Add infra for extra buffers connected to capture buffers
Date: Thu, 6 Jun 2019 10:33:07 +0200	[thread overview]
Message-ID: <20190606083307.b5zpk4n6x3w6mtmb@flea> (raw)
In-Reply-To: <3029072.frl2UAsRGt@jernej-laptop>

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On Mon, Jun 03, 2019 at 05:48:25PM +0200, Jernej Škrabec wrote:
> Dne ponedeljek, 03. junij 2019 ob 14:18:59 CEST je Maxime Ripard napisal(a):
> > > +static void cedrus_buf_cleanup(struct vb2_buffer *vb)
> > > +{
> > > +	struct vb2_queue *vq = vb->vb2_queue;
> > > +
> > > +	if (!V4L2_TYPE_IS_OUTPUT(vq->type)) {
> > > +		struct cedrus_ctx *ctx = vb2_get_drv_priv(vq);
> > > +		struct cedrus_buffer *cedrus_buf;
> > > +
> > > +		cedrus_buf = vb2_to_cedrus_buffer(vq->bufs[vb->index]);
> > > +
> > > +		if (cedrus_buf->extra_buf_size)
> > > +			dma_free_coherent(ctx->dev->dev,
> > > +					  cedrus_buf-
> >extra_buf_size,
> > > +					  cedrus_buf-
> >extra_buf,
> > > +					  cedrus_buf-
> >extra_buf_dma);
> > > +	}
> > > +}
> > > +
> >
> > I'm really not a fan of allocating something somewhere, and freeing it
> > somewhere else. Making sure you don't leak something is hard enough to
> > not have some non-trivial allocation scheme.
>
> Ok, what about introducing two new optional methods in engine callbacks,
> buffer_init and buffer_destroy, which would be called from cedrus_buf_init() and
> cedrus_buf_cleanup(), respectively. That way all (de)allocation logic stays
> within the same engine.

Yep, that would work for me.

Thanks!
Maxime

--
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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