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

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Message-ID: <20190606083307.b5zpk4n6x3w6mtmb@flea>
Date:   Thu, 6 Jun 2019 10:33:07 +0200
From:   Maxime Ripard <maxime.ripard@...tlin.com>
To:     Jernej Škrabec <jernej.skrabec@...l.net>
Cc:     paul.kocialkowski@...tlin.com, wens@...e.org, mchehab@...nel.org,
        gregkh@...uxfoundation.org, linux-media@...r.kernel.org,
        devel@...verdev.osuosl.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 6/7] media: cedrus: Add infra for extra buffers connected
 to capture buffers

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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