Re: [RFC PATCH] component: Add common helpers for compare/release functions

From: Yong Wu via iommu <iommu@lists.linux-foundation.org>
To: Robin Murphy <robin.murphy@arm.com>, <dri-devel@lists.freedesktop.org>
Cc: David Airlie <airlied@linux.ie>,
	Liviu Dudau <liviu.dudau@arm.com>,
	Sebastian Reichel <sre@kernel.org>,
	Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Will Deacon <will@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
	James Wang <james.qian.wang@arm.com>,
	Chun-Kuang Hu <chunkuang.hu@kernel.org>,
	Arnd Bergmann <arnd@arndb.de>,
	linux-mediatek@lists.infradead.org,
	Hsin-Yi Wang <hsinyi@chromium.org>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	linux-arm-kernel@lists.infradead.org,
	AngeloGioacchino Del Regno
	<angelogioacchino.delregno@collabora.com>,
	srv_heupstream@mediatek.com, Stephen Boyd <sboyd@kernel.org>,
	linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
	Daniel Vetter <daniel@ffwll.ch>
Subject: Re: [RFC PATCH] component: Add common helpers for compare/release functions
Date: Thu, 10 Feb 2022 15:49:53 +0800	[thread overview]
Message-ID: <face7ccf80520ecad1b75f01f74314ddb483b88b.camel@mediatek.com> (raw)
In-Reply-To: <29deffd6-aac4-f085-bcd5-f5a2d02784a8@arm.com>

On Fri, 2022-01-28 at 13:04 +0000, Robin Murphy wrote:
> On 2022-01-28 08:11, Yong Wu wrote:
> [...]
> > diff --git a/include/linux/component.h b/include/linux/component.h
> > index 16de18f473d7..5a7468ea827c 100644
> > --- a/include/linux/component.h
> > +++ b/include/linux/component.h
> > @@ -2,6 +2,8 @@
> >   #ifndef COMPONENT_H
> >   #define COMPONENT_H
> >   
> > +#include <linux/device.h>
> > +#include <linux/of.h>
> >   #include <linux/stddef.h>
> >   
> >   
> > @@ -82,6 +84,22 @@ struct component_master_ops {
> >   	void (*unbind)(struct device *master);
> >   };
> >   
> > +/* A set common helpers for compare/release functions */
> > +static inline int compare_of(struct device *dev, void *data)
> > +{
> > +	return dev->of_node == data;
> > +}
> 
> Note that this is effectively just device_match_of_node(), although
> I 
> guess there is an argument that having a nice consistent set of 
> component_match API helpers might be worth more than a tiny code
> saving 
> by borrowing one from a different API.

Thanks for this tip. I could try use this, Let the maintainer decide.

> 
> Either way, however, I don't think there's any good argument for 
> instantiating separate copies of these functions in every driver
> that 
> uses them. If they're used as callbacks then they can't actually be 
> inlined anyway, so they may as well be exported from component.c as 

oh. The MTK iommu keeps this inline for long time... OK, I will try
to move into the component.c and export them.

(Sorry for the late reply due to New Year holidays.)

> normal so that the code really is shared (plus then there's nice 
> symmetry with the aforementioned device_match API helpers too).
> 
> Thanks,
> Robin.

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