Re: [Cocci] Checking the replacement of two specific function calls

From: Julia Lawall <julia.lawall@inria.fr>
To: Markus Elfring <Markus.Elfring@web.de>
Cc: Dejin Zheng <zhengdejin5@gmail.com>, Coccinelle <cocci@systeme.lip6.fr>
Subject: Re: [Cocci] Checking the replacement of two specific function calls
Date: Wed, 15 Apr 2020 19:52:17 +0200 (CEST)	[thread overview]
Message-ID: <alpine.DEB.2.21.2004151949230.2381@hadrien> (raw)
In-Reply-To: <25b804fd-0d04-475d-f614-26c03c9fd544@web.de>

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On Wed, 15 Apr 2020, Markus Elfring wrote:

> Hello,
>
> I noticed the suggestion “i2c: busses: convert to devm_platform_get_and_ioremap_resource”.
> https://lore.kernel.org/linux-i2c/20200414134827.18674-1-zhengdejin5@gmail.com/
> https://lore.kernel.org/patchwork/patch/1223734/
>
> I got into the mood to try another script out for the semantic patch language.
>
>
> @replacement@
> expression* base, device, resource;
> @@
> -resource = platform_get_resource(device, IORESOURCE_MEM, 0);
>  base =
> -       devm_ioremap_resource(&device->dev, resource)
> +       devm_platform_get_and_ioremap_resource(device, 0, &resource)
>  ;
>
>
> Source file example:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/i2c/busses/i2c-rcar.c?id=8632e9b5645bbc2331d21d892b0d6961c1a08429#n921
> https://elixir.bootlin.com/linux/v5.7-rc1/source/drivers/i2c/busses/i2c-rcar.c#L921
>
> // SPDX-License-Identifier: GPL-2.0
> // deleted part
> static int rcar_i2c_probe(struct platform_device *pdev)
> {
> 	struct rcar_i2c_priv *priv;
> 	struct i2c_adapter *adap;
> 	struct device *dev = &pdev->dev;
> // deleted part
> 	priv->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>
> 	priv->io = devm_ioremap_resource(dev, priv->res);
> 	if (IS_ERR(priv->io))
> 		return PTR_ERR(priv->io);
> // deleted part
> }
> // deleted part
>
>
> Now I wonder why the expected patch is not generated by the software
> “Coccinelle 1.0.8-00029-ga549b9f0” at the moment.
> How should this situation be improved?

Probably Coccinelle is not able to determine that priv->res and priv->io
are pointers, if you have not given it enough encouragement to look for
header files to find the defintion of the type of the priv structure.

I don't think that there is any need for the * in the metavariable
declaration.  If the various expressions are not pointers, the C compiler
would have complained.

julia

>
> Regards,
> Markus
> _______________________________________________
> Cocci mailing list
> Cocci@systeme.lip6.fr
> https://systeme.lip6.fr/mailman/listinfo/cocci
>

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