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Subject: Re: [RESEND PATCH v5 3/5] drivers core: allow probe_err accept
 integer and pointer types
To:     Robin Murphy <robin.murphy@arm.com>,
        Mark Brown <broonie@kernel.org>
Cc:     Jernej Skrabec <jernej.skrabec@siol.net>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jonas Karlman <jonas@kwiboo.se>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "open list:DRM DRIVERS" <dri-devel@lists.freedesktop.org>,
        Russell King - ARM Linux <linux@armlinux.org.uk>,
        Neil Armstrong <narmstrong@baylibre.com>,
        Andy Shevchenko <andy.shevchenko@gmail.com>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        linux-arm Mailing List <linux-arm-kernel@lists.infradead.org>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
From:   Andrzej Hajda <a.hajda@samsung.com>
Message-ID: <70b61b75-c68b-ad89-5f6a-f1d681b9f5d0@samsung.com>
Date:   Wed, 24 Jun 2020 21:39:57 +0200
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On 24.06.2020 17:16, Robin Murphy wrote:
> On 2020-06-24 16:04, Mark Brown wrote:
>> On Wed, Jun 24, 2020 at 03:25:33PM +0100, Robin Murphy wrote:
>>
>>> And yeah, anyone who pipes up suggesting that places where an 
>>> ERR_PTR value
>>> could be passed to probe_err() could simply refactor IS_ERR() checks 
>>> with
>>> more uses of the god-awful PTR_ERR_OR_ZERO() obfuscator gets a long 
>>> stare of
>>> disapproval...
>>
>> We could also have a probe_err_ptr() or something that took an ERR_PTR()
>> instead if there really were an issue with explicitly doing this.
>
> Yeah, for all my lyrical objection, a static inline <blah>_ptr_err() 
> helper to wrap <blah>_err() with sensible type checking might actually 
> be an OK compromise if people really feel strongly for having that 
> utility.


I have proposed such thing in my previous iteration[1], except it was 
macro because of variadic arguments.

With current version we save 8 chars and hacky macro, with the old 
version we save only 4 chars and more clear construct - less tempting 
solution for me.

Personally I prefer the current version - it does not seems to me more 
dangerous than all these PTR_ERR, IS_ERR,ERR_PTR helpers, but can 
prevent expression split across  multiple lines due to 80char limit.

Probably the simplest solution is to drop this patch, I will do it then.

[1]: 
https://lwn.net/ml/linux-kernel/20181220102247.4911-4-a.hajda@samsung.com/


Regards

Andrzej


>
> (and then we can debate whether it should also convert NULL to -ENOMEM 
> and !IS_ERR to 0... :D)
>
> Robin.
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