linux-kernel - Re: drm/i915/gvt: Use common error handling code in shadow_workload_ring_buffer()

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Message-Id: <1A433E6A-DE06-4407-9E33-3CBBA4ADF01B@gmail.com>
Date:   Tue, 24 Oct 2017 09:54:58 -0400
From:   Garry Hurley <garry.hurley.jr@...il.com>
To:     SF Markus Elfring <elfring@...rs.sourceforge.net>
Cc:     Jani Nikula <jani.nikula@...ux.intel.com>,
        dri-devel@...ts.freedesktop.org, intel-gfx@...ts.freedesktop.org,
        intel-gvt-dev@...ts.freedesktop.org,
        Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
        kernel-janitors@...r.kernel.org,
        LKML <linux-kernel@...r.kernel.org>,
        Rodrigo Vivi <rodrigo.vivi@...el.com>,
        Zhi Wang <zhi.a.wang@...el.com>
Subject: Re: drm/i915/gvt: Use common error handling code in shadow_workload_ring_buffer()

Markus, 

I normally keep quiet on threads like this. I half agree with you. Yes, perhaps a reportError function would be a good idea, but it seems that what you are suggesting is trading an inline subroutine call for a spaghetti-code vondition. The goto is used only if you do not have any code that follows, and what you are taking out is a function call that DOES return execution flow to the calling block. You are replacing it with a goto call which does not return execution flow. The risks of process termination during a goto call make it a bad idea. In this case, the subroutine call is the right move. If the reuse of the error message bothers you, perhaps it is a good candidate for a static string definition, so that if it is changed it can be changed in one location in the code. The tradeoff there is that the static string definition will eat a few bytes of memory from the variable storage. Just my perspective. I could be wrong. 

Sent from my iPhone

On Oct 24, 2017, at 9:17 AM, SF Markus Elfring <elfring@...rs.sourceforge.net> wrote:

>>> Add a jump target so that a call of the function "gvt_vgpu_err" is stored
>>> only once at the end of this function implementation.
>>> Replace two calls by goto statements.
>>> 
>>> This issue was detected by using the Coccinelle software.
>> 
>> I don't think this is an issue or an improvement.
> 
> Do you care for the detail how often an error message is stored in the code?
> 
> Regards,
> Markus
> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

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