Message-ID: <1393275606.11020.59.camel@joe-AO722>
Subject: Re: [PATCH] checkpatch.pl: Add warning for new __packed additions
From: Joe Perches <joe@perches.com>
To: Tom Rini <trini@ti.com>
Cc: linux-kernel@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>,
        Josh Triplett <josh@joshtriplett.org>
Date: Mon, 24 Feb 2014 13:00:06 -0800
In-Reply-To: <1393274296-26179-1-git-send-email-trini@ti.com>
References: <1393274296-26179-1-git-send-email-trini@ti.com>
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On Mon, 2014-02-24 at 15:38 -0500, Tom Rini wrote:
> While there are valid reasons to use __packed, often the answer is that
> you should be doing something else here instead.
[]
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> @@ -4010,6 +4010,11 @@ sub process {
>  			WARN("PREFER_PACKED",
>  			     "__packed is preferred over __attribute__((packed))\n" . $herecurr);
>  		}
> +# Check for new packed usage, warn to use care
> +		if ($line =~ /\b(__attribute__\s*\(\s*\(.*\bpacked|__packed)\b/) {
> +			WARN("NEW_PACKED",
> +			     "Adding new packed members is to be done with care\n" . $herecurr);
> +		}

Hi Tom.

This might be too noisy as it will warn on any use of __packed,
including existing ones if checking using -f/--file.

(there are some odd, probably broken ones in drivers/char/tpm/tpm_acpi.c)

How often is this actually a problem?

It'll warn on any use of packed not just packed members.

This may be better as
	"Using 'packed' can impact performance\n"
and only tested when not in --file mode.


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