Message-ID: <1424833852.11070.1.camel@perches.com>
Subject: Re: [PATCH v2] scripts: checkpatch.pl: add 2 new checks on memset
 calls
From: Joe Perches <joe@perches.com>
To: Aya Mahfouz <mahfouz.saif.elyazal@gmail.com>
Cc: Andy Whitcroft <apw@canonical.com>, linux-kernel@vger.kernel.org
Date: Tue, 24 Feb 2015 19:10:52 -0800
In-Reply-To: <20150225024043.GA9120@localhost.localdomain>
References: <20150225024043.GA9120@localhost.localdomain>
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On Wed, 2015-02-25 at 04:40 +0200, Aya Mahfouz wrote:
> This patch adds 2 new checks on memset calls in the file
> checkpatch.pl as follows:
> 
> replace memset by eth_zero_addr if the second argument is
> an address of zeros (0x00). eth_zero_addr is a wrapper function
> for memset that takes an address array to set as zero. The size
> address has to be ETH_ALEN.

[]
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> @@ -4901,10 +4901,22 @@ sub process {
>  
>  			if ($ms_size =~ /^(0x|)0$/i) {
>  				ERROR("MEMSET",
> -				      "memset to 0's uses 0 as the 2nd argument, not the 3rd\n" . "$here\n$stat\n");
> +				      "memset to 0's uses 0 as the 2nd argument, not the 3rd\n" . "$here\n$line\n");
>  			} elsif ($ms_size =~ /^(0x|)1$/i) {
>  				WARN("MEMSET",
> -				     "single byte memset is suspicious. Swapped 2nd/3rd argument?\n" . "$here\n$stat\n");
> +				     "single byte memset is suspicious. Swapped 2nd/3rd argument?\n" . "$here\n$line\n");
> +			} elsif ($ms_size =~ /^ETH_ALEN/i) {
> +				if ($ms_val =~ /^0x00/i && WARN("PREFER_ETH_ZERO_ADDR",

This isn't right.  Look again at what I suggested.

This would match 0x00ff and wouldn't match 0

> +					 "Prefer eth_zero_addr() over memset() if the second address is 0x00\n" . $herecurr) &&
> +				    $fix) {
> +
> +					$fixed[$fixlinenr] =~ s/\bmemset\s*\(\s*$FuncArg\s*,\s*$FuncArg\s*\,\s*ETH_ALEN\s*\)/eth_zero_addr($ms_addr)/;
> +				} elsif ($ms_val =~ /^0xff/i && WARN("PREFER_ETH_BROADCAST_ADDR",
> +					 "Prefer eth_broadcast_addr() over memset() if the second address is 0xff\n" . $herecurr) &&
> +				    $fix) {
> +
> +					$fixed[$fixlinenr] =~ s/\bmemset\s*\(\s*$FuncArg\s*,\s*$FuncArg\s*\,\s*ETH_ALEN\s*\)/eth_broadcast_addr($ms_addr)/;
> +				}
>  			}
>  		}
>  


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