linux-kernel - Re: [PATCH] scripts: checkpatch.pl: add 2 new checks on memset calls

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Date:	Mon, 23 Feb 2015 19:06:27 -0800
From:	Joe Perches <joe@...ches.com>
To:	Aya Mahfouz <mahfouz.saif.elyazal@...il.com>
Cc:	Andy Whitcroft <apw@...onical.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] scripts: checkpatch.pl: add 2 new checks on memset calls

On Mon, 2015-02-23 at 21:18 +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.
> 
> replace memset by eth_broadcast_addr if the second argument is
> the broadcast address (0xff). eth_broadcast_addr is a wrapper
> function for memset that sets the passed array the broadcast
> address. The size of the address has to be ETH_ALEN.

Hello Aya.

Good idea but:

there already is a test for memset at (-next) line 4893.

Please extend that as below instead of adding another test.

> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> @@ -4918,6 +4918,25 @@ sub process {
>  			}
>  		}
>  
> +# Check for memset(foo, 0x00|0xff, ETH_ALEN) that could be eth_zero_addr(foo)|eth_broadcast_addr(foo)
> +		if ($^V && $^V ge 5.10.0 &&
> +		    $line =~ /^\+(?:.*?)\bmemset\s*\(\s*$FuncArg\s*,\s*$FuncArg\s*\,\s*ETH_ALEN\s*\)/s) {
> +			my $num = $7;
> +			if ($num =~ "0x00" && WARN("PREFER_ETH_ZERO_ADDR",

# Check for misused memsets
		if ($^V && $^V ge 5.10.0 &&
		    defined $stat &&
		    $stat =~ /^\+(?:.*?)\bmemset\s*\(\s*$FuncArg\s*,\s*$FuncArg\s*\,\s*$FuncArg\s*\)/s) {

			my $ms_addr = $2;
			my $ms_val = $7;
			my $ms_size = $12;

			if ($ms_val =~ /^(?:0|0x0+)$/i &&
			    $ms_size =~ /^ETH_ALEN$/ &&
			    WARN("PREFER_ETH_ADDR_FUNC",
				 "..." . herecurr) &&
			    $fix) {
				$fixed[$fixlinenr] =~ s/\bmemcpy\s*\(\s*\Q$ms_addr\E\s*,\s*\Q$ms_val\E\s*\,\s*ETH_ALEN\s*\)/eth_zero_addr($ms_addr)/;
			} elsif ($ms_val =~ /^(?:0xff|255)$/i &&
				 $ms_size =~ /^ETH_ALEN$/ &&
				 WARN("PREFER_ETH_ADDR_FUNC",
				      "..." . herecurr) &&
				 $fix) {
				$fixed[$fixlinenr] =~ s/\bmemcpy\s*\(\s*\Q$ms_addr\E\s*,\s*\Q$ms_val\E\s*\,\s*ETH_ALEN\s*\)/eth_broadcast_addr($ms_addr)/;
			} elsif (...)


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