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

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Date:	Wed, 25 Feb 2015 04:53:37 +0200
From:	Aya Mahfouz <mahfouz.saif.elyazal@...il.com>
To:	Joe Perches <joe@...ches.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, Feb 23, 2015 at 07:06:27PM -0800, Joe Perches wrote:
> 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.
> 

Hello Joe,

I've adjusted the checks as you requested. Kindly let me know if there
is something else that should be done.

Kind Regards,
Aya Saif El-yazal Mahfouz

> > 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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