Re: [PATCH v3] scripts: checkpatch.pl: add 2 new checks on memset

[Aya Mahfouz <mahfouz.saif.elyazal@gmail.com>]

On Sun, Mar 01, 2015 at 02:13:21PM -0800, Joe Perches wrote:
> On Sun, 2015-03-01 at 23:43 +0200, Aya Mahfouz wrote:
> > calls 
> > Reply-To: 
> > 
> > Add 2 new checks on memset calls in the file checkpatch.pl as follows:
> 
> Hi again Aya
> 
> The initial 3 lines here aren't necessary.
> 
> I think it'd be a better subject line with something like
> "checkpatch: prefer eth_<foo>_addr over memset(,,ETH_ALEN)"
> 
ok, should I resend it as a fresh patch or send the patch with a new
subject line and state that it is v4?

> Please cc Andrew Morton <akpm@linux-foundation.org>
> And please also don't add Signed-off-by: lines for
> anyone other than yourself.
>
ok, I will cc Andrew. As for your tag, I couldn't take credit
for the regex that I did not write. Will not do it in the future again
unless the other side agrees to it.

> Other than those things:
> Acked-by: Joe Perches <joe@perches.com>
> 
> > 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.
> > 
> > In addition, the regex assigned to the variable $stat has been
> > restricted to handle memset function calls of the form:
> > [<identifer> =]* memset(<arg1>, <arg2>, <arg3>)
> > 
> > Cc: Julia Lawall <julia.lawall@lip6.fr>
> > Signed-off-by: Aya Mahfouz <mahfouz.saif.elyazal@gmail.com>
> > Signed-off-by: Joe Perches <joe@perches.com>
> > ---
> > v2: adjusted all checks on memset calls to be in one body
> > v3: adjusted all regular expressions per Joe Perches suggestions. Added
> > a Signed-off-by tag for Joe since all the important regular expressions
> > are written by him.
> > 
> >  scripts/checkpatch.pl | 17 +++++++++++++++--
> >  1 file changed, 15 insertions(+), 2 deletions(-)
> > 
> > diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> > index d124359..cbe973e 100755
> > --- a/scripts/checkpatch.pl
> > +++ b/scripts/checkpatch.pl
> > @@ -4890,10 +4890,11 @@ sub process {
> >  			}
> >  		}
> >  
> > -# Check for misused memsets
> > +# Check for misused memsets then check for memset(foo, 0x00|0xff, ETH_ALEN)
> > +# calls that could be eth_zero_addr(foo)|eth_broadcast_addr(foo)
> >  		if ($^V && $^V ge 5.10.0 &&
> >  		    defined $stat &&
> > -		    $stat =~ /^\+(?:.*?)\bmemset\s*\(\s*$FuncArg\s*,\s*$FuncArg\s*\,\s*$FuncArg\s*\)/s) {
> > +		    $stat =~ /^\+(?:\s*$Ident\s*=)?\s*memset\s*\(\s*$FuncArg\s*,\s*$FuncArg\s*\,\s*$FuncArg\s*\)/s) {
> >  
> >  			my $ms_addr = $2;
> >  			my $ms_val = $7;
> > @@ -4905,6 +4906,18 @@ sub process {
> >  			} elsif ($ms_size =~ /^(0x|)1$/i) {
> >  				WARN("MEMSET",
> >  				     "single byte memset is suspicious. Swapped 2nd/3rd argument?\n" . "$here\n$stat\n");
> > +			} elsif ($ms_val =~ /^(?:0x)?0+$/i &&
> > +				 $ms_size =~ /^ETH_ALEN$/ &&
> > +				 WARN("PREFER_ETH_ADDR",
> > +				     "Prefer eth_zero_addr() over memset() if the second address is 0\n" . $herecurr) &&
> > +				 $fix) {
> > +				$fixed[$fixlinenr] =~ s/\bmemset\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",
> > +				      "Prefer eth_broadcast_addr() over memset() if the second address is 0xff\n" . $herecurr) &&
> > +				 $fix) {
> > +				$fixed[$fixlinenr] =~ s/\bmemset\s*\(\s*\Q$ms_addr\E\s*,\s*\Q$ms_val\E\s*,\s*ETH_ALEN\s*\)/eth_broadcast_addr($ms_addr)/;
> >  			}
> >  		}
> >  
> > -- 
> > 1.9.3
> > 
> > 
> 
> 
> 

-- 
Kind Regards,
Aya Saif El-yazal Mahfouz