Re: [PATCH v4] checkpatch: debugfs_remove() can take NULL

[Andy Whitcroft]

On Sun, Nov 18, 2012 at 12:20:18AM +0200, Constantine Shulyupin wrote:
> From: Constantine Shulyupin <const@xxxxxxxxxxxxx>
> 
> debugfs_remove() and  debugfs_remove_recursive() can take a NULL, so let's check and warn about that.
> 
> Changes since v3, as Joe Perches suggested:
> - removed redundant check
> 
> Changes since v2, as Joe Perches suggested:
> - match whitespace around argument
> 
> Changes since v1, as Joe Perches suggested:
> - added debugfs_remove_recursive
> - all tests for patterns are "if (a) xxx(a)" are consolidated
> 
> Signed-off-by: Constantine Shulyupin <const@xxxxxxxxxxxxx>
> ---
>  scripts/checkpatch.pl |   18 +++++++++++-------
>  1 file changed, 11 insertions(+), 7 deletions(-)
> 
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index f18750e..76ad9f2 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -3213,21 +3213,25 @@ sub process {
>  				$herecurr);
>  		}
>  
> +# check for needless "if (<foo>) fn(<foo>)" uses
> +		if ($prevline =~ /\bif\s*\(\s*($Lval)\s*\)/) {
> +			my $expr = '\s*\(\s*' . quotemeta($1) . '\s*\)\s*;';
> +
>  # check for needless kfree() checks
> -		if ($prevline =~ /\bif\s*\(([^\)]*)\)/) {
> -			my $expr = $1;
> -			if ($line =~ /\bkfree\(\Q$expr\E\);/) {
> +			if ($line =~ /\bkfree$expr/) {
>  				WARN("NEEDLESS_KFREE",
>  				     "kfree(NULL) is safe this check is probably not required\n" . $hereprev);
>  			}
> -		}
>  # check for needless usb_free_urb() checks
> -		if ($prevline =~ /\bif\s*\(([^\)]*)\)/) {
> -			my $expr = $1;
> -			if ($line =~ /\busb_free_urb\(\Q$expr\E\);/) {
> +			if ($line =~ /\busb_free_urb$expr/) {
>  				WARN("NEEDLESS_USB_FREE_URB",
>  				     "usb_free_urb(NULL) is safe this check is probably not required\n" . $hereprev);
>  			}
> +# check for needless debugfs_remove() and debugfs_remove_recursive*() checks
> +			if ($line =~ /\b(debugfs_remove(?:_recursive)?)$expr/) {
> +				WARN("NEEDLESS_DEBUGFS_REMOVE",
> +				     "$1(NULL) is safe this check is probably not required\n" . $hereprev);
> +			}
>  		}
>  
>  # prefer usleep_range over udelay

This all looks sensible, though we still have three blocks doing the
same thing.  How about we standardise this check into a single check,
generating the capacity from the matched name.

Something like the below on top of V4.

-apw