2012-11-17 18:54:29

by Constantine Shulyupin

Subject: [PATCH v3] checkpatch: debugfs_remove() can take NULL

From: Constantine Shulyupin <[email protected]>

debugfs_remove() and debugfs_remove_recursive() can take a NULL, so let's check and warn about that.

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 consolidates

Signed-off-by: Constantine Shulyupin <[email protected]>
---
scripts/checkpatch.pl | 23 ++++++++++++++++-------
1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index f18750e..c041e97 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3213,21 +3213,30 @@ 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" . $hereprev);
+ }
+# check for needless debugfs_remove_recursive() and debugfs_remove_recursive*() checks
+ if ($line =~ /\b(debugfs_remove_recursive(?:_recursive)?)$expr/) {
+ WARN("NEEDLESS_DEBUGFS_REMOVE_RECURSIVE",
+ "$1(NULL) is safe this check is probably not required\n" . $hereprev);
+ }
}

# prefer usleep_range over udelay
--
1.7.9.5

2012-11-17 19:00:47

by Joe Perches

Subject: Re: [PATCH v3] checkpatch: debugfs_remove() can take NULL

On Sat, 2012-11-17 at 20:54 +0200, Constantine Shulyupin wrote:
> From: Constantine Shulyupin <[email protected]>

Hi Constantine.

> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> +# 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);
> + }

OK,

> +# check for needless debugfs_remove_recursive() and debugfs_remove_recursive*() checks
> + if ($line =~ /\b(debugfs_remove_recursive(?:_recursive)?)$expr/) {
> + WARN("NEEDLESS_DEBUGFS_REMOVE_RECURSIVE",
> + "$1(NULL) is safe this check is probably not required\n" . $hereprev);
> + }

You don't need thus second block.
The first check finds both
debugfs_remove(foo)
and
debugfs_remove_recursive(bar)

The second one is redundant