checkpatch: usb_free_urb() can take NULL

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

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 13d7a33..a4e8087 100755 (executable)
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2078,6 +2078,13 @@ sub process {
                                WARN("kfree(NULL) is safe this check is probabally not required\n" . $hereprev);
                        }
                }
+# check for needless usb_free_urb() checks
+               if ($prevline =~ /\bif\s*\(([^\)]*)\)/) {
+                       my $expr = $1;
+                       if ($line =~ /\busb_free_urb\(\Q$expr\E\);/) {
+                               WARN("usb_free_urb(NULL) is safe this check is probably not required\n" . $hereprev);
+                       }
+               }
 
 # warn about #ifdefs in C files
 #              if ($line =~ /^.\s*\#\s*if(|n)def/ && ($realfile =~ /\.c$/)) {