From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932648AbaHVSFe (ORCPT ); Fri, 22 Aug 2014 14:05:34 -0400 Received: from mail-pd0-f179.google.com ([209.85.192.179]:51656 "EHLO mail-pd0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932410AbaHVSFd (ORCPT ); Fri, 22 Aug 2014 14:05:33 -0400 From: Andy Lutomirski To: "Michael Kerrisk (man-pages)" , Andy Whitcroft , Joe Perches Cc: linux-kernel@vger.kernel.org, Andy Lutomirski Subject: [PATCH v3] checkpatch.pl: New instances of ENOSYS are errors Date: Fri, 22 Aug 2014 11:05:25 -0700 Message-Id: <5eb299021dec23c1a48fa7d9f2c8b794e967766d.1408730669.git.luto@amacapital.net> X-Mailer: git-send-email 1.9.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ENOSYS means that a nonexistent system call was called. We have a bad habit of using it for things like invalid operations on otherwise valid syscalls. We should avoid this in new code. Signed-off-by: Andy Lutomirski --- Pervasive incorrect usage of ENOSYS came up at the kernel summit ABI review discussion. Let's see if checkpatch can help. I'll submit a separate patch for include/uapi/asm-generic/errno.h. Changes from v2: - Reduce severity to WARN. - Remove unnecessary clarification. - Rebase onto Linus' tree instead of v3.16. Changes from v1: - Moved later so that it won't warn on context lines. - Use $herecur. - Improve regex pattern. scripts/checkpatch.pl | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index 31a731e..448d075 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -3214,6 +3214,14 @@ sub process { "Prefer dev_$level(... to dev_printk(KERN_$orig, ...\n" . $herecurr); } +# ENOSYS means "bad syscall nr" and nothing else. This will have a small +# number of false positives, but assembly files are not checked, so at +# least the arch entry code will not trigger this warning. + if ($line =~ /\bENOSYS\b/) { + WARN("ENOSYS", + "ENOSYS means 'invalid syscall nr' and nothing else\n" . $herecurr); + } + # function brace can't be on same line, except for #defines of do while, # or if closed on same line if (($line=~/$Type\s*$Ident\(.*\).*\s*{/) and -- 1.9.3