From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754939Ab1JRGve (ORCPT ); Tue, 18 Oct 2011 02:51:34 -0400 Received: from ozlabs.org ([203.10.76.45]:36769 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752360Ab1JRGvd (ORCPT ); Tue, 18 Oct 2011 02:51:33 -0400 From: Rusty Russell To: Michal Schmidt Cc: linux-kernel@vger.kernel.org, Randy Dunlap Subject: Re: [PATCH] params: make dashes and underscores in parameter names truly equal In-Reply-To: <4E96F887.5050103@redhat.com> References: <1318197817-20964-1-git-send-email-mschmidt@redhat.com> <8739exg588.fsf@rustcorp.com.au> <4E96F887.5050103@redhat.com> User-Agent: Notmuch/0.5 (http://notmuchmail.org) Emacs/23.2.1 (i686-pc-linux-gnu) Date: Tue, 18 Oct 2011 14:28:46 +1030 Message-ID: <87obxfq7bd.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 13 Oct 2011 16:41:11 +0200, Michal Schmidt wrote: > On 10/13/2011 01:28 AM, Rusty Russell wrote: > > Idea is solid, implementation has a few quirks. As the name > > obsolete_checksetup() implies, this was only supposed to be a crutch for > > old __setup() calls. Modern code should be using module_param() or > > core_param(). > > ... instead of __setup()? Yep. > No objection to the change in do_early_param() ? Well, for the moment I've applied that, with parameq and parameqn reimplemented more cleanly. See below. > > Did you have a specific example? > > The specific example I had in mind was the one from > Documentation/kernel-parameters.txt: > > log_buf_len=1M print-fatal-signals=1 > can also be entered as > log-buf-len=1M print_fatal_signals=1 Oops. > Let's see how many __setup() parameters there are: > $ git grep -E '^__setup\("' |wc -l > 457 > > Only the ones with a dash or underscore in the name: > $ git grep -E '__setup\(".*[_-].*"' | wc -l > 180 > > It will take some time. The easy things have already been done ;) Just do the non-arch ones, first, and see where that gets us. Thanks! Rusty. From: Michal Schmidt Subject: params: make dashes and underscores in parameter names truly equal Date: Mon, 10 Oct 2011 00:03:37 +0200 The user may use "foo-bar" for a kernel parameter defined as "foo_bar". Make sure it works the other way around too. Apply the equality of dashes and underscores on early_params and __setup params as well. The example given in Documentation/kernel-parameters.txt indicates that this is the intended behaviour. With the patch the kernel accepts "log-buf-len=1M" as expected. https://bugzilla.redhat.com/show_bug.cgi?id=744545 Signed-off-by: Michal Schmidt Signed-off-by: Rusty Russell (neatened implementations) --- include/linux/moduleparam.h | 20 ++++++++++++++++++++ init/main.c | 4 ++-- kernel/params.c | 21 ++++++++++++++------- 3 files changed, 36 insertions(+), 9 deletions(-) diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h --- a/include/linux/moduleparam.h +++ b/include/linux/moduleparam.h @@ -262,6 +262,26 @@ static inline void __kernel_param_unlock .str = &__param_string_##name, 0, perm); \ __MODULE_PARM_TYPE(name, "string") +/** + * parameq - checks if two parameter names match + * @name1: parameter name 1 + * @name2: parameter name 2 + * + * Returns true if the two parameter names are equal. + * Dashes (-) are considered equal to underscores (_). + */ +extern bool parameq(const char *name1, const char *name2); + +/** + * parameqn - checks if two parameter names match + * @name1: parameter name 1 + * @name2: parameter name 2 + * @n: the length to compare + * + * Similar to parameq(), except it compares @n characters. + */ +extern bool parameqn(const char *name1, const char *name2, size_t n); + /* Called on module insert or kernel boot */ extern int parse_args(const char *name, char *args, diff --git a/init/main.c b/init/main.c --- a/init/main.c +++ b/init/main.c @@ -163,7 +163,7 @@ static int __init obsolete_checksetup(ch p = __setup_start; do { int n = strlen(p->str); - if (!strncmp(line, p->str, n)) { + if (parameqn(line, p->str, n)) { if (p->early) { /* Already done in parse_early_param? * (Needs exact match on param part). @@ -392,7 +392,7 @@ static int __init do_early_param(char *p const struct obs_kernel_param *p; for (p = __setup_start; p < __setup_end; p++) { - if ((p->early && strcmp(param, p->str) == 0) || + if ((p->early && parameq(param, p->str)) || (strcmp(param, "console") == 0 && strcmp(p->str, "earlycon") == 0) ) { diff --git a/kernel/params.c b/kernel/params.c --- a/kernel/params.c +++ b/kernel/params.c @@ -67,20 +67,27 @@ static void maybe_kfree_parameter(void * } } -static inline char dash2underscore(char c) +static char dash2underscore(char c) { if (c == '-') return '_'; return c; } -static inline int parameq(const char *input, const char *paramname) +bool parameqn(const char *a, const char *b, size_t n) { - unsigned int i; - for (i = 0; dash2underscore(input[i]) == paramname[i]; i++) - if (input[i] == '\0') - return 1; - return 0; + size_t i; + + for (i = 0; i < n; i++) { + if (dash2underscore(a[i]) != dash2underscore(b[i])) + return false; + } + return true; +} + +bool parameq(const char *a, const char *b) +{ + return parameqn(a, b, strlen(a)+1); } static int parse_one(char *param,