From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755511Ab3AGUFY (ORCPT ); Mon, 7 Jan 2013 15:05:24 -0500 Received: from userp1040.oracle.com ([156.151.31.81]:44129 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751026Ab3AGUFU (ORCPT ); Mon, 7 Jan 2013 15:05:20 -0500 Message-ID: <50EB2A47.9030302@oracle.com> Date: Mon, 07 Jan 2013 15:04:23 -0500 From: Sasha Levin User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Jason Baron CC: Ingo Molnar , Steven Rostedt , Peter Zijlstra , linux-kernel@vger.kernel.org, jamie.iles@oracle.com Subject: Re: [PATCH] jump_label: constify jump_label_text_reserved and friends References: <1357567093-31136-1-git-send-email-sasha.levin@oracle.com> <20130107163955.GB2948@redhat.com> In-Reply-To: <20130107163955.GB2948@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Source-IP: ucsinet21.oracle.com [156.151.31.93] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/07/2013 11:40 AM, Jason Baron wrote: > On Mon, Jan 07, 2013 at 08:58:09AM -0500, Sasha Levin wrote: >> jump_label_text_reserved() doesn't modify the memory it works on, it just >> checks whether there are any jump labels there. >> >> Constify the parameters of it to prevent warnings when working with it. >> > > I don't see any 'const' data passed to jump_label_text_reserved()? Where is the > warning coming from? New users? Out of tree code. Though once we constify jump_label_text_reserved() and some other similar helper functions, we can constify more existing code in kprobes/jumplabels/etc as well. Take check_kprobe_address_safe() for example, the 'struct kprobe *p' it accepts should probably be const as well. > Also, does this mean 'ftrace_text_reserved()' and 'alternatives_text_reserved()' > need to be updated as well? Jamie has raised this point in private as well. It would make sense to fix them as well, I haven't done that here only because we haven't stumbled on this issue with those functions. I'd be happy to send a patch that fixes it for all of them. Thanks, Sasha > Thanks, > > -Jason > > >> Reviewed-by: Jamie Iles >> Signed-off-by: Sasha Levin >> --- >> include/linux/jump_label.h | 4 ++-- >> kernel/jump_label.c | 10 ++++++---- >> 2 files changed, 8 insertions(+), 6 deletions(-) >> >> diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h >> index 0976fc4..d917a2a 100644 >> --- a/include/linux/jump_label.h >> +++ b/include/linux/jump_label.h >> @@ -116,7 +116,7 @@ extern void arch_jump_label_transform(struct jump_entry *entry, >> enum jump_label_type type); >> extern void arch_jump_label_transform_static(struct jump_entry *entry, >> enum jump_label_type type); >> -extern int jump_label_text_reserved(void *start, void *end); >> +extern int jump_label_text_reserved(const void *start, const void *end); >> extern void static_key_slow_inc(struct static_key *key); >> extern void static_key_slow_dec(struct static_key *key); >> extern void static_key_slow_dec_deferred(struct static_key_deferred *key); >> @@ -174,7 +174,7 @@ static inline void static_key_slow_dec_deferred(struct static_key_deferred *key) >> static_key_slow_dec(&key->key); >> } >> >> -static inline int jump_label_text_reserved(void *start, void *end) >> +static inline int jump_label_text_reserved(const void *start, const void *end) >> { >> return 0; >> } >> diff --git a/kernel/jump_label.c b/kernel/jump_label.c >> index 60f48fa..6dc71c6 100644 >> --- a/kernel/jump_label.c >> +++ b/kernel/jump_label.c >> @@ -120,7 +120,8 @@ void jump_label_rate_limit(struct static_key_deferred *key, >> } >> EXPORT_SYMBOL_GPL(jump_label_rate_limit); >> >> -static int addr_conflict(struct jump_entry *entry, void *start, void *end) >> +static int addr_conflict(struct jump_entry *entry, >> + const void *start, const void *end) >> { >> if (entry->code <= (unsigned long)end && >> entry->code + JUMP_LABEL_NOP_SIZE > (unsigned long)start) >> @@ -130,7 +131,8 @@ static int addr_conflict(struct jump_entry *entry, void *start, void *end) >> } >> >> static int __jump_label_text_reserved(struct jump_entry *iter_start, >> - struct jump_entry *iter_stop, void *start, void *end) >> + struct jump_entry *iter_stop, >> + const void *start, const void *end) >> { >> struct jump_entry *iter; >> >> @@ -222,7 +224,7 @@ struct static_key_mod { >> struct module *mod; >> }; >> >> -static int __jump_label_mod_text_reserved(void *start, void *end) >> +static int __jump_label_mod_text_reserved(const void *start, const void *end) >> { >> struct module *mod; >> >> @@ -419,7 +421,7 @@ early_initcall(jump_label_init_module); >> * >> * returns 1 if there is an overlap, 0 otherwise >> */ >> -int jump_label_text_reserved(void *start, void *end) >> +int jump_label_text_reserved(const void *start, const void *end) >> { >> int ret = __jump_label_text_reserved(__start___jump_table, >> __stop___jump_table, start, end); >> -- >> 1.8.0.2 >>