Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756255Ab3JGQ5l (ORCPT ); Mon, 7 Oct 2013 12:57:41 -0400 Received: from order.stressinduktion.org ([87.106.68.36]:46090 "EHLO order.stressinduktion.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752588Ab3JGQ5i (ORCPT ); Mon, 7 Oct 2013 12:57:38 -0400 Date: Mon, 7 Oct 2013 18:57:36 +0200 From: Hannes Frederic Sowa To: Steven Rostedt Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Jason Baron , Peter Zijlstra , Eric Dumazet , "andi @ firstfloor. org David S. Miller" , x86@kernel.org Subject: [PATCH v2] static_key: WARN on usage before jump_label_init was called Message-ID: <20131007165736.GJ9295@order.stressinduktion.org> Mail-Followup-To: Steven Rostedt , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Jason Baron , Peter Zijlstra , Eric Dumazet , "andi @ firstfloor. org David S. Miller" , x86@kernel.org References: <1381015258-7667-1-git-send-email-hannes@stressinduktion.org> <1381015258-7667-4-git-send-email-hannes@stressinduktion.org> <20131005200558.3be2f841@gandalf.local.home> <20131006001247.GB25076@order.stressinduktion.org> <20131006182919.GD9295@order.stressinduktion.org> <20131007115152.0964afde@gandalf.local.home> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20131007115152.0964afde@gandalf.local.home> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5170 Lines: 169 On Mon, Oct 07, 2013 at 11:51:52AM -0400, Steven Rostedt wrote: > On Sun, 6 Oct 2013 20:29:19 +0200 > Hannes Frederic Sowa wrote: > > > > diff --git a/lib/jump_label_initialized.c b/lib/jump_label_initialized.c > > new file mode 100644 > > index 0000000..a668a40 > > --- /dev/null > > +++ b/lib/jump_label_initialized.c > > @@ -0,0 +1,6 @@ > > +#include > > +#include > > + > > +bool static_key_initialized __read_mostly = false; > > +EXPORT_SYMBOL_GPL(static_key_initialized); > > + > > So far, the only thing I don't like about this patch is the creation of > this file for the sole purpose of adding this variable. > > Perhaps it can just be added to init/main.c? Yes, init/main.c seems to be a good fit. I also fixed some whitespace issues and simplified the macro (as it is only one statement). [PATCH v2] static_key: WARN on usage before jump_label_init was called Based on a patch from Andi Kleen. Cc: Steven Rostedt Cc: Peter Zijlstra Cc: Andi Kleen Signed-off-by: Hannes Frederic Sowa --- include/linux/jump_label.h | 10 ++++++++++ include/linux/jump_label_ratelimit.h | 2 ++ init/main.c | 7 +++++++ kernel/jump_label.c | 5 +++++ 4 files changed, 24 insertions(+) diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h index a507907..e96be72 100644 --- a/include/linux/jump_label.h +++ b/include/linux/jump_label.h @@ -48,6 +48,13 @@ #include #include +#include + +extern bool static_key_initialized; + +#define STATIC_KEY_CHECK_USE() WARN(!static_key_initialized, \ + "%s used before call to jump_label_init", \ + __func__) #if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL) @@ -128,6 +135,7 @@ struct static_key { static __always_inline void jump_label_init(void) { + static_key_initialized = true; } static __always_inline bool static_key_false(struct static_key *key) @@ -146,11 +154,13 @@ static __always_inline bool static_key_true(struct static_key *key) static inline void static_key_slow_inc(struct static_key *key) { + STATIC_KEY_CHECK_USE(); atomic_inc(&key->enabled); } static inline void static_key_slow_dec(struct static_key *key) { + STATIC_KEY_CHECK_USE(); atomic_dec(&key->enabled); } diff --git a/include/linux/jump_label_ratelimit.h b/include/linux/jump_label_ratelimit.h index 1137883..089f70f 100644 --- a/include/linux/jump_label_ratelimit.h +++ b/include/linux/jump_label_ratelimit.h @@ -23,12 +23,14 @@ struct static_key_deferred { }; static inline void static_key_slow_dec_deferred(struct static_key_deferred *key) { + STATIC_KEY_CHECK_USE(); static_key_slow_dec(&key->key); } static inline void jump_label_rate_limit(struct static_key_deferred *key, unsigned long rl) { + STATIC_KEY_CHECK_USE(); } #endif /* HAVE_JUMP_LABEL */ #endif /* _LINUX_JUMP_LABEL_RATELIMIT_H */ diff --git a/init/main.c b/init/main.c index af310af..6735b631 100644 --- a/init/main.c +++ b/init/main.c @@ -136,6 +136,13 @@ static char *execute_command; static char *ramdisk_execute_command; /* + * Used to generate warnings if static_key manipulation functions are used + * before boot + */ +bool static_key_initialized __read_mostly = false; +EXPORT_SYMBOL_GPL(static_key_initialized); + +/* * If set, this is an indication to the drivers that reset the underlying * device before going ahead with the initialization otherwise driver might * rely on the BIOS and skip the reset operation. diff --git a/kernel/jump_label.c b/kernel/jump_label.c index 297a924..9019f15 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -58,6 +58,7 @@ static void jump_label_update(struct static_key *key, int enable); void static_key_slow_inc(struct static_key *key) { + STATIC_KEY_CHECK_USE(); if (atomic_inc_not_zero(&key->enabled)) return; @@ -103,12 +104,14 @@ static void jump_label_update_timeout(struct work_struct *work) void static_key_slow_dec(struct static_key *key) { + STATIC_KEY_CHECK_USE(); __static_key_slow_dec(key, 0, NULL); } EXPORT_SYMBOL_GPL(static_key_slow_dec); void static_key_slow_dec_deferred(struct static_key_deferred *key) { + STATIC_KEY_CHECK_USE(); __static_key_slow_dec(&key->key, key->timeout, &key->work); } EXPORT_SYMBOL_GPL(static_key_slow_dec_deferred); @@ -116,6 +119,7 @@ EXPORT_SYMBOL_GPL(static_key_slow_dec_deferred); void jump_label_rate_limit(struct static_key_deferred *key, unsigned long rl) { + STATIC_KEY_CHECK_USE(); key->timeout = rl; INIT_DELAYED_WORK(&key->work, jump_label_update_timeout); } @@ -212,6 +216,7 @@ void __init jump_label_init(void) key->next = NULL; #endif } + static_key_initialized = true; jump_label_unlock(); } -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/