From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 68E23C352AA for ; Mon, 7 Oct 2019 11:24:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 156D321D7C for ; Mon, 7 Oct 2019 11:24:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="jeLDecCF" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728039AbfJGLYN (ORCPT ); Mon, 7 Oct 2019 07:24:13 -0400 Received: from merlin.infradead.org ([205.233.59.134]:58460 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727999AbfJGLYI (ORCPT ); Mon, 7 Oct 2019 07:24:08 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-Id:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=mKt6HGUiKvdfkR+UdJwfyZ1NgwE2ezPWsx2PYLbxIrc=; b=jeLDecCFET8ZzDdxol8EMoYnNt rlW2whjBfELz/hxsuR4gu0Q/JNfIBe7yu+wVQGqAZxgoAD6TnuPbvASFecTLbOuIZ4BGjut3PLxZY ScFnERK+qEo9yPTH/kL69amRYWS+yOZZfhj+PQCUa4OCragiwZZYv7W/9qpYGwgUE9u2Mr3y/J+m8 3am7fv85z2RdfGJYh2z0osLpgHgJf1Re/jiJT/WUwMXj0DYPcFK6FrkGnkWIReyzjKfjp1jn2qPdi uaGLwyGH7UoGPYpCbnRab9swmfTFV+0icJUISPWIysNylfW3OT9q7MgZXPInXJJmHU2Hn0lv4gJha 0nXPkQVA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.2 #3 (Red Hat Linux)) id 1iHR6y-0002BW-Mf; Mon, 07 Oct 2019 11:23:32 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id F1C2C3067F1; Mon, 7 Oct 2019 13:22:35 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 87BC420244E20; Mon, 7 Oct 2019 13:23:26 +0200 (CEST) Message-Id: <20191007082700.02964999.7@infradead.org> User-Agent: quilt/0.65 Date: Mon, 07 Oct 2019 10:25:42 +0200 From: Peter Zijlstra To: x86@kernel.org Cc: peterz@infradead.org, linux-kernel@vger.kernel.org, rostedt@goodmis.org, mhiramat@kernel.org, bristot@redhat.com, jbaron@akamai.com, torvalds@linux-foundation.org, tglx@linutronix.de, mingo@kernel.org, namit@vmware.com, hpa@zytor.com, luto@kernel.org, ard.biesheuvel@linaro.org, Pavel Machek , Alexios Zavras , Allison Randal , Sam Protsenko , "Rafael J. Wysocki" , Andrew Morton , Todd Brandt , Vasily Averin , Len Brown , Greg Kroah-Hartman Subject: [PATCH v2 1/4] notifier: Fix broken error handling pattern References: <20191007082541.64146933.7@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The current notifiers have the following error handling pattern all over the place: int err, nr; err = __foo_notifier_call_chain(&chain, val_up, v, -1, &nr); if (err & NOTIFIER_STOP_MASK) __foo_notifier_call_chain(&chain, val_down, v, nr-1, NULL) And aside from the endless repetition thereof, it is broken. Consider blocking notifiers; both calls take and drop the rwsem, this means that the notifier list can change in between the two calls, making @nr meaningless. Fix this by replacing all the __foo_notifier_call_chain() functions with foo_notifier_call_chain_robust() that embeds the above pattern, but ensures it is inside a single lock region. Note: I switched atomic_notifier_call_chain_robust() to use the spinlock, since RCU cannot provide the guarantee required for the recovery. Note: software_resume() error handling was broken afaict. Signed-off-by: Peter Zijlstra (Intel) Cc: Pavel Machek Cc: Alexios Zavras Cc: Allison Randal Cc: Sam Protsenko Cc: "Rafael J. Wysocki" Cc: Andrew Morton Cc: Todd Brandt Cc: Thomas Gleixner Cc: Vasily Averin Cc: Len Brown Cc: Greg Kroah-Hartman --- include/linux/notifier.h | 15 +-- kernel/cpu_pm.c | 46 ++++------- kernel/notifier.c | 144 ++++++++++++++++++++++--------------- kernel/power/hibernate.c | 26 +++--- kernel/power/main.c | 8 +- kernel/power/power.h | 3 kernel/power/suspend.c | 14 +-- kernel/power/user.c | 14 +-- tools/power/pm-graph/sleepgraph.py | 2 9 files changed, 139 insertions(+), 133 deletions(-) --- a/include/linux/notifier.h +++ b/include/linux/notifier.h @@ -165,20 +165,19 @@ extern int srcu_notifier_chain_unregiste extern int atomic_notifier_call_chain(struct atomic_notifier_head *nh, unsigned long val, void *v); -extern int __atomic_notifier_call_chain(struct atomic_notifier_head *nh, - unsigned long val, void *v, int nr_to_call, int *nr_calls); extern int blocking_notifier_call_chain(struct blocking_notifier_head *nh, unsigned long val, void *v); -extern int __blocking_notifier_call_chain(struct blocking_notifier_head *nh, - unsigned long val, void *v, int nr_to_call, int *nr_calls); extern int raw_notifier_call_chain(struct raw_notifier_head *nh, unsigned long val, void *v); -extern int __raw_notifier_call_chain(struct raw_notifier_head *nh, - unsigned long val, void *v, int nr_to_call, int *nr_calls); extern int srcu_notifier_call_chain(struct srcu_notifier_head *nh, unsigned long val, void *v); -extern int __srcu_notifier_call_chain(struct srcu_notifier_head *nh, - unsigned long val, void *v, int nr_to_call, int *nr_calls); + +extern int atomic_notifier_call_chain_robust(struct atomic_notifier_head *nh, + unsigned long val_up, unsigned long val_down, void *v); +extern int blocking_notifier_call_chain_robust(struct blocking_notifier_head *nh, + unsigned long val_up, unsigned long val_down, void *v); +extern int raw_notifier_call_chain_robust(struct raw_notifier_head *nh, + unsigned long val_up, unsigned long val_down, void *v); #define NOTIFY_DONE 0x0000 /* Don't care */ #define NOTIFY_OK 0x0001 /* Suits me */ --- a/kernel/cpu_pm.c +++ b/kernel/cpu_pm.c @@ -15,23 +15,31 @@ static ATOMIC_NOTIFIER_HEAD(cpu_pm_notifier_chain); -static int cpu_pm_notify(enum cpu_pm_event event, int nr_to_call, int *nr_calls) +static int cpu_pm_notify(enum cpu_pm_event event) { int ret; /* - * __atomic_notifier_call_chain has a RCU read critical section, which + * atomic_notifier_call_chain has a RCU read critical section, which * could be disfunctional in cpu idle. Copy RCU_NONIDLE code to let * RCU know this. */ rcu_irq_enter_irqson(); - ret = __atomic_notifier_call_chain(&cpu_pm_notifier_chain, event, NULL, - nr_to_call, nr_calls); + ret = atomic_notifier_call_chain(&cpu_pm_notifier_chain, event, NULL); rcu_irq_exit_irqson(); return notifier_to_errno(ret); } +static int cpu_pm_notify_robust(enum cpu_pm_event event_up, enum cpu_pm_event event_down) +{ + int ret; + + ret = atomic_notifier_call_chain_robust(&cpu_pm_notifier_chain, event_up, event_down, NULL); + + return notifier_to_errno(ret); +} + /** * cpu_pm_register_notifier - register a driver with cpu_pm * @nb: notifier block to register @@ -80,18 +88,7 @@ EXPORT_SYMBOL_GPL(cpu_pm_unregister_noti */ int cpu_pm_enter(void) { - int nr_calls; - int ret = 0; - - ret = cpu_pm_notify(CPU_PM_ENTER, -1, &nr_calls); - if (ret) - /* - * Inform listeners (nr_calls - 1) about failure of CPU PM - * PM entry who are notified earlier to prepare for it. - */ - cpu_pm_notify(CPU_PM_ENTER_FAILED, nr_calls - 1, NULL); - - return ret; + return cpu_pm_notify_robust(CPU_PM_ENTER, CPU_PM_ENTER_FAILED); } EXPORT_SYMBOL_GPL(cpu_pm_enter); @@ -109,7 +106,7 @@ EXPORT_SYMBOL_GPL(cpu_pm_enter); */ int cpu_pm_exit(void) { - return cpu_pm_notify(CPU_PM_EXIT, -1, NULL); + return cpu_pm_notify(CPU_PM_EXIT); } EXPORT_SYMBOL_GPL(cpu_pm_exit); @@ -131,18 +128,7 @@ EXPORT_SYMBOL_GPL(cpu_pm_exit); */ int cpu_cluster_pm_enter(void) { - int nr_calls; - int ret = 0; - - ret = cpu_pm_notify(CPU_CLUSTER_PM_ENTER, -1, &nr_calls); - if (ret) - /* - * Inform listeners (nr_calls - 1) about failure of CPU cluster - * PM entry who are notified earlier to prepare for it. - */ - cpu_pm_notify(CPU_CLUSTER_PM_ENTER_FAILED, nr_calls - 1, NULL); - - return ret; + return cpu_pm_notify_robust(CPU_CLUSTER_PM_ENTER, CPU_CLUSTER_PM_ENTER_FAILED); } EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter); @@ -163,7 +149,7 @@ EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter); */ int cpu_cluster_pm_exit(void) { - return cpu_pm_notify(CPU_CLUSTER_PM_EXIT, -1, NULL); + return cpu_pm_notify(CPU_CLUSTER_PM_EXIT); } EXPORT_SYMBOL_GPL(cpu_cluster_pm_exit); --- a/kernel/notifier.c +++ b/kernel/notifier.c @@ -106,6 +106,34 @@ static int notifier_call_chain(struct no } NOKPROBE_SYMBOL(notifier_call_chain); +/** + * notifier_call_chain_robust - Inform the registered notifiers about an event + * and rollback on error. + * @nl: Pointer to head of the blocking notifier chain + * @val_up: Value passed unmodified to the notifier function + * @val_down: Value passed unmodified to the notifier function when recovering + * from an error on @val_up + * @v Pointer passed unmodified to the notifier function + * + * NOTE: It is important the @nl chain doesn't change between the two + * invocations of notifier_call_chain() such that we visit the + * exact same notifier callbacks; this rules out any RCU usage. + * + * Returns: the return value of the @val_up call. + */ +static int notifier_call_chain_robust(struct notifier_block **nl, + unsigned long val_up, unsigned long val_down, + void *v) +{ + int ret, nr = 0; + + ret = notifier_call_chain(nl, val_up, v, -1, &nr); + if (ret & NOTIFY_STOP_MASK) + notifier_call_chain(nl, val_down, v, nr-1, NULL); + + return ret; +} + /* * Atomic notifier chain routines. Registration and unregistration * use a spinlock, and call_chain is synchronized by RCU (no locks). @@ -156,13 +184,30 @@ int atomic_notifier_chain_unregister(str } EXPORT_SYMBOL_GPL(atomic_notifier_chain_unregister); +int atomic_notifier_call_chain_robust(struct atomic_notifier_head *nh, + unsigned long val_up, unsigned long val_down, void *v) +{ + unsigned long flags; + int ret; + + /* + * Musn't use RCU; because then the notifier list can + * change between the up and down traversal. + */ + spin_lock_irqsave(&nh->lock, flags); + ret = notifier_call_chain_robust(&nh->head, val_up, val_down, v); + spin_unlock_irqrestore(&nh->lock, flags); + + return ret; +} +EXPORT_SYMBOL_GPL(atomic_notifier_call_chain_robust); +NOKPROBE_SYMBOL(atomic_notifier_call_chain_robust); + /** - * __atomic_notifier_call_chain - Call functions in an atomic notifier chain + * atomic_notifier_call_chain - Call functions in an atomic notifier chain * @nh: Pointer to head of the atomic notifier chain * @val: Value passed unmodified to notifier function * @v: Pointer passed unmodified to notifier function - * @nr_to_call: See the comment for notifier_call_chain. - * @nr_calls: See the comment for notifier_call_chain. * * Calls each function in a notifier chain in turn. The functions * run in an atomic context, so they must not block. @@ -175,24 +220,16 @@ EXPORT_SYMBOL_GPL(atomic_notifier_chain_ * Otherwise the return value is the return value * of the last notifier function called. */ -int __atomic_notifier_call_chain(struct atomic_notifier_head *nh, - unsigned long val, void *v, - int nr_to_call, int *nr_calls) +int atomic_notifier_call_chain(struct atomic_notifier_head *nh, + unsigned long val, void *v) { int ret; rcu_read_lock(); - ret = notifier_call_chain(&nh->head, val, v, nr_to_call, nr_calls); + ret = notifier_call_chain(&nh->head, val, v, -1, NULL); rcu_read_unlock(); - return ret; -} -EXPORT_SYMBOL_GPL(__atomic_notifier_call_chain); -NOKPROBE_SYMBOL(__atomic_notifier_call_chain); -int atomic_notifier_call_chain(struct atomic_notifier_head *nh, - unsigned long val, void *v) -{ - return __atomic_notifier_call_chain(nh, val, v, -1, NULL); + return ret; } EXPORT_SYMBOL_GPL(atomic_notifier_call_chain); NOKPROBE_SYMBOL(atomic_notifier_call_chain); @@ -285,13 +322,30 @@ int blocking_notifier_chain_unregister(s } EXPORT_SYMBOL_GPL(blocking_notifier_chain_unregister); +int blocking_notifier_call_chain_robust(struct blocking_notifier_head *nh, + unsigned long val_up, unsigned long val_down, void *v) +{ + int ret = NOTIFY_DONE; + + /* + * We check the head outside the lock, but if this access is + * racy then it does not matter what the result of the test + * is, we re-check the list after having taken the lock anyway: + */ + if (rcu_access_pointer(nh->head)) { + down_read(&nh->rwsem); + ret = notifier_call_chain_robust(&nh->head, val_up, val_down, v); + up_read(&nh->rwsem); + } + return ret; +} +EXPORT_SYMBOL_GPL(blocking_notifier_call_chain_robust); + /** - * __blocking_notifier_call_chain - Call functions in a blocking notifier chain + * blocking_notifier_call_chain - Call functions in a blocking notifier chain * @nh: Pointer to head of the blocking notifier chain * @val: Value passed unmodified to notifier function * @v: Pointer passed unmodified to notifier function - * @nr_to_call: See comment for notifier_call_chain. - * @nr_calls: See comment for notifier_call_chain. * * Calls each function in a notifier chain in turn. The functions * run in a process context, so they are allowed to block. @@ -303,9 +357,8 @@ EXPORT_SYMBOL_GPL(blocking_notifier_chai * Otherwise the return value is the return value * of the last notifier function called. */ -int __blocking_notifier_call_chain(struct blocking_notifier_head *nh, - unsigned long val, void *v, - int nr_to_call, int *nr_calls) +int blocking_notifier_call_chain(struct blocking_notifier_head *nh, + unsigned long val, void *v) { int ret = NOTIFY_DONE; @@ -316,19 +369,11 @@ int __blocking_notifier_call_chain(struc */ if (rcu_access_pointer(nh->head)) { down_read(&nh->rwsem); - ret = notifier_call_chain(&nh->head, val, v, nr_to_call, - nr_calls); + ret = notifier_call_chain(&nh->head, val, v, -1, NULL); up_read(&nh->rwsem); } return ret; } -EXPORT_SYMBOL_GPL(__blocking_notifier_call_chain); - -int blocking_notifier_call_chain(struct blocking_notifier_head *nh, - unsigned long val, void *v) -{ - return __blocking_notifier_call_chain(nh, val, v, -1, NULL); -} EXPORT_SYMBOL_GPL(blocking_notifier_call_chain); /* @@ -370,13 +415,18 @@ int raw_notifier_chain_unregister(struct } EXPORT_SYMBOL_GPL(raw_notifier_chain_unregister); +int raw_notifier_call_chain_robust(struct raw_notifier_head *nh, + unsigned long val_up, unsigned long val_down, void *v) +{ + return notifier_call_chain_robust(&nh->head, val_up, val_down, v); +} +EXPORT_SYMBOL_GPL(raw_notifier_call_chain_robust); + /** - * __raw_notifier_call_chain - Call functions in a raw notifier chain + * raw_notifier_call_chain - Call functions in a raw notifier chain * @nh: Pointer to head of the raw notifier chain * @val: Value passed unmodified to notifier function * @v: Pointer passed unmodified to notifier function - * @nr_to_call: See comment for notifier_call_chain. - * @nr_calls: See comment for notifier_call_chain * * Calls each function in a notifier chain in turn. The functions * run in an undefined context. @@ -389,18 +439,10 @@ EXPORT_SYMBOL_GPL(raw_notifier_chain_unr * Otherwise the return value is the return value * of the last notifier function called. */ -int __raw_notifier_call_chain(struct raw_notifier_head *nh, - unsigned long val, void *v, - int nr_to_call, int *nr_calls) -{ - return notifier_call_chain(&nh->head, val, v, nr_to_call, nr_calls); -} -EXPORT_SYMBOL_GPL(__raw_notifier_call_chain); - int raw_notifier_call_chain(struct raw_notifier_head *nh, unsigned long val, void *v) { - return __raw_notifier_call_chain(nh, val, v, -1, NULL); + return notifier_call_chain(&nh->head, val, v, -1, NULL); } EXPORT_SYMBOL_GPL(raw_notifier_call_chain); @@ -472,12 +514,10 @@ int srcu_notifier_chain_unregister(struc EXPORT_SYMBOL_GPL(srcu_notifier_chain_unregister); /** - * __srcu_notifier_call_chain - Call functions in an SRCU notifier chain + * srcu_notifier_call_chain - Call functions in an SRCU notifier chain * @nh: Pointer to head of the SRCU notifier chain * @val: Value passed unmodified to notifier function * @v: Pointer passed unmodified to notifier function - * @nr_to_call: See comment for notifier_call_chain. - * @nr_calls: See comment for notifier_call_chain * * Calls each function in a notifier chain in turn. The functions * run in a process context, so they are allowed to block. @@ -489,25 +529,17 @@ EXPORT_SYMBOL_GPL(srcu_notifier_chain_un * Otherwise the return value is the return value * of the last notifier function called. */ -int __srcu_notifier_call_chain(struct srcu_notifier_head *nh, - unsigned long val, void *v, - int nr_to_call, int *nr_calls) +int srcu_notifier_call_chain(struct srcu_notifier_head *nh, + unsigned long val, void *v) { int ret; int idx; idx = srcu_read_lock(&nh->srcu); - ret = notifier_call_chain(&nh->head, val, v, nr_to_call, nr_calls); + ret = notifier_call_chain(&nh->head, val, v, -1, NULL); srcu_read_unlock(&nh->srcu, idx); return ret; } -EXPORT_SYMBOL_GPL(__srcu_notifier_call_chain); - -int srcu_notifier_call_chain(struct srcu_notifier_head *nh, - unsigned long val, void *v) -{ - return __srcu_notifier_call_chain(nh, val, v, -1, NULL); -} EXPORT_SYMBOL_GPL(srcu_notifier_call_chain); /** --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -693,8 +693,8 @@ static int load_image_and_restore(void) */ int hibernate(void) { - int error, nr_calls = 0; bool snapshot_test = false; + int error; if (!hibernation_available()) { pm_pr_dbg("Hibernation not available.\n"); @@ -710,11 +710,9 @@ int hibernate(void) pr_info("hibernation entry\n"); pm_prepare_console(); - error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls); - if (error) { - nr_calls--; - goto Exit; - } + error = pm_notifier_call_chain_robust(PM_HIBERNATION_PREPARE, PM_POST_HIBERNATION); + if (error) + goto Restore; ksys_sync_helper(); @@ -772,7 +770,8 @@ int hibernate(void) /* Don't bother checking whether freezer_test_done is true */ freezer_test_done = false; Exit: - __pm_notifier_call_chain(PM_POST_HIBERNATION, nr_calls, NULL); + pm_notifier_call_chain(PM_POST_HIBERNATION); + Restore: pm_restore_console(); atomic_inc(&snapshot_device_available); Unlock: @@ -800,7 +799,7 @@ int hibernate(void) */ static int software_resume(void) { - int error, nr_calls = 0; + int error; /* * If the user said "noresume".. bail out early. @@ -887,11 +886,9 @@ static int software_resume(void) pr_info("resume from hibernation\n"); pm_prepare_console(); - error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls); - if (error) { - nr_calls--; - goto Close_Finish; - } + error = pm_notifier_call_chain_robust(PM_RESTORE_PREPARE, PM_POST_RESTORE); + if (error) + goto Restore; pm_pr_dbg("Preparing processes for restore.\n"); error = freeze_processes(); @@ -900,7 +897,8 @@ static int software_resume(void) error = load_image_and_restore(); thaw_processes(); Finish: - __pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL); + pm_notifier_call_chain(PM_POST_RESTORE); + Restore: pm_restore_console(); pr_info("resume from hibernation failed (%d)\n", error); atomic_inc(&snapshot_device_available); --- a/kernel/power/main.c +++ b/kernel/power/main.c @@ -79,18 +79,18 @@ int unregister_pm_notifier(struct notifi } EXPORT_SYMBOL_GPL(unregister_pm_notifier); -int __pm_notifier_call_chain(unsigned long val, int nr_to_call, int *nr_calls) +int pm_notifier_call_chain_robust(unsigned long val_up, unsigned long val_down) { int ret; - ret = __blocking_notifier_call_chain(&pm_chain_head, val, NULL, - nr_to_call, nr_calls); + ret = blocking_notifier_call_chain_robust(&pm_chain_head, val_up, val_down, NULL); return notifier_to_errno(ret); } + int pm_notifier_call_chain(unsigned long val) { - return __pm_notifier_call_chain(val, -1, NULL); + return blocking_notifier_call_chain(&pm_chain_head, val, NULL); } /* If set, devices may be suspended and resumed asynchronously. */ --- a/kernel/power/power.h +++ b/kernel/power/power.h @@ -210,8 +210,7 @@ static inline void suspend_test_finish(c #ifdef CONFIG_PM_SLEEP /* kernel/power/main.c */ -extern int __pm_notifier_call_chain(unsigned long val, int nr_to_call, - int *nr_calls); +extern int pm_notifier_call_chain_robust(unsigned long val_up, unsigned long val_down); extern int pm_notifier_call_chain(unsigned long val); #endif --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -352,18 +352,16 @@ static int suspend_test(int level) */ static int suspend_prepare(suspend_state_t state) { - int error, nr_calls = 0; + int error; if (!sleep_state_supported(state)) return -EPERM; pm_prepare_console(); - error = __pm_notifier_call_chain(PM_SUSPEND_PREPARE, -1, &nr_calls); - if (error) { - nr_calls--; - goto Finish; - } + error = pm_notifier_call_chain_robust(PM_SUSPEND_PREPARE, PM_POST_SUSPEND); + if (error) + goto Restore; trace_suspend_resume(TPS("freeze_processes"), 0, true); error = suspend_freeze_processes(); @@ -373,8 +371,8 @@ static int suspend_prepare(suspend_state suspend_stats.failed_freeze++; dpm_save_failed_step(SUSPEND_FREEZE); - Finish: - __pm_notifier_call_chain(PM_POST_SUSPEND, nr_calls, NULL); + pm_notifier_call_chain(PM_POST_SUSPEND); + Restore: pm_restore_console(); return error; } --- a/kernel/power/user.c +++ b/kernel/power/user.c @@ -44,7 +44,7 @@ atomic_t snapshot_device_available = ATO static int snapshot_open(struct inode *inode, struct file *filp) { struct snapshot_data *data; - int error, nr_calls = 0; + int error; if (!hibernation_available()) return -EPERM; @@ -71,9 +71,7 @@ static int snapshot_open(struct inode *i swap_type_of(swsusp_resume_device, 0, NULL) : -1; data->mode = O_RDONLY; data->free_bitmaps = false; - error = __pm_notifier_call_chain(PM_HIBERNATION_PREPARE, -1, &nr_calls); - if (error) - __pm_notifier_call_chain(PM_POST_HIBERNATION, --nr_calls, NULL); + error = pm_notifier_call_chain_robust(PM_HIBERNATION_PREPARE, PM_POST_HIBERNATION); } else { /* * Resuming. We may need to wait for the image device to @@ -83,15 +81,11 @@ static int snapshot_open(struct inode *i data->swap = -1; data->mode = O_WRONLY; - error = __pm_notifier_call_chain(PM_RESTORE_PREPARE, -1, &nr_calls); + error = pm_notifier_call_chain_robust(PM_RESTORE_PREPARE, PM_POST_RESTORE); if (!error) { error = create_basic_memory_bitmaps(); data->free_bitmaps = !error; - } else - nr_calls--; - - if (error) - __pm_notifier_call_chain(PM_POST_RESTORE, nr_calls, NULL); + } } if (error) atomic_inc(&snapshot_device_available); --- a/tools/power/pm-graph/sleepgraph.py +++ b/tools/power/pm-graph/sleepgraph.py @@ -153,7 +153,7 @@ import base64 tracefuncs = { 'sys_sync': {}, 'ksys_sync': {}, - '__pm_notifier_call_chain': {}, + 'pm_notifier_call_chain_robust': {}, 'pm_prepare_console': {}, 'pm_notifier_call_chain': {}, 'freeze_processes': {},