From patchwork Thu Nov 4 14:53:23 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Emanuele Giuseppe Esposito X-Patchwork-Id: 12603303 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 40060C433EF for ; Thu, 4 Nov 2021 14:56:16 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C1D99610FC for ; Thu, 4 Nov 2021 14:56:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org C1D99610FC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:47638 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mieA2-0005ol-PW for qemu-devel@archiver.kernel.org; Thu, 04 Nov 2021 10:56:14 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51120) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mie7v-0002vY-De for qemu-devel@nongnu.org; Thu, 04 Nov 2021 10:54:03 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:27381) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mie7s-0006qF-B8 for qemu-devel@nongnu.org; Thu, 04 Nov 2021 10:54:03 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1636037639; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=E0O4TgLee/XFBAnFSAEoBp6QNy4upsDe28hIOz6AcLc=; b=HycomxxVCsHwFyFLS2OOPxf1DKBSZwOOVSrUOdBH/azho01wMeIsTljx4LdrijGOfVHF/0 NLSGPuqqXwTtTfhq2SJM4C+ZyHn3WjYkusyiWxedxxFZ1KjTEaQ8Z4rLdq7Eql8PdLlZEy Z+aEeDYkXGeWIDeD7DDNid3ezT/+k1A= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-23-WRmBIlNiOnqinximpI7wlQ-1; Thu, 04 Nov 2021 10:53:56 -0400 X-MC-Unique: WRmBIlNiOnqinximpI7wlQ-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id F30B2CF989; Thu, 4 Nov 2021 14:53:53 +0000 (UTC) Received: from virtlab701.virt.lab.eng.bos.redhat.com (virtlab701.virt.lab.eng.bos.redhat.com [10.19.152.228]) by smtp.corp.redhat.com (Postfix) with ESMTP id 090A26418A; Thu, 4 Nov 2021 14:53:52 +0000 (UTC) From: Emanuele Giuseppe Esposito To: qemu-block@nongnu.org Subject: [RFC PATCH v2 03/14] job.h: define locked functions Date: Thu, 4 Nov 2021 10:53:23 -0400 Message-Id: <20211104145334.1346363-4-eesposit@redhat.com> In-Reply-To: <20211104145334.1346363-1-eesposit@redhat.com> References: <20211104145334.1346363-1-eesposit@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eesposit@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=170.10.129.124; envelope-from=eesposit@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -33 X-Spam_score: -3.4 X-Spam_bar: --- X-Spam_report: (-3.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.648, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Fam Zheng , Vladimir Sementsov-Ogievskiy , Wen Congyang , Xie Changlong , Emanuele Giuseppe Esposito , Markus Armbruster , qemu-devel@nongnu.org, Hanna Reitz , Stefan Hajnoczi , Paolo Bonzini , John Snow Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" These functions assume that the job lock is held by the caller, to avoid TOC/TOU conditions. Introduce also additional helpers that define _locked functions (useful when the job_mutex is globally applied). Note: at this stage, job_{lock/unlock} and job lock guard macros are *nop*. Signed-off-by: Emanuele Giuseppe Esposito --- include/qemu/job.h | 66 ++++++++++++++++++++++++++++++++++++++++++---- job.c | 18 +++++++++++-- 2 files changed, 77 insertions(+), 7 deletions(-) diff --git a/include/qemu/job.h b/include/qemu/job.h index f7036ac6b3..c7a6bcad1b 100644 --- a/include/qemu/job.h +++ b/include/qemu/job.h @@ -355,6 +355,8 @@ void job_txn_unref(JobTxn *txn); * the reference that is automatically grabbed here. * * If @txn is NULL, the function does nothing. + * + * Called between job_lock and job_unlock. */ void job_txn_add_job(JobTxn *txn, Job *job); @@ -377,12 +379,16 @@ void *job_create(const char *job_id, const JobDriver *driver, JobTxn *txn, /** * Add a reference to Job refcnt, it will be decreased with job_unref, and then * be freed if it comes to be the last reference. + * + * Called between job_lock and job_unlock. */ void job_ref(Job *job); /** * Release a reference that was previously acquired with job_ref() or * job_create(). If it's the last reference to the object, it will be freed. + * + * Called between job_lock and job_unlock. */ void job_unref(Job *job); @@ -429,6 +435,8 @@ void job_event_completed(Job *job); * Conditionally enter the job coroutine if the job is ready to run, not * already busy and fn() returns true. fn() is called while under the job_lock * critical section. + * + * Called between job_lock and job_unlock, but it releases the lock temporarly. */ void job_enter_cond(Job *job, bool(*fn)(Job *job)); @@ -490,34 +498,52 @@ bool job_is_cancelled(Job *job); */ bool job_cancel_requested(Job *job); -/** Returns whether the job is in a completed state. */ +/** + * Returns whether the job is in a completed state. + * Called between job_lock and job_unlock. + */ bool job_is_completed(Job *job); /** Returns whether the job is ready to be completed. */ bool job_is_ready(Job *job); +/** Same as job_is_ready(), but assumes job_lock is held. */ +bool job_is_ready_locked(Job *job); + /** * Request @job to pause at the next pause point. Must be paired with * job_resume(). If the job is supposed to be resumed by user action, call * job_user_pause() instead. + * + * Called between job_lock and job_unlock. */ void job_pause(Job *job); -/** Resumes a @job paused with job_pause. */ +/** + * Resumes a @job paused with job_pause. + * Called between job_lock and job_unlock. + */ void job_resume(Job *job); /** * Asynchronously pause the specified @job. * Do not allow a resume until a matching call to job_user_resume. + * + * Called between job_lock and job_unlock. */ void job_user_pause(Job *job, Error **errp); -/** Returns true if the job is user-paused. */ +/** + * Returns true if the job is user-paused. + * Called between job_lock and job_unlock. + */ bool job_user_paused(Job *job); /** * Resume the specified @job. * Must be paired with a preceding job_user_pause. + * + * Called between job_lock and job_unlock. */ void job_user_resume(Job *job, Error **errp); @@ -526,6 +552,8 @@ void job_user_resume(Job *job, Error **errp); * first one if @job is %NULL. * * Returns the requested job, or %NULL if there are no more jobs left. + * + * Called between job_lock and job_unlock. */ Job *job_next(Job *job); @@ -533,6 +561,8 @@ Job *job_next(Job *job); * Get the job identified by @id (which must not be %NULL). * * Returns the requested job, or %NULL if it doesn't exist. + * + * Called between job_lock and job_unlock. */ Job *job_get(const char *id); @@ -540,27 +570,39 @@ Job *job_get(const char *id); * Check whether the verb @verb can be applied to @job in its current state. * Returns 0 if the verb can be applied; otherwise errp is set and -EPERM * returned. + * + * Called between job_lock and job_unlock. */ int job_apply_verb(Job *job, JobVerb verb, Error **errp); /** The @job could not be started, free it. */ void job_early_fail(Job *job); +/** Same as job_early_fail(), but assumes job_lock is held. */ +void job_early_fail_locked(Job *job); + /** Moves the @job from RUNNING to READY */ void job_transition_to_ready(Job *job); -/** Asynchronously complete the specified @job. */ +/** + * Asynchronously complete the specified @job. + * Called between job_lock and job_unlock, but it releases the lock temporarly. + */ void job_complete(Job *job, Error **errp); /** * Asynchronously cancel the specified @job. If @force is true, the job should * be cancelled immediately without waiting for a consistent state. + * + * Called between job_lock and job_unlock. */ void job_cancel(Job *job, bool force); /** * Cancels the specified job like job_cancel(), but may refuse to do so if the * operation isn't meaningful in the current state of the job. + * + * Called between job_lock and job_unlock. */ void job_user_cancel(Job *job, bool force, Error **errp); @@ -577,7 +619,13 @@ void job_user_cancel(Job *job, bool force, Error **errp); */ int job_cancel_sync(Job *job, bool force); -/** Synchronously force-cancels all jobs using job_cancel_sync(). */ +/** + * Synchronously force-cancels all jobs using job_cancel_sync(). + * + * Called with job_lock *not* held, unlike most other APIs consumed + * by the monitor! This is primarly to avoid adding unnecessary lock-unlock + * patterns in the caller. + */ void job_cancel_sync_all(void); /** @@ -593,6 +641,8 @@ void job_cancel_sync_all(void); * Returns the return value from the job. * * Callers must hold the AioContext lock of job->aio_context. + * + * Called between job_lock and job_unlock. */ int job_complete_sync(Job *job, Error **errp); @@ -603,12 +653,16 @@ int job_complete_sync(Job *job, Error **errp); * FIXME: Make the below statement universally true: * For jobs that support the manual workflow mode, all graph changes that occur * as a result will occur after this command and before a successful reply. + * + * Called between job_lock and job_unlock. */ void job_finalize(Job *job, Error **errp); /** * Remove the concluded @job from the query list and resets the passed pointer * to %NULL. Returns an error if the job is not actually concluded. + * + * Called between job_lock and job_unlock. */ void job_dismiss(Job **job, Error **errp); @@ -620,6 +674,8 @@ void job_dismiss(Job **job, Error **errp); * cancelled before completing, and -errno in other error cases. * * Callers must hold the AioContext lock of job->aio_context. + * + * Called between job_lock and job_unlock. */ int job_finish_sync(Job *job, void (*finish)(Job *, Error **errp), Error **errp); diff --git a/job.c b/job.c index 0e4dacf028..e393c1222f 100644 --- a/job.c +++ b/job.c @@ -242,7 +242,8 @@ bool job_cancel_requested(Job *job) return job->cancelled; } -bool job_is_ready(Job *job) +/* Called with job_mutex held. */ +bool job_is_ready_locked(Job *job) { switch (job->status) { case JOB_STATUS_UNDEFINED: @@ -264,6 +265,13 @@ bool job_is_ready(Job *job) return false; } +/* Called with job_mutex lock *not* held */ +bool job_is_ready(Job *job) +{ + JOB_LOCK_GUARD(); + return job_is_ready_locked(job); +} + bool job_is_completed(Job *job) { switch (job->status) { @@ -659,12 +667,18 @@ void job_dismiss(Job **jobptr, Error **errp) *jobptr = NULL; } -void job_early_fail(Job *job) +void job_early_fail_locked(Job *job) { assert(job->status == JOB_STATUS_CREATED); job_do_dismiss(job); } +void job_early_fail(Job *job) +{ + JOB_LOCK_GUARD(); + job_early_fail_locked(job); +} + static void job_conclude(Job *job) { job_state_transition(job, JOB_STATUS_CONCLUDED);