From patchwork Wed Nov 29 19:55:41 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 13473391 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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7D15DC4167B for ; Wed, 29 Nov 2023 19:56:24 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.644175.1004871 (Exim 4.92) (envelope-from ) id 1r8QfK-0000Wf-6X; Wed, 29 Nov 2023 19:56:10 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 644175.1004871; Wed, 29 Nov 2023 19:56:10 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1r8QfK-0000WY-3J; Wed, 29 Nov 2023 19:56:10 +0000 Received: by outflank-mailman (input) for mailman id 644175; Wed, 29 Nov 2023 19:56:08 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1r8QfI-0000Sw-Rc for xen-devel@lists.xenproject.org; Wed, 29 Nov 2023 19:56:08 +0000 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id 527b5cdf-8ef1-11ee-98e4-6d05b1d4d9a1; Wed, 29 Nov 2023 20:56:02 +0100 (CET) Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-115-lpKhYjwBNRSAJDcVZt1Ezw-1; Wed, 29 Nov 2023 14:55:59 -0500 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 508B03C02B8C; Wed, 29 Nov 2023 19:55:58 +0000 (UTC) Received: from localhost (unknown [10.39.192.91]) by smtp.corp.redhat.com (Postfix) with ESMTP id 06D9D1C060B1; Wed, 29 Nov 2023 19:55:54 +0000 (UTC) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 527b5cdf-8ef1-11ee-98e4-6d05b1d4d9a1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1701287761; 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; bh=e7N4tRDtP2IBzVTMaL8yeWW0d5GyesAwh+oFp0HXr5s=; b=Gi9RB8Wsnev5AhMm4EMf2Ok1qinUP2NUZ3B8+jl+UvfuQ1n6gKd16N4t2QFhw5wJeNLrT3 LAPRSwSStS/gMlkLslanfrPWgXSNPal8EXF5SATP5CST67TSgEPnTIPPZtST6iKpQ5YvNu jZyNQXI5NDTDrzM0KYwRTJurKWJ+sqw= X-MC-Unique: lpKhYjwBNRSAJDcVZt1Ezw-1 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Cc: Hanna Reitz , Paul Durrant , Paolo Bonzini , Alberto Garcia , Emanuele Giuseppe Esposito , John Snow , Kevin Wolf , Eric Blake , Wen Congyang , , xen-devel@lists.xenproject.org, Coiby Xu , Stefan Hajnoczi , Eduardo Habkost , Xie Changlong , Ari Sundholm , Li Zhijian , Cleber Rosa , Juan Quintela , "Michael S. Tsirkin" , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , Jason Wang , Vladimir Sementsov-Ogievskiy , Zhang Chen , Peter Xu , Anthony Perard , Stefano Stabellini , Leonardo Bras , Pavel Dovgalyuk , Fam Zheng , Fabiano Rosas Subject: [PATCH 00/12] aio: remove AioContext lock Date: Wed, 29 Nov 2023 14:55:41 -0500 Message-ID: <20231129195553.942921-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.7 This series removes the AioContext locking APIs from QEMU. aio_context_acquire() and aio_context_release() are currently only needed to support the locking discipline required by AIO_POLL_WHILE() (except for a stray user that I converted in Patch 1). AIO_POLL_WHILE() doesn't really need the AioContext lock anymore, so it's possible to remove the API. This is a nice simplification because the AioContext locking rules were sometimes tricky or underspecified, leading to many bugs of the years. This patch series removes these APIs across the codebase and cleans up the documentation/comments that refers to them. Patch 1 is a AioContext lock user I forgot to convert in my earlier SCSI conversion series. Patch 2 removes tests for the AioContext lock because they will no longer be needed when the lock is gone. Patches 3-9 remove the AioContext lock. These can be reviewed by categorizing the call sites into 1. places that take the lock because they call an API that requires the lock (ultimately AIO_POLL_WHILE()) and 2. places that take the lock to protect state. There should be no instances of case 2 left. If you see one, you've found a bug in this patch series! Patches 10-12 remove comments. Based-on: 20231123194931.171598-1-stefanha@redhat.com ("[PATCH 0/4] scsi: eliminate AioContext lock") Since SCSI needs to stop relying on the AioContext lock before we can remove the lock. Stefan Hajnoczi (12): virtio-scsi: replace AioContext lock with tmf_bh_lock tests: remove aio_context_acquire() tests aio: make aio_context_acquire()/aio_context_release() a no-op graph-lock: remove AioContext locking block: remove AioContext locking scsi: remove AioContext locking aio-wait: draw equivalence between AIO_WAIT_WHILE() and AIO_WAIT_WHILE_UNLOCKED() aio: remove aio_context_acquire()/aio_context_release() API docs: remove AioContext lock from IOThread docs scsi: remove outdated AioContext lock comment job: remove outdated AioContext locking comments block: remove outdated AioContext locking comments docs/devel/multiple-iothreads.txt | 45 ++-- include/block/aio-wait.h | 16 +- include/block/aio.h | 17 -- include/block/block-common.h | 3 - include/block/block-global-state.h | 9 +- include/block/block-io.h | 12 +- include/block/block_int-common.h | 2 - include/block/graph-lock.h | 21 +- include/block/snapshot.h | 2 - include/hw/virtio/virtio-scsi.h | 17 +- include/qemu/job.h | 20 -- block.c | 357 ++++----------------------- block/backup.c | 4 +- block/blklogwrites.c | 8 +- block/blkverify.c | 4 +- block/block-backend.c | 33 +-- block/commit.c | 16 +- block/copy-before-write.c | 22 +- block/export/export.c | 22 +- block/export/vhost-user-blk-server.c | 4 - block/graph-lock.c | 44 +--- block/io.c | 45 +--- block/mirror.c | 41 +-- block/monitor/bitmap-qmp-cmds.c | 20 +- block/monitor/block-hmp-cmds.c | 29 --- block/qapi-sysemu.c | 27 +- block/qapi.c | 18 +- block/qcow2.c | 4 +- block/quorum.c | 8 +- block/raw-format.c | 5 - block/replication.c | 72 +----- block/snapshot.c | 26 +- block/stream.c | 12 +- block/vmdk.c | 20 +- block/write-threshold.c | 6 - blockdev.c | 315 +++++------------------ blockjob.c | 30 +-- hw/block/dataplane/virtio-blk.c | 10 - hw/block/dataplane/xen-block.c | 17 +- hw/block/virtio-blk.c | 45 +--- hw/core/qdev-properties-system.c | 9 - hw/scsi/scsi-bus.c | 2 - hw/scsi/scsi-disk.c | 29 +-- hw/scsi/virtio-scsi.c | 80 +++--- job.c | 16 -- migration/block.c | 33 +-- migration/migration-hmp-cmds.c | 3 - migration/savevm.c | 22 -- net/colo-compare.c | 2 - qemu-img.c | 4 - qemu-io.c | 10 +- qemu-nbd.c | 2 - replay/replay-debugging.c | 4 - tests/unit/test-aio.c | 67 +---- tests/unit/test-bdrv-drain.c | 91 ++----- tests/unit/test-bdrv-graph-mod.c | 26 +- tests/unit/test-block-iothread.c | 31 --- tests/unit/test-blockjob.c | 137 ---------- tests/unit/test-replication.c | 11 - util/async.c | 14 -- util/vhost-user-server.c | 3 - scripts/block-coroutine-wrapper.py | 7 +- tests/qemu-iotests/202 | 2 +- tests/qemu-iotests/203 | 3 +- tests/tsan/suppressions.tsan | 1 - 65 files changed, 324 insertions(+), 1713 deletions(-)