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Fri, 21 Apr 2023 02:33:44 -0700 (PDT) X-Google-Smtp-Source: AKy350aiB6PKt5Apr6zvKUWLYjAMElWsrQ5f4ElFyzXlZsukpkSNihc29vqtxgqQ0RhcKwR+g0UFYA== X-Received: by 2002:a17:906:488b:b0:94e:56c4:59f2 with SMTP id v11-20020a170906488b00b0094e56c459f2mr1637549ejq.26.1682069623894; Fri, 21 Apr 2023 02:33:43 -0700 (PDT) From: Paolo Bonzini To: qemu-devel@nongnu.org Cc: Stefan Hajnoczi Subject: [PULL 19/25] qemu-coroutine: remove qatomic_mb_read() Date: Fri, 21 Apr 2023 11:33:10 +0200 Message-Id: <20230421093316.17941-20-pbonzini@redhat.com> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230421093316.17941-1-pbonzini@redhat.com> References: <20230421093316.17941-1-pbonzini@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.129.124; envelope-from=pbonzini@redhat.com; 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Reviewed-by: Stefan Hajnoczi Signed-off-by: Paolo Bonzini --- util/qemu-coroutine.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/util/qemu-coroutine.c b/util/qemu-coroutine.c index 849452369201..17a88f65053e 100644 --- a/util/qemu-coroutine.c +++ b/util/qemu-coroutine.c @@ -127,9 +127,13 @@ void qemu_aio_coroutine_enter(AioContext *ctx, Corouti= ne *co) Coroutine *to =3D QSIMPLEQ_FIRST(&pending); CoroutineAction ret; =20 - /* Cannot rely on the read barrier for to in aio_co_wake(), as the= re are - * callers outside of aio_co_wake() */ - const char *scheduled =3D qatomic_mb_read(&to->scheduled); + /* + * Read to before to->scheduled; pairs with qatomic_cmpxchg in + * qemu_co_sleep(), aio_co_schedule() etc. + */ + smp_read_barrier_depends(); + + const char *scheduled =3D qatomic_read(&to->scheduled); =20 QSIMPLEQ_REMOVE_HEAD(&pending, co_queue_next); =20 --=20 2.40.0