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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id CDDE3C35274 for ; Thu, 21 Dec 2023 21:28:41 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rGQWn-0007hg-2H; Thu, 21 Dec 2023 16:24:25 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rGQWj-0007MN-CQ for qemu-devel@nongnu.org; Thu, 21 Dec 2023 16:24:21 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rGQWh-00084s-Ap for qemu-devel@nongnu.org; Thu, 21 Dec 2023 16:24:21 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1703193858; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=HOlY/UHLpbwih8IlglS/FB+polD3t6sdyX3kh+yI1Ao=; b=QtU8xHBYuPcqxiF9oJE/E3l9zMR3dH0r+L8BtEXD0TteUscsI77XY7djySqf4Qz+j0g4d+ RHtvmcgVhDYCuqF/DdvCuItJnM3+zluBRb+1pSNjd4AfnMOgLnNPvGYtL8sQZLxstJIsL4 heBvOyOESuSh5ftWp2d8DsKoDk0PomI= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-350-7bSGIw64N7-c18rE-N0_Fw-1; Thu, 21 Dec 2023 16:24:17 -0500 X-MC-Unique: 7bSGIw64N7-c18rE-N0_Fw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (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 D2B3A88F561; Thu, 21 Dec 2023 21:24:16 +0000 (UTC) Received: from merkur.fritz.box (unknown [10.39.193.128]) by smtp.corp.redhat.com (Postfix) with ESMTP id 266DBC15968; Thu, 21 Dec 2023 21:24:14 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Cc: kwolf@redhat.com, stefanha@redhat.com, qemu-devel@nongnu.org Subject: [PULL 12/33] virtio-scsi: don't lock AioContext around virtio_queue_aio_attach_host_notifier() Date: Thu, 21 Dec 2023 22:23:17 +0100 Message-ID: <20231221212339.164439-13-kwolf@redhat.com> In-Reply-To: <20231221212339.164439-1-kwolf@redhat.com> References: <20231221212339.164439-1-kwolf@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.8 Received-SPF: pass client-ip=170.10.133.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.061, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Stefan Hajnoczi virtio_queue_aio_attach_host_notifier() does not require the AioContext lock. Stop taking the lock and add an explicit smp_wmb() because we were relying on the implicit barrier in the AioContext lock before. Signed-off-by: Stefan Hajnoczi Reviewed-by: Eric Blake Reviewed-by: Kevin Wolf Message-ID: <20231204164259.1515217-3-stefanha@redhat.com> Signed-off-by: Kevin Wolf --- hw/scsi/virtio-scsi-dataplane.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) diff --git a/hw/scsi/virtio-scsi-dataplane.c b/hw/scsi/virtio-scsi-dataplane.c index 1e684beebe..135e23fe54 100644 --- a/hw/scsi/virtio-scsi-dataplane.c +++ b/hw/scsi/virtio-scsi-dataplane.c @@ -149,23 +149,17 @@ int virtio_scsi_dataplane_start(VirtIODevice *vdev) memory_region_transaction_commit(); - /* - * These fields are visible to the IOThread so we rely on implicit barriers - * in aio_context_acquire() on the write side and aio_notify_accept() on - * the read side. - */ s->dataplane_starting = false; s->dataplane_started = true; + smp_wmb(); /* paired with aio_notify_accept() */ if (s->bus.drain_count == 0) { - aio_context_acquire(s->ctx); virtio_queue_aio_attach_host_notifier(vs->ctrl_vq, s->ctx); virtio_queue_aio_attach_host_notifier_no_poll(vs->event_vq, s->ctx); for (i = 0; i < vs->conf.num_queues; i++) { virtio_queue_aio_attach_host_notifier(vs->cmd_vqs[i], s->ctx); } - aio_context_release(s->ctx); } return 0; -- 2.43.0