From patchwork Fri Feb 2 15:31:58 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hanna Czenczek X-Patchwork-Id: 13543044 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 2BB9AC48291 for ; Fri, 2 Feb 2024 15:33:32 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rVvXD-00042Y-DG; Fri, 02 Feb 2024 10:32:55 -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 1rVvXC-000421-6w for qemu-devel@nongnu.org; Fri, 02 Feb 2024 10:32:54 -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 1rVvXA-0000J2-QM for qemu-devel@nongnu.org; Fri, 02 Feb 2024 10:32:53 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1706887972; 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=1+yEfgAn/4T2TbGdJTrV2cdbu8XKqQ9ProoQLlyE1HA=; b=af6bgshVp3iGNrzYHLJgJH5caDMVYpbGe51WwgwVsVNclAfdtg09RO1AhNYaDXkfy/RfE4 SHjvXk1hgYNKjdmZNaf+TvQ527OBP7uevoTiaZ2fsQkgbpWBcz8DudZBIMftGKDSh4ZYTa cC8nQc0y8yPEN24+CWXC2X/1dSh3RKY= 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-78-DA1TbELCPOKi2tEd2mkYeg-1; Fri, 02 Feb 2024 10:32:48 -0500 X-MC-Unique: DA1TbELCPOKi2tEd2mkYeg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (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 4B39F85CBA3; Fri, 2 Feb 2024 15:32:48 +0000 (UTC) Received: from localhost (unknown [10.39.194.28]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E566740C95AD; Fri, 2 Feb 2024 15:32:47 +0000 (UTC) From: Hanna Czenczek To: qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, Hanna Czenczek , qemu-stable@nongnu.org, Stefan Hajnoczi , Fiona Ebner , Paolo Bonzini , Kevin Wolf , "Michael S . Tsirkin" , Fam Zheng Subject: [PATCH v2 3/3] virtio-blk: Use ioeventfd_attach in start_ioeventfd Date: Fri, 2 Feb 2024 16:31:58 +0100 Message-ID: <20240202153158.788922-4-hreitz@redhat.com> In-Reply-To: <20240202153158.788922-1-hreitz@redhat.com> References: <20240202153158.788922-1-hreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.2 Received-SPF: pass client-ip=170.10.133.124; envelope-from=hreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-2.276, 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_H5=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=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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Commit d3f6f294aeadd5f88caf0155e4360808c95b3146 ("virtio-blk: always set ioeventfd during startup") has made virtio_blk_start_ioeventfd() always kick the virtqueue (set the ioeventfd), regardless of whether the BB is drained. That is no longer necessary, because attaching the host notifier will now set the ioeventfd, too; this happens either immediately right here in virtio_blk_start_ioeventfd(), or later when the drain ends, in virtio_blk_ioeventfd_attach(). With event_notifier_set() removed, the code becomes the same as the one in virtio_blk_ioeventfd_attach(), so we can reuse that function. Signed-off-by: Hanna Czenczek --- hw/block/virtio-blk.c | 21 ++++++++++----------- 1 file changed, 10 insertions(+), 11 deletions(-) diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index 227d83569f..22b8eef69b 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -37,6 +37,8 @@ #include "hw/virtio/virtio-blk-common.h" #include "qemu/coroutine.h" +static void virtio_blk_ioeventfd_attach(VirtIOBlock *s); + static void virtio_blk_init_request(VirtIOBlock *s, VirtQueue *vq, VirtIOBlockReq *req) { @@ -1808,17 +1810,14 @@ static int virtio_blk_start_ioeventfd(VirtIODevice *vdev) s->ioeventfd_started = true; smp_wmb(); /* paired with aio_notify_accept() on the read side */ - /* Get this show started by hooking up our callbacks */ - for (i = 0; i < nvqs; i++) { - VirtQueue *vq = virtio_get_queue(vdev, i); - AioContext *ctx = s->vq_aio_context[i]; - - /* Kick right away to begin processing requests already in vring */ - event_notifier_set(virtio_queue_get_host_notifier(vq)); - - if (!blk_in_drain(s->conf.conf.blk)) { - virtio_queue_aio_attach_host_notifier(vq, ctx); - } + /* + * Get this show started by hooking up our callbacks. If drained now, + * virtio_blk_drained_end() will do this later. + * Attaching the notifier also kicks the virtqueues, processing any requests + * they may already have. + */ + if (!blk_in_drain(s->conf.conf.blk)) { + virtio_blk_ioeventfd_attach(s); } return 0;