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 X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8B301ECE58E for ; Mon, 14 Oct 2019 18:00:44 +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 6A2B120873 for ; Mon, 14 Oct 2019 18:00:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6A2B120873 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:55136 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iK4eB-0005Fo-57 for qemu-devel@archiver.kernel.org; Mon, 14 Oct 2019 14:00:43 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:53170) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iK4bk-0003LJ-DW for qemu-devel@nongnu.org; Mon, 14 Oct 2019 13:58:13 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iK4bh-0008Ah-Nf for qemu-devel@nongnu.org; Mon, 14 Oct 2019 13:58:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37494) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iK4bh-0008AC-EX for qemu-devel@nongnu.org; Mon, 14 Oct 2019 13:58:09 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6CBB418CB900 for ; Mon, 14 Oct 2019 17:58:07 +0000 (UTC) Received: from work-vm (unknown [10.36.118.31]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1856E100EBD4; Mon, 14 Oct 2019 17:57:50 +0000 (UTC) Date: Mon, 14 Oct 2019 18:57:48 +0100 From: "Dr. David Alan Gilbert" To: qemu-devel@nongnu.org, mst@redhat.com Subject: Re: [PATCH] virito: Use auto rcu_read macros Message-ID: <20191014175748.GA3251@work-vm> References: <20191014175440.152609-1-dgilbert@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191014175440.152609-1-dgilbert@redhat.com> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.63]); Mon, 14 Oct 2019 17:58:07 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: stefanha@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Dr. David Alan Gilbert (git) (dgilbert@redhat.com) wrote: > From: "Dr. David Alan Gilbert" > > Use RCU_READ_LOCK_GUARD and WITH_RCU_READ_LOCK_GUARD > to replace the manual rcu_read_(un)lock calls. > > I think the only change is virtio_load which was missing unlocks > in error paths; those end up being fatal errors so it's not > that important anyway. > > Signed-off-by: Dr. David Alan Gilbert Oops, I've typo'd virito in the title again... Dave > --- > hw/virtio/virtio.c | 46 ++++++++++++++++------------------------------ > 1 file changed, 16 insertions(+), 30 deletions(-) > > diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c > index 527df03bfd..15ae9da60b 100644 > --- a/hw/virtio/virtio.c > +++ b/hw/virtio/virtio.c > @@ -337,7 +337,7 @@ void virtio_queue_set_notification(VirtQueue *vq, int enable) > return; > } > > - rcu_read_lock(); > + RCU_READ_LOCK_GUARD(); > if (virtio_vdev_has_feature(vq->vdev, VIRTIO_RING_F_EVENT_IDX)) { > vring_set_avail_event(vq, vring_avail_idx(vq)); > } else if (enable) { > @@ -349,7 +349,6 @@ void virtio_queue_set_notification(VirtQueue *vq, int enable) > /* Expose avail event/used flags before caller checks the avail idx. */ > smp_mb(); > } > - rcu_read_unlock(); > } > > int virtio_queue_ready(VirtQueue *vq) > @@ -393,9 +392,8 @@ int virtio_queue_empty(VirtQueue *vq) > return 0; > } > > - rcu_read_lock(); > + RCU_READ_LOCK_GUARD(); > empty = vring_avail_idx(vq) == vq->last_avail_idx; > - rcu_read_unlock(); > return empty; > } > > @@ -530,10 +528,9 @@ void virtqueue_flush(VirtQueue *vq, unsigned int count) > void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem, > unsigned int len) > { > - rcu_read_lock(); > + RCU_READ_LOCK_GUARD(); > virtqueue_fill(vq, elem, len, 0); > virtqueue_flush(vq, 1); > - rcu_read_unlock(); > } > > /* Called within rcu_read_lock(). */ > @@ -624,7 +621,7 @@ void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes, > return; > } > > - rcu_read_lock(); > + RCU_READ_LOCK_GUARD(); > idx = vq->last_avail_idx; > total_bufs = in_total = out_total = 0; > > @@ -719,7 +716,6 @@ done: > if (out_bytes) { > *out_bytes = out_total; > } > - rcu_read_unlock(); > return; > > err: > @@ -869,7 +865,7 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz) > if (unlikely(vdev->broken)) { > return NULL; > } > - rcu_read_lock(); > + RCU_READ_LOCK_GUARD(); > if (virtio_queue_empty_rcu(vq)) { > goto done; > } > @@ -977,7 +973,6 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz) > trace_virtqueue_pop(vq, elem, elem->in_num, elem->out_num); > done: > address_space_cache_destroy(&indirect_desc_cache); > - rcu_read_unlock(); > > return elem; > > @@ -1680,13 +1675,10 @@ static bool virtio_should_notify(VirtIODevice *vdev, VirtQueue *vq) > > void virtio_notify_irqfd(VirtIODevice *vdev, VirtQueue *vq) > { > - bool should_notify; > - rcu_read_lock(); > - should_notify = virtio_should_notify(vdev, vq); > - rcu_read_unlock(); > - > - if (!should_notify) { > - return; > + WITH_RCU_READ_LOCK_GUARD() { > + if (!virtio_should_notify(vdev, vq)) { > + return; > + } > } > > trace_virtio_notify_irqfd(vdev, vq); > @@ -1718,13 +1710,10 @@ static void virtio_irq(VirtQueue *vq) > > void virtio_notify(VirtIODevice *vdev, VirtQueue *vq) > { > - bool should_notify; > - rcu_read_lock(); > - should_notify = virtio_should_notify(vdev, vq); > - rcu_read_unlock(); > - > - if (!should_notify) { > - return; > + WITH_RCU_READ_LOCK_GUARD() { > + if (!virtio_should_notify(vdev, vq)) { > + return; > + } > } > > trace_virtio_notify(vdev, vq); > @@ -2241,7 +2230,7 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id) > vdev->start_on_kick = true; > } > > - rcu_read_lock(); > + RCU_READ_LOCK_GUARD(); > for (i = 0; i < num; i++) { > if (vdev->vq[i].vring.desc) { > uint16_t nheads; > @@ -2289,7 +2278,6 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id) > } > } > } > - rcu_read_unlock(); > > return 0; > } > @@ -2422,21 +2410,19 @@ void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, uint16_t idx) > > void virtio_queue_restore_last_avail_idx(VirtIODevice *vdev, int n) > { > - rcu_read_lock(); > + RCU_READ_LOCK_GUARD(); > if (vdev->vq[n].vring.desc) { > vdev->vq[n].last_avail_idx = vring_used_idx(&vdev->vq[n]); > vdev->vq[n].shadow_avail_idx = vdev->vq[n].last_avail_idx; > } > - rcu_read_unlock(); > } > > void virtio_queue_update_used_idx(VirtIODevice *vdev, int n) > { > - rcu_read_lock(); > + RCU_READ_LOCK_GUARD(); > if (vdev->vq[n].vring.desc) { > vdev->vq[n].used_idx = vring_used_idx(&vdev->vq[n]); > } > - rcu_read_unlock(); > } > > void virtio_queue_invalidate_signalled_used(VirtIODevice *vdev, int n) > -- > 2.23.0 > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK