qemu-kvm/SOURCES/kvm-virtio-blk-Use-ioeventfd_attach-in-start_ioeventfd.patch

76 lines
2.9 KiB
Diff

From 094941b2c3e66e078d93718933eb07e800a7dd60 Mon Sep 17 00:00:00 2001
From: Hanna Czenczek <hreitz@redhat.com>
Date: Fri, 2 Feb 2024 16:31:58 +0100
Subject: [PATCH 3/6] virtio-blk: Use ioeventfd_attach in start_ioeventfd
RH-Author: Hanna Czenczek <hreitz@redhat.com>
RH-MergeRequest: 223: virtio: Re-enable notifications after drain
RH-Jira: RHEL-3934
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Commit: [3/3] 96d6760d1b7b12df695b6825b15a2a3b8a79a74c (hreitz/qemu-kvm-c-9-s)
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 <hreitz@redhat.com>
Message-ID: <20240202153158.788922-4-hreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit 52bff01f64eec017ffb0d5903a0ee1d67ca7a548)
---
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 0b9100b746..7fdeaf2d12 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;
--
2.39.3