netdev - [PATCH v2] vdpasim: allow to enable a vq repeatedly

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Date:   Thu, 19 May 2022 16:59:19 +0200
From:   Eugenio Pérez <eperezma@...hat.com>
To:     mst@...hat.com, jasowang@...hat.com
Cc:     lvivier@...hat.com, netdev@...r.kernel.org, lulu@...hat.com,
        eli@...lanox.com, sgarzare@...hat.com, parav@...dia.com,
        virtualization@...ts.linux-foundation.org, kvm@...r.kernel.org,
        lingshan.zhu@...el.com, linux-kernel@...r.kernel.org,
        gdawar@...inx.com
Subject: [PATCH v2] vdpasim: allow to enable a vq repeatedly

Code must be resilient to enable a queue many times.

At the moment the queue is resetting so it's definitely not the expected
behavior.

v2: set vq->ready = 0 at disable.

Fixes: 2c53d0f64c06 ("vdpasim: vDPA device simulator")
Cc: stable@...r.kernel.org
Signed-off-by: Eugenio Pérez <eperezma@...hat.com>
---
 drivers/vdpa/vdpa_sim/vdpa_sim.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
index ddbe142af09a..881f9864c437 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -353,11 +353,14 @@ static void vdpasim_set_vq_ready(struct vdpa_device *vdpa, u16 idx, bool ready)
 {
 	struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
 	struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
+	bool old_ready;
 
 	spin_lock(&vdpasim->lock);
+	old_ready = vq->ready;
 	vq->ready = ready;
-	if (vq->ready)
+	if (vq->ready && !old_ready) {
 		vdpasim_queue_ready(vdpasim, idx);
+	}
 	spin_unlock(&vdpasim->lock);
 }
 
-- 
2.27.0