vduse: Use proper spinlock for IRQ injection

The IRQ injection work used spin_lock_irq() to protect the
scheduling of the softirq, but spin_lock_bh() should be
used.

With spin_lock_irq(), we noticed delay of more than 6
seconds between the time a NAPI polling work is scheduled
and the time it is executed.

Fixes: c8a6153 ("vduse: Introduce VDUSE - vDPA Device in Userspace")
Cc: xieyongji@bytedance.com

Suggested-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Message-Id: <20230705114505.63274-1-maxime.coquelin@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Xie Yongji <xieyongji@bytedance.com>

Author: mcoquelin

drivers/vdpa/vdpa_user/vduse_dev.c

@@ -935,21 +935,21 @@ static void vduse_dev_irq_inject(struct work_struct *work)
 {
 	struct vduse_dev *dev = container_of(work, struct vduse_dev, inject);
 
-	spin_lock_irq(&dev->irq_lock);
+	spin_lock_bh(&dev->irq_lock);
 	if (dev->config_cb.callback)
 		dev->config_cb.callback(dev->config_cb.private);
-	spin_unlock_irq(&dev->irq_lock);
+	spin_unlock_bh(&dev->irq_lock);
 }
 
 static void vduse_vq_irq_inject(struct work_struct *work)
 {
 	struct vduse_virtqueue *vq = container_of(work,
 					struct vduse_virtqueue, inject);
 
-	spin_lock_irq(&vq->irq_lock);
+	spin_lock_bh(&vq->irq_lock);
 	if (vq->ready && vq->cb.callback)
 		vq->cb.callback(vq->cb.private);
-	spin_unlock_irq(&vq->irq_lock);
+	spin_unlock_bh(&vq->irq_lock);
 }
 
 static bool vduse_vq_signal_irqfd(struct vduse_virtqueue *vq)