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From:   Maxime Coquelin <maxime.coquelin@redhat.com>
To:     xieyongji@bytedance.com, jasowang@redhat.com, mst@redhat.com,
        david.marchand@redhat.com, lulu@redhat.com
Cc:     linux-kernel@vger.kernel.org,
        virtualization@lists.linux-foundation.org, netdev@vger.kernel.org,
        xuanzhuo@linux.alibaba.com, eperezma@redhat.com,
        Maxime Coquelin <maxime.coquelin@redhat.com>
Subject: [PATCH] vduse: Use proper spinlock for IRQ injection
Date:   Wed,  5 Jul 2023 13:45:05 +0200
Message-ID: <20230705114505.63274-1-maxime.coquelin@redhat.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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: c8a6153b6c59 ("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>
---
 drivers/vdpa/vdpa_user/vduse_dev.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index dc38ed21319d..df7869537ef1 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -935,10 +935,10 @@ 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)
@@ -946,10 +946,10 @@ 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)
-- 
2.41.0