Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Xie Yongji <xieyongji@bytedance.com>
To:     mst@redhat.com, jasowang@redhat.com, stefanha@redhat.com,
        sgarzare@redhat.com, parav@nvidia.com, hch@infradead.org,
        christian.brauner@canonical.com, rdunlap@infradead.org,
        willy@infradead.org, viro@zeniv.linux.org.uk, axboe@kernel.dk,
        bcrl@kvack.org, corbet@lwn.net, mika.penttila@nextfour.com,
        dan.carpenter@oracle.com, joro@8bytes.org,
        gregkh@linuxfoundation.org, zhe.he@windriver.com,
        xiaodong.liu@intel.com
Cc:     songmuchun@bytedance.com,
        virtualization@lists.linux-foundation.org, netdev@vger.kernel.org,
        kvm@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Subject: [PATCH v9 04/17] vdpa: Fail the vdpa_reset() if fail to set device status to zero
Date:   Tue, 13 Jul 2021 16:46:43 +0800
Message-Id: <20210713084656.232-5-xieyongji@bytedance.com>
In-Reply-To: <20210713084656.232-1-xieyongji@bytedance.com>
References: <20210713084656.232-1-xieyongji@bytedance.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Re-read the device status to ensure it's set to zero during
resetting. Otherwise, fail the vdpa_reset() after timeout.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
 include/linux/vdpa.h | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
index f822490db584..198c30e84b5d 100644
--- a/include/linux/vdpa.h
+++ b/include/linux/vdpa.h
@@ -6,6 +6,7 @@
 #include <linux/device.h>
 #include <linux/interrupt.h>
 #include <linux/vhost_iotlb.h>
+#include <linux/delay.h>
 
 /**
  * struct vdpa_calllback - vDPA callback definition.
@@ -340,12 +341,24 @@ static inline struct device *vdpa_get_dma_dev(struct vdpa_device *vdev)
 	return vdev->dma_dev;
 }
 
-static inline void vdpa_reset(struct vdpa_device *vdev)
+#define VDPA_RESET_TIMEOUT_MS 1000
+
+static inline int vdpa_reset(struct vdpa_device *vdev)
 {
 	const struct vdpa_config_ops *ops = vdev->config;
+	int timeout = 0;
 
 	vdev->features_valid = false;
 	ops->set_status(vdev, 0);
+	while (ops->get_status(vdev)) {
+		timeout += 20;
+		if (timeout > VDPA_RESET_TIMEOUT_MS)
+			return -EIO;
+
+		msleep(20);
+	}
+
+	return 0;
 }
 
 static inline int vdpa_set_features(struct vdpa_device *vdev, u64 features)
-- 
2.11.0