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Date:   Thu, 12 May 2022 14:15:27 -0700
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Subject: Re: [PATCH v5 3/3] vdpa/mlx5: Add support for reading descriptor
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From:   Si-Wei Liu <si-wei.liu@oracle.com>
To:     Eli Cohen <elic@nvidia.com>, mst@redhat.com, jasowang@redhat.com
Cc:     virtualization@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org
References: <20220510112734.205669-1-elic@nvidia.com>
 <20220510112734.205669-4-elic@nvidia.com>
 <eda33c78-fd39-a5bb-9e9e-06b2c37d3fe5@oracle.com>
Organization: Oracle Corporation
In-Reply-To: <eda33c78-fd39-a5bb-9e9e-06b2c37d3fe5@oracle.com>
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On 5/11/2022 10:25 AM, Si-Wei Liu wrote:
>>
>> +
>> +static int mlx5_vdpa_get_vendor_vq_stats(struct vdpa_device *vdev, 
>> u16 idx,
>> +                     struct sk_buff *msg,
>> +                     struct netlink_ext_ack *extack)
>> +{
>> +    struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
>> +    struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
>> +    struct mlx5_vdpa_virtqueue *mvq;
>> +    struct mlx5_control_vq *cvq;
>> +    u64 received_desc;
>> +    u64 completed_desc;
>> +    int err = 0;
>> +    u16 max_vqp;
>> +
>> +    mutex_lock(&ndev->reslock);
> I wonder if we can change this lock to r/w semaphore too, otherwise it 
> almost defeats the merit of converting vdpa_dev_mutex to the same. 
> This change would benefit multiple parallel readers. 
It looks like the lately posted v6 series missed this change somehow?

-Siwei