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Subject: Re: [PATCH 2/2] virtio_ring: add unlikely annotation for free descs
 check
To:     Stefano Garzarella <sgarzare@redhat.com>
Cc:     mst@redhat.com, jasowang@redhat.com,
        virtualization@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org
References: <20220328105817.1028065-1-xianting.tian@linux.alibaba.com>
 <20220328105817.1028065-2-xianting.tian@linux.alibaba.com>
 <20220329075024.eoajm5ufrcfytug4@sgarzare-redhat>
From:   Xianting Tian <xianting.tian@linux.alibaba.com>
Message-ID: <073dc28b-1707-cd04-daba-13aa4fac5a85@linux.alibaba.com>
Date:   Mon, 4 Apr 2022 23:11:16 +0800
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I can't find it in next branch, will you apply this patch?

在 2022/3/29 下午3:50, Stefano Garzarella 写道:
> On Mon, Mar 28, 2022 at 06:58:17PM +0800, Xianting Tian wrote:
>> The 'if (vq->vq.num_free < descs_used)' check will almost always be 
>> false.
>>
>> Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com>
>> ---
>> drivers/virtio/virtio_ring.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
>
>>
>> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
>> index d597fc0874ec..ab6d5f0cb579 100644
>> --- a/drivers/virtio/virtio_ring.c
>> +++ b/drivers/virtio/virtio_ring.c
>> @@ -525,7 +525,7 @@ static inline int virtqueue_add_split(struct 
>> virtqueue *_vq,
>>         descs_used = total_sg;
>>     }
>>
>> -    if (vq->vq.num_free < descs_used) {
>> +    if (unlikely(vq->vq.num_free < descs_used)) {
>>         pr_debug("Can't add buf len %i - avail = %i\n",
>>              descs_used, vq->vq.num_free);
>>         /* FIXME: for historical reasons, we force a notify here if
>> -- 
>> 2.17.1
>>