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From:   Alvaro Karsz <alvaro.karsz@solid-run.com>
To:     "Michael S. Tsirkin" <mst@redhat.com>
CC:     "jasowang@redhat.com" <jasowang@redhat.com>,
        "davem@davemloft.net" <davem@davemloft.net>,
        "edumazet@google.com" <edumazet@google.com>,
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        "pabeni@redhat.com" <pabeni@redhat.com>,
        "virtualization@lists.linux-foundation.org" 
        <virtualization@lists.linux-foundation.org>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH net] virtio-net: reject small vring sizes
Thread-Topic: [PATCH net] virtio-net: reject small vring sizes
Thread-Index: AQHZcDeGnH5xR2OGlkuo4s6jvhNMC68uZkiAgACnyXQ=
Date:   Mon, 17 Apr 2023 06:43:39 +0000
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> > +static int virtnet_validate_vqs(struct virtnet_info *vi)=0A=
> > +{=0A=
> > +     u32 i, min_size =3D roundup_pow_of_two(MAX_SKB_FRAGS + 2);=0A=
> =0A=
> why power of two?=0A=
=0A=
The ring size is always a power of 2, so checking against MAX_SKB_FRAGS + 2=
 or against roundup_pow_of_two will result in the same, and I think that pr=
inting the warning with the actual min value is more helpful.=0A=
I can check the condition against MAX_SKB_FRAGS + 2, and print the rounded =
value in case of an error.=0A=