search for: virtnet_uses_svring

...ax_descs(struct virtnet_info *vi) +{ + if (vi->svring) { + if (virtnet_check_host_gso(vi)) + return 4; /* 1 fragment + linear part + virtio header + GSO header */ + else + return 3; /* 1 fragment + linear part + virtio header */ + } else { + return MAX_SKB_FRAGS + 2; + } +} + +static bool virtnet_uses_svring(struct virtnet_info *vi) +{ + u32 i; + + /* If a transmit/receive virtqueue is small, + * we cannot handle fragmented packets. + */ + for (i = 0; i < vi->max_queue_pairs; i++) { + if (IS_SMALL_VRING(virtqueue_get_vring_size(vi->sq[i].vq)) || + IS_SMALL_VRING(virtqueue_get_vring_siz...

...svring) { > + if (virtnet_check_host_gso(vi)) > + return 4; /* 1 fragment + linear part + virtio header + GSO header */ > + else > + return 3; /* 1 fragment + linear part + virtio header */ > + } else { > + return MAX_SKB_FRAGS + 2; > + } > +} > + > +static bool virtnet_uses_svring(struct virtnet_info *vi) > +{ > + u32 i; > + > + /* If a transmit/receive virtqueue is small, > + * we cannot handle fragmented packets. > + */ > + for (i = 0; i < vi->max_queue_pairs; i++) { > + if (IS_SMALL_VRING(virtqueue_get_vring_size(vi->sq[i].vq)) || >...

...lly need bool svring? can't we just check single_pkt_max_descs > all the time? > We can work without the bool, we could always check if single_pkt_max_descs != MAX_SKB_FRAGS + 2. It doesn't really matter to me, I was thinking it may be more readable this way. > > +static bool virtnet_uses_svring(struct virtnet_info *vi) > > +{ > > + u32 i; > > + > > + /* If a transmit/receive virtqueue is small, > > + * we cannot handle fragmented packets. > > + */ > > + for (i = 0; i < vi->max_queue_pairs; i++) { > > +...

At the moment, if a virtio network device uses vrings with less than MAX_SKB_FRAGS + 2 entries, the device won't be functional. The following condition vq->num_free >= 2 + MAX_SKB_FRAGS will always evaluate to false, leading to TX timeouts. This patchset attempts this fix this bug, and to allow small rings down to 4 entries. The first patch introduces a new mechanism in virtio core -

...just check single_pkt_max_descs > > all the time? > > > > We can work without the bool, we could always check if single_pkt_max_descs != MAX_SKB_FRAGS + 2. > It doesn't really matter to me, I was thinking it may be more readable this way. > > > > +static bool virtnet_uses_svring(struct virtnet_info *vi) > > > +{ > > > + u32 i; > > > + > > > + /* If a transmit/receive virtqueue is small, > > > + * we cannot handle fragmented packets. > > > + */ > > > + for (i = 0; i < vi->max_queue_pa...