search for: single_pkt_max_desc

At the moment, if a 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 patch introduces a new variable, single_pkt_max_descs, that holds the max number of descriptors we may need to handle a single packet. This patch also detects the small vring during probe, blocks some features that can't be used with small vrings, and fails probe, leading to a reset and features re-negotiation. Features that can't be used w...

...if a 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 patch introduces a new variable, single_pkt_max_descs, that holds > the max number of descriptors we may need to handle a single packet. > > This patch also detects the small vring during probe, blocks some > features that can't be used with small vrings, and fails probe, > leading to a reset and features re-negotiation. > &gt...

...ings 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 patch introduces a new variable, single_pkt_max_descs, that holds > > the max number of descriptors we may need to handle a single packet. > > > > This patch also detects the small vring during probe, blocks some > > features that can't be used with small vrings, and fails probe, > > leading to a reset and features r...

...> 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 patch introduces a new variable, single_pkt_max_descs, that holds > > > the max number of descriptors we may need to handle a single packet. > > > > > > This patch also detects the small vring during probe, blocks some > > > features that can't be used with small vrings, and fails probe, > > > leading...

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 -