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netmap: vtnet: fix RX virtqueue initialization bug

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The vtnet_netmap_rxq_populate() function erroneously assumed
that kring->nr_hwcur = 0, i.e. the kring was in the initial
state. However, this is not always the case: for example,
when a vtnet reinit is triggered by some changes in the
interface flags or capenable.
This patch changes the behaviour of vtnet_netmap_kring_refill()
so that it always starts publishing the netmap buffers starting
from the current value of kring->nr_hwcur.

MFC after:	1 week
This commit is contained in:
vmaffione 2020-06-01 16:10:44 +00:00
parent cf86529c2e
commit 6271d55836
1 changed files with 19 additions and 7 deletions
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26
sys/dev/netmap/if_vtnet_netmap.h
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@ -232,14 +232,20 @@ vtnet_netmap_txsync(struct netmap_kring *kring, int flags)
return 0;
}
/*
* Publish (up to) num netmap receive buffers to the host,
* starting from the first one that the user made available
* (kring->nr_hwcur).
*/
static int
vtnet_netmap_kring_refill(struct netmap_kring *kring, u_int nm_i, u_int head)
vtnet_netmap_kring_refill(struct netmap_kring *kring, u_int num)
{
struct netmap_adapter *na = kring->na;
struct ifnet *ifp = na->ifp;
struct netmap_ring *ring = kring->ring;
u_int ring_nr = kring->ring_id;
u_int const lim = kring->nkr_num_slots - 1;
u_int nm_i = kring->nr_hwcur;
/* device-specific */
struct vtnet_softc *sc = ifp->if_softc;
@ -250,7 +256,7 @@ vtnet_netmap_kring_refill(struct netmap_kring *kring, u_int nm_i, u_int head)
struct sglist_seg ss[2];
struct sglist sg = { ss, 0, 0, 2 };
for (; nm_i != head; nm_i = nm_next(nm_i, lim)) {
for (; num > 0; nm_i = nm_next(nm_i, lim), num--) {
struct netmap_slot *slot = &ring->slot[nm_i];
uint64_t paddr;
void *addr = PNMB(na, slot, &paddr);
@ -302,10 +308,11 @@ vtnet_netmap_rxq_populate(struct vtnet_rxq *rxq)
kring->nr_pending_mode == NKR_NETMAP_ON))
return -1;
/* Expose all the RX netmap buffers. Note that the number of
* netmap slots in the RX ring matches the maximum number of
* 2-elements sglist that the RX virtqueue can accommodate. */
error = vtnet_netmap_kring_refill(kring, 0, na->num_rx_desc);
/* Expose all the RX netmap buffers we can. In case of no indirect
* buffers, the number of netmap slots in the RX ring matches the
* maximum number of 2-elements sglist that the RX virtqueue can
* accommodate. */
error = vtnet_netmap_kring_refill(kring, na->num_rx_desc);
virtqueue_notify(rxq->vtnrx_vq);
return error < 0 ? ENXIO : 0;
@ -381,7 +388,12 @@ vtnet_netmap_rxsync(struct netmap_kring *kring, int flags)
*/
nm_i = kring->nr_hwcur; /* netmap ring index */
if (nm_i != head) {
int nm_j = vtnet_netmap_kring_refill(kring, nm_i, head);
int howmany = head - nm_i;
int nm_j;
if (howmany < 0)
howmany += kring->nkr_num_slots;
nm_j = vtnet_netmap_kring_refill(kring, howmany);
if (nm_j < 0)
return nm_j;
kring->nr_hwcur = nm_j;