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virtio/ringtest: fix up need_event math

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last kicked event index must be updated unconditionally:
even if we don't need to kick, we do not want to re-check
the same entry for events.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
This commit is contained in:
Michael S. Tsirkin 2017-10-26 04:48:01 +03:00
parent 31919140ff
commit f229a55c31
1 changed files with 15 additions and 9 deletions
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18
tools/virtio/ringtest/ring.c
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@ -188,15 +188,17 @@ bool enable_call()
void kick_available(void) void kick_available(void)
{ {
bool need;
/* Flush in previous flags write */ /* Flush in previous flags write */
/* Barrier C (for pairing) */ /* Barrier C (for pairing) */
smp_mb(); smp_mb();
if (!need_event(event->kick_index, need = need_event(event->kick_index,
guest.avail_idx, guest.avail_idx,
guest.kicked_avail_idx)) guest.kicked_avail_idx);
return;
guest.kicked_avail_idx = guest.avail_idx; guest.kicked_avail_idx = guest.avail_idx;
if (need)
kick(); kick();
} }
@ -253,14 +255,18 @@ bool use_buf(unsigned *lenp, void **bufp)
void call_used(void) void call_used(void)
{ {
bool need;
/* Flush in previous flags write */ /* Flush in previous flags write */
/* Barrier D (for pairing) */ /* Barrier D (for pairing) */
smp_mb(); smp_mb();
if (!need_event(event->call_index,
need = need_event(event->call_index,
host.used_idx, host.used_idx,
host.called_used_idx)) host.called_used_idx);
return;
host.called_used_idx = host.used_idx; host.called_used_idx = host.used_idx;
if (need)
call(); call();
} }