To depend on vq.num and the usage of VHOST_MAX_PEND is not succinct
and in some case unexpected, so revert its logic part only.
Signed-off-by: Koichiro Den <den@xxxxxxxxxxxxx>
---
drivers/vhost/net.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 06d044862e58..99cf99b308a7 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -433,11 +433,15 @@ static int vhost_net_tx_get_vq_desc(struct vhost_net *net,
static bool vhost_exceeds_maxpend(struct vhost_net *net)
{
+ int num_pends;
struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
struct vhost_virtqueue *vq = &nvq->vq;
- return (nvq->upend_idx + vq->num - VHOST_MAX_PEND) % UIO_MAXIOV
- == nvq->done_idx;
+ num_pends = likely(nvq->upend_idx >= nvq->done_idx) ?
+ (nvq->upend_idx - nvq->done_idx) :
+ (nvq->upend_idx + UIO_MAXIOV - nvq->done_idx);
+
+ return num_pends > VHOST_MAX_PEND;
}
/* Expects to be always run from workqueue - which acts as
--
2.9.4
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