/* Low latency socket callback. Called with bh disabled */
static int sn_poll_ll(struct napi_struct *napi)
{
struct sn_queue *rx_queue = container_of(napi, struct sn_queue, napi);
int idle_cnt = 0;
int ret;
if (!spin_trylock(&rx_queue->lock))
return LL_FLUSH_BUSY;
rx_queue->rx_stats.ll_polls++;
sn_disable_interrupt(rx_queue);
/* Meh... Since there is no notification for busy loop completion,
* there is no clean way to avoid race condition w.r.t. interrupts.
* Instead, do a roughly 5-us polling in this function. */
do {
ret = sn_poll_action(rx_queue, SN_BUSY_POLL_BUDGET);
if (ret == 0)
cpu_relax();
} while (ret == 0 && idle_cnt++ < 1000);
sn_enable_interrupt(rx_queue);
if (rx_queue->dev->ops->pending_rx(rx_queue)) {
sn_disable_interrupt(rx_queue);
napi_schedule(napi);
}
spin_unlock(&rx_queue->lock);
return ret;
}
/* The return value says how many packets are actually received */
static int sn_poll(struct napi_struct *napi, int budget)
{
struct sn_queue *rx_queue;
int ret;
rx_queue = container_of(napi, struct sn_queue, rx.napi);
if (!spin_trylock(&rx_queue->rx.lock))
return 0;
rx_queue->rx.stats.polls++;
ret = sn_poll_action(rx_queue, budget);
if (ret < budget) {
napi_complete(napi);
sn_enable_interrupt(rx_queue);
/* last check for race condition.
* see sn_enable_interrupt() */
if (rx_queue->dev->ops->pending_rx(rx_queue)) {
napi_reschedule(napi);
sn_disable_interrupt(rx_queue);
}
}
spin_unlock(&rx_queue->rx.lock);
return ret;
}