On 6/29/19 11:57 AM, Jakub Kicinski wrote:
On Fri, 28 Jun 2019 14:39:29 -0700, Shannon Nelson wrote:
+static int ionic_tx(struct queue *q, struct sk_buff *skb)
+{
+ struct tx_stats *stats = q_to_tx_stats(q);
+ int err;
+
+ if (skb->ip_summed == CHECKSUM_PARTIAL)
+ err = ionic_tx_calc_csum(q, skb);
+ else
+ err = ionic_tx_calc_no_csum(q, skb);
+ if (err)
+ return err;
+
+ err = ionic_tx_skb_frags(q, skb);
+ if (err)
+ return err;
+
+ skb_tx_timestamp(skb);
+ stats->pkts++;
+ stats->bytes += skb->len;
Presumably this is 64bit so you should use
u64_stats_update_begin()
u64_stats_update_end()
around it (and all other stats).
Since the device won't work in a 32-bit arch and I have the the Kconfig
set to depend on 64BIT, I wasn't sure I needed to bother with the extra
syntactic sugar.
+
+ ionic_txq_post(q, !netdev_xmit_more(), ionic_tx_clean, skb);
+
+ return 0;
+}
+
+static int ionic_tx_descs_needed(struct queue *q, struct sk_buff *skb)
+{
+ struct tx_stats *stats = q_to_tx_stats(q);
+ int err;
+
+ /* If TSO, need roundup(skb->len/mss) descs */
+ if (skb_is_gso(skb))
+ return (skb->len / skb_shinfo(skb)->gso_size) + 1;
+
+ /* If non-TSO, just need 1 desc and nr_frags sg elems */
+ if (skb_shinfo(skb)->nr_frags <= IONIC_TX_MAX_SG_ELEMS)
+ return 1;
+
+ /* Too many frags, so linearize */
+ err = skb_linearize(skb);
+ if (err)
+ return err;
+
+ stats->linearize++;
+
+ /* Need 1 desc and zero sg elems */
+ return 1;
+}
+
+netdev_tx_t ionic_start_xmit(struct sk_buff *skb, struct net_device *netdev)
+{
+ u16 queue_index = skb_get_queue_mapping(skb);
+ struct lif *lif = netdev_priv(netdev);
+ struct queue *q;
+ int ndescs;
+ int err;
+
+ if (unlikely(!test_bit(LIF_UP, lif->state))) {
+ dev_kfree_skb(skb);
+ return NETDEV_TX_OK;
+ }
+
+ if (likely(lif_to_txqcq(lif, queue_index)))
+ q = lif_to_txq(lif, queue_index);
+ else
+ q = lif_to_txq(lif, 0);
+
+ ndescs = ionic_tx_descs_needed(q, skb);
+ if (ndescs < 0)
+ goto err_out_drop;
+
+ if (!ionic_q_has_space(q, ndescs)) {
+ netif_stop_subqueue(netdev, queue_index);
+ q->stop++;
+
+ /* Might race with ionic_tx_clean, check again */
+ smp_rmb();
+ if (ionic_q_has_space(q, ndescs)) {
+ netif_wake_subqueue(netdev, queue_index);
+ q->wake++;
+ } else {
+ return NETDEV_TX_BUSY;
This should never really happen..
Couldn't we have an Rx interrupt and a call to ionic_tx_clean() in the
middle of this?
+ }
+ }
+
+ if (skb_is_gso(skb))
+ err = ionic_tx_tso(q, skb);
+ else
+ err = ionic_tx(q, skb);
+
+ if (err)
+ goto err_out_drop;
.. at this point if you can't guarantee fitting biggest possible frame
in, you have to stop the ring.
Yep, that would work.
Thanks,
sln
