sfc: ef100 representor RX NAPI poll

This patch adds the 'bottom half' napi->poll routine for representor RX.
See the next patch (with the top half) for an explanation of the 'fake
 interrupt' scheme used to drive this NAPI context.

Signed-off-by: Edward Cree <ecree.xilinx@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/sfc/ef100_rep.c b/drivers/net/ethernet/sfc/ef100_rep.c
index 102071ed051b6b71d68de28115f5e2cc8b8d7833..fe45ae963391025821796fd0785a228ab8e42ed3 100644 (file)
--- a/drivers/net/ethernet/sfc/ef100_rep.c
+++ b/drivers/net/ethernet/sfc/ef100_rep.c
@@ -16,12 +16,16 @@
 
 #define EFX_EF100_REP_DRIVER   "efx_ef100_rep"
 
+static int efx_ef100_rep_poll(struct napi_struct *napi, int weight);
+
 static int efx_ef100_rep_init_struct(struct efx_nic *efx, struct efx_rep *efv,
                                     unsigned int i)
 {
        efv->parent = efx;
        efv->idx = i;
        INIT_LIST_HEAD(&efv->list);
+       INIT_LIST_HEAD(&efv->rx_list);
+       spin_lock_init(&efv->rx_lock);
        efv->msg_enable = NETIF_MSG_DRV | NETIF_MSG_PROBE |
                          NETIF_MSG_LINK | NETIF_MSG_IFDOWN |
                          NETIF_MSG_IFUP | NETIF_MSG_RX_ERR |
@@ -29,6 +33,25 @@ static int efx_ef100_rep_init_struct(struct efx_nic *efx, struct efx_rep *efv,
        return 0;
 }
 
+static int efx_ef100_rep_open(struct net_device *net_dev)
+{
+       struct efx_rep *efv = netdev_priv(net_dev);
+
+       netif_napi_add(net_dev, &efv->napi, efx_ef100_rep_poll,
+                      NAPI_POLL_WEIGHT);
+       napi_enable(&efv->napi);
+       return 0;
+}
+
+static int efx_ef100_rep_close(struct net_device *net_dev)
+{
+       struct efx_rep *efv = netdev_priv(net_dev);
+
+       napi_disable(&efv->napi);
+       netif_napi_del(&efv->napi);
+       return 0;
+}
+
 static netdev_tx_t efx_ef100_rep_xmit(struct sk_buff *skb,
                                      struct net_device *dev)
 {
@@ -93,6 +116,8 @@ static void efx_ef100_rep_get_stats64(struct net_device *dev,
 }
 
 static const struct net_device_ops efx_ef100_rep_netdev_ops = {
+       .ndo_open               = efx_ef100_rep_open,
+       .ndo_stop               = efx_ef100_rep_close,
        .ndo_start_xmit         = efx_ef100_rep_xmit,
        .ndo_get_port_parent_id = efx_ef100_rep_get_port_parent_id,
        .ndo_get_phys_port_name = efx_ef100_rep_get_phys_port_name,
@@ -256,3 +281,42 @@ void efx_ef100_fini_vfreps(struct efx_nic *efx)
        list_for_each_entry_safe(efv, next, &efx->vf_reps, list)
                efx_ef100_vfrep_destroy(efx, efv);
 }
+
+static int efx_ef100_rep_poll(struct napi_struct *napi, int weight)
+{
+       struct efx_rep *efv = container_of(napi, struct efx_rep, napi);
+       unsigned int read_index;
+       struct list_head head;
+       struct sk_buff *skb;
+       bool need_resched;
+       int spent = 0;
+
+       INIT_LIST_HEAD(&head);
+       /* Grab up to 'weight' pending SKBs */
+       spin_lock_bh(&efv->rx_lock);
+       read_index = efv->write_index;
+       while (spent < weight && !list_empty(&efv->rx_list)) {
+               skb = list_first_entry(&efv->rx_list, struct sk_buff, list);
+               list_del(&skb->list);
+               list_add_tail(&skb->list, &head);
+               spent++;
+       }
+       spin_unlock_bh(&efv->rx_lock);
+       /* Receive them */
+       netif_receive_skb_list(&head);
+       if (spent < weight)
+               if (napi_complete_done(napi, spent)) {
+                       spin_lock_bh(&efv->rx_lock);
+                       efv->read_index = read_index;
+                       /* If write_index advanced while we were doing the
+                        * RX, then storing our read_index won't re-prime the
+                        * fake-interrupt.  In that case, we need to schedule
+                        * NAPI again to consume the additional packet(s).
+                        */
+                       need_resched = efv->write_index != read_index;
+                       spin_unlock_bh(&efv->rx_lock);
+                       if (need_resched)
+                               napi_schedule(&efv->napi);
+               }
+       return spent;
+}

diff --git a/drivers/net/ethernet/sfc/ef100_rep.h b/drivers/net/ethernet/sfc/ef100_rep.h
index d47fd8ff6220af36c25f7bb748f0972eb737a470..77037ab22052556a2bc3ccf1c90fe21e5ee01796 100644 (file)
--- a/drivers/net/ethernet/sfc/ef100_rep.h
+++ b/drivers/net/ethernet/sfc/ef100_rep.h
@@ -29,7 +29,13 @@ struct efx_rep_sw_stats {
  * @msg_enable: log message enable flags
  * @mport: m-port ID of corresponding VF
  * @idx: VF index
+ * @write_index: number of packets enqueued to @rx_list
+ * @read_index: number of packets consumed from @rx_list
+ * @rx_pring_size: max length of RX list
  * @list: entry on efx->vf_reps
+ * @rx_list: list of SKBs queued for receive in NAPI poll
+ * @rx_lock: protects @rx_list
+ * @napi: NAPI control structure
  * @stats: software traffic counters for netdev stats
  */
 struct efx_rep {
@@ -38,7 +44,12 @@ struct efx_rep {
        u32 msg_enable;
        u32 mport;
        unsigned int idx;
+       unsigned int write_index, read_index;
+       unsigned int rx_pring_size;
        struct list_head list;
+       struct list_head rx_list;
+       spinlock_t rx_lock;
+       struct napi_struct napi;
        struct efx_rep_sw_stats stats;
 };