netdev - [PATCH net-next 06/14] sfc: receive packets from EF100 VFs into representors

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Message-ID: <539b243ca106075d1ed1b78e4eb6b38ba3b92ec1.1658497661.git.ecree.xilinx@gmail.com>
Date:   Fri, 22 Jul 2022 17:04:15 +0100
From:   <ecree@...inx.com>
To:     <davem@...emloft.net>, <kuba@...nel.org>, <pabeni@...hat.com>,
        <linux-net-drivers@....com>
CC:     <netdev@...r.kernel.org>, Edward Cree <ecree.xilinx@...il.com>
Subject: [PATCH net-next 06/14] sfc: receive packets from EF100 VFs into representors

From: Edward Cree <ecree.xilinx@...il.com>

If the source m-port of a packet in __ef100_rx_packet() is a VF,
 hand off the packet to the corresponding representor with
 efx_ef100_rep_rx_packet().

Signed-off-by: Edward Cree <ecree.xilinx@...il.com>
---
 drivers/net/ethernet/sfc/ef100_rep.c | 19 +++++++++++++++++++
 drivers/net/ethernet/sfc/ef100_rep.h |  5 +++++
 drivers/net/ethernet/sfc/ef100_rx.c  | 17 +++++++++++++++++
 3 files changed, 41 insertions(+)

diff --git a/drivers/net/ethernet/sfc/ef100_rep.c b/drivers/net/ethernet/sfc/ef100_rep.c
index e6c6e9e764b2..c0bc12b9e348 100644
--- a/drivers/net/ethernet/sfc/ef100_rep.c
+++ b/drivers/net/ethernet/sfc/ef100_rep.c
@@ -224,6 +224,7 @@ static void efx_ef100_rep_destroy_netdev(struct efx_rep *efv)
 	list_del(&efv->list);
 	spin_unlock_bh(&efx->vf_reps_lock);
 	rtnl_unlock();
+	synchronize_rcu();
 	free_netdev(efv->net_dev);
 }
 
@@ -375,3 +376,21 @@ void efx_ef100_rep_rx_packet(struct efx_rep *efv, struct efx_rx_buffer *rx_buf)
 	if (primed)
 		napi_schedule(&efv->napi);
 }
+
+struct efx_rep *efx_ef100_find_rep_by_mport(struct efx_nic *efx, u16 mport)
+{
+	struct efx_rep *efv, *out = NULL;
+
+	/* spinlock guards against list mutation while we're walking it;
+	 * but caller must also hold rcu_read_lock() to ensure the netdev
+	 * isn't freed after we drop the spinlock.
+	 */
+	spin_lock_bh(&efx->vf_reps_lock);
+	list_for_each_entry(efv, &efx->vf_reps, list)
+		if (efv->mport == mport) {
+			out = efv;
+			break;
+		}
+	spin_unlock_bh(&efx->vf_reps_lock);
+	return out;
+}
diff --git a/drivers/net/ethernet/sfc/ef100_rep.h b/drivers/net/ethernet/sfc/ef100_rep.h
index 7d2f15cee8d1..f3787133f793 100644
--- a/drivers/net/ethernet/sfc/ef100_rep.h
+++ b/drivers/net/ethernet/sfc/ef100_rep.h
@@ -58,4 +58,9 @@ void efx_ef100_vfrep_destroy(struct efx_nic *efx, struct efx_rep *efv);
 void efx_ef100_fini_vfreps(struct efx_nic *efx);
 
 void efx_ef100_rep_rx_packet(struct efx_rep *efv, struct efx_rx_buffer *rx_buf);
+/* Returns the representor corresponding to a VF m-port, or NULL
+ * @mport is an m-port label, *not* an m-port ID!
+ * Caller must hold rcu_read_lock().
+ */
+struct efx_rep *efx_ef100_find_rep_by_mport(struct efx_nic *efx, u16 mport);
 #endif /* EF100_REP_H */
diff --git a/drivers/net/ethernet/sfc/ef100_rx.c b/drivers/net/ethernet/sfc/ef100_rx.c
index b8da9e3b7bf2..2b5568170340 100644
--- a/drivers/net/ethernet/sfc/ef100_rx.c
+++ b/drivers/net/ethernet/sfc/ef100_rx.c
@@ -85,6 +85,23 @@ void __ef100_rx_packet(struct efx_channel *channel)
 	nic_data = efx->nic_data;
 
 	if (nic_data->have_mport && ing_port != nic_data->base_mport) {
+		struct efx_rep *efv;
+
+		rcu_read_lock();
+		efv = efx_ef100_find_rep_by_mport(efx, ing_port);
+		if (efv) {
+			if (efv->net_dev->flags & IFF_UP)
+				efx_ef100_rep_rx_packet(efv, rx_buf);
+			rcu_read_unlock();
+			/* Representor Rx doesn't care about PF Rx buffer
+			 * ownership, it just makes a copy. So, we are done
+			 * with the Rx buffer from PF point of view and should
+			 * free it.
+			 */
+			goto free_rx_buffer;
+		}
+		rcu_read_unlock();
+
 		if (net_ratelimit())
 			netif_warn(efx, drv, efx->net_dev,
 				   "Unrecognised ing_port %04x (base %04x), dropping\n",