From: Jon Cooper <jcoo...@solarflare.com>

If a function is in promiscuous mode and another function has a broadcast or
 multicast filter inserted, the function in promiscuous mode won't see that
 broadcast or multicast traffic.
Most notably this breaks broadcast, which means ARP doesn't work. Less
 show-stoppingly, a function listening on a multicast address that's also in
 promiscuous mode will not see that multicast traffic if another function is
 also listening on that multicast address.

Signed-off-by: Edward Cree <ec...@solarflare.com>
---
 drivers/net/ethernet/sfc/ef10.c | 104 ++++++++++++++++++++--------------------
 1 file changed, 53 insertions(+), 51 deletions(-)

diff --git a/drivers/net/ethernet/sfc/ef10.c b/drivers/net/ethernet/sfc/ef10.c
index 18d6388..784b46f 100644
--- a/drivers/net/ethernet/sfc/ef10.c
+++ b/drivers/net/ethernet/sfc/ef10.c
@@ -3758,7 +3758,8 @@ static void efx_ef10_filter_sync_rx_mode(struct efx_nic 
*efx)
        struct netdev_hw_addr *uc;
        struct netdev_hw_addr *mc;
        unsigned int filter_idx;
-       int i, n, rc;
+       int i, rc;
+       bool uc_promisc = false, mc_promisc = false;
 
        if (!efx_dev_registered(efx))
                return;
@@ -3768,13 +3769,11 @@ static void efx_ef10_filter_sync_rx_mode(struct efx_nic 
*efx)
 
        /* Mark old filters that may need to be removed */
        spin_lock_bh(&efx->filter_lock);
-       n = table->dev_uc_count < 0 ? 1 : table->dev_uc_count;
-       for (i = 0; i < n; i++) {
+       for (i = 0; i < table->dev_uc_count; i++) {
                filter_idx = table->dev_uc_list[i].id % HUNT_FILTER_TBL_ROWS;
                table->entry[filter_idx].spec |= EFX_EF10_FILTER_FLAG_AUTO_OLD;
        }
-       n = table->dev_mc_count < 0 ? 1 : table->dev_mc_count;
-       for (i = 0; i < n; i++) {
+       for (i = 0; i < table->dev_mc_count; i++) {
                filter_idx = table->dev_mc_list[i].id % HUNT_FILTER_TBL_ROWS;
                table->entry[filter_idx].spec |= EFX_EF10_FILTER_FLAG_AUTO_OLD;
        }
@@ -3786,7 +3785,8 @@ static void efx_ef10_filter_sync_rx_mode(struct efx_nic 
*efx)
        netif_addr_lock_bh(net_dev);
        if (net_dev->flags & IFF_PROMISC ||
            netdev_uc_count(net_dev) >= EFX_EF10_FILTER_DEV_UC_MAX) {
-               table->dev_uc_count = -1;
+               table->dev_uc_count = 0;
+               uc_promisc = true;
        } else {
                table->dev_uc_count = 1 + netdev_uc_count(net_dev);
                ether_addr_copy(table->dev_uc_list[0].addr, net_dev->dev_addr);
@@ -3796,9 +3796,11 @@ static void efx_ef10_filter_sync_rx_mode(struct efx_nic 
*efx)
                        i++;
                }
        }
-       if (net_dev->flags & (IFF_PROMISC | IFF_ALLMULTI) ||
-           netdev_mc_count(net_dev) >= EFX_EF10_FILTER_DEV_MC_MAX) {
-               table->dev_mc_count = -1;
+       if (netdev_mc_count(net_dev) + 2 /* room for broadcast and promisc */
+                       >= EFX_EF10_FILTER_DEV_MC_MAX) {
+               table->dev_mc_count = 1;
+               eth_broadcast_addr(table->dev_mc_list[0].addr);
+               mc_promisc = true;
        } else {
                table->dev_mc_count = 1 + netdev_mc_count(net_dev);
                eth_broadcast_addr(table->dev_mc_list[0].addr);
@@ -3807,31 +3809,32 @@ static void efx_ef10_filter_sync_rx_mode(struct efx_nic 
*efx)
                        ether_addr_copy(table->dev_mc_list[i].addr, mc->addr);
                        i++;
                }
+               if (net_dev->flags & (IFF_PROMISC | IFF_ALLMULTI))
+                       mc_promisc = true;
        }
        netif_addr_unlock_bh(net_dev);
 
        /* Insert/renew unicast filters */
-       if (table->dev_uc_count >= 0) {
-               for (i = 0; i < table->dev_uc_count; i++) {
-                       efx_filter_init_rx(&spec, EFX_FILTER_PRI_AUTO,
-                                          EFX_FILTER_FLAG_RX_RSS,
-                                          0);
-                       efx_filter_set_eth_local(&spec, EFX_FILTER_VID_UNSPEC,
-                                                table->dev_uc_list[i].addr);
-                       rc = efx_ef10_filter_insert(efx, &spec, true);
-                       if (rc < 0) {
-                               /* Fall back to unicast-promisc */
-                               while (i--)
-                                       efx_ef10_filter_remove_safe(
-                                               efx, EFX_FILTER_PRI_AUTO,
-                                               table->dev_uc_list[i].id);
-                               table->dev_uc_count = -1;
-                               break;
-                       }
-                       table->dev_uc_list[i].id = rc;
+       for (i = 0; i < table->dev_uc_count; i++) {
+               efx_filter_init_rx(&spec, EFX_FILTER_PRI_AUTO,
+                                  EFX_FILTER_FLAG_RX_RSS,
+                                  0);
+               efx_filter_set_eth_local(&spec, EFX_FILTER_VID_UNSPEC,
+                                        table->dev_uc_list[i].addr);
+               rc = efx_ef10_filter_insert(efx, &spec, true);
+               if (rc < 0) {
+                       /* Fall back to unicast-promisc */
+                       while (i--)
+                               efx_ef10_filter_remove_safe(
+                                       efx, EFX_FILTER_PRI_AUTO,
+                                       table->dev_uc_list[i].id);
+                       table->dev_uc_count = 0;
+                       uc_promisc = true;
+                       break;
                }
+               table->dev_uc_list[i].id = rc;
        }
-       if (table->dev_uc_count < 0) {
+       if (uc_promisc) {
                efx_filter_init_rx(&spec, EFX_FILTER_PRI_AUTO,
                                   EFX_FILTER_FLAG_RX_RSS,
                                   0);
@@ -3839,34 +3842,34 @@ static void efx_ef10_filter_sync_rx_mode(struct efx_nic 
*efx)
                rc = efx_ef10_filter_insert(efx, &spec, true);
                if (rc < 0) {
                        WARN_ON(1);
-                       table->dev_uc_count = 0;
                } else {
-                       table->dev_uc_list[0].id = rc;
+                       table->dev_uc_list[table->dev_uc_count++].id = rc;
                }
        }
 
        /* Insert/renew multicast filters */
-       if (table->dev_mc_count >= 0) {
-               for (i = 0; i < table->dev_mc_count; i++) {
-                       efx_filter_init_rx(&spec, EFX_FILTER_PRI_AUTO,
-                                          EFX_FILTER_FLAG_RX_RSS,
-                                          0);
-                       efx_filter_set_eth_local(&spec, EFX_FILTER_VID_UNSPEC,
-                                                table->dev_mc_list[i].addr);
-                       rc = efx_ef10_filter_insert(efx, &spec, true);
-                       if (rc < 0) {
-                               /* Fall back to multicast-promisc */
-                               while (i--)
-                                       efx_ef10_filter_remove_safe(
-                                               efx, EFX_FILTER_PRI_AUTO,
-                                               table->dev_mc_list[i].id);
-                               table->dev_mc_count = -1;
-                               break;
-                       }
-                       table->dev_mc_list[i].id = rc;
+       for (i = 0; i < table->dev_mc_count; i++) {
+               efx_filter_init_rx(&spec, EFX_FILTER_PRI_AUTO,
+                                  EFX_FILTER_FLAG_RX_RSS,
+                                  0);
+               efx_filter_set_eth_local(&spec, EFX_FILTER_VID_UNSPEC,
+                                        table->dev_mc_list[i].addr);
+               rc = efx_ef10_filter_insert(efx, &spec, true);
+               if (rc < 0) {
+                       /* Fall back to multicast-promisc.
+                        * Leave the broadcast filter.
+                        */
+                       while (i > 1)
+                               efx_ef10_filter_remove_safe(
+                                       efx, EFX_FILTER_PRI_AUTO,
+                                       table->dev_mc_list[--i].id);
+                       table->dev_mc_count = i;
+                       mc_promisc = true;
+                       break;
                }
+               table->dev_mc_list[i].id = rc;
        }
-       if (table->dev_mc_count < 0) {
+       if (mc_promisc) {
                efx_filter_init_rx(&spec, EFX_FILTER_PRI_AUTO,
                                   EFX_FILTER_FLAG_RX_RSS,
                                   0);
@@ -3874,9 +3877,8 @@ static void efx_ef10_filter_sync_rx_mode(struct efx_nic 
*efx)
                rc = efx_ef10_filter_insert(efx, &spec, true);
                if (rc < 0) {
                        WARN_ON(1);
-                       table->dev_mc_count = 0;
                } else {
-                       table->dev_mc_list[0].id = rc;
+                       table->dev_mc_list[table->dev_mc_count++].id = rc;
                }
        }
 

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