sfc: Match calls to netif_napi_add() and netif_napi_del()

sfc could call netif_napi_add() multiple times for the same
napi_struct, corrupting the list of napi_structs for the associated
device and leading to a busy-loop on device removal.  Move the call to
netif_napi_add() and add a call to netif_napi_del() in the obvious
places.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 3 deletions

diff --git a/drivers/net/sfc/efx.c b/drivers/net/sfc/efx.c
index dee23b159df2..7269a426051c 100644
--- a/drivers/net/sfc/efx.c
+++ b/drivers/net/sfc/efx.c
@@ -448,9 +448,6 @@ static void efx_init_channels(struct efx_nic *efx)
 
                 WARN_ON(channel->rx_pkt != NULL);
                 efx_rx_strategy(channel);
-
-                netif_napi_add(channel->napi_dev, &channel->napi_str,
-                               efx_poll, napi_weight);
         }
 }
 
@@ -1321,6 +1318,8 @@ static int efx_init_napi(struct efx_nic *efx)
 
         efx_for_each_channel(channel, efx) {
                 channel->napi_dev = efx->net_dev;
+                netif_napi_add(channel->napi_dev, &channel->napi_str,
+                               efx_poll, napi_weight);
         }
         return 0;
 }
@@ -1330,6 +1329,8 @@ static void efx_fini_napi(struct efx_nic *efx)
         struct efx_channel *channel;
 
         efx_for_each_channel(channel, efx) {
+                if (channel->napi_dev)
+                        netif_napi_del(&channel->napi_str);
                 channel->napi_dev = NULL;
         }
 }