sfc: Fix NAPI list corruption during ring reallocation

Call netif_napi_{add,del}() on the NAPI contexts in the new and
old channels, respectively.

Since efx_init_napi() cannot fail, make its return type void.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>

1 files changed, 19 insertions, 12 deletions

diff --git a/drivers/net/sfc/efx.c b/drivers/net/sfc/efx.c
index d06cb742164b..fb83cdd94643 100644
--- a/drivers/net/sfc/efx.c
+++ b/drivers/net/sfc/efx.c
@@ -197,7 +197,9 @@ MODULE_PARM_DESC(debug, "Bitmapped debugging message enable value");
 
 static void efx_remove_channels(struct efx_nic *efx);
 static void efx_remove_port(struct efx_nic *efx);
+static void efx_init_napi(struct efx_nic *efx);
 static void efx_fini_napi(struct efx_nic *efx);
+static void efx_fini_napi_channel(struct efx_channel *channel);
 static void efx_fini_struct(struct efx_nic *efx);
 static void efx_start_all(struct efx_nic *efx);
 static void efx_stop_all(struct efx_nic *efx);
@@ -430,6 +432,7 @@ efx_alloc_channel(struct efx_nic *efx, int i, struct efx_channel *old_channel)
 
                 *channel = *old_channel;
 
+                channel->napi_dev = NULL;
                 memset(&channel->eventq, 0, sizeof(channel->eventq));
 
                 rx_queue = &channel->rx_queue;
@@ -740,9 +743,13 @@ efx_realloc_channels(struct efx_nic *efx, u32 rxq_entries, u32 txq_entries)
         if (rc)
                 goto rollback;
 
+        efx_init_napi(efx);
+
         /* Destroy old channels */
-        for (i = 0; i < efx->n_channels; i++)
+        for (i = 0; i < efx->n_channels; i++) {
+                efx_fini_napi_channel(other_channel[i]);
                 efx_remove_channel(other_channel[i]);
+        }
 out:
         /* Free unused channel structures */
         for (i = 0; i < efx->n_channels; i++)
@@ -1601,7 +1608,7 @@ static int efx_ioctl(struct net_device *net_dev, struct ifreq *ifr, int cmd)
  *
  **************************************************************************/
 
-static int efx_init_napi(struct efx_nic *efx)
+static void efx_init_napi(struct efx_nic *efx)
 {
         struct efx_channel *channel;
 
@@ -1610,18 +1617,21 @@ static int efx_init_napi(struct efx_nic *efx)
                 netif_napi_add(channel->napi_dev, &channel->napi_str,
                                efx_poll, napi_weight);
         }
-        return 0;
+}
+
+static void efx_fini_napi_channel(struct efx_channel *channel)
+{
+        if (channel->napi_dev)
+                netif_napi_del(&channel->napi_str);
+        channel->napi_dev = NULL;
 }
 
 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;
-        }
+        efx_for_each_channel(channel, efx)
+                efx_fini_napi_channel(channel);
 }
 
 /**************************************************************************
@@ -2343,9 +2353,7 @@ static int efx_pci_probe_main(struct efx_nic *efx)
         if (rc)
                 goto fail1;
 
-        rc = efx_init_napi(efx);
-        if (rc)
-                goto fail2;
+        efx_init_napi(efx);
 
         rc = efx->type->init(efx);
         if (rc) {
@@ -2376,7 +2384,6 @@ static int efx_pci_probe_main(struct efx_nic *efx)
         efx->type->fini(efx);
  fail3:
         efx_fini_napi(efx);
- fail2:
         efx_remove_all(efx);
  fail1:
         return rc;