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>

diff --git a/drivers/net/sfc/efx.c b/drivers/net/sfc/efx.c
index d06cb742164b90b3ba338ad3b98498a5f5a439d8..fb83cdd946436561dbe645f5d742317fea8cfe91 100644 (file)
--- 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;