sfc: Replace stats_enabled flag with a disable count
Currently we use a spin-lock to serialise statistics fetches and also
to inhibit them for short periods of time, plus a flag to
enable/disable statistics fetches for longer periods of time, during
online reset. This was apparently insufficient to deal with the several
reasons for stats being disabled.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/sfc/efx.c b/drivers/net/sfc/efx.c
index b0e5308..ab0e09b 100644
--- a/drivers/net/sfc/efx.c
+++ b/drivers/net/sfc/efx.c
@@ -685,7 +685,7 @@
efx->mac_op->reconfigure(efx);
efx->port_initialized = true;
- efx->stats_enabled = true;
+ efx_stats_enable(efx);
return 0;
fail:
@@ -734,6 +734,7 @@
if (!efx->port_initialized)
return;
+ efx_stats_disable(efx);
efx->phy_op->fini(efx);
efx->port_initialized = false;
@@ -1360,6 +1361,20 @@
return 0;
}
+void efx_stats_disable(struct efx_nic *efx)
+{
+ spin_lock(&efx->stats_lock);
+ ++efx->stats_disable_count;
+ spin_unlock(&efx->stats_lock);
+}
+
+void efx_stats_enable(struct efx_nic *efx)
+{
+ spin_lock(&efx->stats_lock);
+ --efx->stats_disable_count;
+ spin_unlock(&efx->stats_lock);
+}
+
/* Context: process, dev_base_lock or RTNL held, non-blocking. */
static struct net_device_stats *efx_net_stats(struct net_device *net_dev)
{
@@ -1368,12 +1383,12 @@
struct net_device_stats *stats = &net_dev->stats;
/* Update stats if possible, but do not wait if another thread
- * is updating them (or resetting the NIC); slightly stale
- * stats are acceptable.
+ * is updating them or if MAC stats fetches are temporarily
+ * disabled; slightly stale stats are acceptable.
*/
if (!spin_trylock(&efx->stats_lock))
return stats;
- if (efx->stats_enabled) {
+ if (!efx->stats_disable_count) {
efx->mac_op->update_stats(efx);
falcon_update_nic_stats(efx);
}
@@ -1626,12 +1641,7 @@
{
EFX_ASSERT_RESET_SERIALISED(efx);
- /* The net_dev->get_stats handler is quite slow, and will fail
- * if a fetch is pending over reset. Serialise against it. */
- spin_lock(&efx->stats_lock);
- efx->stats_enabled = false;
- spin_unlock(&efx->stats_lock);
-
+ efx_stats_disable(efx);
efx_stop_all(efx);
mutex_lock(&efx->mac_lock);
mutex_lock(&efx->spi_lock);
@@ -1682,7 +1692,7 @@
if (ok) {
efx_start_all(efx);
- efx->stats_enabled = true;
+ efx_stats_enable(efx);
}
return rc;
}
@@ -1888,6 +1898,7 @@
efx->rx_checksum_enabled = true;
spin_lock_init(&efx->netif_stop_lock);
spin_lock_init(&efx->stats_lock);
+ efx->stats_disable_count = 1;
mutex_init(&efx->mac_lock);
efx->mac_op = &efx_dummy_mac_operations;
efx->phy_op = &efx_dummy_phy_operations;