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>

1 files changed, 11 insertions, 4 deletions

diff --git a/drivers/net/sfc/falcon.c b/drivers/net/sfc/falcon.c
index d9412f83a78e..d5378e60fcdd 100644
--- a/drivers/net/sfc/falcon.c
+++ b/drivers/net/sfc/falcon.c
@@ -1883,7 +1883,7 @@ static int falcon_reset_macs(struct efx_nic *efx)
 
         /* MAC stats will fail whilst the TX fifo is draining. Serialise
          * the drain sequence with the statistics fetch */
-        spin_lock(&efx->stats_lock);
+        efx_stats_disable(efx);
 
         falcon_read(efx, &reg, MAC0_CTRL_REG_KER);
         EFX_SET_OWORD_FIELD(reg, TXFIFO_DRAIN_EN_B0, 1);
@@ -1913,7 +1913,7 @@ static int falcon_reset_macs(struct efx_nic *efx)
                 udelay(10);
         }
 
-        spin_unlock(&efx->stats_lock);
+        efx_stats_enable(efx);
 
         /* If we've reset the EM block and the link is up, then
          * we'll have to kick the XAUI link so the PHY can recover */
@@ -2273,6 +2273,10 @@ int falcon_switch_mac(struct efx_nic *efx)
         struct efx_mac_operations *old_mac_op = efx->mac_op;
         efx_oword_t nic_stat;
         unsigned strap_val;
+        int rc = 0;
+
+        /* Don't try to fetch MAC stats while we're switching MACs */
+        efx_stats_disable(efx);
 
         /* Internal loopbacks override the phy speed setting */
         if (efx->loopback_mode == LOOPBACK_GMAC) {
@@ -2302,13 +2306,16 @@ int falcon_switch_mac(struct efx_nic *efx)
         }
 
         if (old_mac_op == efx->mac_op)
-                return 0;
+                goto out;
 
         EFX_LOG(efx, "selected %cMAC\n", EFX_IS10G(efx) ? 'X' : 'G');
         /* Not all macs support a mac-level link state */
         efx->mac_up = true;
 
-        return falcon_reset_macs(efx);
+        rc = falcon_reset_macs(efx);
+out:
+        efx_stats_enable(efx);
+        return rc;
 }
 
 /* This call is responsible for hooking in the MAC and PHY operations */