sfc: take correct lock in ef100_reset()

When downing and upping the ef100 filter table, we need to take a write
 lock on efx->filter_sem, not just a read lock, because we may kfree()
 the table pointers.
Without this, resets cause a WARN_ON from efx_rwsem_assert_write_locked().

Fixes: a9dc3d5612ce ("sfc_ef100: RX filter table management and related gubbins")
Signed-off-by: Edward Cree <ecree@solarflare.com>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/sfc/ef100_nic.c b/drivers/net/ethernet/sfc/ef100_nic.c
index b8a7e9ed7913624e28ef0cd007bb0ebef689e2a7..19fe86b3b3169b0636ba698738c31d2031588926 100644 (file)
--- a/drivers/net/ethernet/sfc/ef100_nic.c
+++ b/drivers/net/ethernet/sfc/ef100_nic.c
@@ -431,18 +431,18 @@ static int ef100_reset(struct efx_nic *efx, enum reset_type reset_type)
                /* A RESET_TYPE_ALL will cause filters to be removed, so we remove filters
                 * and reprobe after reset to avoid removing filters twice
                 */
-               down_read(&efx->filter_sem);
+               down_write(&efx->filter_sem);
                ef100_filter_table_down(efx);
-               up_read(&efx->filter_sem);
+               up_write(&efx->filter_sem);
                rc = efx_mcdi_reset(efx, reset_type);
                if (rc)
                        return rc;
 
                netif_device_attach(efx->net_dev);
 
-               down_read(&efx->filter_sem);
+               down_write(&efx->filter_sem);
                rc = ef100_filter_table_up(efx);
-               up_read(&efx->filter_sem);
+               up_write(&efx->filter_sem);
                if (rc)
                        return rc;