igb: Use smp_rmb rather than read_barrier_depends

The original issue being fixed in this patch was seen with the ixgbe
driver, but the same issue exists with igb as well, as the code is
very similar. read_barrier_depends is not sufficient to ensure
loads following it are not speculatively loaded out of order
by the CPU, which can result in stale data being loaded, causing
potential system crashes.

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Acked-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index e94d3c256667637c8186fd83299b64ea2de53c72..c208753ff5b7cec52259e15b5c545b5af4b51c6f 100644 (file)
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -7317,7 +7317,7 @@ static bool igb_clean_tx_irq(struct igb_q_vector *q_vector, int napi_budget)
                        break;
 
                /* prevent any other reads prior to eop_desc */
-               read_barrier_depends();
+               smp_rmb();
 
                /* if DD is not set pending work has not been completed */
                if (!(eop_desc->wb.status & cpu_to_le32(E1000_TXD_STAT_DD)))