ixgbevf: Use smp_rmb rather than read_barrier_depends

commit ae0c585d93dfaf923d2c7eb44b2c3ab92854ea9b upstream.

The original issue being fixed in this patch was seen with the ixgbe
driver, but the same issue exists with ixgbevf 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.

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Acked-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
index cbf70fe4028a8191118d8c0b41cec7d202042bc2..1499ce2bf9f6e9b5b269740b01356e4c45cefce4 100644 (file)
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
@@ -325,7 +325,7 @@ static bool ixgbevf_clean_tx_irq(struct ixgbevf_q_vector *q_vector,
                        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(IXGBE_TXD_STAT_DD)))