e1000e: cleanup strict checkpatch MEMORY_BARRIER checks

Add comments to memory barriers per strict checkpatch.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 46c3b1f9ff89..fb6c813f5f86 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -3746,6 +3746,10 @@ static irqreturn_t e1000_intr_msi_test(int irq, void *data)
         e_dbg("icr is %08X\n", icr);
         if (icr & E1000_ICR_RXSEQ) {
                 adapter->flags &= ~FLAG_MSI_TEST_FAILED;
+                /*
+                 * Force memory writes to complete before acknowledging the
+                 * interrupt is handled.
+                 */
                 wmb();
         }
 
@@ -3787,6 +3791,10 @@ static int e1000_test_msi_interrupt(struct e1000_adapter *adapter)
                 goto msi_test_failed;
         }
 
+        /*
+         * Force memory writes to complete before enabling and firing an
+         * interrupt.
+         */
         wmb();
 
         e1000_irq_enable(adapter);
@@ -3798,7 +3806,7 @@ static int e1000_test_msi_interrupt(struct e1000_adapter *adapter)
 
         e1000_irq_disable(adapter);
 
-        rmb();
+        rmb();                  /* read flags after interrupt has been fired */
 
         if (adapter->flags & FLAG_MSI_TEST_FAILED) {
                 adapter->int_mode = E1000E_INT_MODE_LEGACY;