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>

diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 46c3b1f9ff8997af685836bb82fb0e1bd5e599cf..fb6c813f5f86a4ecbfd073fe09070710524db596 100644 (file)
--- 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;