1 files changed, 16 insertions, 0 deletions

diff --git a/drivers/net/ixgbevf/ixgbevf_main.c b/drivers/net/ixgbevf/ixgbevf_main.c
index 08707402eb18..460c37fee965 100644
--- a/drivers/net/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ixgbevf/ixgbevf_main.c
@@ -961,12 +961,28 @@ static irqreturn_t ixgbevf_msix_mbx(int irq, void *data)
         eicr = IXGBE_READ_REG(hw, IXGBE_VTEICS);
         IXGBE_WRITE_REG(hw, IXGBE_VTEICR, eicr);
 
+        if (!hw->mbx.ops.check_for_ack(hw)) {
+                /*
+                 * checking for the ack clears the PFACK bit.  Place
+                 * it back in the v2p_mailbox cache so that anyone
+                 * polling for an ack will not miss it.  Also
+                 * avoid the read below because the code to read
+                 * the mailbox will also clear the ack bit.  This was
+                 * causing lost acks.  Just cache the bit and exit
+                 * the IRQ handler.
+                 */
+                hw->mbx.v2p_mailbox |= IXGBE_VFMAILBOX_PFACK;
+                goto out;
+        }
+
+        /* Not an ack interrupt, go ahead and read the message */
         hw->mbx.ops.read(hw, &msg, 1);
 
         if ((msg & IXGBE_MBVFICR_VFREQ_MASK) == IXGBE_PF_CONTROL_MSG)
                 mod_timer(&adapter->watchdog_timer,
                           round_jiffies(jiffies + 1));
 
+out:
         return IRQ_HANDLED;
 }