ixgbevf: Prevent possible race condition by checking for message
The mailbox interrupt routine might cause a race condition sometimes
and cause a message to be missed.
Signed-off-by: Greg Rose <gregory.v.rose@intel.com>
Tested-by: Sibai Li <sibai.li@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
index 891162d..1cad3b6 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
@@ -917,31 +917,34 @@
struct ixgbe_hw *hw = &adapter->hw;
u32 eicr;
u32 msg;
+ bool got_ack = false;
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;
+ if (!hw->mbx.ops.check_for_ack(hw))
+ got_ack = true;
+
+ if (!hw->mbx.ops.check_for_msg(hw)) {
+ 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));
+
+ if (msg & IXGBE_VT_MSGTYPE_NACK)
+ pr_warn("Last Request of type %2.2x to PF Nacked\n",
+ msg & 0xFF);
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));
-
+ /*
+ * 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
+ */
+ if (got_ack)
+ hw->mbx.v2p_mailbox |= IXGBE_VFMAILBOX_PFACK;
out:
return IRQ_HANDLED;
}