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Commit 375b27cf authored by Greg Rose's avatar Greg Rose Committed by David S. Miller
Browse files

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: default avatarGreg Rose <gregory.v.rose@intel.com>
Tested-by: default avatarSibai Li <sibai.li@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 795be954

drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c

+21 −18
Original line number Diff line number Diff line
@@ -917,31 +917,34 @@ static irqreturn_t ixgbevf_msix_mbx(int irq, void *data) 
	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;

		goto out;

	}

	if (!hw->mbx.ops.check_for_ack(hw))

		got_ack = true;



	/* Not an ack interrupt, go ahead and read the message */

	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;

	}



	/*

	 * 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;

}