From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Kirsher Subject: [net 6/9] ixgbevf: Prevent possible race condition by checking for message Date: Thu, 19 Jan 2012 00:13:31 -0800 Message-ID: <1326960814-16976-7-git-send-email-jeffrey.t.kirsher@intel.com> References: <1326960814-16976-1-git-send-email-jeffrey.t.kirsher@intel.com> Cc: Greg Rose , netdev@vger.kernel.org, gospo@redhat.com, sassmann@redhat.com, Jeff Kirsher To: davem@davemloft.net Return-path: Received: from mga11.intel.com ([192.55.52.93]:7452 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754608Ab2ASINy (ORCPT ); Thu, 19 Jan 2012 03:13:54 -0500 In-Reply-To: <1326960814-16976-1-git-send-email-jeffrey.t.kirsher@intel.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Greg Rose The mailbox interrupt routine might cause a race condition sometimes and cause a message to be missed. Signed-off-by: Greg Rose Tested-by: Sibai Li Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c | 39 +++++++++++--------- 1 files changed, 21 insertions(+), 18 deletions(-) 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 @@ 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 */ - hw->mbx.ops.read(hw, &msg, 1); + 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_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; } -- 1.7.7.5