From 375b27cf5db963e2bc2a34dc5643d0d7ceca1ee2 Mon Sep 17 00:00:00 2001 From: Greg Rose Date: Wed, 18 Jan 2012 22:13:31 +0000 Subject: [PATCH] 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 Tested-by: Sibai Li Signed-off-by: Jeff Kirsher Signed-off-by: David S. Miller --- .../net/ethernet/intel/ixgbevf/ixgbevf_main.c | 39 ++++++++++--------- 1 file 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 891162d1610c..1cad3b6d2c30 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; } -- 2.20.1