netdev - [net-next 10/15] i40e: expand comment

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Message-Id: <1455786252-71881-11-git-send-email-jeffrey.t.kirsher@intel.com>
Date:	Thu, 18 Feb 2016 01:04:07 -0800
From:	Jeff Kirsher <jeffrey.t.kirsher@...el.com>
To:	davem@...emloft.net
Cc:	Mitch Williams <mitch.a.williams@...el.com>,
	netdev@...r.kernel.org, nhorman@...hat.com, sassmann@...hat.com,
	jogreene@...hat.com, Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Subject: [net-next 10/15] i40e: expand comment

From: Mitch Williams <mitch.a.williams@...el.com>

Explain why we cannot remove this code, even though it works differently
than any of our other interrupt cause handling code.

Change-ID: Ie66203bd037a466066036611c31d44f759ec5176
Signed-off-by: Mitch Williams <mitch.a.williams@...el.com>
Tested-by: Andrew Bowers <andrewx.bowers@...el.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
---
 drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
index 597f209..5dcd198 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
@@ -2037,7 +2037,11 @@ int i40e_vc_process_vflr_event(struct i40e_pf *pf)
 	if (!test_bit(__I40E_VFLR_EVENT_PENDING, &pf->state))
 		return 0;
 
-	/* re-enable vflr interrupt cause */
+	/* Re-enable the VFLR interrupt cause here, before looking for which
+	 * VF got reset. Otherwise, if another VF gets a reset while the
+	 * first one is being processed, that interrupt will be lost, and
+	 * that VF will be stuck in reset forever.
+	 */
 	reg = rd32(hw, I40E_PFINT_ICR0_ENA);
 	reg |= I40E_PFINT_ICR0_ENA_VFLR_MASK;
 	wr32(hw, I40E_PFINT_ICR0_ENA, reg);
-- 
2.5.0