netdev - [net 11/11] i40e: fix condition of WARN

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Message-Id: <20180824184735.32175-12-jeffrey.t.kirsher@intel.com>
Date:   Fri, 24 Aug 2018 11:47:35 -0700
From:   Jeff Kirsher <jeffrey.t.kirsher@...el.com>
To:     davem@...emloft.net
Cc:     Jacob Keller <jacob.e.keller@...el.com>, netdev@...r.kernel.org,
        nhorman@...hat.com, sassmann@...hat.com, jogreene@...hat.com,
        Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Subject: [net 11/11] i40e: fix condition of WARN_ONCE for stat strings

From: Jacob Keller <jacob.e.keller@...el.com>

Commit 9b10df596bd4 ("i40e: use WARN_ONCE to replace the commented
BUG_ON size check") introduced a warning check to make sure
that the size of the stat strings was always the expected value. This
code accidentally inverted the check of the data pointer. Fix this so
that we accurately count the size of the stats we copied in.

This fixes an erroneous WARN kernel splat that occurs when requesting
ethtool statistics.

Signed-off-by: Jacob Keller <jacob.e.keller@...el.com>
Tested-by: Andrew Bowers <andrewx.bowers@...el.com>
Tested-by: Mauro S M Rodrigues <maurosr@...ux.vnet.ibm.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
---
 drivers/net/ethernet/intel/i40e/i40e_ethtool.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
index abcd096ede14..5ff6caa83948 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
@@ -2013,7 +2013,7 @@ static void i40e_get_stat_strings(struct net_device *netdev, u8 *data)
 	for (i = 0; i < I40E_MAX_USER_PRIORITY; i++)
 		i40e_add_stat_strings(&data, i40e_gstrings_pfc_stats, i);
 
-	WARN_ONCE(p - data != i40e_get_stats_count(netdev) * ETH_GSTRING_LEN,
+	WARN_ONCE(data - p != i40e_get_stats_count(netdev) * ETH_GSTRING_LEN,
 		  "stat strings count mismatch!");
 }
 
-- 
2.17.1