i40e: fix condition of WARN_ONCE for stat strings

jacob-keller · Jeff Kirsher · commit 07f3701387dc · 2018-08-24T08:52:35.000-07:00
Commit 9b10df5 ("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@intel.com> Tested-by: Andrew Bowers <andrewx.bowers@intel.com> Tested-by: Mauro S M Rodrigues <maurosr@linux.vnet.ibm.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git 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!");
 }
 

Original file line number	Diff line number	Diff line change
`@@ -2013,7 +2013,7 @@ static void i40e_get_stat_strings(struct net_device netdev, u8 data)`
`2013`	`2013`	`for (i = 0; i < I40E_MAX_USER_PRIORITY; i++)`
`2014`	`2014`	`i40e_add_stat_strings(&data, i40e_gstrings_pfc_stats, i);`
`2015`	`2015`
`2016`		`- WARN_ONCE(p - data != i40e_get_stats_count(netdev) * ETH_GSTRING_LEN,`
	`2016`	`+ WARN_ONCE(data - p != i40e_get_stats_count(netdev) * ETH_GSTRING_LEN,`
`2017`	`2017`	`"stat strings count mismatch!");`
`2018`	`2018`	`}`
`2019`	`2019`