intel: i40evf: Replace GFP_ATOMIC with GFP_KERNEL in i40evf_add_vlan

Message ID 1523412498-2177-1-git-send-email-baijiaju1990@gmail.com
State Accepted
Delegated to: Jeff Kirsher
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Series
  • intel: i40evf: Replace GFP_ATOMIC with GFP_KERNEL in i40evf_add_vlan
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Commit Message

Jia-Ju Bai April 11, 2018, 2:08 a.m.
i40evf_add_vlan() is never called in atomic context.

i40evf_add_vlan() is only called by i40evf_vlan_rx_add_vid(), 
which is only set as ".ndo_vlan_rx_add_vid" in struct net_device_ops.
".ndo_vlan_rx_add_vid" is not called in atomic context.

Despite never getting called from atomic context, 
i40evf_add_vlan() calls kzalloc() with GFP_ATOMIC, 
which does not sleep for allocation.
GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL, 
which can sleep and improve the possibility of sucessful allocation.

This is found by a static analysis tool named DCNS written by myself.
And I also manually check it.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
---
 drivers/net/ethernet/intel/i40evf/i40evf_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Bowers, AndrewX April 11, 2018, 8:54 p.m. | #1
> -----Original Message-----
> From: Intel-wired-lan [mailto:intel-wired-lan-bounces@osuosl.org] On
> Behalf Of Jia-Ju Bai
> Sent: Tuesday, April 10, 2018 7:08 PM
> To: Kirsher, Jeffrey T <jeffrey.t.kirsher@intel.com>
> Cc: netdev@vger.kernel.org; Jia-Ju Bai <baijiaju1990@gmail.com>; intel-
> wired-lan@lists.osuosl.org; linux-kernel@vger.kernel.org
> Subject: [Intel-wired-lan] [PATCH] intel: i40evf: Replace GFP_ATOMIC with
> GFP_KERNEL in i40evf_add_vlan
> 
> i40evf_add_vlan() is never called in atomic context.
> 
> i40evf_add_vlan() is only called by i40evf_vlan_rx_add_vid(), which is only
> set as ".ndo_vlan_rx_add_vid" in struct net_device_ops.
> ".ndo_vlan_rx_add_vid" is not called in atomic context.
> 
> Despite never getting called from atomic context,
> i40evf_add_vlan() calls kzalloc() with GFP_ATOMIC, which does not sleep for
> allocation.
> GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL, which
> can sleep and improve the possibility of sucessful allocation.
> 
> This is found by a static analysis tool named DCNS written by myself.
> And I also manually check it.
> 
> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
> ---
>  drivers/net/ethernet/intel/i40evf/i40evf_main.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Tested-by: Andrew Bowers <andrewx.bowers@intel.com>

Patch

diff --git a/drivers/net/ethernet/intel/i40evf/i40evf_main.c b/drivers/net/ethernet/intel/i40evf/i40evf_main.c
index 1825d95..04b2b9c 100644
--- a/drivers/net/ethernet/intel/i40evf/i40evf_main.c
+++ b/drivers/net/ethernet/intel/i40evf/i40evf_main.c
@@ -770,7 +770,7 @@  i40evf_vlan_filter *i40evf_add_vlan(struct i40evf_adapter *adapter, u16 vlan)
 
 	f = i40evf_find_vlan(adapter, vlan);
 	if (!f) {
-		f = kzalloc(sizeof(*f), GFP_ATOMIC);
+		f = kzalloc(sizeof(*f), GFP_KERNEL);
 		if (!f)
 			goto clearout;