linux-kernel - Re: [PATCH] net: i40e: avoid unused function warnings

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Message-ID: <8814508.SjLecHrQqA@wuerfel>
Date:	Wed, 20 Jan 2016 23:28:34 +0100
From:	Arnd Bergmann <arnd@...db.de>
To:	linux-arm-kernel@...ts.infradead.org
Cc:	Jeff Kirsher <jeffrey.t.kirsher@...el.com>, netdev@...r.kernel.org,
	Mitch Williams <mitch.a.williams@...el.com>,
	Don Skidmore <donald.c.skidmore@...el.com>,
	Shannon Nelson <shannon.nelson@...el.com>,
	Bruce Allan <bruce.w.allan@...el.com>,
	Jesse Brandeburg <jesse.brandeburg@...el.com>,
	linux-kernel@...r.kernel.org,
	John Ronciak <john.ronciak@...el.com>,
	intel-wired-lan@...ts.osuosl.org,
	Carolyn Wyborny <carolyn.wyborny@...el.com>,
	davem@...emloft.net
Subject: Re: [PATCH] net: i40e: avoid unused function warnings

On Wednesday 20 January 2016 14:17:25 Jeff Kirsher wrote:
> On Wed, 2016-01-20 at 11:42 +0100, Arnd Bergmann wrote:
> > The addition of the geneve tunnel offload code left a couple
> > of functions unconditionally defined but empty whenever CONFIG_VXLAN
> > and CONFIG_GENEVE are disabled. gcc warns about this:
> > 
> > i40e_main.c:7049:13: warning: 'i40e_sync_udp_filters_subtask' defined
> > but not used [-Wunused-function]
> > i40e_main.c:8516:13: warning: 'i40e_add_vxlan_port' defined but not
> > used [-Wunused-function]
> > i40e_main.c:8561:13: warning: 'i40e_del_vxlan_port' defined but not
> > used [-Wunused-function]
> > i40e_main.c:8596:13: warning: 'i40e_add_geneve_port' defined but not
> > used [-Wunused-function]
> > i40e_main.c:8643:13: warning: 'i40e_del_geneve_port' defined but not
> > used [-Wunused-function]
> > 
> > This moves the #ifdef statements to the outside of the affected
> > functions, which avoids the warnings.
> > 
> > Signed-off-by: Arnd Bergmann <arnd@...db.de>
> > Fixes: 6a899024058d ("i40e: geneve tunnel offload support")
> > ---
> > This is a harmless regression against v4.4, found on ARM randconfig
> > builds
> 
> Thanks Arnd, I already have a patch from Eric Dumazet and Alex Duyck to
> resolve this issue.
> 
> Dave- I plan on pushing the fix later today to net.

Ok, thanks.

FWIW, I have another patch for this driver that I did not yet submit
because it's not a regression and I haven't written a proper changelog
for it (it's in a set of 15 patches for netdev that fix harmless warnings).

Do you have one for the warning below as well? I could not come up
with a better way than adding a bogus initialization, but maybe
there is one.

	Arnd

>From d89be3f0f932a71dfb5480ee396db514879097c4 Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@...db.de>
Date: Fri, 15 Jan 2016 17:31:07 +0100
Subject: [PATCH] net: i40e: shut up uninitialized variable warnings

intel/i40e/i40e_txrx.c: In function 'i40e_xmit_frame_ring':
intel/i40e/i40e_txrx.c:2367:20: error: 'oiph' may be used uninitialized in this function [-Werror=maybe-uninitialized]
intel/i40e/i40e_txrx.c:2317:16: note: 'oiph' was declared here
intel/i40e/i40e_txrx.c:2367:17: error: 'oudph' may be used uninitialized in this function [-Werror=maybe-uninitialized]
intel/i40e/i40e_txrx.c:2316:17: note: 'oudph' was declared here

Signed-off-by: Arnd Bergmann <arnd@...db.de>

diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index 720516b0e8ee..47bd8b3145a7 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -2313,8 +2313,8 @@ static void i40e_tx_enable_csum(struct sk_buff *skb, u32 *tx_flags,
 	struct iphdr *this_ip_hdr;
 	u32 network_hdr_len;
 	u8 l4_hdr = 0;
-	struct udphdr *oudph;
-	struct iphdr *oiph;
+	struct udphdr *oudph = NULL;
+	struct iphdr *oiph = NULL;
 	u32 l4_tunnel = 0;
 
 	if (skb->encapsulation) {