[PATCH] net: export netdev_txq_to_tc to allow sch_mqprio to compile as module

In commit 32302902ff09 ("mqprio: Reserve last 32 classid values for HW
traffic classes and misc IDs") sch_mqprio started using netdev_txq_to_tc
to find the correct tc instead of dev->tc_to_txq[]

However, when mqprio is compiled as a module, it cannot resolve the
symbol, leading to this error:

     ERROR: "netdev_txq_to_tc" [net/sched/sch_mqprio.ko] undefined!

This adds an EXPORT_SYMBOL() since the other user in the kernel
(netif_set_xps_queue) is also EXPORT_SYMBOL() (and not _GPL) or in a
sysfs-callback.

Cc: Alexander Duyck <redacted>
Cc: Jesus Sanchez-Palencia <redacted>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Henrik Austad <redacted>
---
 net/core/dev.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/core/dev.c b/net/core/dev.c
index fcddccb..d2b20e7 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c

@@ -2040,6 +2040,7 @@ int netdev_txq_to_tc(struct net_device *dev, unsigned int txq)
 
 	return 0;
 }
+EXPORT_SYMBOL(netdev_txq_to_tc);
 
 #ifdef CONFIG_XPS
 static DEFINE_MUTEX(xps_map_mutex);

-- 
2.7.4

On Tue, Oct 17, 2017 at 3:10 AM, Henrik Austad [off-list ref] wrote:

In commit 32302902ff09 ("mqprio: Reserve last 32 classid values for HW
traffic classes and misc IDs") sch_mqprio started using netdev_txq_to_tc
to find the correct tc instead of dev->tc_to_txq[]

However, when mqprio is compiled as a module, it cannot resolve the
symbol, leading to this error:

     ERROR: "netdev_txq_to_tc" [net/sched/sch_mqprio.ko] undefined!

This adds an EXPORT_SYMBOL() since the other user in the kernel
(netif_set_xps_queue) is also EXPORT_SYMBOL() (and not _GPL) or in a
sysfs-callback.

Cc: Alexander Duyck <redacted>
Cc: Jesus Sanchez-Palencia <redacted>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Henrik Austad <redacted>

Reviewed-by: Eric Dumazet <edumazet@google.com>

-----Original Message-----
From: Eric Dumazet [mailto:edumazet@google.com]
Sent: Tuesday, October 17, 2017 4:21 AM
To: Henrik Austad <redacted>
Cc: netdev <redacted>; David S . Miller
[off-list ref]; Daniel Borkmann [off-list ref]; David
Ahern [off-list ref]; Duyck, Alexander H
[off-list ref]; Willem de Bruijn [off-list ref];
John Fastabend [off-list ref]; tcharding [off-list ref]; LKML
[off-list ref]; Henrik Austad [off-list ref]; Sanchez-
Palencia, Jesus [off-list ref]
Subject: Re: [PATCH] net: export netdev_txq_to_tc to allow sch_mqprio to
compile as module

On Tue, Oct 17, 2017 at 3:10 AM, Henrik Austad [off-list ref] wrote:

quoted

In commit 32302902ff09 ("mqprio: Reserve last 32 classid values for HW
traffic classes and misc IDs") sch_mqprio started using
netdev_txq_to_tc to find the correct tc instead of dev->tc_to_txq[]

However, when mqprio is compiled as a module, it cannot resolve the
symbol, leading to this error:

     ERROR: "netdev_txq_to_tc" [net/sched/sch_mqprio.ko] undefined!

This adds an EXPORT_SYMBOL() since the other user in the kernel
(netif_set_xps_queue) is also EXPORT_SYMBOL() (and not _GPL) or in a
sysfs-callback.

Cc: Alexander Duyck <redacted>
Cc: Jesus Sanchez-Palencia <redacted>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Henrik Austad <redacted>

Reviewed-by: Eric Dumazet <edumazet@google.com>

This is identical to a patch I submitted yesterday when I got the report from the kbuild robot. I would say your description looks much better than mine though so I would be good with dropping my patch in favor of this one.

Acked-by: Alexander Duyck <redacted>

From: Henrik Austad <redacted>
Date: Tue, 17 Oct 2017 12:10:10 +0200

In commit 32302902ff09 ("mqprio: Reserve last 32 classid values for HW
traffic classes and misc IDs") sch_mqprio started using netdev_txq_to_tc
to find the correct tc instead of dev->tc_to_txq[]

However, when mqprio is compiled as a module, it cannot resolve the
symbol, leading to this error:

     ERROR: "netdev_txq_to_tc" [net/sched/sch_mqprio.ko] undefined!

This adds an EXPORT_SYMBOL() since the other user in the kernel
(netif_set_xps_queue) is also EXPORT_SYMBOL() (and not _GPL) or in a
sysfs-callback.

Cc: Alexander Duyck <redacted>
Cc: Jesus Sanchez-Palencia <redacted>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Henrik Austad <redacted>

Applied, thanks.