Re: [RFC PATCH v3] net: sched: convert qdisc linked list to hashtable

From: Fengguang Wu
Date: Thu Jul 28 2016 - 08:52:30 EST

Hi Jiri,

On Thu, Jul 14, 2016 at 04:14:58PM +0200, Jiri Kosina wrote:

[ added CCs ]

On Tue, 12 Jul 2016, kbuild test robot wrote:


[auto build test ERROR on net/master]
[also build test ERROR on v4.7-rc7 next-20160711]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

config: arm-tct_hammer_defconfig (attached as .config)
compiler: arm-linux-gnueabi-gcc (Debian 5.3.1-8) 5.3.1 20160205
wget -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=arm

All errors (new ones prefixed by >>):

net/built-in.o: In function `dev_activate':
>> wext-proc.c:(.text+0x38544): undefined reference to `qdisc_hash_add'

This issue is be there even without my patch (but with qdisc_list_add
instead), isn't it?

Yes it looks so, this number happens in a number of places:

dns_query.c:(.text+0x39b84): undefined reference to `qdisc_hash_add'
include/linux/netdevice.h:1935: undefined reference to `qdisc_hash_add'
net/core/netevent.c:31: undefined reference to `qdisc_hash_add'
net/sched/sch_generic.c:789: undefined reference to `qdisc_hash_add'
sch_generic.c:(.text+0x33487): undefined reference to `qdisc_hash_add'
switchdev.c:(.text+0x3bf58): undefined reference to `qdisc_hash_add'
sysctl_net.c:(.text+0x31f70): undefined reference to `qdisc_hash_add'
(.text.dev_activate+0x228): undefined reference to `qdisc_hash_add'
(.text+0x37d0b): undefined reference to `qdisc_hash_add'
wext-proc.c:(.text+0x390a8): undefined reference to `qdisc_hash_add'

The problem is that sch_generic.c (where dev_activate() is) is being
compiled everytime CONFIG_NET is set, but sch_api.c (where
qdisc_list_add() is defined) only when CONFIG_NET_SCHED is set (and there
is no stub for !CONFIG_NET_SCHED case).

So it looks like a more general problem than specific to this patch.