Re: [PATCH] kni: fix use of undefined comma variable in makefile

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 5/30/2016 5:46 PM, Ferruh Yigit wrote:
> On 5/30/2016 5:21 PM, Olivier Matz wrote:
>> Hi Ferruh,
>>
>> On 05/30/2016 05:49 PM, Ferruh Yigit wrote:
>>> On 5/30/2016 12:56 PM, Olivier Matz wrote:
>>>> The $(comma) variable is not defined in this Makefile, nor in
>>>> any included Makefile. Seen while doing a "make clean" on ubuntu:
>>>>
>>>>   $ make clean
>>>>   == Clean lib
>>>>   == Clean lib/librte_compat
>>>>   == Clean lib/librte_eal
>>>>   == Clean lib/librte_eal/common
>>>>   == Clean lib/librte_eal/linuxapp
>>>>   == Clean lib/librte_eal/linuxapp/eal
>>>>   == Clean lib/librte_eal/linuxapp/igb_uio
>>>>   == Clean lib/librte_eal/linuxapp/kni
>>>>   tr: missing operand after ‘.-’
>>>>   Two strings must be given when translating.
>>>>   Try 'tr --help' for more information.
>>>
>>> I don't observe this error on Ubuntu.
>>>
>>> Also did a quick check and $(comma) seems defined, but not sure exactly
>>> where. What I test:
>>>
>>> $ lsb_release -si
>>> Ubuntu
>>>
>>>
>>> $ git diff
>>> diff --git a/lib/librte_eal/linuxapp/kni/Makefile
>>> b/lib/librte_eal/linuxapp/kni/Makefile
>>> index ac99d3f..dcad241 100644
>>> --- a/lib/librte_eal/linuxapp/kni/Makefile
>>> +++ b/lib/librte_eal/linuxapp/kni/Makefile
>>> @@ -90,4 +90,7 @@ SRCS-y += kni_net.c
>>>  SRCS-y += kni_ethtool.c
>>>  SRCS-$(CONFIG_RTE_KNI_VHOST) += kni_vhost.c
>>>
>>> +test_comma:
>>> +       @echo "= comma: $(comma) ="
>>> +
>>>
>>>
>>>
>>> $ make -C lib/librte_eal/linuxapp/kni test_comma
>>> make: Entering directory '.../dpdk/lib/librte_eal/linuxapp/kni'
>>> = comma: , =
>>> make: Leaving directory '.../dpdk/lib/librte_eal/linuxapp/kni'
>>
>> Thanks for testing and review.
>> I added the following lines to the makefile (just after the include
>> rte.vars.mk):
>>
>> 	$(info ------------------)
>> 	$(info comma=$(comma))
>> 	$(info $(origin comma))
>>
>> And it gives me:
>>
>> 	$ make clean
>> 	== Clean lib/librte_eal/linuxapp/kni
>> 	--------------------
>> 	comma=,
>> 	file
>> 	make -C /lib/modules/3.13.0-79-generic/build
>> M=/home/user/dpdk.org/build/build/lib/librte_eal/linuxapp/kni
>> O=/lib/modules/3.13.0-79-generic/build clean
>> 	make -C /usr/src/linux-headers-3.13.0-79-generic \
>>         KBUILD_SRC=/usr/src/linux-headers-3.13.0-79-generic \
>>
>> KBUILD_EXTMOD="/home/user/dpdk.org/build/build/lib/librte_eal/linuxapp/kni"
>> -f /usr/src/linux-headers-3.13.0-79-generic/Makefile \
>> 	        clean
>> 	make -f /usr/src/linux-headers-3.13.0-79-generic/scripts/Makefile.clean
>> obj=/home/user/dpdk.org/build/build/lib/librte_eal/linuxapp/kni
>> 	--------------------
>> 	comma=
>> 	undefined
>> 	tr: missing operand after ‘.-’
>> 	Two strings must be given when translating.
>> 	Try 'tr --help' for more information.
>> 	[...]
>>
>> Actually this Makefile is used twice, and second time the $(comma)
>> variable is not defined.
>>
>> It seems the $(comma) variable is defined in rte.cpuflags.mk when
>> including rte.vars.mk:
>>
>>   mk/rte.vars.mk
>>     mk/target/generic/rte.vars.mk
>>       mk/rte.cpuflags.mk    (only if KERNELRELEASE is unset, which is
>>                              not the case for the second call)
>>
>>
>> Do you see the issue when you do a "make clean"?
>>
> 
> No issue on "make clean".
> 
> I did same modification as you did, for me comma defined for both times,
> a system variable can be triggering the behavior perhaps.
> 
> What I got with "make clean" is:
> 
> ...
> == Clean lib/librte_eal/linuxapp/kni
> ------------
> comma=,
> file
> make -C /lib/modules/4.4.0-22-generic/build
> M=/home/ferruhy/development/dpdk/build/build/lib/librte_eal/linuxapp/kni
> O=/lib/modules/4.4.0-22-generic/build clean
> make -C /usr/src/linux-headers-4.4.0-22-generic
> KBUILD_SRC=/usr/src/linux-headers-4.4.0-22-generic \
> -f /usr/src/linux-headers-4.4.0-22-generic/Makefile clean
> make -f /usr/src/linux-headers-4.4.0-22-generic/scripts/Makefile.clean
> obj=/home/ferruhy/development/dpdk/build/build/lib/librte_eal/linuxapp/kni
> ------------
> comma=,
> file
>   rm -rf
> /home/ferruhy/development/dpdk/build/build/lib/librte_eal/linuxapp/kni/.tmp_versions
>   rm -f
> /home/ferruhy/development/dpdk/build/build/lib/librte_eal/linuxapp/kni/Module.symvers
> == Clean lib/librte_eal/linuxapp/xen_dom0
> ...
> 

Error is related to the kernel version, in second call "comma"
definition comes from kernel makefiles.

Following commit causes comma to be defined:
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=371fdc77af44f4cb32475fd499e1d912ccc30890

So this is valid issue for old kernels, and using "," directly looks OK.

> Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
Acked-by Ferruh Yigit <ferruh.yigit@intel.com>