question about samsung/sxgbe/sxgbe_xpcs.c

question about samsung/sxgbe/sxgbe_xpcs.c

[Julia Lawall]

Hello,

I was windering what is the purpose of the file
drivers/net/ethernet/samsung/sxgbe/sxgbe_xpcs.c

I can't find anything that refers to it, and if I remove it from the
makefile:

@@ -1,4 +1,4 @@
 obj-$(CONFIG_SXGBE_ETH) += samsung-sxgbe.o
 samsung-sxgbe-objs:= sxgbe_platform.o sxgbe_main.o sxgbe_desc.o \
                sxgbe_dma.o sxgbe_core.o sxgbe_mtl.o  sxgbe_mdio.o \
-               sxgbe_ethtool.o sxgbe_xpcs.o $(samsung-sxgbe-y)
+               sxgbe_ethtool.o $(samsung-sxgbe-y)

and then make clean and recompile, I see no bad effect.

thanks,
julia

Re: question about samsung/sxgbe/sxgbe_xpcs.c

[Shuah Khan]

2016-01-19 9:26 GMT-07:00 Julia Lawall <julia.lawall@lip6.fr>:
> Hello,
>
> I was windering what is the purpose of the file
> drivers/net/ethernet/samsung/sxgbe/sxgbe_xpcs.c

>From git log and comments, it appears this driver is for
Samsung SoCs.

>
> I can't find anything that refers to it, and if I remove it from the
> makefile:
>
> @@ -1,4 +1,4 @@
>  obj-$(CONFIG_SXGBE_ETH) += samsung-sxgbe.o
>  samsung-sxgbe-objs:= sxgbe_platform.o sxgbe_main.o sxgbe_desc.o \
>                 sxgbe_dma.o sxgbe_core.o sxgbe_mtl.o  sxgbe_mdio.o \
> -               sxgbe_ethtool.o sxgbe_xpcs.o $(samsung-sxgbe-y)
> +               sxgbe_ethtool.o $(samsung-sxgbe-y)
>
> and then make clean and recompile, I see no bad effect.
>

What is the motivation for the experiment to remove it?
This file probably gets used only on Samsung SoCs.

thanks,
-- Shuah

Re: question about samsung/sxgbe/sxgbe_xpcs.c

[Julia Lawall]

On Tue, 19 Jan 2016, Shuah Khan wrote:

> 2016-01-19 9:26 GMT-07:00 Julia Lawall <julia.lawall@lip6.fr>:
> > Hello,
> >
> > I was windering what is the purpose of the file
> > drivers/net/ethernet/samsung/sxgbe/sxgbe_xpcs.c
>
> From git log and comments, it appears this driver is for
> Samsung SoCs.
>
> >
> > I can't find anything that refers to it, and if I remove it from the
> > makefile:
> >
> > @@ -1,4 +1,4 @@
> >  obj-$(CONFIG_SXGBE_ETH) += samsung-sxgbe.o
> >  samsung-sxgbe-objs:= sxgbe_platform.o sxgbe_main.o sxgbe_desc.o \
> >                 sxgbe_dma.o sxgbe_core.o sxgbe_mtl.o  sxgbe_mdio.o \
> > -               sxgbe_ethtool.o sxgbe_xpcs.o $(samsung-sxgbe-y)
> > +               sxgbe_ethtool.o $(samsung-sxgbe-y)
> >
> > and then make clean and recompile, I see no bad effect.
> >
>
> What is the motivation for the experiment to remove it?
> This file probably gets used only on Samsung SoCs.

I just wondered.  I was looking at dependencies between networking files.
This one stands out because nothing is dependenton it, even the files it
is compiled with, and it doesn't contain the usual functions,
register_netdev, etc.

Thanks for the explanation.

julia

Re: question about samsung/sxgbe/sxgbe_xpcs.c

[David Miller]

From: Julia Lawall <julia.lawall@lip6.fr>
Date: Tue, 19 Jan 2016 19:54:20 +0100 (CET)

> On Tue, 19 Jan 2016, Shuah Khan wrote:
> 
>> 2016-01-19 9:26 GMT-07:00 Julia Lawall <julia.lawall@lip6.fr>:
>> > Hello,
>> >
>> > I was windering what is the purpose of the file
>> > drivers/net/ethernet/samsung/sxgbe/sxgbe_xpcs.c
>>
>> From git log and comments, it appears this driver is for
>> Samsung SoCs.
>>
>> >
>> > I can't find anything that refers to it, and if I remove it from the
>> > makefile:
>> >
>> > @@ -1,4 +1,4 @@
>> >  obj-$(CONFIG_SXGBE_ETH) += samsung-sxgbe.o
>> >  samsung-sxgbe-objs:= sxgbe_platform.o sxgbe_main.o sxgbe_desc.o \
>> >                 sxgbe_dma.o sxgbe_core.o sxgbe_mtl.o  sxgbe_mdio.o \
>> > -               sxgbe_ethtool.o sxgbe_xpcs.o $(samsung-sxgbe-y)
>> > +               sxgbe_ethtool.o $(samsung-sxgbe-y)
>> >
>> > and then make clean and recompile, I see no bad effect.
>> >
>>
>> What is the motivation for the experiment to remove it?
>> This file probably gets used only on Samsung SoCs.
> 
> I just wondered.  I was looking at dependencies between networking files.
> This one stands out because nothing is dependenton it, even the files it
> is compiled with, and it doesn't contain the usual functions,
> register_netdev, etc.

Even with that explanation, this is a bogus situation.

There are no in-tree callers of this code.  It should be removed until there
are in-tree users.

Nobody can figure out if the interface for this is done properly without seeing
the call sites and how they work.  It is therefore impossible to review this
code and judge it's design.

If someone doesn't send me a removal patch, I will remove this code myself.

Re: question about samsung/sxgbe/sxgbe_xpcs.c

[Jεan Sacren]

From: David Miller <davem@davemloft.net>
Date: Tue, 19 Jan 2016 14:36:28 -0500
>
> From: Julia Lawall <julia.lawall@lip6.fr>
> Date: Tue, 19 Jan 2016 19:54:20 +0100 (CET)

[...]

> > I just wondered.  I was looking at dependencies between networking files.
> > This one stands out because nothing is dependenton it, even the files it
> > is compiled with, and it doesn't contain the usual functions,
> > register_netdev, etc.
> 
> Even with that explanation, this is a bogus situation.
> 
> There are no in-tree callers of this code.  It should be removed until there
> are in-tree users.
> 
> Nobody can figure out if the interface for this is done properly without seeing
> the call sites and how they work.  It is therefore impossible to review this
> code and judge it's design.
> 
> If someone doesn't send me a removal patch, I will remove this code myself.

I have the patch ready.

Do you want me to submit it now during the merge window or wait till
net-next opens up again?

Re: question about samsung/sxgbe/sxgbe_xpcs.c

[Shuah Khan]

On 01/20/2016 10:10 PM, Jεan Sacren wrote:
> From: David Miller <davem@davemloft.net>
> Date: Tue, 19 Jan 2016 14:36:28 -0500
>>
>> From: Julia Lawall <julia.lawall@lip6.fr>
>> Date: Tue, 19 Jan 2016 19:54:20 +0100 (CET)
> 
> [...]
> 
>>> I just wondered.  I was looking at dependencies between networking files.
>>> This one stands out because nothing is dependenton it, even the files it
>>> is compiled with, and it doesn't contain the usual functions,
>>> register_netdev, etc.
>>
>> Even with that explanation, this is a bogus situation.
>>
>> There are no in-tree callers of this code.  It should be removed until there
>> are in-tree users.
>>
>> Nobody can figure out if the interface for this is done properly without seeing
>> the call sites and how they work.  It is therefore impossible to review this
>> code and judge it's design.
>>
>> If someone doesn't send me a removal patch, I will remove this code myself.
> 
> I have the patch ready.
> 
> Do you want me to submit it now during the merge window or wait till
> net-next opens up again?
> 

My second attempt to locate the author for a comment
on this before it gets removed. Maybe this code could
be fixed just in case it is important for some product
out there.

I am cc'ing the original author in case he has any
comments.

thanks,
-- Shuah


-- 
Shuah Khan
Sr. Linux Kernel Developer
Open Source Innovation Group
Samsung Research America (Silicon Valley)
shuahkh@osg.samsung.com | (970) 217-8978

Re: question about samsung/sxgbe/sxgbe_xpcs.c

[David Miller]

From: Jεan Sacren <sakiwit@gmail.com>
Date: Wed, 20 Jan 2016 22:10:56 -0700

> From: David Miller <davem@davemloft.net>
> Date: Tue, 19 Jan 2016 14:36:28 -0500
>>
>> From: Julia Lawall <julia.lawall@lip6.fr>
>> Date: Tue, 19 Jan 2016 19:54:20 +0100 (CET)
> 
> [...]
> 
>> > I just wondered.  I was looking at dependencies between networking files.
>> > This one stands out because nothing is dependenton it, even the files it
>> > is compiled with, and it doesn't contain the usual functions,
>> > register_netdev, etc.
>> 
>> Even with that explanation, this is a bogus situation.
>> 
>> There are no in-tree callers of this code.  It should be removed until there
>> are in-tree users.
>> 
>> Nobody can figure out if the interface for this is done properly without seeing
>> the call sites and how they work.  It is therefore impossible to review this
>> code and judge it's design.
>> 
>> If someone doesn't send me a removal patch, I will remove this code myself.
> 
> I have the patch ready.
> 
> Do you want me to submit it now during the merge window or wait till
> net-next opens up again?

This is rediculous.

No, you cannot submit patches for new features now.

Yes, you will submit to me a patch to remove the unused code.

Am I being clear enough now?

Re: question about samsung/sxgbe/sxgbe_xpcs.c

[David Miller]

From: Shuah Khan <shuahkh@osg.samsung.com>
Date: Thu, 21 Jan 2016 07:04:17 -0700

> On 01/20/2016 10:10 PM, Jεan Sacren wrote:
>> From: David Miller <davem@davemloft.net>
>> Date: Tue, 19 Jan 2016 14:36:28 -0500
>>>
>>> From: Julia Lawall <julia.lawall@lip6.fr>
>>> Date: Tue, 19 Jan 2016 19:54:20 +0100 (CET)
>> 
>> [...]
>> 
>>>> I just wondered.  I was looking at dependencies between networking files.
>>>> This one stands out because nothing is dependenton it, even the files it
>>>> is compiled with, and it doesn't contain the usual functions,
>>>> register_netdev, etc.
>>>
>>> Even with that explanation, this is a bogus situation.
>>>
>>> There are no in-tree callers of this code.  It should be removed until there
>>> are in-tree users.
>>>
>>> Nobody can figure out if the interface for this is done properly without seeing
>>> the call sites and how they work.  It is therefore impossible to review this
>>> code and judge it's design.
>>>
>>> If someone doesn't send me a removal patch, I will remove this code myself.
>> 
>> I have the patch ready.
>> 
>> Do you want me to submit it now during the merge window or wait till
>> net-next opens up again?
>> 
> 
> My second attempt to locate the author for a comment
> on this before it gets removed. Maybe this code could
> be fixed just in case it is important for some product
> out there.
> 
> I am cc'ing the original author in case he has any
> comments.

It never should have been added in the first place, I really don't
care at all right now what it's used for.

The simple fact is that it isn't used, and therefore must be removed
now.

Re: question about samsung/sxgbe/sxgbe_xpcs.c

[Jεan Sacren]

From: David Miller <davem@davemloft.net>
Date: Thu, 21 Jan 2016 10:45:20 -0800
> 
> Yes, you will submit to me a patch to remove the unused code.

I should have paraphrased it better:

"I have the patch ready and will submit it when net-next opens again."