Source organization for two drivers sharing coomon code

Source organization for two drivers sharing coomon code

[Subbu Seetharaman]

What is the recommended way for two drivers to share common code ?
Our device has two PCI functions and hence two drivers -  NIC and 
SCSI driver.   The source code for these dirvers will fit under 
drivers/net and drivers/scsi.  But both drivers share some common 
code.  If possible, I would like to avoid duplicating the common 
code under the two driver directories.   Is there any recommened 
way to organize such common  code ?  Thanks.

Subbu

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Re: Source organization for two drivers sharing coomon code

[Alan Cox]

On Fri, 27 Jul 2007 10:17:29 -0700
"Subbu Seetharaman" <subbus@serverengines.com> wrote:

> 
> 
> What is the recommended way for two drivers to share common code ?
> Our device has two PCI functions and hence two drivers -  NIC and 
> SCSI driver.   The source code for these dirvers will fit under 
> drivers/net and drivers/scsi.  But both drivers share some common 
> code.  If possible, I would like to avoid duplicating the common 
> code under the two driver directories.   Is there any recommened 
> way to organize such common  code ?  Thanks.

What sort of code is shared - historically the cases we have had in the
driver space have mostly been common message passing interfaces to
co-processor type boards (eg I2O or MPT Fusion) and those have lived
under drivers/message/type/...

I don't think there is any hard rule here.

Alan

Re: Source organization for two drivers sharing coomon code

[Jan Engelhardt]

On Jul 27 2007 10:17, Subbu Seetharaman wrote:
>What is the recommended way for two drivers to share common code ?
>Our device has two PCI functions and hence two drivers -  NIC and 
>SCSI driver.   The source code for these dirvers will fit under 
>drivers/net and drivers/scsi.  But both drivers share some common 
>code.  If possible, I would like to avoid duplicating the common 
>code under the two driver directories.   Is there any recommened 
>way to organize such common  code ?  Thanks.

You could create (in total) three modules, e.g. my-common.ko,
my-net.ko and my-scsi.ko, of which the latter two use functions from the first.


	Jan
-- 

Re: Source organization for two drivers sharing coomon code

[Chris Friesen]

Jan Engelhardt wrote:
> On Jul 27 2007 10:17, Subbu Seetharaman wrote:
> 
>>What is the recommended way for two drivers to share common code ?
>><snip>...The source code for these dirvers will fit under 
>>drivers/net and drivers/scsi.  But both drivers share some common 
>>code.

> You could create (in total) three modules, e.g. my-common.ko,
> my-net.ko and my-scsi.ko, of which the latter two use functions from the first.

Where would the common code live, in such a case?  Would you just pick 
one of the two locations at random, or put it in drivers/misc or maybe lib?

Chris

Re: Source organization for two drivers sharing coomon code

[Jan Engelhardt]

On Jul 27 2007 13:12, Chris Friesen wrote:
> Jan Engelhardt wrote:
>> On Jul 27 2007 10:17, Subbu Seetharaman wrote:
>> 
>> >What is the recommended way for two drivers to share common code ?
>> ><snip>...The source code for these dirvers will fit under drivers/net and
>> >drivers/scsi.  But both drivers share some common code.
>
>> You could create (in total) three modules, e.g. my-common.ko,
>> my-net.ko and my-scsi.ko, of which the latter two use functions from the
>> first.
>
> Where would the common code live, in such a case?  Would you just pick one of
> the two locations at random, or put it in drivers/misc or maybe lib?

Perhaps drivers/message - well I can't answer that exactly.

As far as the output object files are concerned, it is not relevant,
since they will be autoloaded anyway :)



	Jan
-- 

Re: Source organization for two drivers sharing coomon code

[Subbu Seetharaman]

Thanks for all the answers.  The common code is mostly handling
the message passing for hardware  initialization, rings creation
and some ioctls.  drivers/message looks like a good place for this
code to live.

Subbu



From: Jan Engelhardt [mailto:jengelh@computergmbh.de]
To: Chris Friesen [mailto:cfriesen@nortel.com]
Cc: Subbu Seetharaman [mailto:subbus@serverengines.com], linux-kernel@vger.kernel.org
Sent: Fri, 27 Jul 2007 12:34:16 -0700
Subject: Re: Source organization for two drivers sharing coomon code


On Jul 27 2007 13:12, Chris Friesen wrote:
> Jan Engelhardt wrote:
>> On Jul 27 2007 10:17, Subbu Seetharaman wrote:
>> 
>> >What is the recommended way for two drivers to share common code ?
>> ><snip>...The source code for these dirvers will fit under drivers/net and
>> >drivers/scsi. But both drivers share some common code.
>
>> You could create (in total) three modules, e.g. my-common.ko,
>> my-net.ko and my-scsi.ko, of which the latter two use functions from the
>> first.
>
> Where would the common code live, in such a case? Would you just pick one of
> the two locations at random, or put it in drivers/misc or maybe lib?

Perhaps drivers/message - well I can't answer that exactly.

As far as the output object files are concerned, it is not relevant,
since they will be autoloaded anyway :)



Jan
-- 

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