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Message-ID: <987f4ee8-57ab-71c2-597d-7835c3e1e202@linux.ibm.com>
Date:   Thu, 28 Sep 2023 11:10:53 +0200
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Subject: Re: [PATCH net-next v4 05/18] net/smc: reserve CHID range for SMC-D
 virtual device
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To:     Jan Karcher <jaka@linux.ibm.com>, Wen Gu <guwen@linux.alibaba.com>,
        kgraul@linux.ibm.com, wenjia@linux.ibm.com, davem@davemloft.net,
        edumazet@google.com, kuba@kernel.org, pabeni@redhat.com
Cc:     schnelle@linux.ibm.com, gbayer@linux.ibm.com, pasic@linux.ibm.com,
        alibuda@linux.alibaba.com, tonylu@linux.alibaba.com,
        dust.li@linux.alibaba.com, linux-s390@vger.kernel.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
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 <d5cf999b-ec76-844a-873b-e8767be9ffb5@linux.ibm.com>
From:   Alexandra Winter <wintera@linux.ibm.com>
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On 28.09.23 05:08, Jan Karcher wrote:
> On 24/09/2023 17:16, Wen Gu wrote:
>> This patch reserve CHID range from 0xFF00 to 0xFFFF for SMC-D virtual
> 
> The current state is that 0xFF00 - 0xFFFF is the range of all virtual SMC-D devices. This range devides into:
> - 0xFF00 - 0xFFFE is for virto-ism
> - 0xFFFF is for loopback
> 
> 
>> device and introduces helpers to identify them.
>>
>> Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
>> ---
>>   net/smc/smc_ism.h | 15 +++++++++++++++
>>   1 file changed, 15 insertions(+)
>>
>> diff --git a/net/smc/smc_ism.h b/net/smc/smc_ism.h
>> index 14d2e77..2ecc8de 100644
>> --- a/net/smc/smc_ism.h
>> +++ b/net/smc/smc_ism.h
>> @@ -15,6 +15,9 @@
>>     #include "smc.h"
>>   +#define SMC_VIRT_ISM_CHID_MAX        0xFFFF
> 
> SMC_VIRT_ISM_MAX is 0xFFFE. Or do you mean virtual devices as the whole group. If yes i think that this naming will be very confusing in a few months/years.
> Maybe something like SMC_VIRTUAL_DEV_CHID_{MIN|MAX}?


IMO names are important. They can make future lives easier or harder.

Your first group of patches aims at 'decouple ISM device hard code from SMC-D stack'
Maybe now would be a good point in time to decide what ISM should mean in net/smc.
a) the s390 ISM devices
b) SMC-D devices in general
I would vote for a). (today a) and b) can be found in the code, as well as the term smcd_dev)

Then like Jan wrote above:
"0xFF00 - 0xFFFF is the range of all virtual SMC-D devices" and it should NOT be called SMC_VIRT_ISM_CHID_MAX.


Then in many places in net/smc 'ism' should be replaces by 'smcd_dev' or something similar.
Wen Gu, is that something you would offer to do as part of the preparation work for this series?