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Message-ID: <3e761be7-c441-4629-3539-f067c6d8c1e8@linux.alibaba.com>
Date:   Fri, 4 Aug 2023 14:40:27 +0800
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Subject: Re: [RFC PATCH net-next 4/6] net/smc: support max connections per lgr
 negotiation
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To:     Simon Horman <horms@kernel.org>
Cc:     wenjia@linux.ibm.com, jaka@linux.ibm.com, kgraul@linux.ibm.com,
        tonylu@linux.alibaba.com, davem@davemloft.net, edumazet@google.com,
        kuba@kernel.org, pabeni@redhat.com, alibuda@linux.alibaba.com,
        guwen@linux.alibaba.com, linux-s390@vger.kernel.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20230803132422.6280-1-guangguan.wang@linux.alibaba.com>
 <20230803132422.6280-5-guangguan.wang@linux.alibaba.com>
 <ZMvqJ6FYR6gWS+ZK@kernel.org>
From:   Guangguan Wang <guangguan.wang@linux.alibaba.com>
In-Reply-To: <ZMvqJ6FYR6gWS+ZK@kernel.org>
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Got it.
I will remove the check in the next version.

Thanks,
Guangguan Wang

On 2023/8/4 01:55, Simon Horman wrote:
> On Thu, Aug 03, 2023 at 09:24:20PM +0800, Guangguan Wang wrote:
>> Support max connections per lgr negotiation for SMCR v2.1,
>> which is one of smc v2.1 features.
>>
>> Signed-off-by: Guangguan Wang <guangguan.wang@linux.alibaba.com>
>> Reviewed-by: Tony Lu <tonylu@linux.alibaba.com>
> 
> ...
> 
> Hi Guangguan Wang,
> 
>>  int smc_clc_cli_v2x_features_validate(struct smc_clc_first_contact_ext *fce,
>>  				      struct smc_init_info *ini)
>>  {
>> +	struct smc_clc_first_contact_ext_v2x *fce_v2x =
>> +		(struct smc_clc_first_contact_ext_v2x *)fce;
>> +
>>  	if (ini->release_ver < SMC_RELEASE_1)
>>  		return 0;
>>  
>> +	if (!ini->is_smcd) {
>> +		if (fce_v2x->max_conns > SMC_CONN_PER_LGR_MAX)
> 
> The type of the max_cons field is u8.
> The value of SMC_CONN_PER_LGR_MAX is 255 (in another patch of this series),
> the maximum value that the max_cons field can be assigned.
> So it seems that this condition cannot ever be true.
> 
> As flagged by Smatch.
> 
>> +			return SMC_CLC_DECL_MAXCONNERR;
>> +		ini->max_conns = fce_v2x->max_conns;
>> +	}
>> +
>>  	return 0;
>>  }
> 
> ...
> 
>> diff --git a/net/smc/smc_clc.h b/net/smc/smc_clc.h
> 
> ...
> 
>> @@ -236,7 +238,8 @@ struct smc_clc_first_contact_ext {
>>  
>>  struct smc_clc_first_contact_ext_v2x {
>>  	struct smc_clc_first_contact_ext fce_v20;
>> -	u8 reserved3[4];
>> +	u8 max_conns; /* for SMC-R only */
>> +	u8 reserved3[3];
>>  	__be32 vendor_exp_options;
>>  	u8 reserved4[8];
>>  } __packed;		/* format defined in
> 
> ...
> 
>> diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
>> index 1a97fef39127..065369dc6584 100644
>> --- a/net/smc/smc_core.h
>> +++ b/net/smc/smc_core.h
>> @@ -22,6 +22,7 @@
>>  #include "smc_ib.h"
>>  
>>  #define SMC_RMBS_PER_LGR_MAX	255	/* max. # of RMBs per link group */
>> +#define SMC_CONN_PER_LGR_MAX	255	/* max. # of connections per link group */
>>  
>>  struct smc_lgr_list {			/* list of link group definition */
>>  	struct list_head	list;