Re: [RFC PATCH net-next v4 03/11] net/smc: implement ID-related operations of loopback-ism

[Wen Gu <guwen@linux.alibaba.com>]

On 2024/3/21 16:12, Jan Karcher wrote:
> 
> 
> On 17/03/2024 11:05, Wen Gu wrote:
>> This implements GID and CHID related operations of loopback-ism device.
>> loopback-ism acts as an ISMv2. It's GID is generated randomly by UUIDv4
>> algorithm and CHID is reserved 0xFFFF.
> 
> Hi Wen Gu,
> 
> Please add that loopback-ism uses an extended GID instead of a GID here aswell.
> 

OK, will add that. Thanks!
>>
>> Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
>> ---
>>   net/smc/smc_loopback.c | 62 ++++++++++++++++++++++++++++++++++++++----
>>   net/smc/smc_loopback.h |  3 ++
>>   2 files changed, 60 insertions(+), 5 deletions(-)
>>
>> diff --git a/net/smc/smc_loopback.c b/net/smc/smc_loopback.c
>> index e9170d86e58f..7656a2474500 100644
>> --- a/net/smc/smc_loopback.c
>> +++ b/net/smc/smc_loopback.c
>> @@ -19,11 +19,62 @@
>>   #include "smc_loopback.h"
>>   #if IS_ENABLED(CONFIG_SMC_LO)
>> +#define SMC_LO_V2_CAPABLE    0x1 /* loopback-ism acts as ISMv2 */
>> +
>>   static const char smc_lo_dev_name[] = "loopback-ism";
>>   static struct smc_lo_dev *lo_dev;
>> +static void smc_lo_generate_id(struct smc_lo_dev *ldev)
>> +{
>> +    struct smcd_gid *lgid = &ldev->local_gid;
>> +    uuid_t uuid;
>> +
>> +    uuid_gen(&uuid);
>> +    memcpy(&lgid->gid, &uuid, sizeof(lgid->gid));
>> +    memcpy(&lgid->gid_ext, (u8 *)&uuid + sizeof(lgid->gid),
>> +           sizeof(lgid->gid_ext));
>> +
>> +    ldev->chid = SMC_LO_CHID;
>> +}
> 
> Minor comment. The function name implies that there is one id set whle
> there are two different ones. The chid assignment can be easily looked over. Maybe changing the function name to 
> `smc_lo_generate_ids` would prevent this. What do you think?
> 

Agree. I will change the function name to 'smc_lo_generate_ids'. Thanks!

> Thanks
> - Jan
> 
>> +
>> +static int smc_lo_query_rgid(struct smcd_dev *smcd, struct smcd_gid *rgid,
>> +                 u32 vid_valid, u32 vid)
>> +{
>> +    struct smc_lo_dev *ldev = smcd->priv;
>> +
>> +    /* rgid should be the same as lgid */
>> +    if (!ldev || rgid->gid != ldev->local_gid.gid ||
>> +        rgid->gid_ext != ldev->local_gid.gid_ext)
>> +        return -ENETUNREACH;
>> +    return 0;
>> +}
>> +
>> +static int smc_lo_supports_v2(void)
>> +{
>> +    return SMC_LO_V2_CAPABLE;
>> +}
>> +
>> +static void smc_lo_get_local_gid(struct smcd_dev *smcd,
>> +                 struct smcd_gid *smcd_gid)
>> +{
>> +    struct smc_lo_dev *ldev = smcd->priv;
>> +
>> +    smcd_gid->gid = ldev->local_gid.gid;
>> +    smcd_gid->gid_ext = ldev->local_gid.gid_ext;
>> +}
>> +
>> +static u16 smc_lo_get_chid(struct smcd_dev *smcd)
>> +{
>> +    return ((struct smc_lo_dev *)smcd->priv)->chid;
>> +}
>> +
>> +static struct device *smc_lo_get_dev(struct smcd_dev *smcd)
>> +{
>> +    return &((struct smc_lo_dev *)smcd->priv)->dev;
>> +}
>> +
>>   static const struct smcd_ops lo_ops = {
>> -    .query_remote_gid    = NULL,
>> +    .query_remote_gid = smc_lo_query_rgid,
>>       .register_dmb        = NULL,
>>       .unregister_dmb        = NULL,
>>       .add_vlan_id        = NULL,
>> @@ -32,10 +83,10 @@ static const struct smcd_ops lo_ops = {
>>       .reset_vlan_required    = NULL,
>>       .signal_event        = NULL,
>>       .move_data        = NULL,
>> -    .supports_v2        = NULL,
>> -    .get_local_gid        = NULL,
>> -    .get_chid        = NULL,
>> -    .get_dev        = NULL,
>> +    .supports_v2 = smc_lo_supports_v2,
>> +    .get_local_gid = smc_lo_get_local_gid,
>> +    .get_chid = smc_lo_get_chid,
>> +    .get_dev = smc_lo_get_dev,
>>   };
>>   static struct smcd_dev *smcd_lo_alloc_dev(const struct smcd_ops *ops,
>> @@ -95,6 +146,7 @@ static void smcd_lo_unregister_dev(struct smc_lo_dev *ldev)
>>   static int smc_lo_dev_init(struct smc_lo_dev *ldev)
>>   {
>> +    smc_lo_generate_id(ldev);
>>       return smcd_lo_register_dev(ldev);
>>   }
>> diff --git a/net/smc/smc_loopback.h b/net/smc/smc_loopback.h
>> index 9dd44d4c0ca3..55b41133a97f 100644
>> --- a/net/smc/smc_loopback.h
>> +++ b/net/smc/smc_loopback.h
>> @@ -20,10 +20,13 @@
>>   #if IS_ENABLED(CONFIG_SMC_LO)
>>   #define SMC_LO_MAX_DMBS        5000
>> +#define SMC_LO_CHID        0xFFFF
>>   struct smc_lo_dev {
>>       struct smcd_dev *smcd;
>>       struct device dev;
>> +    u16 chid;
>> +    struct smcd_gid local_gid;
>>   };
>>   #endif