netdev - Re: [PATCH net-next 1/2] net/smc: rework peer ID handling

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Message-Id: <35171bea-1940-ef31-4266-3f421cac6225@linux.ibm.com>
Date:   Tue, 25 Feb 2020 16:17:08 +0100
From:   Karsten Graul <kgraul@...ux.ibm.com>
To:     Hans Wippel <ndev@...pl.net>, ubraun@...ux.ibm.com,
        davem@...emloft.net
Cc:     netdev@...r.kernel.org
Subject: Re: [PATCH net-next 1/2] net/smc: rework peer ID handling

On 25/02/2020 00:59, Hans Wippel wrote:
> This patch initializes the peer ID to a random instance ID and a zero
> MAC address. If a RoCE device is in the host, the MAC address part of
> the peer ID is overwritten with the respective address. Also, a function
> for checking if the peer ID is valid is added. A peer ID is considered
> valid if the MAC address part contains a non-zero MAC address.
> 
> Signed-off-by: Hans Wippel <ndev@...pl.net>
> ---
>  net/smc/smc_ib.c | 19 ++++++++++++-------
>  1 file changed, 12 insertions(+), 7 deletions(-)
> 
> diff --git a/net/smc/smc_ib.c b/net/smc/smc_ib.c
> index 6756bd5a3fe4..3444de27fecd 100644
> --- a/net/smc/smc_ib.c
> +++ b/net/smc/smc_ib.c
> @@ -37,11 +37,7 @@ struct smc_ib_devices smc_ib_devices = {	/* smc-registered ib devices */
>  	.list = LIST_HEAD_INIT(smc_ib_devices.list),
>  };
>  
> -#define SMC_LOCAL_SYSTEMID_RESET	"%%%%%%%"
> -
> -u8 local_systemid[SMC_SYSTEMID_LEN] = SMC_LOCAL_SYSTEMID_RESET;	/* unique system
> -								 * identifier
> -								 */
> +u8 local_systemid[SMC_SYSTEMID_LEN];		/* unique system identifier */
>  
>  static int smc_ib_modify_qp_init(struct smc_link *lnk)
>  {
> @@ -168,6 +164,15 @@ static inline void smc_ib_define_local_systemid(struct smc_ib_device *smcibdev,
>  {
>  	memcpy(&local_systemid[2], &smcibdev->mac[ibport - 1],
>  	       sizeof(smcibdev->mac[ibport - 1]));
> +}
> +
> +bool smc_ib_is_valid_local_systemid(void)

You introduce a non-static but its used only from this module.

> +{
> +	return !is_zero_ether_addr(&local_systemid[2]);
> +}
> +
> +static void smc_ib_init_local_systemid(void)
> +{
>  	get_random_bytes(&local_systemid[0], 2);
>  }
>  
> @@ -224,8 +229,7 @@ static int smc_ib_remember_port_attr(struct smc_ib_device *smcibdev, u8 ibport)
>  	rc = smc_ib_fill_mac(smcibdev, ibport);
>  	if (rc)
>  		goto out;
> -	if (!strncmp(local_systemid, SMC_LOCAL_SYSTEMID_RESET,
> -		     sizeof(local_systemid)) &&
> +	if (!smc_ib_is_valid_local_systemid() &&
>  	    smc_ib_port_active(smcibdev, ibport))
>  		/* create unique system identifier */
>  		smc_ib_define_local_systemid(smcibdev, ibport);
> @@ -605,6 +609,7 @@ static struct ib_client smc_ib_client = {
>  
>  int __init smc_ib_register_client(void)
>  {
> +	smc_ib_init_local_systemid();
>  	return ib_register_client(&smc_ib_client);
>  }
>  
> 

-- 
Karsten

(I'm a dude)