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Message-ID: <ef936c58-e87c-4078-a4dc-ed7313dba2a3@linux.ibm.com>
Date: Thu, 25 Apr 2024 13:29:51 +0200
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Subject: Re: [PATCH net-next v6 07/11] net/smc: register loopback-ism into
 SMC-D device list
Content-Language: en-GB
To: Wen Gu <guwen@linux.alibaba.com>, wintera@linux.ibm.com,
        twinkler@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com,
        agordeev@linux.ibm.com, davem@davemloft.net, edumazet@google.com,
        kuba@kernel.org, pabeni@redhat.com, jaka@linux.ibm.com
Cc: borntraeger@linux.ibm.com, svens@linux.ibm.com, alibuda@linux.alibaba.com,
        tonylu@linux.alibaba.com, linux-kernel@vger.kernel.org,
        linux-s390@vger.kernel.org, netdev@vger.kernel.org
References: <20240414040304.54255-1-guwen@linux.alibaba.com>
 <20240414040304.54255-8-guwen@linux.alibaba.com>
From: Wenjia Zhang <wenjia@linux.ibm.com>
In-Reply-To: <20240414040304.54255-8-guwen@linux.alibaba.com>
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On 14.04.24 06:03, Wen Gu wrote:
> After the loopback-ism device is ready, add it to the SMC-D device list
> as an ISMv2 device, and always keep it at the beginning to ensure it is
> preferred for providing a shortcut for data transfer within the same
> kernel.
> 
> Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
> ---
>   net/smc/smc_ism.c      | 30 +++++++++++++++++++++---------
>   net/smc/smc_ism.h      |  1 +
>   net/smc/smc_loopback.c | 20 +++++++++++++-------
>   3 files changed, 35 insertions(+), 16 deletions(-)
> 
> diff --git a/net/smc/smc_ism.c b/net/smc/smc_ism.c
> index 188fd28423c2..6bed0a61b746 100644
> --- a/net/smc/smc_ism.c
> +++ b/net/smc/smc_ism.c
> @@ -91,6 +91,11 @@ bool smc_ism_is_v2_capable(void)
>   	return smc_ism_v2_capable;
>   }
>   
> +void smc_ism_set_v2_capable(void)
> +{
> +	smc_ism_v2_capable = true;
> +}
> +
>   /* Set a connection using this DMBE. */
>   void smc_ism_set_conn(struct smc_connection *conn)
>   {
> @@ -439,7 +444,7 @@ static struct smcd_dev *smcd_alloc_dev(struct device *parent, const char *name,
>   static void smcd_register_dev(struct ism_dev *ism)
>   {
>   	const struct smcd_ops *ops = ism_get_smcd_ops();
> -	struct smcd_dev *smcd;
> +	struct smcd_dev *smcd, *fentry;
>   
>   	if (!ops)
>   		return;
> @@ -454,16 +459,23 @@ static void smcd_register_dev(struct ism_dev *ism)
>   	if (smc_pnetid_by_dev_port(&ism->pdev->dev, 0, smcd->pnetid))
>   		smc_pnetid_by_table_smcd(smcd);
>   
> +	if (smcd->ops->supports_v2())
> +		smc_ism_set_v2_capable();
>   	mutex_lock(&smcd_dev_list.mutex);
> -	if (list_empty(&smcd_dev_list.list)) {
> -		if (smcd->ops->supports_v2())
> -			smc_ism_v2_capable = true;
> -	}
> -	/* sort list: devices without pnetid before devices with pnetid */
> -	if (smcd->pnetid[0])
> +	/* sort list:
> +	 * - devices without pnetid before devices with pnetid;
> +	 * - loopback-ism always at the very beginning;
> +	 */
> +	if (!smcd->pnetid[0]) {
> +		fentry = list_first_entry_or_null(&smcd_dev_list.list,
> +						  struct smcd_dev, list);
> +		if (fentry && smc_ism_is_loopback(fentry))
> +			list_add(&smcd->list, &fentry->list);
> +		else
> +			list_add(&smcd->list, &smcd_dev_list.list);
> +	} else {
>   		list_add_tail(&smcd->list, &smcd_dev_list.list);
> -	else
> -		list_add(&smcd->list, &smcd_dev_list.list);
> +	}

Nit: here the pair of curly brackets are unnecessary.

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