Received-SPF: pass (google.com: domain of linux-kernel+bounces-38823-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45e3:2400::1 as permitted sender) client-ip=2604:1380:45e3:2400::1;
Message-ID: <54f9622f-7e62-4089-91dc-df541f8f37f8@linux.ibm.com>
Date: Thu, 25 Jan 2024 16:26:22 +0100
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH net] net/smc: fix incorrect SMC-D link group matching
 logic
Content-Language: en-US
To: Wen Gu <guwen@linux.alibaba.com>, mjrosato@linux.ibm.com,
        wenjia@linux.ibm.com, jaka@linux.ibm.com, davem@davemloft.net,
        edumazet@google.com, kuba@kernel.org, pabeni@redhat.com
Cc: alibuda@linux.alibaba.com, tonylu@linux.alibaba.com,
        linux-s390@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20240125123916.77928-1-guwen@linux.alibaba.com>
From: Alexandra Winter <wintera@linux.ibm.com>
In-Reply-To: <20240125123916.77928-1-guwen@linux.alibaba.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk
MIME-Version: 1.0


On 25.01.24 13:39, Wen Gu wrote:
> The logic to determine if SMC-D link group matches is incorrect. The
> correct logic should be that it only returns true when the GID is the
> same, and the SMC-D device is the same and the extended GID is the same
> (in the case of virtual ISM).
> 
> It can be fixed by adding brackets around the conditional (or ternary)
> operator expression. But for better readability and maintainability, it
> has been changed to an if-else statement.
> 
> Reported-by: Matthew Rosato <mjrosato@linux.ibm.com>
> Closes: https://lore.kernel.org/r/13579588-eb9d-4626-a063-c0b77ed80f11@linux.ibm.com
> Fixes: b40584d14570 ("net/smc: compatible with 128-bits extended GID of virtual ISM device")
> Link: https://lore.kernel.org/r/13579588-eb9d-4626-a063-c0b77ed80f11@linux.ibm.com
> Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
> ---
>  net/smc/smc_core.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
> index 95cc95458e2d..e4c858411207 100644
> --- a/net/smc/smc_core.c
> +++ b/net/smc/smc_core.c
> @@ -1877,9 +1877,15 @@ static bool smcd_lgr_match(struct smc_link_group *lgr,
>  			   struct smcd_dev *smcismdev,
>  			   struct smcd_gid *peer_gid)
>  {
> -	return lgr->peer_gid.gid == peer_gid->gid && lgr->smcd == smcismdev &&
> -		smc_ism_is_virtual(smcismdev) ?
> -		(lgr->peer_gid.gid_ext == peer_gid->gid_ext) : 1;
> +	if (lgr->peer_gid.gid != peer_gid->gid ||
> +	    lgr->smcd != smcismdev)
> +		return false;
> +
> +	if (smc_ism_is_virtual(smcismdev) &&
> +	    lgr->peer_gid.gid_ext != peer_gid->gid_ext)
> +		return false;
> +
> +	return true;
>  }
>  
>  /* create a new SMC connection (and a new link group if necessary) */

Thank you Wen Gu

Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>