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Message-ID: <d5cf999b-ec76-844a-873b-e8767be9ffb5@linux.ibm.com>
Date:   Thu, 28 Sep 2023 05:08:16 +0200
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From:   Jan Karcher <jaka@linux.ibm.com>
Subject: Re: [PATCH net-next v4 05/18] net/smc: reserve CHID range for SMC-D
 virtual device
To:     Wen Gu <guwen@linux.alibaba.com>, kgraul@linux.ibm.com,
        wenjia@linux.ibm.com, davem@davemloft.net, edumazet@google.com,
        kuba@kernel.org, pabeni@redhat.com
Cc:     wintera@linux.ibm.com, schnelle@linux.ibm.com,
        gbayer@linux.ibm.com, pasic@linux.ibm.com,
        alibuda@linux.alibaba.com, tonylu@linux.alibaba.com,
        dust.li@linux.alibaba.com, linux-s390@vger.kernel.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
References: <1695568613-125057-1-git-send-email-guwen@linux.alibaba.com>
 <1695568613-125057-6-git-send-email-guwen@linux.alibaba.com>
Organization: IBM - Network Linux on Z
In-Reply-To: <1695568613-125057-6-git-send-email-guwen@linux.alibaba.com>
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On 24/09/2023 17:16, Wen Gu wrote:
> This patch reserve CHID range from 0xFF00 to 0xFFFF for SMC-D virtual

The current state is that 0xFF00 - 0xFFFF is the range of all virtual 
SMC-D devices. This range devides into:
- 0xFF00 - 0xFFFE is for virto-ism
- 0xFFFF is for loopback


> device and introduces helpers to identify them.
> 
> Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
> ---
>   net/smc/smc_ism.h | 15 +++++++++++++++
>   1 file changed, 15 insertions(+)
> 
> diff --git a/net/smc/smc_ism.h b/net/smc/smc_ism.h
> index 14d2e77..2ecc8de 100644
> --- a/net/smc/smc_ism.h
> +++ b/net/smc/smc_ism.h
> @@ -15,6 +15,9 @@
>   
>   #include "smc.h"
>   
> +#define SMC_VIRT_ISM_CHID_MAX		0xFFFF

SMC_VIRT_ISM_MAX is 0xFFFE. Or do you mean virtual devices as the whole 
group. If yes i think that this naming will be very confusing in a few 
months/years.
Maybe something like SMC_VIRTUAL_DEV_CHID_{MIN|MAX}?

> +#define SMC_VIRT_ISM_CHID_MIN		0xFF00
> +
>   struct smcd_dev_list {	/* List of SMCD devices */
>   	struct list_head list;
>   	struct mutex mutex;	/* Protects list of devices */
> @@ -57,4 +60,16 @@ static inline int smc_ism_write(struct smcd_dev *smcd, u64 dmb_tok,
>   	return rc < 0 ? rc : 0;
>   }
>   
> +static inline bool __smc_ism_is_virtdev(u16 chid)
> +{
> +	return (chid >= SMC_VIRT_ISM_CHID_MIN && chid <= SMC_VIRT_ISM_CHID_MAX);
> +}
> +
> +static inline bool smc_ism_is_virtdev(struct smcd_dev *smcd)
> +{
> +	u16 chid = smcd->ops->get_chid(smcd);
> +
> +	return __smc_ism_is_virtdev(chid);
> +}
> +
>   #endif