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From: Karsten Graul <kgraul@linux.ibm.com>
To: Wen Gu <guwen@linux.alibaba.com>, davem@davemloft.net, kuba@kernel.org
Cc: linux-s390@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, dust.li@linux.alibaba.com,
	tonylu@linux.alibaba.com
Subject: Re: [RFC PATCH net v2 2/2] net/smc: Resolve the race between SMC-R link access and clear
Date: Wed, 29 Dec 2021 13:51:27 +0100	[thread overview]
Message-ID: <7311029c-2c56-d9c7-9ed5-87bc6a36511f@linux.ibm.com> (raw)
In-Reply-To: <1640704432-76825-3-git-send-email-guwen@linux.alibaba.com>

On 28/12/2021 16:13, Wen Gu wrote:
> We encountered some crashes caused by the race between SMC-R
> link access and link clear triggered by link group termination
> in abnormal case, like port error.

Without to dig deeper into this, there is already a refcount for links, see smc_wr_tx_link_hold().
In smc_wr_free_link() there are waits for the refcounts to become zero.

Why do you need to introduce another refcounting instead of using the existing?
And if you have a good reason, do we still need the existing refcounting with your new
implementation?

Maybe its enough to use the existing refcounting in the other functions like smc_llc_flow_initiate()?

Btw: it is interesting what kind of crashes you see, we never met them in our setup.
Its great to see you evaluating SMC in a cloud environment!


  reply	other threads:[~2021-12-29 12:51 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-28 15:13 [RFC PATCH net v2 0/2] net/smc: Fix for race in smc link group termination Wen Gu
2021-12-28 15:13 ` [RFC PATCH net v2 1/2] net/smc: Resolve the race between link group access and termination Wen Gu
2021-12-29 12:56   ` Karsten Graul
2021-12-31  9:44     ` Wen Gu
2022-01-03 10:36       ` Karsten Graul
2022-01-05  8:27         ` Wen Gu
2022-01-05 12:03           ` Karsten Graul
2022-01-06 13:02             ` Wen Gu
2022-01-07  9:54               ` Karsten Graul
2022-01-07 12:04                 ` Wen Gu
2021-12-28 15:13 ` [RFC PATCH net v2 2/2] net/smc: Resolve the race between SMC-R link access and clear Wen Gu
2021-12-29 12:51   ` Karsten Graul [this message]
2021-12-30  4:00     ` dust.li
2021-12-31  9:45     ` Wen Gu
2022-01-03 10:39       ` Karsten Graul

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