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Date: Wed, 31 Jan 2024 20:04:08 -0400
From: Jason Gunthorpe <jgg@ziepe.ca>
To: Shifeng Li <lishifeng@sangfor.com.cn>
Cc: Ding Hui <dinghui@sangfor.com.cn>, leon@kernel.org,
	wenglianfa@huawei.com, gustavoars@kernel.org,
	linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org,
	Shifeng Li <lishifeng1992@126.com>
Subject: Re: [PATCH] RDMA/device: Fix a race between mad_client and cm_client
 init
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On Fri, Jan 26, 2024 at 10:25:01AM +0800, Shifeng Li wrote:
> > I believe this modification is effective, rather than expanding the clients_rwsem range,
> > the key point is down_write(&devices_rwsem), which prevents ib_register_client() from
> > being executed in the gap of ib_register_device().
> > 
> > However, this may cause a little confusion, as ib_register_client() does not modify
> > anything related to devices, but it is protected by a write lock.
> > 
> Do you have any differing opinions about above?

I'd rather see the client side have a comment explaining the confusing
lock then disturb the locking on the devices side..

I think the write/read lock scheme there was done for a reason I just
haven't had time to recall exactly why..

Please send a patch with this arrangement

Jason