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Date:   Mon, 19 Jul 2021 09:40:07 +0300
From:   Leon Romanovsky <leon@kernel.org>
To:     Chesnokov Gleb <Chesnokov.G@raidix.com>
Cc:     "lanevdenoche@gmail.com" <lanevdenoche@gmail.com>,
        "linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
        "sagi@grimberg.me" <sagi@grimberg.me>,
        "dledford@redhat.com" <dledford@redhat.com>,
        "jgg@ziepe.ca" <jgg@ziepe.ca>
Subject: Re: [PATCH 1/1] iser-target: Fix handling of
 RDMA_CV_EVENT_ADDR_CHANGE
Message-ID: <YPUeR9h6Zf6nGe6e@unreal>
References: <20210714182646.112181-1-Chesnokov.G@raidix.com>
 <YPPrY1MW51aFRSVb@unreal>
 <9e97e113abb64952a22430462310ca83@raidix.com>
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On Sun, Jul 18, 2021 at 06:24:26PM +0000, Chesnokov Gleb wrote:
> Hi Leon,

Please don't use top-posting format. Thanks

> 
> 
> isert_cma_handler() is called from cma_work_handler(), which holds id_priv->handler_mutex.
> The call of rdma_destroy_id() from isert_cma_handler() will cause recursive acquisition of the mutex, leading to a deadlock.
> 
> -- cma_work_handler()
> ---- mutex_lock(&id_priv->handler_mutex)
> ---- isert_cma_handler()
> ------ rmda_destroy_id()
> -------- mutex_lock(&id_priv->handler_mutex)

This answers why you needed workqueue.

> 
> Therefore, you cannot directly call isert_np_reinit_id().

I would expect rdma-cm to be changed to support such flow.
However it is probably overkill.

Thanks,
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>