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Subject: Re: [PATCH] xprtrdma: Wake up re_connect_wait on disconnect
From:   Chuck Lever <chuck.lever@oracle.com>
In-Reply-To: <20200620171805.1748399-1-dan@kernelim.com>
Date:   Sat, 20 Jun 2020 14:46:55 -0400
Cc:     linux-rdma@vger.kernel.org,
        Linux NFS Mailing List <linux-nfs@vger.kernel.org>
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Message-Id: <AC3CC4DE-C508-4F95-9F0D-B2977CD7301F@oracle.com>
References: <20200620171805.1748399-1-dan@kernelim.com>
To:     Dan Aloni <dan@kernelim.com>
Sender: linux-nfs-owner@vger.kernel.org
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Hi Dan-

> On Jun 20, 2020, at 1:18 PM, Dan Aloni <dan@kernelim.com> wrote:
>=20
> Given that rpcrdma_xprt_connect() happens from workqueue context, on =
cases where
> connections don't succeeds, something needs to wake it up. In my case, =
this has
> been observed when the CM callback received `RDMA_CM_EVENT_REJECTED`, =
and
> `rpcrdma_xprt_connect()` slept forever.

Interesting. My development and testing generates plenty of REJECTED =
connection
requests, but I never saw this particular failure mode.


> This continues the fix in commit 58bd6656f808 ('xprtrdma: Restore =
wake-up-all to
> rpcrdma_cm_event_handler()').

The patch looks sensible. I'll pull it into my test harness.


> Signed-off-by: Dan Aloni <dan@kernelim.com>
> CC: Chuck Lever <chuck.lever@oracle.com>
> ---
>=20
> Notes:
>    Hi Chuck,
>=20
>    Maybe I missd something, as it is not clear to me how otherwise =
(without this
>    patch), re_connect_wait can be woken up in this situation. Please =
explain?
>=20
> net/sunrpc/xprtrdma/verbs.c | 1 +
> 1 file changed, 1 insertion(+)
>=20
> diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
> index 2ae348377806..8bd76a47a91f 100644
> --- a/net/sunrpc/xprtrdma/verbs.c
> +++ b/net/sunrpc/xprtrdma/verbs.c
> @@ -289,6 +289,7 @@ rpcrdma_cm_event_handler(struct rdma_cm_id *id, =
struct rdma_cm_event *event)
> 		ep->re_connect_status =3D -ECONNABORTED;
> disconnected:
> 		xprt_force_disconnect(xprt);
> +		wake_up_all(&ep->re_connect_wait);
> 		return rpcrdma_ep_destroy(ep);
> 	default:
> 		break;
> --=20
> 2.25.4
>=20

--
Chuck Lever