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Date:   Sun, 25 Apr 2021 20:00:34 +0300
From:   Dan Aloni <dan@kernelim.com>
To:     Chuck Lever III <chuck.lever@oracle.com>
Cc:     Trond Myklebust <trondmy@hammerspace.com>,
        Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
        "linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>
Subject: Re: [PATCH v3 15/26] xprtrdma: Do not recycle MR after
 FastReg/LocalInv flushes
Message-ID: <20210425170034.pxukfflpqtsvu2dq@gmail.com>
References: <161885481568.38598.16682844600209775665.stgit@manet.1015granger.net>
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 <20210425141914.6govk2lm2hfosdie@gmail.com>
 <53AD14DC-65A2-4E93-A467-1DE43894DC03@oracle.com>
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On Sun, Apr 25, 2021 at 04:21:03PM +0000, Chuck Lever III wrote:
> 
> 
> > On Apr 25, 2021, at 10:19 AM, Dan Aloni <dan@kernelim.com> wrote:
> > 
> > On Mon, Apr 19, 2021 at 02:03:12PM -0400, Chuck Lever wrote:
> >> Better not to touch MRs involved in a flush or post error until the
> >> Send and Receive Queues are drained and the transport is fully
> >> quiescent. Simply don't insert such MRs back onto the free list.
> >> They remain on mr_all and will be released when the connection is
> >> torn down.
> >> 
> >> I had thought that recycling would prevent hardware resources from
> >> being tied up for a long time. However, since v5.7, a transport
> >> disconnect destroys the QP and other hardware-owned resources. The
> >> MRs get cleaned up nicely at that point.
> >> 
> >> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> > 
> > Is this a fix for the crash below?
> 
> Yes, it is plausible. That is a familiar backtrace.
> 
> However, it's usually because the provider called the LocalInv
> completion handler twice for the same CQE. Which provider is this?

It's mlx5 driver, ConnectX-4 (MT27700).

-- 
Dan Aloni