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Date:   Thu, 11 Mar 2021 10:43:45 +0100
From:   Daniel Wagner <dwagner@suse.de>
To:     Sagi Grimberg <sagi@grimberg.me>
Cc:     linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
        Jens Axboe <axboe@fb.com>, Hannes Reinecke <hare@suse.de>,
        Keith Busch <kbusch@kernel.org>, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v2] nvme-tcp: Check if request has started before
 processing it
Message-ID: <20210311094345.ogm2lxqfuszktuhp@beryllium.lan>
References: <20210301175601.116405-1-dwagner@suse.de>
 <6b51a989-5551-e243-abda-5872411ec3ff@grimberg.me>
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Hi Sagi,

On Fri, Mar 05, 2021 at 11:57:30AM -0800, Sagi Grimberg wrote:
> Daniel, again, there is nothing specific about this to nvme-tcp,
> this is a safeguard against a funky controller (or a different
> bug that is hidden by this).

As far I can tell, the main difference between nvme-tcp and FC/NVMe,
nvme-tcp has not a FW or a big driver which filter out some noise from a
misbehaving controller. I haven't really checked the other transports
but I wouldn't surprised they share the same properties as FC/NVMe.

> The same can happen in any other transport so I would suggest that if
> this is a safeguard we want to put in place, we should make it a
> generic one.
> 
> i.e. nvme_tag_to_rq() that _all_ transports call consistently.

Okay, I'll review all the relevant code and see what could made more
generic and consistent.

Though I think nvme-tcp plays in a different league as it is exposed to
normal networking traffic and this is a very hostile environment.

Thanks,
Daniel