From: Sagi Grimberg <sagi@grimberg.me>
To: Christoph Hellwig <hch@lst.de>
Cc: Keith Busch <kbusch@kernel.org>,
James Smart <james.smart@broadcom.com>,
linux-nvme@lists.infradead.org
Subject: Re: [PATCH v2 1/8] nvme-fabrics: allow to queue requests for live queues
Date: Fri, 14 Aug 2020 10:49:52 -0700 [thread overview]
Message-ID: <ed79addc-8fdf-fa77-c91a-316101a384f4@grimberg.me> (raw)
In-Reply-To: <20200814072202.GA2429@lst.de>
>>> Which will still happen with the admin queue user passthrough
>>> commands with this patch, so I don't think it actually solves anything,
>>> it just reduces the exposure a bit.
>>
>> The original version of the patch removed that as well, but james
>> indicated that it's still needed because we have no way to make sure
>> the admin (re)connect will be the first request when we unquiesce.
>
> Is that whole thing really a problem? All the pass through requests
> are inserted at the head of the queue, so how could something else
> slip in before it? If we have a race window we probably need
> to use BLK_MQ_REQ_PREEMPT or something like to force executing the
> connect on an otherwise frozen queue.
The problem is that we have to unquiesce the admin queue in order
to send the connect request (because it's sent on the ctrl->admin_q),
and once we do that, quiesced commands go through and the condition
being discussed is what's preventing them from passing through.
As James noted, not only before the admin connect but also before
the controller was enabled.
Anyways, this needs to be resolved, but it doesn't make this change
incorrect.
_______________________________________________
Linux-nvme mailing list
Linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme
next prev parent reply other threads:[~2020-08-14 17:50 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-06 19:11 [PATCH v2 0/8] fix possible controller reset hangs in nvme-tcp/nvme-rdma Sagi Grimberg
2020-08-06 19:11 ` [PATCH v2 1/8] nvme-fabrics: allow to queue requests for live queues Sagi Grimberg
2020-08-14 6:44 ` Christoph Hellwig
2020-08-14 7:08 ` Sagi Grimberg
2020-08-14 7:22 ` Christoph Hellwig
2020-08-14 15:55 ` James Smart
2020-08-14 17:49 ` Sagi Grimberg [this message]
2020-08-06 19:11 ` [PATCH v2 2/8] nvme: have nvme_wait_freeze_timeout return if it timed out Sagi Grimberg
2020-08-14 6:45 ` Christoph Hellwig
2020-08-14 7:09 ` Sagi Grimberg
2020-08-06 19:11 ` [PATCH v2 3/8] nvme-tcp: serialize controller teardown double completion Sagi Grimberg
2020-08-06 19:11 ` [PATCH v2 4/8] nvme-tcp: fix timeout handler Sagi Grimberg
2020-08-06 19:11 ` [PATCH v2 5/8] nvme-tcp: fix reset hang if controller died in the middle of a reset Sagi Grimberg
2020-08-06 19:11 ` [PATCH v2 6/8] nvme-rdma: serialize controller teardown sequences Sagi Grimberg
2020-08-14 6:45 ` Christoph Hellwig
2020-08-14 21:12 ` James Smart
2020-08-19 0:35 ` Sagi Grimberg
2020-08-06 19:11 ` [PATCH v2 7/8] nvme-rdma: fix timeout handler Sagi Grimberg
2020-08-14 6:52 ` Christoph Hellwig
2020-08-14 7:14 ` Sagi Grimberg
2020-08-14 23:19 ` James Smart
2020-08-19 0:26 ` Sagi Grimberg
2020-08-14 23:27 ` James Smart
2020-08-14 23:30 ` James Smart
2020-08-19 0:39 ` Sagi Grimberg
2020-08-19 0:38 ` Sagi Grimberg
2020-08-06 19:11 ` [PATCH v2 8/8] nvme-rdma: fix reset hang if controller died in the middle of a reset Sagi Grimberg
2020-08-14 6:53 ` Christoph Hellwig
2020-08-11 22:16 ` [PATCH v2 0/8] fix possible controller reset hangs in nvme-tcp/nvme-rdma Sagi Grimberg
2020-08-13 15:39 ` Christoph Hellwig
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=ed79addc-8fdf-fa77-c91a-316101a384f4@grimberg.me \
--to=sagi@grimberg.me \
--cc=hch@lst.de \
--cc=james.smart@broadcom.com \
--cc=kbusch@kernel.org \
--cc=linux-nvme@lists.infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).