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Date:   Thu, 22 Jun 2023 05:57:53 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Keith Busch <kbusch@kernel.org>
Cc:     Breno Leitao <leitao@debian.org>, Jens Axboe <axboe@kernel.dk>,
        Christoph Hellwig <hch@lst.de>,
        Sagi Grimberg <sagi@grimberg.me>, leit@fb.com,
        "open list:NVM EXPRESS DRIVER" <linux-nvme@lists.infradead.org>,
        open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] nvme: Print capabilities changes just once
Message-ID: <20230622035753.GA4736@lst.de>
References: <20230615094903.1341683-1-leitao@debian.org> <ZJMpWaMxKMFE8hmK@kbusch-mbp.dhcp.thefacebook.com>
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On Wed, Jun 21, 2023 at 10:46:17AM -0600, Keith Busch wrote:
> On Thu, Jun 15, 2023 at 02:49:03AM -0700, Breno Leitao wrote:
> >  	if (effects & NVME_CMD_EFFECTS_CCC) {
> > -		dev_info(ctrl->device,
> > +		if (!test_and_set_bit(NVME_CTRL_DIRTY_CAPABILITY,
> > +				      &ctrl->flags)) {
> > +			dev_info(ctrl->device,
> >  "controller capabilities changed, reset may be required to take effect.\n");
> > +		}
> >  	}
> 
> Thanks, patch applied to nvme-6.5.
> 
> A question for Christoph and future consideration: I *think* the
> complications that had the driver stop refreshing the controller
> attributes are largely mitigated by the fact we now handle effects
> after the request is freed. Perhaps I'm missing something. Is there
> a risk in just bringing that feature back into the driver?

No, the main issue was and is that we can't just call
nvme_init_ctrl_finish on a live controller.