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Subject: Re: [PATCH v11 8/9] nvmet-passthru: Add enable/disable helpers
To:     Logan Gunthorpe <logang@deltatee.com>,
        linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org
Cc:     Christoph Hellwig <hch@lst.de>, Keith Busch <kbusch@kernel.org>,
        Jens Axboe <axboe@fb.com>,
        Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>,
        Max Gurtovoy <maxg@mellanox.com>,
        Stephen Bates <sbates@raithlin.com>
References: <20200220203652.26734-1-logang@deltatee.com>
 <20200220203652.26734-9-logang@deltatee.com>
From:   Sagi Grimberg <sagi@grimberg.me>
Message-ID: <96234649-fbc1-fb56-54d8-2f73dc455ffd@grimberg.me>
Date:   Wed, 26 Feb 2020 15:33:56 -0800
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> +	if (subsys->ver < NVME_VS(1, 2, 1)) {
> +		pr_warn("nvme controller version is too old: %d.%d.%d, advertising 1.2.1\n",
> +			(int)NVME_MAJOR(subsys->ver),
> +			(int)NVME_MINOR(subsys->ver),
> +			(int)NVME_TERTIARY(subsys->ver));
> +		subsys->ver = NVME_VS(1, 2, 1);

Umm.. is this OK? do we implement the mandatory 1.2.1 features on behalf
of the passthru device?

> +	}
> +
> +	mutex_unlock(&subsys->lock);
> +	return 0;
> +
> +out_put_ctrl:
> +	nvme_put_ctrl(ctrl);
> +out_unlock:
> +	mutex_unlock(&subsys->lock);
> +	return ret;
> +}
> +
> +static void __nvmet_passthru_ctrl_disable(struct nvmet_subsys *subsys)
> +{
> +	if (subsys->passthru_ctrl) {
> +		xa_erase(&passthru_subsystems, subsys->passthru_ctrl->cntlid);
> +		nvme_put_ctrl(subsys->passthru_ctrl);
> +	}
> +	subsys->passthru_ctrl = NULL;
> +	subsys->ver = NVMET_DEFAULT_VS;
> +}

Isn't it strange that a subsystem changes its version in its lifetime?

> +
> +void nvmet_passthru_ctrl_disable(struct nvmet_subsys *subsys)
> +{
> +	mutex_lock(&subsys->lock);
> +	__nvmet_passthru_ctrl_disable(subsys);
> +	mutex_unlock(&subsys->lock);
> +}
> +
> +void nvmet_passthru_subsys_free(struct nvmet_subsys *subsys)
> +{
> +	mutex_lock(&subsys->lock);
> +	__nvmet_passthru_ctrl_disable(subsys);
> +	kfree(subsys->passthru_ctrl_path);
> +	mutex_unlock(&subsys->lock);

Nit, any reason why the free is in the mutex?