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To:     Christoph Hellwig <hch@lst.de>, Keith Busch <kbusch@kernel.org>
Cc:     linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
        Sagi Grimberg <sagi@grimberg.me>, Jens Axboe <axboe@fb.com>,
        Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>,
        Max Gurtovoy <maxg@mellanox.com>,
        Stephen Bates <sbates@raithlin.com>
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 <20200724193351.GA2857771@dhcp-10-100-145-180.wdl.wdc.com>
 <20200726154104.GA23930@lst.de>
From:   Logan Gunthorpe <logang@deltatee.com>
Message-ID: <2963e23f-5f37-7720-f8f2-fb1a73f31ac5@deltatee.com>
Date:   Mon, 27 Jul 2020 09:44:12 -0600
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Subject: Re: [PATCH v16 6/9] nvmet-passthru: Add passthru code to process
 commands
Sender: linux-kernel-owner@vger.kernel.org
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On 2020-07-26 9:41 a.m., Christoph Hellwig wrote:
> On Fri, Jul 24, 2020 at 12:33:51PM -0700, Keith Busch wrote:
>> On Fri, Jul 24, 2020 at 11:25:17AM -0600, Logan Gunthorpe wrote:
>>> +	/*
>>> +	 * The passthru NVMe driver may have a limit on the number of segments
>>> +	 * which depends on the host's memory fragementation. To solve this,
>>> +	 * ensure mdts is limitted to the pages equal to the number of
>>
>>                           limited
> 
> I've fixed this when applying.
> 
>>> +	/* don't support fuse commands */
>>> +	id->fuses = 0;
>>
>> If a host were to set a fuse, the target should return an Invalid Field
>> error. Just to future-proof, rejecting commands with any flags set
>> (other than SGL, which you handled in patch 1/9) is probably what should
>> happen, like:
>>
>>> +u16 nvmet_parse_passthru_io_cmd(struct nvmet_req *req)
>>> +{
>>
>> 	if (req->cmd->common.flags & ~NVME_CMD_SGL_ALL)
>> 		return NVME_SC_INVALID_FIELD;
>>
>> Or maybe we could obviate the need for 1/9 with something like:
>>
>> 	req->cmd->common.flags &= ~NVME_CMD_SGL_ALL;
>> 	if (req->cmd->common.flags)
>> 		return NVME_SC_INVALID_FIELD;
> 
> We'll also need this for the admin commands, but otherwise this sounds
> like a good idea.  For now I've applied the series as-is, but an
> incremental patch for this would be nice.

Great, I can send one later in the week.

Thanks,

Logan