Re: [PATCH for-next 4/4] nvme-multipath: add multipathing for uring-passthrough commands

From: Sagi Grimberg <sagi@grimberg.me>
To: Stefan Metzmacher <metze@samba.org>,
	Kanchan Joshi <joshi.k@samsung.com>,
	hch@lst.de, kbusch@kernel.org, axboe@kernel.dk
Cc: io-uring@vger.kernel.org, linux-nvme@lists.infradead.org,
	linux-block@vger.kernel.org, asml.silence@gmail.com,
	joshiiitr@gmail.com, anuj20.g@samsung.com, gost.dev@samsung.com
Subject: Re: [PATCH for-next 4/4] nvme-multipath: add multipathing for uring-passthrough commands
Date: Mon, 11 Jul 2022 19:58:07 +0300	[thread overview]
Message-ID: <2dde0a5b-e4ce-dd44-0f4b-661c860dd5bd@grimberg.me> (raw)
In-Reply-To: <5c71b8f6-afec-8ef6-0a70-d13e71ded79c@samba.org>

>>> +static inline struct nvme_uring_cmd_pdu *nvme_uring_cmd_pdu(
>>> +        struct io_uring_cmd *ioucmd)
>>> +{
> 
> Shouldn't we have a BUILD_BUG_ON(sizeof(struct nvme_uring_cmd_pdu) > 
> sizeof(ioucmd->pdu));
> here?

Probably...

>>> +    return (struct nvme_uring_cmd_pdu *)&ioucmd->pdu;
>>> +}
>>> +
> 
>>> diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h
>>> index d734599cbcd7..57f4dfc83316 100644
>>> --- a/include/linux/io_uring.h
>>> +++ b/include/linux/io_uring.h
>>> @@ -15,6 +15,8 @@ enum io_uring_cmd_flags {
>>>       IO_URING_F_SQE128        = 4,
>>>       IO_URING_F_CQE32        = 8,
>>>       IO_URING_F_IOPOLL        = 16,
>>> +    /* to indicate that it is a MPATH req*/
>>> +    IO_URING_F_MPATH        = 32,
> 
> Isn't that nvme specific? If so I don't think it belongs in io_uring.h 
> at all...

Yes, it doesn't, it should be completely internal to nvme.