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From: Christoph Hellwig <[email protected]>
To: Kanchan Joshi <[email protected]>
Cc: "Christoph Hellwig" <[email protected]>,
	"Kanchan Joshi" <[email protected]>,
	"Jens Axboe" <[email protected]>,
	[email protected], [email protected],
	"Pavel Begunkov" <[email protected]>,
	"Ming Lei" <[email protected]>,
	"Luis Chamberlain" <[email protected]>,
	"Pankaj Raghav" <[email protected]>,
	"Javier González" <[email protected]>,
	"Anuj Gupta" <[email protected]>
Subject: Re: [RFC 5/5] nvme: wire-up support for async-passthru on char-device.
Date: Tue, 5 Apr 2022 08:02:24 +0200	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <CA+1E3rJ+iWAhUVzVrRDiFTUmp5sNF7wqw_7oVqru2qLCTBQrqQ@mail.gmail.com>

On Mon, Apr 04, 2022 at 07:55:05PM +0530, Kanchan Joshi wrote:
> > Something like this (untested) patch should help to separate
> > the much better:
> 
> It does, thanks. But the only thing is - it would be good to support
> vectored-passthru too (i.e. NVME_IOCTL_IO64_CMD_VEC) for this path.
> For the new opcode "NVME_URING_CMD_IO" , either we can change the
> cmd-structure or flag-based handling so that vectored-io is supported.
> Or we introduce NVME_URING_CMD_IO_VEC also for that.
> Which one do you prefer?

I agree vectored I/O support is useful.

Do we even need to support the non-vectored case?

Also I think we'll want admin command passthrough on /dev/nvmeX as
well, but I'm fine solving the other items first.

> > +static int nvme_ioctl_finish_metadata(struct bio *bio, int ret,
> > +               void __user *meta_ubuf)
> > +{
> > +       struct bio_integrity_payload *bip = bio_integrity(bio);
> > +
> > +       if (bip) {
> > +               void *meta = bvec_virt(bip->bip_vec);
> > +
> > +               if (!ret && bio_op(bio) == REQ_OP_DRV_IN &&
> > +                   copy_to_user(meta_ubuf, meta, bip->bip_vec->bv_len))
> > +                       ret = -EFAULT;
> 
> Maybe it is better to move the check "bio_op(bio) != REQ_OP_DRV_IN" outside.
> Because this can be common, and for that we can avoid entering into
> the function call itself (i.e. nvme_ioctl_finish_metadata).

Function calls are pretty cheap, but I'll see what we can do.  I'll try
to come up with a prep series to refactor the passthrough support for
easier adding of the io_uring in the next days.

  reply	other threads:[~2022-04-05  6:02 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20220401110829epcas5p39f3cf4d3f6eb8a5c59794787a2b72b15@epcas5p3.samsung.com>
2022-04-01 11:03 ` [RFC 0/5] big-cqe based uring-passthru Kanchan Joshi
     [not found]   ` <CGME20220401110831epcas5p403bacabe8f7e5262356fdc1a2e66df90@epcas5p4.samsung.com>
2022-04-01 11:03     ` [RFC 1/5] io_uring: add support for 128-byte SQEs Kanchan Joshi
     [not found]   ` <CGME20220401110833epcas5p18e828a307a646cef5b7aa429be4396e0@epcas5p1.samsung.com>
2022-04-01 11:03     ` [RFC 2/5] fs: add file_operations->async_cmd() Kanchan Joshi
2022-04-04  7:09       ` Christoph Hellwig
     [not found]   ` <CGME20220401110834epcas5p4d1e5e8d1beb1a6205d670bbcb932bf77@epcas5p4.samsung.com>
2022-04-01 11:03     ` [RFC 3/5] io_uring: add infra and support for IORING_OP_URING_CMD Kanchan Joshi
2022-04-04  7:16       ` Christoph Hellwig
2022-04-04  8:20         ` Pavel Begunkov
2022-04-05  5:58           ` Christoph Hellwig
2022-04-06  6:37             ` Kanchan Joshi
2022-04-04 15:14         ` Kanchan Joshi
2022-04-05  6:00           ` Christoph Hellwig
2022-04-05 16:27             ` Kanchan Joshi
     [not found]   ` <CGME20220401110836epcas5p37bd59ab5a48cf77ca3ac05052a164b0b@epcas5p3.samsung.com>
2022-04-01 11:03     ` [RFC 4/5] io_uring: add support for big-cqe Kanchan Joshi
2022-04-04  7:07       ` Christoph Hellwig
2022-04-04 14:04         ` Kanchan Joshi
     [not found]   ` <CGME20220401110838epcas5p2c1a2e776923dfe5bf65a3e7946820150@epcas5p2.samsung.com>
2022-04-01 11:03     ` [RFC 5/5] nvme: wire-up support for async-passthru on char-device Kanchan Joshi
2022-04-04  7:20       ` Christoph Hellwig
2022-04-04 14:25         ` Kanchan Joshi
2022-04-05  6:02           ` Christoph Hellwig [this message]
2022-04-05 15:40             ` Jens Axboe
2022-04-05 15:49             ` Kanchan Joshi
2022-04-06  5:20               ` Kanchan Joshi
2022-04-06  5:23                 ` Christoph Hellwig
2022-04-23 17:53                 ` Christoph Hellwig
2022-04-25 17:38                   ` Kanchan Joshi
2022-04-29 13:16                     ` Kanchan Joshi
2022-04-04  7:21   ` [RFC 0/5] big-cqe based uring-passthru Christoph Hellwig
2022-04-05 15:37     ` Kanchan Joshi

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