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    SubjectRe: [PATCH v8 13/13] nvmet-passthru: support block accounting
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    >>>>> Support block disk accounting by setting the RQF_IO_STAT flag
    >>>>> and gendisk in the request.
    >>>>>
    >>>>> After this change, IO counts will be reflected correctly in
    >>>>> /proc/diskstats for drives being used by passthru.
    >>>>>
    >>>>> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
    >>>>> ---
    >>>>> drivers/nvme/target/io-cmd-passthru.c | 5 ++++-
    >>>>> 1 file changed, 4 insertions(+), 1 deletion(-)
    >>>>>
    >>>>> diff --git a/drivers/nvme/target/io-cmd-passthru.c b/drivers/nvme/target/io-cmd-passthru.c
    >>>>> index 7557927a3451..63f12750a80d 100644
    >>>>> --- a/drivers/nvme/target/io-cmd-passthru.c
    >>>>> +++ b/drivers/nvme/target/io-cmd-passthru.c
    >>>>> @@ -410,6 +410,9 @@ static struct request *nvmet_passthru_blk_make_request(struct nvmet_req *req,
    >>>>> if (unlikely(IS_ERR(rq)))
    >>>>> return rq;
    >>>>>
    >>>>> + if (blk_queue_io_stat(q) && cmd->common.opcode != nvme_cmd_flush)
    >>>>> + rq->rq_flags |= RQF_IO_STAT;
    >>>
    >>> Thanks for the review!
    >>>
    >>>> Does flush has data bytes in the request? Why the special casing?
    >>>
    >>> Well it was special cased in the vanilla blk account flow... But I think
    >>> it's required to be special cased so the IO and in_flight counts don't
    >>> count flushes (as they do not for regular block device traffic).
    >>
    >> I think that the accounting exclude I/O that is yielded from the flush
    >> sequence. Don't think its relevant here...
    >
    > What? Per blk_account_io_done(), RQF_FLUSH_SEQ will not be set by us for
    > passthru commands and I don't think it's appropriate to do so. Thus, if
    > we set RQF_IO_STAT for passthru flush commands, they will be counted
    > which we do not want.

    Have you considered to have nvmet_passthru_blk_make_request set RQF_FUA
    for nvme_cmd_flush? this way blk_insert_flush will be called and
    RQF_FLUSH_SEQ will be set and you don't need to worry about this
    special casing...

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