Re: [PATCH 1/2] added stream id write support

From: Jeff Moyer
Date: Tue Apr 21 2015 - 09:45:21 EST


"kwan.huen" <kwan.huen@xxxxxxxxxxx> writes:

> ---
> drivers/block/nvme-core.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
> index 85b8036..332341a 100644
> --- a/drivers/block/nvme-core.c
> +++ b/drivers/block/nvme-core.c
> @@ -769,6 +769,9 @@ static int nvme_submit_iod(struct nvme_queue *nvmeq, struct nvme_iod *iod,
> if (req->cmd_flags & REQ_RAHEAD)
> dsmgmt |= NVME_RW_DSM_FREQ_PREFETCH;
>
> + if (rq_data_dir(req))
> + dsmgmt |= bio_get_streamid(req->bio) << 8;
> +

There's no public specification for this, yet. How many bits are set
aside for the stream id? Do you need to do bounds checking/input
validation? What happens on adapters with older firmware when these
bits are set?

Cheers,
Jeff
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