Re: [PATCH v5 4/5] sd: limit to use write life hints

Christoph Hellwig
2024-09-12T13:03:57Z

On Tue, Sep 10, 2024 at 08:31:59PM +0530, Kanchan Joshi wrote:
> From: Nitesh Shetty <nj.shetty@samsung.com>
>
> The incoming hint value maybe either lifetime hint or placement hint.

.. may either be .. ?

> Make SCSI interpret only temperature-based write lifetime hints.
>
> Signed-off-by: Nitesh Shetty <nj.shetty@samsung.com>
> Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
> ---
> drivers/scsi/sd.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
> index dad3991397cf..82bd4b07314e 100644
> --- a/drivers/scsi/sd.c
> +++ b/drivers/scsi/sd.c
> @@ -1191,8 +1191,8 @@ static u8 sd_group_number(struct scsi_cmnd *cmd)
> if (!sdkp->rscs)
> return 0;
>
> - return min3((u32)rq->write_hint, (u32)sdkp->permanent_stream_count,
> - 0x3fu);
> + return min3((u32)WRITE_LIFETIME_HINT(rq->write_hint),

No fan of the screaming WRITE_LIFETIME_HINT. Or the fact that multiple
things are multiplexed into the single rq->write_hint field to
start with.

This code could also use a bit of documentation already in the existing
version, but even more so now.