Re: [PATCH] ata: libata: Remove ata_noop_qc_prep()

[John Garry <john.g.garry@oracle.com>]

On 01/08/2024 10:01, Damien Le Moal wrote:
> The function ata_noop_qc_prep(), as its name implies, does nothing and
> simply returns AC_ERR_OK. For drivers that do not need any special
> preparations of queued commands, we can avoid having to define struct
> ata_port qc_prep operation by simply testing if that operation is
> defined or not in ata_qc_issue(). Make this change and remove
> ata_noop_qc_prep().
> 
> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>

Reviewed-by: John Garry <john.g.garry@oracle.com>

> ---
>   drivers/ata/libata-core.c     | 18 +++++++-----------
>   drivers/ata/libata-sff.c      |  1 -
>   drivers/ata/pata_ep93xx.c     |  2 --
>   drivers/ata/pata_icside.c     |  2 --
>   drivers/ata/pata_mpc52xx.c    |  1 -
>   drivers/ata/pata_octeon_cf.c  |  1 -
>   drivers/scsi/libsas/sas_ata.c |  1 -
>   include/linux/libata.h        |  1 -
>   8 files changed, 7 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
> index fc9fcfda42b8..b4fdb78579c8 100644
> --- a/drivers/ata/libata-core.c
> +++ b/drivers/ata/libata-core.c
> @@ -4696,12 +4696,6 @@ int ata_std_qc_defer(struct ata_queued_cmd *qc)
>   }
>   EXPORT_SYMBOL_GPL(ata_std_qc_defer);
>   
> -enum ata_completion_errors ata_noop_qc_prep(struct ata_queued_cmd *qc)
> -{
> -	return AC_ERR_OK;
> -}
> -EXPORT_SYMBOL_GPL(ata_noop_qc_prep);
> -
>   /**
>    *	ata_sg_init - Associate command with scatter-gather table.
>    *	@qc: Command to be associated
> @@ -5088,10 +5082,13 @@ void ata_qc_issue(struct ata_queued_cmd *qc)
>   		return;
>   	}
>   
> -	trace_ata_qc_prep(qc);

I assume qc->err_mask must be zero here.

> -	qc->err_mask |= ap->ops->qc_prep(qc);
> -	if (unlikely(qc->err_mask))
> -		goto err;
> +	if (ap->ops->qc_prep) {
> +		trace_ata_qc_prep(qc);