linux-kernel - Re: [PATCH v3 5/6] ata: libata: Set ATA_QCFLAG_RTF_FILLED in fill_result

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Date: Fri, 28 Jun 2024 22:12:19 +0200
From: Niklas Cassel <cassel@...nel.org>
To: Igor Pylypiv <ipylypiv@...gle.com>
Cc: Damien Le Moal <dlemoal@...nel.org>, Tejun Heo <tj@...nel.org>,
	Hannes Reinecke <hare@...e.de>, linux-ide@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 5/6] ata: libata: Set ATA_QCFLAG_RTF_FILLED in
 fill_result_tf()

On Wed, Jun 26, 2024 at 11:04:10PM +0000, Igor Pylypiv wrote:
> ATA_QCFLAG_RTF_FILLED is not specific to ahci and can be used generally
> to check if qc->result_tf contains valid data.
> 
> Reviewed-by: Hannes Reinecke <hare@...e.de>
> Reviewed-by: Damien Le Moal <dlemoal@...nel.org>
> Signed-off-by: Igor Pylypiv <ipylypiv@...gle.com>
> ---
>  drivers/ata/libahci.c     | 10 ----------
>  drivers/ata/libata-core.c |  8 ++++++++
>  2 files changed, 8 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
> index 83431aae74d8..0728d445e531 100644
> --- a/drivers/ata/libahci.c
> +++ b/drivers/ata/libahci.c
> @@ -2075,13 +2075,6 @@ static void ahci_qc_fill_rtf(struct ata_queued_cmd *qc)
>  	struct ahci_port_priv *pp = qc->ap->private_data;
>  	u8 *rx_fis = pp->rx_fis;
>  
> -	/*
> -	 * rtf may already be filled (e.g. for successful NCQ commands).
> -	 * If that is the case, we have nothing to do.
> -	 */
> -	if (qc->flags & ATA_QCFLAG_RTF_FILLED)
> -		return;
> -
>  	if (pp->fbs_enabled)
>  		rx_fis += qc->dev->link->pmp * AHCI_RX_FIS_SZ;
>  
> @@ -2095,7 +2088,6 @@ static void ahci_qc_fill_rtf(struct ata_queued_cmd *qc)
>  	    !(qc->flags & ATA_QCFLAG_EH)) {
>  		ata_tf_from_fis(rx_fis + RX_FIS_PIO_SETUP, &qc->result_tf);
>  		qc->result_tf.status = (rx_fis + RX_FIS_PIO_SETUP)[15];
> -		qc->flags |= ATA_QCFLAG_RTF_FILLED;
>  		return;
>  	}
>  
> @@ -2118,12 +2110,10 @@ static void ahci_qc_fill_rtf(struct ata_queued_cmd *qc)
>  		 */
>  		qc->result_tf.status = fis[2];
>  		qc->result_tf.error = fis[3];
> -		qc->flags |= ATA_QCFLAG_RTF_FILLED;
>  		return;
>  	}
>  
>  	ata_tf_from_fis(rx_fis + RX_FIS_D2H_REG, &qc->result_tf);
> -	qc->flags |= ATA_QCFLAG_RTF_FILLED;
>  }
>  
>  static void ahci_qc_ncq_fill_rtf(struct ata_port *ap, u64 done_mask)
> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
> index e1bf8a19b3c8..a9fc3ec9300f 100644
> --- a/drivers/ata/libata-core.c
> +++ b/drivers/ata/libata-core.c
> @@ -4801,8 +4801,16 @@ static void fill_result_tf(struct ata_queued_cmd *qc)
>  {
>  	struct ata_port *ap = qc->ap;
>  
> +	/*
> +	 * rtf may already be filled (e.g. for successful NCQ commands).
> +	 * If that is the case, we have nothing to do.
> +	 */
> +	if (qc->flags & ATA_QCFLAG_RTF_FILLED)
> +		return;
> +
>  	qc->result_tf.flags = qc->tf.flags;

One functional change that I can see from this is that after this commit,
we will no longer do: qc->result_tf.flags = qc->tf.flags;
if ATA_QCFLAG_RTF_FILLED was set.

e.g. ata_scsi_set_passthru_sense_fields() and ata_gen_ata_sense()
makes use of result_tf->flags, so we probably still want to do this.


Perhaps keep this function as you have it and simply do:

diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index 0728d445e531..fdfa7b266218 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -2148,6 +2148,7 @@ static void ahci_qc_ncq_fill_rtf(struct ata_port *ap, u64 done_mask)
                        if (qc && ata_is_ncq(qc->tf.protocol)) {
                                qc->result_tf.status = status;
                                qc->result_tf.error = error;
+                               qc->result_tf.flags = qc->tf.flags;
                                qc->flags |= ATA_QCFLAG_RTF_FILLED;
                        }
                        done_mask &= ~(1ULL << tag);
@@ -2172,6 +2173,7 @@ static void ahci_qc_ncq_fill_rtf(struct ata_port *ap, u64 done_mask)
                        fis += RX_FIS_SDB;
                        qc->result_tf.status = fis[2];
                        qc->result_tf.error = fis[3];
+                       qc->result_tf.flags = qc->tf.flags;
                        qc->flags |= ATA_QCFLAG_RTF_FILLED;
                }
                done_mask &= ~(1ULL << tag);



>  	ap->ops->qc_fill_rtf(qc);
> +	qc->flags |= ATA_QCFLAG_RTF_FILLED;
>  }
>  
>  static void ata_verify_xfer(struct ata_queued_cmd *qc)
> -- 
> 2.45.2.803.g4e1b14247a-goog
>