linux-kernel - Re: [PATCH] ata: libata-scsi: Set INFORMATION sense data field consistently

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Message-ID: <93ec66ce-4fa3-4913-a0b5-9debe47ef8b0@kernel.org>
Date: Tue, 1 Apr 2025 16:33:55 +0900
From: Damien Le Moal <dlemoal@...nel.org>
To: Igor Pylypiv <ipylypiv@...gle.com>, Niklas Cassel <cassel@...nel.org>
Cc: linux-ide@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ata: libata-scsi: Set INFORMATION sense data field
 consistently

On 3/29/25 03:30, Igor Pylypiv wrote:
> Populate the INFORMATION field with ATA LBA when sense data is obtained
> by the ata_eh_request_sense(). Kernel already populates the INFORMATION

s/by the/with
s/Kernel/The kernel or s/Kernel/libata-eh

> field when sense data is reported via autosense or when it is generated
> by the ata_gen_ata_sense().
> 
> ATA PASS-THROUGH commands, unlike regular ATA commands, populate
> the INFORMATION field with ATA ERROR, STATUS, DEVICE, and COUNT(7:0)
> fields thus setting ATA LBA into the INFORMATION field is incorrect.

Could you rephrase all of this is a manner that is clearer ? That is, describe
the problem first and then how you fix it. As-is, this is hard to understand.

> diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
> index 2796c0da8257..7e93581439b2 100644
> --- a/drivers/ata/libata-scsi.c
> +++ b/drivers/ata/libata-scsi.c
> @@ -216,17 +216,30 @@ void ata_scsi_set_sense(struct ata_device *dev, struct scsi_cmnd *cmd,
>  	scsi_build_sense(cmd, d_sense, sk, asc, ascq);
>  }
>  
> -void ata_scsi_set_sense_information(struct ata_device *dev,
> -				    struct scsi_cmnd *cmd,
> -				    const struct ata_taskfile *tf)
> +/**
> + *	ata_scsi_set_sense_information - Populate INFORMATION field
> + *	@qc: ATA command
> + *
> + *	Populates the INFORMATION field with ATA LBA.
> + *
> + *	LOCKING:
> + *	None.
> + */

The function name is clear enough. We do not need this kdoc block to clarify it
and this is a static function anyway.

> +static void ata_scsi_set_sense_information(struct ata_queued_cmd *qc)
>  {
>  	u64 information;
>  
> -	information = ata_tf_read_block(tf, dev);
> +	if (!(qc->flags & ATA_QCFLAG_RTF_FILLED)) {
> +		ata_dev_dbg(qc->dev,
> +			    "missing result TF: can't set INFORMATION sense field\n");

Why ata_dev_dbg() ? This should be ata_dev_err(), no ? With your change, this is
not supposed to be called without the rtf filled...

> +		return;
> +	}
> +
> +	information = ata_tf_read_block(&qc->result_tf, qc->dev);
>  	if (information == U64_MAX)
>  		return;
>  
> -	scsi_set_sense_information(cmd->sense_buffer,
> +	scsi_set_sense_information(qc->scsicmd->sense_buffer,
>  				   SCSI_SENSE_BUFFERSIZE, information);
>  }
>  
> @@ -971,8 +984,7 @@ static void ata_gen_passthru_sense(struct ata_queued_cmd *qc)
>   *	ata_gen_ata_sense - generate a SCSI fixed sense block
>   *	@qc: Command that we are erroring out
>   *
> - *	Generate sense block for a failed ATA command @qc.  Descriptor
> - *	format is used to accommodate LBA48 block address.
> + *	Generate sense block for a failed ATA command @qc.
>   *
>   *	LOCKING:
>   *	None.
> @@ -982,8 +994,6 @@ static void ata_gen_ata_sense(struct ata_queued_cmd *qc)
>  	struct ata_device *dev = qc->dev;
>  	struct scsi_cmnd *cmd = qc->scsicmd;
>  	struct ata_taskfile *tf = &qc->result_tf;
> -	unsigned char *sb = cmd->sense_buffer;
> -	u64 block;
>  	u8 sense_key, asc, ascq;
>  
>  	if (ata_dev_disabled(dev)) {
> @@ -1014,12 +1024,6 @@ static void ata_gen_ata_sense(struct ata_queued_cmd *qc)
>  		ata_scsi_set_sense(dev, cmd, ABORTED_COMMAND, 0, 0);
>  		return;
>  	}
> -
> -	block = ata_tf_read_block(&qc->result_tf, dev);
> -	if (block == U64_MAX)
> -		return;
> -
> -	scsi_set_sense_information(sb, SCSI_SENSE_BUFFERSIZE, block);
>  }
>  
>  void ata_scsi_sdev_config(struct scsi_device *sdev)
> @@ -1679,8 +1683,10 @@ static void ata_scsi_qc_complete(struct ata_queued_cmd *qc)
>  		ata_scsi_set_passthru_sense_fields(qc);
>  		if (is_ck_cond_request)
>  			set_status_byte(qc->scsicmd, SAM_STAT_CHECK_CONDITION);
> -	} else if (is_error && !have_sense) {
> -		ata_gen_ata_sense(qc);
> +	} else if (is_error) {
> +		if (!have_sense)
> +			ata_gen_ata_sense(qc);
> +		ata_scsi_set_sense_information(qc);
>  	}
>  
>  	ata_qc_done(qc);
> diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
> index 0337be4faec7..ce5c628fa6fd 100644
> --- a/drivers/ata/libata.h
> +++ b/drivers/ata/libata.h
> @@ -141,9 +141,6 @@ extern int ata_scsi_offline_dev(struct ata_device *dev);
>  extern bool ata_scsi_sense_is_valid(u8 sk, u8 asc, u8 ascq);
>  extern void ata_scsi_set_sense(struct ata_device *dev,
>  			       struct scsi_cmnd *cmd, u8 sk, u8 asc, u8 ascq);
> -extern void ata_scsi_set_sense_information(struct ata_device *dev,
> -					   struct scsi_cmnd *cmd,
> -					   const struct ata_taskfile *tf);
>  extern void ata_scsi_media_change_notify(struct ata_device *dev);
>  extern void ata_scsi_hotplug(struct work_struct *work);
>  extern void ata_scsi_dev_rescan(struct work_struct *work);


-- 
Damien Le Moal
Western Digital Research