Re: [PATCH 04/14] sd: rename the scsi_disk.dev field

[Ming Lei <ming.lei@redhat.com>]

On Fri, Mar 04, 2022 at 05:03:21PM +0100, Christoph Hellwig wrote:
> dev is very hard to grab for.  Give the field a more descriptive name and
> documents it's purpose.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  drivers/scsi/sd.c | 22 +++++++++++-----------
>  drivers/scsi/sd.h | 10 ++++++++--
>  2 files changed, 19 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
> index 2a1e19e871d30..7479e7cb36b43 100644
> --- a/drivers/scsi/sd.c
> +++ b/drivers/scsi/sd.c
> @@ -672,7 +672,7 @@ static struct scsi_disk *scsi_disk_get(struct gendisk *disk)
>  	if (disk->private_data) {
>  		sdkp = scsi_disk(disk);
>  		if (scsi_device_get(sdkp->device) == 0)
> -			get_device(&sdkp->dev);
> +			get_device(&sdkp->disk_dev);
>  		else
>  			sdkp = NULL;
>  	}
> @@ -685,7 +685,7 @@ static void scsi_disk_put(struct scsi_disk *sdkp)
>  	struct scsi_device *sdev = sdkp->device;
>  
>  	mutex_lock(&sd_ref_mutex);
> -	put_device(&sdkp->dev);
> +	put_device(&sdkp->disk_dev);
>  	scsi_device_put(sdev);
>  	mutex_unlock(&sd_ref_mutex);
>  }
> @@ -3529,14 +3529,14 @@ static int sd_probe(struct device *dev)
>  					     SD_MOD_TIMEOUT);
>  	}
>  
> -	device_initialize(&sdkp->dev);
> -	sdkp->dev.parent = get_device(dev);
> -	sdkp->dev.class = &sd_disk_class;
> -	dev_set_name(&sdkp->dev, "%s", dev_name(dev));
> +	device_initialize(&sdkp->disk_dev);
> +	sdkp->disk_dev.parent = get_device(dev);
> +	sdkp->disk_dev.class = &sd_disk_class;
> +	dev_set_name(&sdkp->disk_dev, "%s", dev_name(dev));
>  
> -	error = device_add(&sdkp->dev);
> +	error = device_add(&sdkp->disk_dev);
>  	if (error) {
> -		put_device(&sdkp->dev);
> +		put_device(&sdkp->disk_dev);
>  		goto out;
>  	}
>  
> @@ -3577,7 +3577,7 @@ static int sd_probe(struct device *dev)
>  
>  	error = device_add_disk(dev, gd, NULL);
>  	if (error) {
> -		put_device(&sdkp->dev);
> +		put_device(&sdkp->disk_dev);
>  		goto out;
>  	}
>  
> @@ -3628,7 +3628,7 @@ static int sd_remove(struct device *dev)
>  	sdkp = dev_get_drvdata(dev);
>  	scsi_autopm_get_device(sdkp->device);
>  
> -	device_del(&sdkp->dev);
> +	device_del(&sdkp->disk_dev);
>  	del_gendisk(sdkp->disk);
>  	sd_shutdown(dev);
>  
> @@ -3636,7 +3636,7 @@ static int sd_remove(struct device *dev)
>  
>  	mutex_lock(&sd_ref_mutex);
>  	dev_set_drvdata(dev, NULL);
> -	put_device(&sdkp->dev);
> +	put_device(&sdkp->disk_dev);
>  	mutex_unlock(&sd_ref_mutex);
>  
>  	return 0;
> diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
> index 303aa1c23aefb..7625a90b0fa69 100644
> --- a/drivers/scsi/sd.h
> +++ b/drivers/scsi/sd.h
> @@ -69,7 +69,13 @@ enum {
>  
>  struct scsi_disk {
>  	struct scsi_device *device;
> -	struct device	dev;
> +
> +	/*
> +	 * This device is mostly just used to show a bunch of attributes in a
> +	 * weird place.  In doubt don't add any new users, and most importantly
> +	 * don't use if for any actual refcounting.
> +	 */

The device looks partner of gendisk, I think it could just be a
private data of gendisk, and the attributes can be added to gendisk.

But scsi has the tradition of adding class device of scsi_host,
scsi_device, scsi_disk and scsi_generic.

Adding such device makes things complicated, such as refcounting
in open/close disk. But looks scsi_disk isn't part of sysfs ABI, maybe it
can be removed, anyway:

Reviewed-by: Ming Lei <ming.lei@redhat.com>


Thanks,
Ming