[PATCH 44/44] block: stop using bdget_disk for partition 0

Jan Kara jack at suse.cz
Fri Nov 27 08:22:21 EST 2020


On Thu 26-11-20 14:04:22, Christoph Hellwig wrote:
> We can just dereference the point in struct gendisk instead.  Also
> remove the now unused export.
> 
> Signed-off-by: Christoph Hellwig <hch at lst.de>

Looks good to me. You can add:

Reviewed-by: Jan Kara <jack at suse.cz>

								Honza

> ---
>  block/genhd.c                   |  1 -
>  drivers/block/nbd.c             |  4 +---
>  drivers/block/xen-blkfront.c    | 20 +++++---------------
>  drivers/block/zram/zram_drv.c   | 14 ++------------
>  drivers/md/dm.c                 | 16 ++--------------
>  drivers/s390/block/dasd_ioctl.c |  5 ++---
>  fs/block_dev.c                  |  2 +-
>  7 files changed, 13 insertions(+), 49 deletions(-)
> 
> diff --git a/block/genhd.c b/block/genhd.c
> index af76c2fff40d31..01876a162f5813 100644
> --- a/block/genhd.c
> +++ b/block/genhd.c
> @@ -920,7 +920,6 @@ struct block_device *bdget_disk(struct gendisk *disk, int partno)
>  
>  	return bdev;
>  }
> -EXPORT_SYMBOL(bdget_disk);
>  
>  /*
>   * print a full list of all partitions - intended for places where the root
> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> index 014683968ce174..92f84ed0ba9eb6 100644
> --- a/drivers/block/nbd.c
> +++ b/drivers/block/nbd.c
> @@ -1488,12 +1488,10 @@ static int nbd_open(struct block_device *bdev, fmode_t mode)
>  static void nbd_release(struct gendisk *disk, fmode_t mode)
>  {
>  	struct nbd_device *nbd = disk->private_data;
> -	struct block_device *bdev = bdget_disk(disk, 0);
>  
>  	if (test_bit(NBD_RT_DISCONNECT_ON_CLOSE, &nbd->config->runtime_flags) &&
> -			bdev->bd_openers == 0)
> +			disk->part0->bd_openers == 0)
>  		nbd_disconnect_and_put(nbd);
> -	bdput(bdev);
>  
>  	nbd_config_put(nbd);
>  	nbd_put(nbd);
> diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
> index 79521e33d30ed5..188e0b47534bcf 100644
> --- a/drivers/block/xen-blkfront.c
> +++ b/drivers/block/xen-blkfront.c
> @@ -2153,7 +2153,7 @@ static void blkfront_closing(struct blkfront_info *info)
>  	}
>  
>  	if (info->gd)
> -		bdev = bdget_disk(info->gd, 0);
> +		bdev = bdgrab(info->gd->part0);
>  
>  	mutex_unlock(&info->mutex);
>  
> @@ -2518,7 +2518,7 @@ static int blkfront_remove(struct xenbus_device *xbdev)
>  
>  	disk = info->gd;
>  	if (disk)
> -		bdev = bdget_disk(disk, 0);
> +		bdev = bdgrab(disk->part0);
>  
>  	info->xbdev = NULL;
>  	mutex_unlock(&info->mutex);
> @@ -2595,19 +2595,11 @@ static int blkif_open(struct block_device *bdev, fmode_t mode)
>  static void blkif_release(struct gendisk *disk, fmode_t mode)
>  {
>  	struct blkfront_info *info = disk->private_data;
> -	struct block_device *bdev;
>  	struct xenbus_device *xbdev;
>  
>  	mutex_lock(&blkfront_mutex);
> -
> -	bdev = bdget_disk(disk, 0);
> -
> -	if (!bdev) {
> -		WARN(1, "Block device %s yanked out from us!\n", disk->disk_name);
> +	if (disk->part0->bd_openers)
>  		goto out_mutex;
> -	}
> -	if (bdev->bd_openers)
> -		goto out;
>  
>  	/*
>  	 * Check if we have been instructed to close. We will have
> @@ -2619,7 +2611,7 @@ static void blkif_release(struct gendisk *disk, fmode_t mode)
>  
>  	if (xbdev && xbdev->state == XenbusStateClosing) {
>  		/* pending switch to state closed */
> -		dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
> +		dev_info(disk_to_dev(disk), "releasing disk\n");
>  		xlvbd_release_gendisk(info);
>  		xenbus_frontend_closed(info->xbdev);
>   	}
> @@ -2628,14 +2620,12 @@ static void blkif_release(struct gendisk *disk, fmode_t mode)
>  
>  	if (!xbdev) {
>  		/* sudden device removal */
> -		dev_info(disk_to_dev(bdev->bd_disk), "releasing disk\n");
> +		dev_info(disk_to_dev(disk), "releasing disk\n");
>  		xlvbd_release_gendisk(info);
>  		disk->private_data = NULL;
>  		free_info(info);
>  	}
>  
> -out:
> -	bdput(bdev);
>  out_mutex:
>  	mutex_unlock(&blkfront_mutex);
>  }
> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> index dc8957d173d37c..b0701bae6e9800 100644
> --- a/drivers/block/zram/zram_drv.c
> +++ b/drivers/block/zram/zram_drv.c
> @@ -1760,15 +1760,12 @@ static ssize_t reset_store(struct device *dev,
>  		return -EINVAL;
>  
>  	zram = dev_to_zram(dev);
> -	bdev = bdget_disk(zram->disk, 0);
> -	if (!bdev)
> -		return -ENOMEM;
> +	bdev = zram->disk->part0;
>  
>  	mutex_lock(&bdev->bd_mutex);
>  	/* Do not reset an active device or claimed device */
>  	if (bdev->bd_openers || zram->claim) {
>  		mutex_unlock(&bdev->bd_mutex);
> -		bdput(bdev);
>  		return -EBUSY;
>  	}
>  
> @@ -1779,7 +1776,6 @@ static ssize_t reset_store(struct device *dev,
>  	/* Make sure all the pending I/O are finished */
>  	fsync_bdev(bdev);
>  	zram_reset_device(zram);
> -	bdput(bdev);
>  
>  	mutex_lock(&bdev->bd_mutex);
>  	zram->claim = false;
> @@ -1965,16 +1961,11 @@ static int zram_add(void)
>  
>  static int zram_remove(struct zram *zram)
>  {
> -	struct block_device *bdev;
> -
> -	bdev = bdget_disk(zram->disk, 0);
> -	if (!bdev)
> -		return -ENOMEM;
> +	struct block_device *bdev = zram->disk->part0;
>  
>  	mutex_lock(&bdev->bd_mutex);
>  	if (bdev->bd_openers || zram->claim) {
>  		mutex_unlock(&bdev->bd_mutex);
> -		bdput(bdev);
>  		return -EBUSY;
>  	}
>  
> @@ -1986,7 +1977,6 @@ static int zram_remove(struct zram *zram)
>  	/* Make sure all the pending I/O are finished */
>  	fsync_bdev(bdev);
>  	zram_reset_device(zram);
> -	bdput(bdev);
>  
>  	pr_info("Removed device: %s\n", zram->disk->disk_name);
>  
> diff --git a/drivers/md/dm.c b/drivers/md/dm.c
> index 176adcff56b380..ed7e836efbcdbc 100644
> --- a/drivers/md/dm.c
> +++ b/drivers/md/dm.c
> @@ -2375,16 +2375,11 @@ struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table)
>   */
>  static int lock_fs(struct mapped_device *md)
>  {
> -	struct block_device *bdev;
>  	int r;
>  
>  	WARN_ON(test_bit(DMF_FROZEN, &md->flags));
>  
> -	bdev = bdget_disk(md->disk, 0);
> -	if (!bdev)
> -		return -ENOMEM;
> -	r = freeze_bdev(bdev);
> -	bdput(bdev);
> +	r = freeze_bdev(md->disk->part0);
>  	if (!r)
>  		set_bit(DMF_FROZEN, &md->flags);
>  	return r;
> @@ -2392,16 +2387,9 @@ static int lock_fs(struct mapped_device *md)
>  
>  static void unlock_fs(struct mapped_device *md)
>  {
> -	struct block_device *bdev;
> -
>  	if (!test_bit(DMF_FROZEN, &md->flags))
>  		return;
> -
> -	bdev = bdget_disk(md->disk, 0);
> -	if (!bdev)
> -		return;
> -	thaw_bdev(bdev);
> -	bdput(bdev);
> +	thaw_bdev(md->disk->part0);
>  	clear_bit(DMF_FROZEN, &md->flags);
>  }
>  
> diff --git a/drivers/s390/block/dasd_ioctl.c b/drivers/s390/block/dasd_ioctl.c
> index 304eba1acf163c..9f642440894655 100644
> --- a/drivers/s390/block/dasd_ioctl.c
> +++ b/drivers/s390/block/dasd_ioctl.c
> @@ -220,9 +220,8 @@ dasd_format(struct dasd_block *block, struct format_data_t *fdata)
>  	 * enabling the device later.
>  	 */
>  	if (fdata->start_unit == 0) {
> -		struct block_device *bdev = bdget_disk(block->gdp, 0);
> -		bdev->bd_inode->i_blkbits = blksize_bits(fdata->blksize);
> -		bdput(bdev);
> +		block->gdp->part0->bd_inode->i_blkbits =
> +			blksize_bits(fdata->blksize);
>  	}
>  
>  	rc = base->discipline->format_device(base, fdata, 1);
> diff --git a/fs/block_dev.c b/fs/block_dev.c
> index 58fd6625966511..4edb9f23092285 100644
> --- a/fs/block_dev.c
> +++ b/fs/block_dev.c
> @@ -1295,7 +1295,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode)
>  			if (ret)
>  				return ret;
>  		} else {
> -			struct block_device *whole = bdget_disk(disk, 0);
> +			struct block_device *whole = bdgrab(disk->part0);
>  
>  			mutex_lock_nested(&whole->bd_mutex, 1);
>  			ret = __blkdev_get(whole, mode);
> -- 
> 2.29.2
> 
-- 
Jan Kara <jack at suse.com>
SUSE Labs, CR



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