On Thu 22-02-24 20:45:54, Yu Kuai wrote:
> From: Yu Kuai <yukuai3@xxxxxxxxxx>
>
> scsi_bios_ptable() is reading without opening disk as file, factor out
> a helper to read into block device page cache to prevent access bd_inode
> directly from scsi.
>
> Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
Looks good to me. Either before or after split feel free to add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> block/bdev.c | 19 +++++++++++++++++++
> drivers/scsi/scsicam.c | 3 +--
> include/linux/blkdev.h | 1 +
> 3 files changed, 21 insertions(+), 2 deletions(-)
>
> diff --git a/block/bdev.c b/block/bdev.c
> index 60a1479eae83..b7af04d34af2 100644
> --- a/block/bdev.c
> +++ b/block/bdev.c
> @@ -1211,6 +1211,25 @@ unsigned int block_size(struct block_device *bdev)
> }
> EXPORT_SYMBOL_GPL(block_size);
>
> +/**
> + * bdev_read_folio - Read into block device page cache.
> + * @bdev: the block device which holds the cache to read.
> + * @pos: the offset that allocated folio will contain.
> + *
> + * Read one page into the block device page cache. If it succeeds, the folio
> + * returned will contain @pos;
> + *
> + * This is only used for scsi_bios_ptable(), the bdev is not opened as files.
> + *
> + * Return: Uptodate folio on success, ERR_PTR() on failure.
> + */
> +struct folio *bdev_read_folio(struct block_device *bdev, loff_t pos)
> +{
> + return mapping_read_folio_gfp(bdev_mapping(bdev),
> + pos >> PAGE_SHIFT, GFP_KERNEL);
> +}
> +EXPORT_SYMBOL_GPL(bdev_read_folio);
> +
> static int __init setup_bdev_allow_write_mounted(char *str)
> {
> if (kstrtobool(str, &bdev_allow_write_mounted))
> diff --git a/drivers/scsi/scsicam.c b/drivers/scsi/scsicam.c
> index e2c7d8ef205f..1c99b964a0eb 100644
> --- a/drivers/scsi/scsicam.c
> +++ b/drivers/scsi/scsicam.c
> @@ -32,11 +32,10 @@
> */
> unsigned char *scsi_bios_ptable(struct block_device *dev)
> {
> - struct address_space *mapping = bdev_whole(dev)->bd_inode->i_mapping;
> unsigned char *res = NULL;
> struct folio *folio;
>
> - folio = read_mapping_folio(mapping, 0, NULL);
> + folio = bdev_read_folio(bdev_whole(dev), 0);
> if (IS_ERR(folio))
> return NULL;
>
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index c510f334c84f..3fb02e3a527a 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -1514,6 +1514,7 @@ struct file *bdev_file_open_by_path(const char *path, blk_mode_t mode,
> int bd_prepare_to_claim(struct block_device *bdev, void *holder,
> const struct blk_holder_ops *hops);
> void bd_abort_claiming(struct block_device *bdev, void *holder);
> +struct folio *bdev_read_folio(struct block_device *bdev, loff_t pos);
>
> /* just for blk-cgroup, don't use elsewhere */
> struct block_device *blkdev_get_no_open(dev_t dev);
> --
> 2.39.2
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
