Re: [PATCH v2 10/13] btrfs: add boilerplate code for directly including the crypto framework

[David Sterba <dsterba@suse.cz>]

On Thu, May 16, 2019 at 10:48:00AM +0200, Johannes Thumshirn wrote:
> Add boilerplate code for directly including the crypto framework.
> 
> This helps us flipping the switch for new algorithms.
> 
> Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
> Reviewed-by: Nikolay Borisov <nborisov@suse.com>
> ---
>  fs/btrfs/ctree.h   | 11 +++++++++++
>  fs/btrfs/disk-io.c | 49 ++++++++++++++++++++++++++++++++++++++++++-------
>  2 files changed, 53 insertions(+), 7 deletions(-)
> 
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index 2ec742db2001..0624057423d4 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -73,6 +73,7 @@ struct btrfs_ref;
>  
>  /* four bytes for CRC32 */
>  static const int btrfs_csum_sizes[] = { 4 };
> +static char *btrfs_csum_names[] = { "crc32c" };
>  
>  #define BTRFS_EMPTY_DIR_SIZE 0
>  
> @@ -1165,6 +1166,8 @@ struct btrfs_fs_info {
>  	spinlock_t ref_verify_lock;
>  	struct rb_root block_tree;
>  #endif
> +
> +	struct crypto_shash *csum_shash;
>  };
>  
>  static inline struct btrfs_fs_info *btrfs_sb(struct super_block *sb)
> @@ -2452,6 +2455,14 @@ static inline int btrfs_super_csum_size(const struct btrfs_super_block *s)
>  	return btrfs_csum_sizes[t];
>  }
>  
> +static inline char *btrfs_super_csum_name(const struct btrfs_super_block *s)
> +{
> +	u16 t = btrfs_super_csum_type(s);

Please don't use single letter variables, 'sb' and 'type' are fine.

> +static int btrfs_init_csum_hash(struct btrfs_fs_info *fs_info,
> +				struct btrfs_super_block *sb)
> +{
> +	struct crypto_shash *csum_shash;
> +	const char *csum_name = btrfs_super_csum_name(sb);
> +
> +	csum_shash = crypto_alloc_shash(csum_name, 0, 0);
> +
> +	if (IS_ERR(csum_shash)) {
> +		btrfs_err(fs_info, "error allocating %s hash for checksum\n",

No newline for the btrfs_* message helpers

> +			  csum_name);
> +		return PTR_ERR(csum_shash);
> +	}
> +
> +	fs_info->csum_shash = csum_shash;
> +
> +	return 0;
> +}
> +
> +static void btrfs_free_csum_hash(struct btrfs_fs_info *fs_info)
> +{
> +	crypto_free_shash(fs_info->csum_shash);
> +}
> +
>  static int btrfs_replay_log(struct btrfs_fs_info *fs_info,
>  			    struct btrfs_fs_devices *fs_devices)
>  {
> @@ -2819,6 +2844,14 @@ int open_ctree(struct super_block *sb,
>  		goto fail_alloc;
>  	}
>  
> +

Extra newline

> +	ret = btrfs_init_csum_hash(fs_info, (struct btrfs_super_block *)
> +							   bh->b_data);

It would be better to avoid the cast and only pass the type, I don't see
anything else the init function would need from the sb.