Re: [PATCH 02/17] btrfs: resurrect btrfs_crc32c()

[Nikolay Borisov <nborisov@suse.com>]

On 10.05.19 г. 14:15 ч., Johannes Thumshirn wrote:
> Commit 9678c54388b6 ("btrfs: Remove custom crc32c init code") removed the
> btrfs_crc32c() function, because it was a duplicate of the crc32c() library
> function we already have in the kernel.
> 
> Resurrect it as a shim wrapper over crc32c() to make following
> transformations of the checksumming code in btrfs easier.
> 
> Also provide a btrfs_crc32_final() to ease following transformations.
> 
> Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>

Mechanical patch so :

Reviewed-by: Nikolay Borisov <nborisov@suse.com>

> ---
>  fs/btrfs/ctree.h       | 12 ++++++++++++
>  fs/btrfs/extent-tree.c |  6 +++---
>  fs/btrfs/send.c        |  2 +-
>  3 files changed, 16 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index b81c331b28fa..d85541f13f65 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -19,6 +19,7 @@
>  #include <linux/kobject.h>
>  #include <trace/events/btrfs.h>
>  #include <asm/kmap_types.h>
> +#include <asm/unaligned.h>
>  #include <linux/pagemap.h>
>  #include <linux/btrfs.h>
>  #include <linux/btrfs_tree.h>
> @@ -2642,6 +2643,17 @@ BTRFS_SETGET_STACK_FUNCS(stack_dev_replace_cursor_right,
>  	((unsigned long)(BTRFS_LEAF_DATA_OFFSET + \
>  	btrfs_item_offset_nr(leaf, slot)))
>  
> +
> +static inline u32 btrfs_crc32c(u32 crc, const void *address, unsigned length)
> +{
> +	return crc32c(crc, address, length);
> +}
> +
> +static inline void btrfs_crc32c_final(u32 crc, u8 *result)
> +{
> +	put_unaligned_le32(~crc, result);
> +}
> +
>  static inline u64 btrfs_name_hash(const char *name, int len)
>  {
>         return crc32c((u32)~1, name, len);
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index f79e477a378e..06a30f2cd2e0 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -1119,11 +1119,11 @@ static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
>  	__le64 lenum;
>  
>  	lenum = cpu_to_le64(root_objectid);
> -	high_crc = crc32c(high_crc, &lenum, sizeof(lenum));
> +	high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
>  	lenum = cpu_to_le64(owner);
> -	low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
> +	low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
>  	lenum = cpu_to_le64(offset);
> -	low_crc = crc32c(low_crc, &lenum, sizeof(lenum));
> +	low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
>  
>  	return ((u64)high_crc << 31) ^ (u64)low_crc;
>  }
> diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
> index dd38dfe174df..c029ca6d5eba 100644
> --- a/fs/btrfs/send.c
> +++ b/fs/btrfs/send.c
> @@ -686,7 +686,7 @@ static int send_cmd(struct send_ctx *sctx)
>  	hdr->len = cpu_to_le32(sctx->send_size - sizeof(*hdr));
>  	hdr->crc = 0;
>  
> -	crc = crc32c(0, (unsigned char *)sctx->send_buf, sctx->send_size);
> +	crc = btrfs_crc32c(0, (unsigned char *)sctx->send_buf, sctx->send_size);
>  	hdr->crc = cpu_to_le32(crc);
>  
>  	ret = write_buf(sctx->send_filp, sctx->send_buf, sctx->send_size,
>