Re: [PATCH 09/16] udf: create common function for tag checksumming

[Jan Kara <jack@suse.cz>]

On Thu 10-01-08 23:06:25, marcin.slusarz@gmail.com wrote:
> Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
> CC: Jan Kara <jack@suse.cz>
> CC: Christoph Hellwig <hch@infradead.org>
  Acked-by: Jan Kara <jack@suse.cz>

> ---
>  fs/udf/inode.c   |   15 ++-------------
>  fs/udf/misc.c    |   35 ++++++++++++++---------------------
>  fs/udf/namei.c   |    9 +--------
>  fs/udf/super.c   |   16 ++--------------
>  fs/udf/udfdecl.h |    3 +++
>  5 files changed, 22 insertions(+), 56 deletions(-)
> 
> diff --git a/fs/udf/inode.c b/fs/udf/inode.c
> index 9adde18..6751945 100644
> --- a/fs/udf/inode.c
> +++ b/fs/udf/inode.c
> @@ -1440,7 +1440,6 @@ static int udf_update_inode(struct inode *inode, int do_sync)
>  	uint32_t udfperms;
>  	uint16_t icbflags;
>  	uint16_t crclen;
> -	int i;
>  	kernel_timestamp cpu_time;
>  	int err = 0;
>  	struct udf_sb_info *sbi = UDF_SB(inode->i_sb);
> @@ -1476,12 +1475,7 @@ static int udf_update_inode(struct inode *inode, int do_sync)
>  		use->descTag.descCRC = cpu_to_le16(udf_crc((char *)use +
>  							   sizeof(tag), crclen,
>  							   0));
> -
> -		use->descTag.tagChecksum = 0;
> -		for (i = 0; i < 16; i++)
> -			if (i != 4)
> -				use->descTag.tagChecksum +=
> -						((uint8_t *)&(use->descTag))[i];
> +		use->descTag.tagChecksum = udf_tag_checksum(&use->descTag);
>  
>  		mark_buffer_dirty(bh);
>  		brelse(bh);
> @@ -1650,12 +1644,7 @@ static int udf_update_inode(struct inode *inode, int do_sync)
>  	fe->descTag.descCRCLength = cpu_to_le16(crclen);
>  	fe->descTag.descCRC = cpu_to_le16(udf_crc((char *)fe + sizeof(tag),
>  						  crclen, 0));
> -
> -	fe->descTag.tagChecksum = 0;
> -	for (i = 0; i < 16; i++)
> -		if (i != 4)
> -			fe->descTag.tagChecksum +=
> -				((uint8_t *)&(fe->descTag))[i];
> +	fe->descTag.tagChecksum = udf_tag_checksum(&fe->descTag);
>  
>  	/* write the data blocks */
>  	mark_buffer_dirty(bh);
> diff --git a/fs/udf/misc.c b/fs/udf/misc.c
> index a0bf415..585e4ea 100644
> --- a/fs/udf/misc.c
> +++ b/fs/udf/misc.c
> @@ -51,7 +51,6 @@ struct genericFormat *udf_add_extendedattr(struct inode *inode, uint32_t size,
>  	uint8_t *ea = NULL, *ad = NULL;
>  	int offset;
>  	uint16_t crclen;
> -	int i;
>  
>  	ea = UDF_I_DATA(inode);
>  	if (UDF_I_LENEATTR(inode)) {
> @@ -138,11 +137,7 @@ struct genericFormat *udf_add_extendedattr(struct inode *inode, uint32_t size,
>  		eahd->descTag.descCRCLength = cpu_to_le16(crclen);
>  		eahd->descTag.descCRC = cpu_to_le16(udf_crc((char *)eahd +
>  						sizeof(tag), crclen, 0));
> -		eahd->descTag.tagChecksum = 0;
> -		for (i = 0; i < 16; i++)
> -			if (i != 4)
> -				eahd->descTag.tagChecksum +=
> -					((uint8_t *)&(eahd->descTag))[i];
> +		eahd->descTag.tagChecksum = udf_tag_checksum(&eahd->descTag);
>  		UDF_I_LENEATTR(inode) += size;
>  		return (struct genericFormat *)&ea[offset];
>  	}
> @@ -207,8 +202,6 @@ struct buffer_head *udf_read_tagged(struct super_block *sb, uint32_t block,
>  {
>  	tag *tag_p;
>  	struct buffer_head *bh = NULL;
> -	register uint8_t checksum;
> -	register int i;
>  	struct udf_sb_info *sbi = UDF_SB(sb);
>  
>  	/* Read the block */
> @@ -234,12 +227,7 @@ struct buffer_head *udf_read_tagged(struct super_block *sb, uint32_t block,
>  	}
>  
>  	/* Verify the tag checksum */
> -	checksum = 0U;
> -	for (i = 0; i < 4; i++)
> -		checksum += (uint8_t)(bh->b_data[i]);
> -	for (i = 5; i < 16; i++)
> -		checksum += (uint8_t)(bh->b_data[i]);
> -	if (checksum != tag_p->tagChecksum) {
> +	if (udf_tag_checksum(tag_p) != tag_p->tagChecksum) {
>  		printk(KERN_ERR "udf: tag checksum failed block %d\n", block);
>  		goto error_out;
>  	}
> @@ -277,17 +265,11 @@ struct buffer_head *udf_read_ptagged(struct super_block *sb, kernel_lb_addr loc,
>  void udf_update_tag(char *data, int length)
>  {
>  	tag *tptr = (tag *)data;
> -	int i;
> -
>  	length -= sizeof(tag);
>  
> -	tptr->tagChecksum = 0;
>  	tptr->descCRCLength = cpu_to_le16(length);
>  	tptr->descCRC = cpu_to_le16(udf_crc(data + sizeof(tag), length, 0));
> -
> -	for (i = 0; i < 16; i++)
> -		if (i != 4)
> -			tptr->tagChecksum += (uint8_t)(data[i]);
> +	tptr->tagChecksum = udf_tag_checksum(tptr);
>  }
>  
>  void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum,
> @@ -300,3 +282,14 @@ void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum,
>  	tptr->tagLocation = cpu_to_le32(loc);
>  	udf_update_tag(data, length);
>  }
> +
> +u8 udf_tag_checksum(const tag *t)
> +{
> +	u8 *data = (u8 *)t;
> +	u8 checksum = 0;
> +	int i;
> +	for (i = 0; i < sizeof(tag); ++i)
> +		if (i != 4) /* position of checksum */
> +			checksum += data[i];
> +	return checksum;
> +}
> diff --git a/fs/udf/namei.c b/fs/udf/namei.c
> index 25d518b..f1cf18f 100644
> --- a/fs/udf/namei.c
> +++ b/fs/udf/namei.c
> @@ -47,8 +47,6 @@ int udf_write_fi(struct inode *inode, struct fileIdentDesc *cfi,
>  {
>  	uint16_t crclen = fibh->eoffset - fibh->soffset - sizeof(tag);
>  	uint16_t crc;
> -	uint8_t checksum = 0;
> -	int i;
>  	int offset;
>  	uint16_t liu = le16_to_cpu(cfi->lengthOfImpUse);
>  	uint8_t lfi = cfi->lengthFileIdent;
> @@ -122,13 +120,8 @@ int udf_write_fi(struct inode *inode, struct fileIdentDesc *cfi,
>  
>  	cfi->descTag.descCRC = cpu_to_le16(crc);
>  	cfi->descTag.descCRCLength = cpu_to_le16(crclen);
> +	cfi->descTag.tagChecksum = udf_tag_checksum(&cfi->descTag);
>  
> -	for (i = 0; i < 16; i++) {
> -		if (i != 4)
> -			checksum += ((uint8_t *)&cfi->descTag)[i];
> -	}
> -
> -	cfi->descTag.tagChecksum = checksum;
>  	if (adinicb || (sizeof(struct fileIdentDesc) <= -fibh->soffset)) {
>  		memcpy((uint8_t *)sfi, (uint8_t *)cfi,
>  			sizeof(struct fileIdentDesc));
> diff --git a/fs/udf/super.c b/fs/udf/super.c
> index 7f75a94..12fb91d 100644
> --- a/fs/udf/super.c
> +++ b/fs/udf/super.c
> @@ -1564,7 +1564,6 @@ static void udf_open_lvid(struct super_block *sb)
>  	struct udf_sb_info *sbi = UDF_SB(sb);
>  	struct buffer_head *bh = sbi->s_lvid_bh;
>  	if (bh) {
> -		int i;
>  		kernel_timestamp cpu_time;
>  		struct logicalVolIntegrityDesc *lvid =
>  				(struct logicalVolIntegrityDesc *)bh->b_data;
> @@ -1582,12 +1581,7 @@ static void udf_open_lvid(struct super_block *sb)
>  				le16_to_cpu(lvid->descTag.descCRCLength),
>  				0));
>  
> -		lvid->descTag.tagChecksum = 0;
> -		for (i = 0; i < 16; i++)
> -			if (i != 4)
> -				lvid->descTag.tagChecksum +=
> -					((uint8_t *) &(lvid->descTag))[i];
> -
> +		lvid->descTag.tagChecksum = udf_tag_checksum(&lvid->descTag);
>  		mark_buffer_dirty(bh);
>  	}
>  }
> @@ -1595,7 +1589,6 @@ static void udf_open_lvid(struct super_block *sb)
>  static void udf_close_lvid(struct super_block *sb)
>  {
>  	kernel_timestamp cpu_time;
> -	int i;
>  	struct udf_sb_info *sbi = UDF_SB(sb);
>  	struct buffer_head *bh = sbi->s_lvid_bh;
>  	struct logicalVolIntegrityDesc *lvid;
> @@ -1626,12 +1619,7 @@ static void udf_close_lvid(struct super_block *sb)
>  				le16_to_cpu(lvid->descTag.descCRCLength),
>  				0));
>  
> -		lvid->descTag.tagChecksum = 0;
> -		for (i = 0; i < 16; i++)
> -			if (i != 4)
> -				lvid->descTag.tagChecksum +=
> -					((uint8_t *)&(lvid->descTag))[i];
> -
> +		lvid->descTag.tagChecksum = udf_tag_checksum(&lvid->descTag);
>  		mark_buffer_dirty(bh);
>  	}
>  }
> diff --git a/fs/udf/udfdecl.h b/fs/udf/udfdecl.h
> index b17ca67..005e3ad 100644
> --- a/fs/udf/udfdecl.h
> +++ b/fs/udf/udfdecl.h
> @@ -36,6 +36,9 @@
>  
>  #define udf_get_lb_pblock(sb,loc,offset) udf_get_pblock((sb), (loc).logicalBlockNum, (loc).partitionReferenceNum, (offset))
>  
> +/* computes tag checksum */
> +u8 udf_tag_checksum(const tag *t);
> +
>  struct dentry;
>  struct inode;
>  struct task_struct;

								Honza
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR