From 3f2587bb22bbcd679e9cf034fb4a29bb48b051b3 Mon Sep 17 00:00:00 2001 From: Marcin Slusarz Date: Fri, 8 Feb 2008 04:20:39 -0800 Subject: udf: create common function for tag checksumming Signed-off-by: Marcin Slusarz Acked-by: Jan Kara Cc: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/udf/misc.c | 35 ++++++++++++++--------------------- 1 file changed, 14 insertions(+), 21 deletions(-) (limited to 'fs/udf/misc.c') diff --git a/fs/udf/misc.c b/fs/udf/misc.c index a0bf4158f1f..585e4eaed25 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; +} -- cgit v1.2.3