[PATCH] udf: use crc_itu_t from lib instead of udf_crc

[Bob Copeland <me@bobcopeland.com>]

Hi Jan,

In reviewing a patch of mine, Sergey Vlasov noticed that the CRC used
in UDF was recently added to lib/.  Would you accept a patch to switch
UDF over?  Such as:

From: Bob Copeland <me@bobcopeland.com>
Date: Wed, 16 Apr 2008 20:23:31 -0400
Subject: [PATCH] udf: use crc_itu_t from lib instead of udf_crc

As pointed out by Sergey Vlasov, UDF implements its own version of
the CRC ITU-T V.41.  Convert it to use the one in the library.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
Cc: Sergey Vlasov <vsu@altlinux.ru>
---
 fs/Kconfig       |    1 +
 fs/udf/Makefile  |    2 +-
 fs/udf/crc.c     |  172 ------------------------------------------------------
 fs/udf/inode.c   |   11 ++--
 fs/udf/misc.c    |   12 ++--
 fs/udf/namei.c   |   21 +++----
 fs/udf/super.c   |   11 ++--
 fs/udf/udfdecl.h |    3 -
 fs/udf/unicode.c |    3 +-
 9 files changed, 32 insertions(+), 204 deletions(-)
 delete mode 100644 fs/udf/crc.c

diff --git a/fs/Kconfig b/fs/Kconfig
index 5dd8f94..f18564f 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -663,6 +663,7 @@ config ZISOFS
 
 config UDF_FS
 	tristate "UDF file system support"
+	select CRC_ITU_T
 	help
 	  This is the new file system used on some CD-ROMs and DVDs. Say Y if
 	  you intend to mount DVD discs or CDRW's written in packet mode, or
diff --git a/fs/udf/Makefile b/fs/udf/Makefile
index be845e7..0d4503f 100644
--- a/fs/udf/Makefile
+++ b/fs/udf/Makefile
@@ -6,4 +6,4 @@ obj-$(CONFIG_UDF_FS) += udf.o
 
 udf-objs     := balloc.o dir.o file.o ialloc.o inode.o lowlevel.o namei.o \
 		partition.o super.o truncate.o symlink.o fsync.o \
-		crc.o directory.o misc.o udftime.o unicode.o
+		directory.o misc.o udftime.o unicode.o
diff --git a/fs/udf/crc.c b/fs/udf/crc.c
deleted file mode 100644
index b166129..0000000
--- a/fs/udf/crc.c
+++ /dev/null
@@ -1,172 +0,0 @@
-/*
- * crc.c
- *
- * PURPOSE
- *	Routines to generate, calculate, and test a 16-bit CRC.
- *
- * DESCRIPTION
- *	The CRC code was devised by Don P. Mitchell of AT&T Bell Laboratories
- *	and Ned W. Rhodes of Software Systems Group. It has been published in
- *	"Design and Validation of Computer Protocols", Prentice Hall,
- *	Englewood Cliffs, NJ, 1991, Chapter 3, ISBN 0-13-539925-4.
- *
- *	Copyright is held by AT&T.
- *
- *	AT&T gives permission for the free use of the CRC source code.
- *
- * COPYRIGHT
- *	This file is distributed under the terms of the GNU General Public
- *	License (GPL). Copies of the GPL can be obtained from:
- *		ftp://prep.ai.mit.edu/pub/gnu/GPL
- *	Each contributing author retains all rights to their own work.
- */
-
-#include "udfdecl.h"
-
-static uint16_t crc_table[256] = {
-	0x0000U, 0x1021U, 0x2042U, 0x3063U, 0x4084U, 0x50a5U, 0x60c6U, 0x70e7U,
-	0x8108U, 0x9129U, 0xa14aU, 0xb16bU, 0xc18cU, 0xd1adU, 0xe1ceU, 0xf1efU,
-	0x1231U, 0x0210U, 0x3273U, 0x2252U, 0x52b5U, 0x4294U, 0x72f7U, 0x62d6U,
-	0x9339U, 0x8318U, 0xb37bU, 0xa35aU, 0xd3bdU, 0xc39cU, 0xf3ffU, 0xe3deU,
-	0x2462U, 0x3443U, 0x0420U, 0x1401U, 0x64e6U, 0x74c7U, 0x44a4U, 0x5485U,
-	0xa56aU, 0xb54bU, 0x8528U, 0x9509U, 0xe5eeU, 0xf5cfU, 0xc5acU, 0xd58dU,
-	0x3653U, 0x2672U, 0x1611U, 0x0630U, 0x76d7U, 0x66f6U, 0x5695U, 0x46b4U,
-	0xb75bU, 0xa77aU, 0x9719U, 0x8738U, 0xf7dfU, 0xe7feU, 0xd79dU, 0xc7bcU,
-	0x48c4U, 0x58e5U, 0x6886U, 0x78a7U, 0x0840U, 0x1861U, 0x2802U, 0x3823U,
-	0xc9ccU, 0xd9edU, 0xe98eU, 0xf9afU, 0x8948U, 0x9969U, 0xa90aU, 0xb92bU,
-	0x5af5U, 0x4ad4U, 0x7ab7U, 0x6a96U, 0x1a71U, 0x0a50U, 0x3a33U, 0x2a12U,
-	0xdbfdU, 0xcbdcU, 0xfbbfU, 0xeb9eU, 0x9b79U, 0x8b58U, 0xbb3bU, 0xab1aU,
-	0x6ca6U, 0x7c87U, 0x4ce4U, 0x5cc5U, 0x2c22U, 0x3c03U, 0x0c60U, 0x1c41U,
-	0xedaeU, 0xfd8fU, 0xcdecU, 0xddcdU, 0xad2aU, 0xbd0bU, 0x8d68U, 0x9d49U,
-	0x7e97U, 0x6eb6U, 0x5ed5U, 0x4ef4U, 0x3e13U, 0x2e32U, 0x1e51U, 0x0e70U,
-	0xff9fU, 0xefbeU, 0xdfddU, 0xcffcU, 0xbf1bU, 0xaf3aU, 0x9f59U, 0x8f78U,
-	0x9188U, 0x81a9U, 0xb1caU, 0xa1ebU, 0xd10cU, 0xc12dU, 0xf14eU, 0xe16fU,
-	0x1080U, 0x00a1U, 0x30c2U, 0x20e3U, 0x5004U, 0x4025U, 0x7046U, 0x6067U,
-	0x83b9U, 0x9398U, 0xa3fbU, 0xb3daU, 0xc33dU, 0xd31cU, 0xe37fU, 0xf35eU,
-	0x02b1U, 0x1290U, 0x22f3U, 0x32d2U, 0x4235U, 0x5214U, 0x6277U, 0x7256U,
-	0xb5eaU, 0xa5cbU, 0x95a8U, 0x8589U, 0xf56eU, 0xe54fU, 0xd52cU, 0xc50dU,
-	0x34e2U, 0x24c3U, 0x14a0U, 0x0481U, 0x7466U, 0x6447U, 0x5424U, 0x4405U,
-	0xa7dbU, 0xb7faU, 0x8799U, 0x97b8U, 0xe75fU, 0xf77eU, 0xc71dU, 0xd73cU,
-	0x26d3U, 0x36f2U, 0x0691U, 0x16b0U, 0x6657U, 0x7676U, 0x4615U, 0x5634U,
-	0xd94cU, 0xc96dU, 0xf90eU, 0xe92fU, 0x99c8U, 0x89e9U, 0xb98aU, 0xa9abU,
-	0x5844U, 0x4865U, 0x7806U, 0x6827U, 0x18c0U, 0x08e1U, 0x3882U, 0x28a3U,
-	0xcb7dU, 0xdb5cU, 0xeb3fU, 0xfb1eU, 0x8bf9U, 0x9bd8U, 0xabbbU, 0xbb9aU,
-	0x4a75U, 0x5a54U, 0x6a37U, 0x7a16U, 0x0af1U, 0x1ad0U, 0x2ab3U, 0x3a92U,
-	0xfd2eU, 0xed0fU, 0xdd6cU, 0xcd4dU, 0xbdaaU, 0xad8bU, 0x9de8U, 0x8dc9U,
-	0x7c26U, 0x6c07U, 0x5c64U, 0x4c45U, 0x3ca2U, 0x2c83U, 0x1ce0U, 0x0cc1U,
-	0xef1fU, 0xff3eU, 0xcf5dU, 0xdf7cU, 0xaf9bU, 0xbfbaU, 0x8fd9U, 0x9ff8U,
-	0x6e17U, 0x7e36U, 0x4e55U, 0x5e74U, 0x2e93U, 0x3eb2U, 0x0ed1U, 0x1ef0U
-};
-
-/*
- * udf_crc
- *
- * PURPOSE
- *	Calculate a 16-bit CRC checksum using ITU-T V.41 polynomial.
- *
- * DESCRIPTION
- *	The OSTA-UDF(tm) 1.50 standard states that using CRCs is mandatory.
- *	The polynomial used is:	x^16 + x^12 + x^15 + 1
- *
- * PRE-CONDITIONS
- *	data		Pointer to the data block.
- *	size		Size of the data block.
- *
- * POST-CONDITIONS
- *	<return>	CRC of the data block.
- *
- * HISTORY
- *	July 21, 1997 - Andrew E. Mileski
- *	Adapted from OSTA-UDF(tm) 1.50 standard.
- */
-uint16_t udf_crc(uint8_t *data, uint32_t size, uint16_t crc)
-{
-	while (size--)
-		crc = crc_table[(crc >> 8 ^ *(data++)) & 0xffU] ^ (crc << 8);
-
-	return crc;
-}
-
-/****************************************************************************/
-#if defined(TEST)
-
-/*
- * PURPOSE
- *	Test udf_crc()
- *
- * HISTORY
- *	July 21, 1997 - Andrew E. Mileski
- *	Adapted from OSTA-UDF(tm) 1.50 standard.
- */
-
-unsigned char bytes[] = { 0x70U, 0x6AU, 0x77U };
-
-int main(void)
-{
-	unsigned short x;
-
-	x = udf_crc(bytes, sizeof bytes);
-	printf("udf_crc: calculated = %4.4x, correct = %4.4x\n", x, 0x3299U);
-
-	return 0;
-}
-
-#endif /* defined(TEST) */
-
-/****************************************************************************/
-#if defined(GENERATE)
-
-/*
- * PURPOSE
- *	Generate a table for fast 16-bit CRC calculations (any polynomial).
- *
- * DESCRIPTION
- *	The ITU-T V.41 polynomial is 010041.
- *
- * HISTORY
- *	July 21, 1997 - Andrew E. Mileski
- *	Adapted from OSTA-UDF(tm) 1.50 standard.
- */
-
-#include <stdio.h>
-
-int main(int argc, char **argv)
-{
-	unsigned long crc, poly;
-	int n, i;
-
-	/* Get the polynomial */
-	sscanf(argv[1], "%lo", &poly);
-	if (poly & 0xffff0000U) {
-		fprintf(stderr, "polynomial is too large\en");
-		exit(1);
-	}
-
-	printf("/* CRC 0%o */\n", poly);
-
-	/* Create a table */
-	printf("static unsigned short crc_table[256] = {\n");
-	for (n = 0; n < 256; n++) {
-		if (n % 8 == 0)
-			printf("\t");
-		crc = n << 8;
-		for (i = 0; i < 8; i++) {
-			if (crc & 0x8000U)
-				crc = (crc << 1) ^ poly;
-			else
-				crc <<= 1;
-			crc &= 0xFFFFU;
-		}
-		if (n == 255)
-			printf("0x%04xU ", crc);
-		else
-			printf("0x%04xU, ", crc);
-		if (n % 8 == 7)
-			printf("\n");
-	}
-	printf("};\n");
-
-	return 0;
-}
-
-#endif /* defined(GENERATE) */
diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 24cfa55..97297e7 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -37,6 +37,7 @@
 #include <linux/buffer_head.h>
 #include <linux/writeback.h>
 #include <linux/slab.h>
+#include <linux/crc-itu-t.h>
 
 #include "udf_i.h"
 #include "udf_sb.h"
@@ -1488,9 +1489,9 @@ static int udf_update_inode(struct inode *inode, int do_sync)
 						iinfo->i_location.
 							logicalBlockNum);
 		use->descTag.descCRCLength = cpu_to_le16(crclen);
-		use->descTag.descCRC = cpu_to_le16(udf_crc((char *)use +
-							   sizeof(tag), crclen,
-							   0));
+		use->descTag.descCRC = cpu_to_le16(crc_itu_t(0, (char *)use +
+							   sizeof(tag), 
+							   crclen));
 		use->descTag.tagChecksum = udf_tag_checksum(&use->descTag);
 
 		mark_buffer_dirty(bh);
@@ -1660,8 +1661,8 @@ static int udf_update_inode(struct inode *inode, int do_sync)
 	crclen += iinfo->i_lenEAttr + iinfo->i_lenAlloc -
 								sizeof(tag);
 	fe->descTag.descCRCLength = cpu_to_le16(crclen);
-	fe->descTag.descCRC = cpu_to_le16(udf_crc((char *)fe + sizeof(tag),
-						  crclen, 0));
+	fe->descTag.descCRC = cpu_to_le16(crc_itu_t(0, (char *)fe + sizeof(tag),
+						  crclen));
 	fe->descTag.tagChecksum = udf_tag_checksum(&fe->descTag);
 
 	/* write the data blocks */
diff --git a/fs/udf/misc.c b/fs/udf/misc.c
index a1d6da0..532bdf0 100644
--- a/fs/udf/misc.c
+++ b/fs/udf/misc.c
@@ -25,6 +25,7 @@
 #include <linux/string.h>
 #include <linux/udf_fs.h>
 #include <linux/buffer_head.h>
+#include <linux/crc-itu-t.h>
 
 #include "udf_i.h"
 #include "udf_sb.h"
@@ -136,8 +137,8 @@ struct genericFormat *udf_add_extendedattr(struct inode *inode, uint32_t size,
 		/* rewrite CRC + checksum of eahd */
 		crclen = sizeof(struct extendedAttrHeaderDesc) - sizeof(tag);
 		eahd->descTag.descCRCLength = cpu_to_le16(crclen);
-		eahd->descTag.descCRC = cpu_to_le16(udf_crc((char *)eahd +
-						sizeof(tag), crclen, 0));
+		eahd->descTag.descCRC = cpu_to_le16(crc_itu_t(0, (char *)eahd +
+						sizeof(tag), crclen));
 		eahd->descTag.tagChecksum = udf_tag_checksum(&eahd->descTag);
 		iinfo->i_lenEAttr += size;
 		return (struct genericFormat *)&ea[offset];
@@ -244,8 +245,9 @@ struct buffer_head *udf_read_tagged(struct super_block *sb, uint32_t block,
 
 	/* Verify the descriptor CRC */
 	if (le16_to_cpu(tag_p->descCRCLength) + sizeof(tag) > sb->s_blocksize ||
-	    le16_to_cpu(tag_p->descCRC) == udf_crc(bh->b_data + sizeof(tag),
-					le16_to_cpu(tag_p->descCRCLength), 0))
+	    le16_to_cpu(tag_p->descCRC) == crc_itu_t(0, 
+					bh->b_data + sizeof(tag),
+					le16_to_cpu(tag_p->descCRCLength)))
 		return bh;
 
 	udf_debug("Crc failure block %d: crc = %d, crclen = %d\n",
@@ -270,7 +272,7 @@ void udf_update_tag(char *data, int length)
 	length -= sizeof(tag);
 
 	tptr->descCRCLength = cpu_to_le16(length);
-	tptr->descCRC = cpu_to_le16(udf_crc(data + sizeof(tag), length, 0));
+	tptr->descCRC = cpu_to_le16(crc_itu_t(0, data + sizeof(tag), length));
 	tptr->tagChecksum = udf_tag_checksum(tptr);
 }
 
diff --git a/fs/udf/namei.c b/fs/udf/namei.c
index 112a5fb..168d2e9 100644
--- a/fs/udf/namei.c
+++ b/fs/udf/namei.c
@@ -31,6 +31,7 @@
 #include <linux/smp_lock.h>
 #include <linux/buffer_head.h>
 #include <linux/sched.h>
+#include <linux/crc-itu-t.h>
 
 static inline int udf_match(int len1, const char *name1, int len2,
 			    const char *name2)
@@ -97,25 +98,23 @@ int udf_write_fi(struct inode *inode, struct fileIdentDesc *cfi,
 		memset(fibh->ebh->b_data, 0x00, padlen + offset);
 	}
 
-	crc = udf_crc((uint8_t *)cfi + sizeof(tag),
-		      sizeof(struct fileIdentDesc) - sizeof(tag), 0);
+	crc = crc_itu_t(0, (uint8_t *)cfi + sizeof(tag),
+		      sizeof(struct fileIdentDesc) - sizeof(tag));
 
 	if (fibh->sbh == fibh->ebh) {
-		crc = udf_crc((uint8_t *)sfi->impUse,
+		crc = crc_itu_t(crc, (uint8_t *)sfi->impUse,
 			      crclen + sizeof(tag) -
-			      sizeof(struct fileIdentDesc), crc);
+			      sizeof(struct fileIdentDesc));
 	} else if (sizeof(struct fileIdentDesc) >= -fibh->soffset) {
-		crc = udf_crc(fibh->ebh->b_data +
+		crc = crc_itu_t(crc, fibh->ebh->b_data +
 					sizeof(struct fileIdentDesc) +
 					fibh->soffset,
 			      crclen + sizeof(tag) -
-					sizeof(struct fileIdentDesc),
-			      crc);
+					sizeof(struct fileIdentDesc));
 	} else {
-		crc = udf_crc((uint8_t *)sfi->impUse,
-			      -fibh->soffset - sizeof(struct fileIdentDesc),
-			      crc);
-		crc = udf_crc(fibh->ebh->b_data, fibh->eoffset, crc);
+		crc = crc_itu_t(crc, (uint8_t *)sfi->impUse,
+			      -fibh->soffset - sizeof(struct fileIdentDesc));
+		crc = crc_itu_t(crc, fibh->ebh->b_data, fibh->eoffset);
 	}
 
 	cfi->descTag.descCRC = cpu_to_le16(crc);
diff --git a/fs/udf/super.c b/fs/udf/super.c
index f3ac4ab..a8194c7 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -55,6 +55,7 @@
 #include <linux/errno.h>
 #include <linux/mount.h>
 #include <linux/seq_file.h>
+#include <linux/crc-itu-t.h>
 #include <asm/byteorder.h>
 
 #include <linux/udf_fs.h>
@@ -1644,9 +1645,8 @@ static void udf_open_lvid(struct super_block *sb)
 		lvid->integrityType = LVID_INTEGRITY_TYPE_OPEN;
 
 		lvid->descTag.descCRC = cpu_to_le16(
-			udf_crc((char *)lvid + sizeof(tag),
-				le16_to_cpu(lvid->descTag.descCRCLength),
-				0));
+			crc_itu_t(0, (char *)lvid + sizeof(tag),
+				le16_to_cpu(lvid->descTag.descCRCLength)));
 
 		lvid->descTag.tagChecksum = udf_tag_checksum(&lvid->descTag);
 		mark_buffer_dirty(bh);
@@ -1682,9 +1682,8 @@ static void udf_close_lvid(struct super_block *sb)
 		lvid->integrityType = cpu_to_le32(LVID_INTEGRITY_TYPE_CLOSE);
 
 		lvid->descTag.descCRC = cpu_to_le16(
-			udf_crc((char *)lvid + sizeof(tag),
-				le16_to_cpu(lvid->descTag.descCRCLength),
-				0));
+			crc_itu_t(0, (char *)lvid + sizeof(tag),
+				le16_to_cpu(lvid->descTag.descCRCLength)));
 
 		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 681dc2b..82ac3aa 100644
--- a/fs/udf/udfdecl.h
+++ b/fs/udf/udfdecl.h
@@ -191,9 +191,6 @@ extern struct fileIdentDesc *udf_get_fileident(void *buffer, int bufsize,
 extern long_ad *udf_get_filelongad(uint8_t *, int, uint32_t *, int);
 extern short_ad *udf_get_fileshortad(uint8_t *, int, uint32_t *, int);
 
-/* crc.c */
-extern uint16_t udf_crc(uint8_t *, uint32_t, uint16_t);
-
 /* udftime.c */
 extern time_t *udf_stamp_to_time(time_t *, long *, kernel_timestamp);
 extern kernel_timestamp *udf_time_to_stamp(kernel_timestamp *, struct timespec);
diff --git a/fs/udf/unicode.c b/fs/udf/unicode.c
index e533b11..e951cca 100644
--- a/fs/udf/unicode.c
+++ b/fs/udf/unicode.c
@@ -24,6 +24,7 @@
 #include <linux/string.h>	/* for memset */
 #include <linux/nls.h>
 #include <linux/udf_fs.h>
+#include <linux/crc-itu-t.h>
 
 #include "udf_sb.h"
 
@@ -463,7 +464,7 @@ static int udf_translate_to_linux(uint8_t *newName, uint8_t *udfName,
 		} else if (newIndex > 250)
 			newIndex = 250;
 		newName[newIndex++] = CRC_MARK;
-		valueCRC = udf_crc(fidName, fidNameLen, 0);
+		valueCRC = crc_itu_t(0, fidName, fidNameLen);
 		newName[newIndex++] = hexChar[(valueCRC & 0xf000) >> 12];
 		newName[newIndex++] = hexChar[(valueCRC & 0x0f00) >> 8];
 		newName[newIndex++] = hexChar[(valueCRC & 0x00f0) >> 4];
-- 
1.5.4.2.182.gb3092

-- 
Bob Copeland %% www.bobcopeland.com