Remove long-unmaintained ftape driver subsystem.

It's bitrotten, long unmaintained, long hidden under BROKEN_ON_SMP,
etc.  As scheduled in feature-removal-schedule.txt, and ack'd several
times on lkml.

Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 0 insertions, 1203 deletions

diff --git a/drivers/char/ftape/compressor/zftape-compress.c b/drivers/char/ftape/compressor/zftape-compress.c
deleted file mode 100644
index 65ffc0be3df9..000000000000
--- a/drivers/char/ftape/compressor/zftape-compress.c
+++ /dev/null
@@ -1,1203 +0,0 @@
-/*
- *      Copyright (C) 1994-1997 Claus-Justus Heine
-
- This program is free software; you can redistribute it and/or
- modify it under the terms of the GNU General Public License as
- published by the Free Software Foundation; either version 2, or (at
- your option) any later version.
- 
- This program is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- General Public License for more details.
- 
- You should have received a copy of the GNU General Public License
- along with this program; see the file COPYING.  If not, write to
- the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
- USA.
- 
- *
- *     This file implements a "generic" interface between the *
- *     zftape-driver and a compression-algorithm. The *
- *     compression-algorithm currently used is a LZ77. I use the *
- *     implementation lzrw3 by Ross N. Williams (Renaissance *
- *     Software). The compression program itself is in the file
- *     lzrw3.c * and lzrw3.h.  To adopt another compression algorithm
- *     the functions * zft_compress() and zft_uncompress() must be
- *     changed * appropriately. See below.
- */
-
-#include <linux/errno.h>
-#include <linux/mm.h>
-#include <linux/module.h>
-
-#include <linux/zftape.h>
-
-#include <asm/uaccess.h>
-
-#include "../zftape/zftape-init.h"
-#include "../zftape/zftape-eof.h"
-#include "../zftape/zftape-ctl.h"
-#include "../zftape/zftape-write.h"
-#include "../zftape/zftape-read.h"
-#include "../zftape/zftape-rw.h"
-#include "../compressor/zftape-compress.h"
-#include "../zftape/zftape-vtbl.h"
-#include "../compressor/lzrw3.h"
-
-/*
- *   global variables
- */
-
-/* I handle the allocation of this buffer as a special case, because
- * it's size varies depending on the tape length inserted.
- */
-
-/* local variables 
- */
-static void *zftc_wrk_mem = NULL;
-static __u8 *zftc_buf     = NULL;
-static void *zftc_scratch_buf  = NULL;
-
-/* compression statistics 
- */
-static unsigned int zftc_wr_uncompressed = 0;
-static unsigned int zftc_wr_compressed   = 0;
-static unsigned int zftc_rd_uncompressed = 0;
-static unsigned int zftc_rd_compressed   = 0;
-
-/* forward */
-static int  zftc_write(int *write_cnt,
-		       __u8 *dst_buf, const int seg_sz,
-		       const __u8 __user *src_buf, const int req_len,
-		       const zft_position *pos, const zft_volinfo *volume);
-static int  zftc_read(int *read_cnt,
-		      __u8  __user *dst_buf, const int to_do,
-		      const __u8 *src_buf, const int seg_sz,
-		      const zft_position *pos, const zft_volinfo *volume);
-static int  zftc_seek(unsigned int new_block_pos, 
-		      zft_position *pos, const zft_volinfo *volume,
-		      __u8 *buffer);
-static void zftc_lock   (void);
-static void zftc_reset  (void);
-static void zftc_cleanup(void);
-static void zftc_stats      (void);
-
-/* compressed segment. This conforms to QIC-80-MC, Revision K.
- * 
- * Rev. K applies to tapes with `fixed length format' which is
- * indicated by format code 2,3 and 5. See below for format code 4 and 6
- *
- * 2 bytes: offset of compression segment structure
- *          29k > offset >= 29k-18: data from previous segment ens in this
- *                                  segment and no compressed block starts
- *                                  in this segment
- *                     offset == 0: data from previous segment occupies entire
- *                                  segment and continues in next segment
- * n bytes: remainder from previous segment
- * 
- * Rev. K:  
- * 4 bytes: 4 bytes: files set byte offset
- * Post Rev. K and QIC-3020/3020:
- * 8 bytes: 8 bytes: files set byte offset
- * 2 bytes: byte count N (amount of data following)
- *          bit 15 is set if data is compressed, bit 15 is not
- *          set if data is uncompressed
- * N bytes: data (as much as specified in the byte count)
- * 2 bytes: byte count N_1 of next cluster
- * N_1 bytes: data of next cluset
- * 2 bytes: byte count N_2 of next cluster
- * N_2 bytes: ...  
- *
- * Note that the `N' byte count accounts only for the bytes that in the
- * current segment if the cluster spans to the next segment.
- */
-
-typedef struct
-{
-	int cmpr_pos;             /* actual position in compression buffer */
-	int cmpr_sz;              /* what is left in the compression buffer
-				   * when copying the compressed data to the
-				   * deblock buffer
-				   */
-	unsigned int first_block; /* location of header information in
-				   * this segment
-				   */
-	unsigned int count;       /* amount of data of current block
-				   * contained in current segment 
-				   */
-	unsigned int offset;      /* offset in current segment */
-	unsigned int spans:1;     /* might continue in next segment */
-	unsigned int uncmpr;      /* 0x8000 if this block contains
-				   * uncompressed data 
-				   */
-	__s64 foffs;              /* file set byte offset, same as in 
-				   * compression map segment
-				   */
-} cmpr_info;
-
-static cmpr_info cseg; /* static data. Must be kept uptodate and shared by 
-			* read, write and seek functions
-			*/
-
-#define DUMP_CMPR_INFO(level, msg, info)				\
-	TRACE(level, msg "\n"						\
-	      KERN_INFO "cmpr_pos   : %d\n"				\
-	      KERN_INFO "cmpr_sz    : %d\n"				\
-	      KERN_INFO "first_block: %d\n"				\
-	      KERN_INFO "count      : %d\n"				\
-	      KERN_INFO "offset     : %d\n"				\
-	      KERN_INFO "spans      : %d\n"				\
-	      KERN_INFO "uncmpr     : 0x%04x\n"				\
-	      KERN_INFO "foffs      : " LL_X,				\
-	      (info)->cmpr_pos, (info)->cmpr_sz, (info)->first_block,	\
-	      (info)->count, (info)->offset, (info)->spans == 1,	\
-	      (info)->uncmpr, LL((info)->foffs))
-
-/*   dispatch compression segment info, return error code
- *  
- *   afterwards, cseg->offset points to start of data of the NEXT
- *   compressed block, and cseg->count contains the amount of data
- *   left in the actual compressed block. cseg->spans is set to 1 if
- *   the block is continued in the following segment. Otherwise it is
- *   set to 0. 
- */
-static int get_cseg (cmpr_info *cinfo, const __u8 *buff, 
-		     const unsigned int seg_sz,
-		     const zft_volinfo *volume)
-{
-	TRACE_FUN(ft_t_flow);
-
- 	cinfo->first_block = GET2(buff, 0);
-	if (cinfo->first_block == 0) { /* data spans to next segment */
-		cinfo->count  = seg_sz - sizeof(__u16);
-		cinfo->offset = seg_sz;
-		cinfo->spans = 1;
-	} else { /* cluster definetely ends in this segment */
-		if (cinfo->first_block > seg_sz) {
-			/* data corrupted */
-			TRACE_ABORT(-EIO, ft_t_err, "corrupted data:\n"
-				    KERN_INFO "segment size: %d\n"
-				    KERN_INFO "first block : %d",
-				    seg_sz, cinfo->first_block);
-		}
-	        cinfo->count  = cinfo->first_block - sizeof(__u16);
-		cinfo->offset = cinfo->first_block;
-		cinfo->spans = 0;
-	}
-	/* now get the offset the first block should have in the
-	 * uncompressed data stream.
-	 *
-	 * For this magic `18' refer to CRF-3 standard or QIC-80MC,
-	 * Rev. K.  
-	 */
-	if ((seg_sz - cinfo->offset) > 18) {
-		if (volume->qic113) { /* > revision K */
-			TRACE(ft_t_data_flow, "New QIC-113 compliance");
-			cinfo->foffs = GET8(buff, cinfo->offset);
-			cinfo->offset += sizeof(__s64); 
-		} else {
-			TRACE(/* ft_t_data_flow */ ft_t_noise, "pre QIC-113 version");
-			cinfo->foffs   = (__s64)GET4(buff, cinfo->offset);
-			cinfo->offset += sizeof(__u32); 
-		}
-	}
-	if (cinfo->foffs > volume->size) {
-		TRACE_ABORT(-EIO, ft_t_err, "Inconsistency:\n"
-			    KERN_INFO "offset in current volume: %d\n"
-			    KERN_INFO "size of current volume  : %d",
-			    (int)(cinfo->foffs>>10), (int)(volume->size>>10));
-	}
-	if (cinfo->cmpr_pos + cinfo->count > volume->blk_sz) {
-		TRACE_ABORT(-EIO, ft_t_err, "Inconsistency:\n"
-			    KERN_INFO "block size : %d\n"
-			    KERN_INFO "data record: %d",
-			    volume->blk_sz, cinfo->cmpr_pos + cinfo->count);
-	}
-	DUMP_CMPR_INFO(ft_t_noise /* ft_t_any */, "", cinfo);
-	TRACE_EXIT 0;
-}
-
-/*  This one is called, when a new cluster starts in same segment.
- *  
- *  Note: if this is the first cluster in the current segment, we must
- *  not check whether there are more than 18 bytes available because
- *  this have already been done in get_cseg() and there may be less
- *  than 18 bytes available due to header information.
- * 
- */
-static void get_next_cluster(cmpr_info *cluster, const __u8 *buff, 
-			     const int seg_sz, const int finish)
-{
-	TRACE_FUN(ft_t_flow);
-
-	if (seg_sz - cluster->offset > 18 || cluster->foffs != 0) {
-		cluster->count   = GET2(buff, cluster->offset);
-		cluster->uncmpr  = cluster->count & 0x8000;
-		cluster->count  -= cluster->uncmpr;
-		cluster->offset += sizeof(__u16);
-		cluster->foffs   = 0;
-		if ((cluster->offset + cluster->count) < seg_sz) {
-			cluster->spans = 0;
-		} else if (cluster->offset + cluster->count == seg_sz) {
-			cluster->spans = !finish;
-		} else {
-			/* either an error or a volume written by an 
-			 * old version. If this is a data error, then we'll
-			 * catch it later.
-			 */
-			TRACE(ft_t_data_flow, "Either error or old volume");
-			cluster->spans = 1;
-			cluster->count = seg_sz - cluster->offset;
-		}
-	} else {
-		cluster->count = 0;
-		cluster->spans = 0;
-		cluster->foffs = 0;
-	}
-	DUMP_CMPR_INFO(ft_t_noise /* ft_t_any */ , "", cluster);
-	TRACE_EXIT;
-}
-
-static void zftc_lock(void)
-{
-}
-
-/*  this function is needed for zftape_reset_position in zftape-io.c 
- */
-static void zftc_reset(void)
-{
-	TRACE_FUN(ft_t_flow);
-
-	memset((void *)&cseg, '\0', sizeof(cseg));
-	zftc_stats();
-	TRACE_EXIT;
-}
-
-static int cmpr_mem_initialized = 0;
-static unsigned int alloc_blksz = 0;
-
-static int zft_allocate_cmpr_mem(unsigned int blksz)
-{
-	TRACE_FUN(ft_t_flow);
-
-	if (cmpr_mem_initialized && blksz == alloc_blksz) {
-		TRACE_EXIT 0;
-	}
-	TRACE_CATCH(zft_vmalloc_once(&zftc_wrk_mem, CMPR_WRK_MEM_SIZE),
-		    zftc_cleanup());
-	TRACE_CATCH(zft_vmalloc_always(&zftc_buf, blksz + CMPR_OVERRUN),
-		    zftc_cleanup());
-	alloc_blksz = blksz;
-	TRACE_CATCH(zft_vmalloc_always(&zftc_scratch_buf, blksz+CMPR_OVERRUN),
-		    zftc_cleanup());
-	cmpr_mem_initialized = 1;
-	TRACE_EXIT 0;
-}
-
-static void zftc_cleanup(void)
-{
-	TRACE_FUN(ft_t_flow);
-
-	zft_vfree(&zftc_wrk_mem, CMPR_WRK_MEM_SIZE);
-	zft_vfree(&zftc_buf, alloc_blksz + CMPR_OVERRUN);
-	zft_vfree(&zftc_scratch_buf, alloc_blksz + CMPR_OVERRUN);
-	cmpr_mem_initialized = alloc_blksz = 0;
-	TRACE_EXIT;
-}
-
-/*****************************************************************************
- *                                                                           *
- *  The following two functions "ftape_compress()" and                       *
- *  "ftape_uncompress()" are the interface to the actual compression         *
- *  algorithm (i.e. they are calling the "compress()" function from          *
- *  the lzrw3 package for now). These routines could quite easily be         *
- *  changed to adopt another compression algorithm instead of lzrw3,         *
- *  which currently is used.                                                 *
- *                                                                           *
- *****************************************************************************/
-
-/* called by zft_compress_write() to perform the compression. Must
- * return the size of the compressed data.
- *
- * NOTE: The size of the compressed data should not exceed the size of
- *       the uncompressed data. Most compression algorithms have means
- *       to store data unchanged if the "compressed" data amount would
- *       exceed the original one. Mostly this is done by storing some
- *       flag-bytes in front of the compressed data to indicate if it
- *       is compressed or not. Thus the worst compression result
- *       length is the original length plus those flag-bytes.
- *
- *       We don't want that, as the QIC-80 standard provides a means
- *       of marking uncompressed blocks by simply setting bit 15 of
- *       the compressed block's length. Thus a compessed block can
- *       have at most a length of 2^15-1 bytes. The QIC-80 standard
- *       restricts the block-length even further, allowing only 29k -
- *       6 bytes.
- *
- *       Currently, the maximum blocksize used by zftape is 28k.
- *
- *       In short: don't exceed the length of the input-package, set
- *       bit 15 of the compressed size to 1 if you have copied data
- *       instead of compressing it.
- */
-static int zft_compress(__u8 *in_buffer, unsigned int in_sz, __u8 *out_buffer)
-{ 
-	__s32 compressed_sz;
-	TRACE_FUN(ft_t_flow);
-	
-
-	lzrw3_compress(COMPRESS_ACTION_COMPRESS, zftc_wrk_mem,
-		       in_buffer, in_sz, out_buffer, &compressed_sz);
-	if (TRACE_LEVEL >= ft_t_info) {
-		/*  the compiler will optimize this away when
-		 *  compiled with NO_TRACE_AT_ALL option
-		 */
-		TRACE(ft_t_data_flow, "\n"
-		      KERN_INFO "before compression: %d bytes\n"
-		      KERN_INFO "after compresison : %d bytes", 
-		      in_sz, 
-		      (int)(compressed_sz < 0 
-		      ? -compressed_sz : compressed_sz));
-		/*  for statistical purposes
-		 */
-		zftc_wr_compressed   += (compressed_sz < 0 
-					   ? -compressed_sz : compressed_sz);
-		zftc_wr_uncompressed += in_sz;
-	}
-	TRACE_EXIT (int)compressed_sz;
-}
-
-/* called by zft_compress_read() to decompress the data. Must
- * return the size of the decompressed data for sanity checks
- * (compared with zft_blk_sz)
- *
- * NOTE: Read the note for zft_compress() above!  If bit 15 of the
- *       parameter in_sz is set, then the data in in_buffer isn't
- *       compressed, which must be handled by the un-compression
- *       algorithm. (I changed lzrw3 to handle this.)
- *
- *  The parameter max_out_sz is needed to prevent buffer overruns when 
- *  uncompressing corrupt data.
- */
-static unsigned int zft_uncompress(__u8 *in_buffer, 
-				   int in_sz, 
-				   __u8 *out_buffer,
-				   unsigned int max_out_sz)
-{ 
-	TRACE_FUN(ft_t_flow);
-	
-	lzrw3_compress(COMPRESS_ACTION_DECOMPRESS, zftc_wrk_mem,
-		       in_buffer, (__s32)in_sz,
-		       out_buffer, (__u32 *)&max_out_sz);
-	
-	if (TRACE_LEVEL >= ft_t_info) {
-		TRACE(ft_t_data_flow, "\n"
-		      KERN_INFO "before decompression: %d bytes\n"
-		      KERN_INFO "after decompression : %d bytes", 
-		      in_sz < 0 ? -in_sz : in_sz,(int)max_out_sz);
-		/*  for statistical purposes
-		 */
-		zftc_rd_compressed   += in_sz < 0 ? -in_sz : in_sz;
-		zftc_rd_uncompressed += max_out_sz;
-	}
-	TRACE_EXIT (unsigned int)max_out_sz;
-}
-
-/* print some statistics about the efficiency of the compression to
- * the kernel log 
- */
-static void zftc_stats(void)
-{
-	TRACE_FUN(ft_t_flow);
-
-	if (TRACE_LEVEL < ft_t_info) {
-		TRACE_EXIT;
-	}
-	if (zftc_wr_uncompressed != 0) {
-		if (zftc_wr_compressed > (1<<14)) {
-			TRACE(ft_t_info, "compression statistics (writing):\n"
-			      KERN_INFO " compr./uncmpr.   : %3d %%",
-			      (((zftc_wr_compressed>>10) * 100)
-			       / (zftc_wr_uncompressed>>10)));
-		} else {
-			TRACE(ft_t_info, "compression statistics (writing):\n"
-			      KERN_INFO " compr./uncmpr.   : %3d %%",
-			      ((zftc_wr_compressed * 100)
-			       / zftc_wr_uncompressed));
-		}
-	}
-	if (zftc_rd_uncompressed != 0) {
-		if (zftc_rd_compressed > (1<<14)) {
-			TRACE(ft_t_info, "compression statistics (reading):\n"
-			      KERN_INFO " compr./uncmpr.   : %3d %%",
-			      (((zftc_rd_compressed>>10) * 100)
-			       / (zftc_rd_uncompressed>>10)));
-		} else {
-			TRACE(ft_t_info, "compression statistics (reading):\n"
-			      KERN_INFO " compr./uncmpr.   : %3d %%",
-			      ((zftc_rd_compressed * 100)
-			       / zftc_rd_uncompressed));
-		}
-	}
-	/* only print it once: */
-	zftc_wr_uncompressed = 
-		zftc_wr_compressed  =
-		zftc_rd_uncompressed =
-		zftc_rd_compressed   = 0;
-	TRACE_EXIT;
-}
-
-/* start new compressed block 
- */
-static int start_new_cseg(cmpr_info *cluster, 
-			  char *dst_buf, 
-			  const zft_position *pos,
-			  const unsigned int blk_sz,
-			  const char *src_buf,
-			  const int this_segs_sz,
-			  const int qic113)
-{
-	int size_left;
-	int cp_cnt;
-	int buf_pos;
-	TRACE_FUN(ft_t_flow);
-
-	size_left = this_segs_sz - sizeof(__u16) - cluster->cmpr_sz;
-	TRACE(ft_t_data_flow,"\n" 
-	      KERN_INFO "segment size   : %d\n"
-	      KERN_INFO "compressed_sz: %d\n"
-	      KERN_INFO "size_left      : %d",
-	      this_segs_sz, cluster->cmpr_sz, size_left);
-	if (size_left > 18) { /* start a new cluseter */
-		cp_cnt = cluster->cmpr_sz;
-		cluster->cmpr_sz = 0;
-		buf_pos = cp_cnt + sizeof(__u16);
-		PUT2(dst_buf, 0, buf_pos);
-
-		if (qic113) {
-			__s64 foffs = pos->volume_pos;
-			if (cp_cnt) foffs += (__s64)blk_sz;
-
-			TRACE(ft_t_data_flow, "new style QIC-113 header");
-			PUT8(dst_buf, buf_pos, foffs);
-			buf_pos += sizeof(__s64);
-		} else {
-			__u32 foffs = (__u32)pos->volume_pos;
-			if (cp_cnt) foffs += (__u32)blk_sz;
-			
-			TRACE(ft_t_data_flow, "old style QIC-80MC header");
-			PUT4(dst_buf, buf_pos, foffs);
-			buf_pos += sizeof(__u32);
-		}
-	} else if (size_left >= 0) {
-		cp_cnt = cluster->cmpr_sz;
-		cluster->cmpr_sz = 0;
-		buf_pos = cp_cnt + sizeof(__u16);
-		PUT2(dst_buf, 0, buf_pos);  
-		/* zero unused part of segment. */
-		memset(dst_buf + buf_pos, '\0', size_left);
-		buf_pos = this_segs_sz;
-	} else { /* need entire segment and more space */
-		PUT2(dst_buf, 0, 0); 
-		cp_cnt = this_segs_sz - sizeof(__u16);
-		cluster->cmpr_sz  -= cp_cnt;
-		buf_pos = this_segs_sz;
-	}
-	memcpy(dst_buf + sizeof(__u16), src_buf + cluster->cmpr_pos, cp_cnt);
-	cluster->cmpr_pos += cp_cnt;
-	TRACE_EXIT buf_pos;
-}
-
-/* return-value: the number of bytes removed from the user-buffer
- *               `src_buf' or error code
- *
- *  int *write_cnt           : how much actually has been moved to the
- *                             dst_buf. Need not be initialized when
- *                             function returns with an error code
- *                             (negativ return value) 
- *  __u8 *dst_buf            : kernel space buffer where the has to be
- *                             copied to. The contents of this buffers
- *                             goes to a specific segment.
- *  const int seg_sz         : the size of the segment dst_buf will be
- *                             copied to.
- *  const zft_position *pos  : struct containing the coordinates in
- *                             the current volume (byte position,
- *                             segment id of current segment etc)
- *  const zft_volinfo *volume: information about the current volume,
- *                             size etc.
- *  const __u8 *src_buf      : user space buffer that contains the
- *                             data the user wants to be written to
- *                             tape.
- *  const int req_len        : the amount of data the user wants to be
- *                             written to tape.
- */
-static int zftc_write(int *write_cnt,
-		      __u8 *dst_buf, const int seg_sz,
-		      const __u8 __user *src_buf, const int req_len,
-		      const zft_position *pos, const zft_volinfo *volume)
-{
-	int req_len_left = req_len;
-	int result;
-	int len_left;
-	int buf_pos_write = pos->seg_byte_pos;
-	TRACE_FUN(ft_t_flow);
-	
-	/* Note: we do not unlock the module because
-	 * there are some values cached in that `cseg' variable.  We
-	 * don't don't want to use this information when being
-	 * unloaded by kerneld even when the tape is full or when we
-	 * cannot allocate enough memory.
-	 */
-	if (pos->tape_pos > (volume->size-volume->blk_sz-ZFT_CMPR_OVERHEAD)) {
-		TRACE_EXIT -ENOSPC;
-	}    
-	if (zft_allocate_cmpr_mem(volume->blk_sz) < 0) {
-		/* should we unlock the module? But it shouldn't 
-		 * be locked anyway ...
-		 */
-		TRACE_EXIT -ENOMEM;
-	}
-	if (buf_pos_write == 0) { /* fill a new segment */
-		*write_cnt = buf_pos_write = start_new_cseg(&cseg,
-							    dst_buf,
-							    pos,
-							    volume->blk_sz,
-							    zftc_buf, 
-							    seg_sz,
-							    volume->qic113);
-		if (cseg.cmpr_sz == 0 && cseg.cmpr_pos != 0) {
-			req_len_left -= result = volume->blk_sz;
-			cseg.cmpr_pos  = 0;
-		} else {
-			result = 0;
-		}
-	} else {
-		*write_cnt = result = 0;
-	}
-	
-	len_left = seg_sz - buf_pos_write;
-	while ((req_len_left > 0) && (len_left > 18)) {
-		/* now we have some size left for a new compressed
-		 * block.  We know, that the compression buffer is
-		 * empty (else there wouldn't be any space left).  
-		 */
-		if (copy_from_user(zftc_scratch_buf, src_buf + result, 
-				   volume->blk_sz) != 0) {
-			TRACE_EXIT -EFAULT;
-		}
-		req_len_left -= volume->blk_sz;
-		cseg.cmpr_sz = zft_compress(zftc_scratch_buf, volume->blk_sz, 
-					    zftc_buf);
-		if (cseg.cmpr_sz < 0) {
-			cseg.uncmpr = 0x8000;
-			cseg.cmpr_sz = -cseg.cmpr_sz;
-		} else {
-			cseg.uncmpr = 0;
-		}
-		/* increment "result" iff we copied the entire
-		 * compressed block to the zft_deblock_buf 
-		 */
-		len_left -= sizeof(__u16);
-		if (len_left >= cseg.cmpr_sz) {
-			len_left -= cseg.count = cseg.cmpr_sz;
-			cseg.cmpr_pos = cseg.cmpr_sz = 0;
-			result += volume->blk_sz;
-		} else {
-			cseg.cmpr_sz       -= 
-				cseg.cmpr_pos =
-				cseg.count    = len_left;
-			len_left = 0;
-		}
-		PUT2(dst_buf, buf_pos_write, cseg.uncmpr | cseg.count);
-		buf_pos_write += sizeof(__u16);
-		memcpy(dst_buf + buf_pos_write, zftc_buf, cseg.count);
-		buf_pos_write += cseg.count;
-		*write_cnt    += cseg.count + sizeof(__u16);
-		FT_SIGNAL_EXIT(_DONT_BLOCK);
-	}
-	/* erase the remainder of the segment if less than 18 bytes
-	 * left (18 bytes is due to the QIC-80 standard) 
-	 */
-	if (len_left <= 18) {
-		memset(dst_buf + buf_pos_write, '\0', len_left);
-		(*write_cnt) += len_left;
-	}
-	TRACE(ft_t_data_flow, "returning %d", result);
-	TRACE_EXIT result;
-}   
-
-/* out:
- *
- * int *read_cnt: the number of bytes we removed from the zft_deblock_buf
- *                (result)
- * int *to_do   : the remaining size of the read-request.
- *
- * in:
- *
- * char *buff          : buff is the address of the upper part of the user
- *                       buffer, that hasn't been filled with data yet.
-
- * int buf_pos_read    : copy of from _ftape_read()
- * int buf_len_read    : copy of buf_len_rd from _ftape_read()
- * char *zft_deblock_buf: zft_deblock_buf
- * unsigned short blk_sz: the block size valid for this volume, may differ
- *                            from zft_blk_sz.
- * int finish: if != 0 means that this is the last segment belonging
- *  to this volume
- * returns the amount of data actually copied to the user-buffer
- *
- * to_do MUST NOT SHRINK except to indicate an EOF. In this case *to_do has to
- * be set to 0 
- */
-static int zftc_read (int *read_cnt, 
-		      __u8  __user *dst_buf, const int to_do, 
-		      const __u8 *src_buf, const int seg_sz, 
-		      const zft_position *pos, const zft_volinfo *volume)
-{          
-	int uncompressed_sz;         
-	int result = 0;
-	int remaining = to_do;
-	TRACE_FUN(ft_t_flow);
-
-	TRACE_CATCH(zft_allocate_cmpr_mem(volume->blk_sz),);
-	if (pos->seg_byte_pos == 0) {
-		/* new segment just read
-		 */
-		TRACE_CATCH(get_cseg(&cseg, src_buf, seg_sz, volume),
-			    *read_cnt = 0);
-		memcpy(zftc_buf + cseg.cmpr_pos, src_buf + sizeof(__u16), 
-		       cseg.count);
-		cseg.cmpr_pos += cseg.count;
-		*read_cnt      = cseg.offset;
-		DUMP_CMPR_INFO(ft_t_noise /* ft_t_any */, "", &cseg);
-	} else {
-		*read_cnt = 0;
-	}
-	/* loop and uncompress until user buffer full or
-	 * deblock-buffer empty 
-	 */
-	TRACE(ft_t_data_flow, "compressed_sz: %d, compos : %d, *read_cnt: %d",
-	      cseg.cmpr_sz, cseg.cmpr_pos, *read_cnt);
-	while ((cseg.spans == 0) && (remaining > 0)) {
-		if (cseg.cmpr_pos  != 0) { /* cmpr buf is not empty */
-			uncompressed_sz = 
-				zft_uncompress(zftc_buf,
-					       cseg.uncmpr == 0x8000 ?
-					       -cseg.cmpr_pos : cseg.cmpr_pos,
-					       zftc_scratch_buf,
-					       volume->blk_sz);
-			if (uncompressed_sz != volume->blk_sz) {
-				*read_cnt = 0;
-				TRACE_ABORT(-EIO, ft_t_warn,
-				      "Uncompressed blk (%d) != blk size (%d)",
-				      uncompressed_sz, volume->blk_sz);
-			}       
-			if (copy_to_user(dst_buf + result, 
-					 zftc_scratch_buf, 
-					 uncompressed_sz) != 0 ) {
-				TRACE_EXIT -EFAULT;
-			}
-			remaining      -= uncompressed_sz;
-			result     += uncompressed_sz;
-			cseg.cmpr_pos  = 0;
-		}                                              
-		if (remaining > 0) {
-			get_next_cluster(&cseg, src_buf, seg_sz, 
-					 volume->end_seg == pos->seg_pos);
-			if (cseg.count != 0) {
-				memcpy(zftc_buf, src_buf + cseg.offset,
-				       cseg.count);
-				cseg.cmpr_pos = cseg.count;
-				cseg.offset  += cseg.count;
-				*read_cnt += cseg.count + sizeof(__u16);
-			} else {
-				remaining = 0;
-			}
-		}
-		TRACE(ft_t_data_flow, "\n" 
-		      KERN_INFO "compressed_sz: %d\n"
-		      KERN_INFO "compos       : %d\n"
-		      KERN_INFO "*read_cnt    : %d",
-		      cseg.cmpr_sz, cseg.cmpr_pos, *read_cnt);
-	}
-	if (seg_sz - cseg.offset <= 18) {
-		*read_cnt += seg_sz - cseg.offset;
-		TRACE(ft_t_data_flow, "expanding read cnt to: %d", *read_cnt);
-	}
-	TRACE(ft_t_data_flow, "\n"
-	      KERN_INFO "segment size   : %d\n"
-	      KERN_INFO "read count     : %d\n"
-	      KERN_INFO "buf_pos_read   : %d\n"
-	      KERN_INFO "remaining      : %d",
-		seg_sz, *read_cnt, pos->seg_byte_pos, 
-		seg_sz - *read_cnt - pos->seg_byte_pos);
-	TRACE(ft_t_data_flow, "returning: %d", result);
-	TRACE_EXIT result;
-}                
-
-/* seeks to the new data-position. Reads sometimes a segment.
- *  
- * start_seg and end_seg give the boundaries of the current volume
- * blk_sz is the blk_sz of the current volume as stored in the
- * volume label
- *
- * We don't allow blocksizes less than 1024 bytes, therefore we don't need
- * a 64 bit argument for new_block_pos.
- */
-
-static int seek_in_segment(const unsigned int to_do, cmpr_info  *c_info,
-			   const char *src_buf, const int seg_sz, 
-			   const int seg_pos, const zft_volinfo *volume);
-static int slow_seek_forward_until_error(const unsigned int distance,
-					 cmpr_info *c_info, zft_position *pos, 
-					 const zft_volinfo *volume, __u8 *buf);
-static int search_valid_segment(unsigned int segment,
-				const unsigned int end_seg,
-				const unsigned int max_foffs,
-				zft_position *pos, cmpr_info *c_info,
-				const zft_volinfo *volume, __u8 *buf);
-static int slow_seek_forward(unsigned int dest, cmpr_info *c_info,
-			     zft_position *pos, const zft_volinfo *volume,
-			     __u8 *buf);
-static int compute_seg_pos(unsigned int dest, zft_position *pos,
-			   const zft_volinfo *volume);
-
-#define ZFT_SLOW_SEEK_THRESHOLD  10 /* segments */
-#define ZFT_FAST_SEEK_MAX_TRIALS 10 /* times */
-#define ZFT_FAST_SEEK_BACKUP     10 /* segments */
-
-static int zftc_seek(unsigned int new_block_pos,
-		     zft_position *pos, const zft_volinfo *volume, __u8 *buf)
-{
-	unsigned int dest;
-	int limit;
-	int distance;
-	int result = 0;
-	int seg_dist;
-	int new_seg;
-	int old_seg = 0;
-	int fast_seek_trials = 0;
-	TRACE_FUN(ft_t_flow);
-
-	if (new_block_pos == 0) {
-		pos->seg_pos      = volume->start_seg;
-		pos->seg_byte_pos = 0;
-		pos->volume_pos   = 0;
-		zftc_reset();
-		TRACE_EXIT 0;
-	}
-	dest = new_block_pos * (volume->blk_sz >> 10);
-	distance = dest - (pos->volume_pos >> 10);
-	while (distance != 0) {
-		seg_dist = compute_seg_pos(dest, pos, volume);
-		TRACE(ft_t_noise, "\n"
-		      KERN_INFO "seg_dist: %d\n"
-		      KERN_INFO "distance: %d\n"
-		      KERN_INFO "dest    : %d\n"
-		      KERN_INFO "vpos    : %d\n"
-		      KERN_INFO "seg_pos : %d\n"
-		      KERN_INFO "trials  : %d",
-		      seg_dist, distance, dest,
-		      (unsigned int)(pos->volume_pos>>10), pos->seg_pos,
-		      fast_seek_trials);
-		if (distance > 0) {
-			if (seg_dist < 0) {
-				TRACE(ft_t_bug, "BUG: distance %d > 0, "
-				      "segment difference %d < 0",
-				      distance, seg_dist);
-				result = -EIO;
-				break;
-			}
-			new_seg = pos->seg_pos + seg_dist;
-			if (new_seg > volume->end_seg) {
-				new_seg = volume->end_seg;
-			}
-			if (old_seg == new_seg || /* loop */
-			    seg_dist <= ZFT_SLOW_SEEK_THRESHOLD ||
-			    fast_seek_trials >= ZFT_FAST_SEEK_MAX_TRIALS) {
-				TRACE(ft_t_noise, "starting slow seek:\n"
-				   KERN_INFO "fast seek failed too often: %s\n"
-				   KERN_INFO "near target position      : %s\n"
-				   KERN_INFO "looping between two segs  : %s",
-				      (fast_seek_trials >= 
-				       ZFT_FAST_SEEK_MAX_TRIALS)
-				      ? "yes" : "no",
-				      (seg_dist <= ZFT_SLOW_SEEK_THRESHOLD) 
-				      ? "yes" : "no",
-				      (old_seg == new_seg)
-				      ? "yes" : "no");
-				result = slow_seek_forward(dest, &cseg, 
-							   pos, volume, buf);
-				break;
-			}
-			old_seg = new_seg;
-			limit = volume->end_seg;
-			fast_seek_trials ++;
-			for (;;) {
-				result = search_valid_segment(new_seg, limit,
-							      volume->size,
-							      pos, &cseg,
-							      volume, buf);
-				if (result == 0 || result == -EINTR) {
-					break;
-				}
-				if (new_seg == volume->start_seg) {
-					result = -EIO; /* set errror 
-							* condition
-							*/
-					break;
-				}
-				limit    = new_seg;
-				new_seg -= ZFT_FAST_SEEK_BACKUP;
-				if (new_seg < volume->start_seg) {
-					new_seg = volume->start_seg;
-				}
-			}
-			if (result < 0) {
-				TRACE(ft_t_warn,
-				      "Couldn't find a readable segment");
-				break;
-			}
-		} else /* if (distance < 0) */ {
-			if (seg_dist > 0) {
-				TRACE(ft_t_bug, "BUG: distance %d < 0, "
-				      "segment difference %d >0",
-				      distance, seg_dist);
-				result = -EIO;
-				break;
-			}
-			new_seg = pos->seg_pos + seg_dist;
-			if (fast_seek_trials > 0 && seg_dist == 0) {
-				/* this avoids sticking to the same
-				 * segment all the time. On the other hand:
-				 * if we got here for the first time, and the
-				 * deblock_buffer still contains a valid
-				 * segment, then there is no need to skip to 
-				 * the previous segment if the desired position
-				 * is inside this segment.
-				 */
-				new_seg --;
-			}
-			if (new_seg < volume->start_seg) {
-				new_seg = volume->start_seg;
-			}
-			limit   = pos->seg_pos;
-			fast_seek_trials ++;
-			for (;;) {
-				result = search_valid_segment(new_seg, limit,
-							      pos->volume_pos,
-							      pos, &cseg,
-							      volume, buf);
-				if (result == 0 || result == -EINTR) {
-					break;
-				}
-				if (new_seg == volume->start_seg) {
-					result = -EIO; /* set errror 
-							* condition
-							*/
-					break;
-				}
-				limit    = new_seg;
-				new_seg -= ZFT_FAST_SEEK_BACKUP;
-				if (new_seg < volume->start_seg) {
-					new_seg = volume->start_seg;
-				}
-			}
-			if (result < 0) {
-				TRACE(ft_t_warn,
-				      "Couldn't find a readable segment");
-				break;
-			}
-		}
-		distance = dest - (pos->volume_pos >> 10);
-	}
-	TRACE_EXIT result;
-}
-
-
-/*  advance inside the given segment at most to_do bytes.
- *  of kilobytes moved
- */
-
-static int seek_in_segment(const unsigned int to_do,
-			   cmpr_info  *c_info,
-			   const char *src_buf, 
-			   const int seg_sz, 
-			   const int seg_pos,
-			   const zft_volinfo *volume)
-{
-	int result = 0;
-	int blk_sz = volume->blk_sz >> 10;
-	int remaining = to_do;
-	TRACE_FUN(ft_t_flow);
-
-	if (c_info->offset == 0) {
-		/* new segment just read
-		 */
-		TRACE_CATCH(get_cseg(c_info, src_buf, seg_sz, volume),);
-		c_info->cmpr_pos += c_info->count;
-		DUMP_CMPR_INFO(ft_t_noise, "", c_info);
-	}
-	/* loop and uncompress until user buffer full or
-	 * deblock-buffer empty 
-	 */
-	TRACE(ft_t_noise, "compressed_sz: %d, compos : %d",
-	      c_info->cmpr_sz, c_info->cmpr_pos);
-	while (c_info->spans == 0 && remaining > 0) {
-		if (c_info->cmpr_pos  != 0) { /* cmpr buf is not empty */
-			result       += blk_sz;
-			remaining    -= blk_sz;
-			c_info->cmpr_pos = 0;
-		}
-		if (remaining > 0) {
-			get_next_cluster(c_info, src_buf, seg_sz, 
-					 volume->end_seg == seg_pos);
-			if (c_info->count != 0) {
-				c_info->cmpr_pos = c_info->count;
-				c_info->offset  += c_info->count;
-			} else {
-				break;
-			}
-		}
-		/*  Allow escape from this loop on signal!
-		 */
-		FT_SIGNAL_EXIT(_DONT_BLOCK);
-		DUMP_CMPR_INFO(ft_t_noise, "", c_info);
-		TRACE(ft_t_noise, "to_do: %d", remaining);
-	}
-	if (seg_sz - c_info->offset <= 18) {
-		c_info->offset = seg_sz;
-	}
-	TRACE(ft_t_noise, "\n"
-	      KERN_INFO "segment size   : %d\n"
-	      KERN_INFO "buf_pos_read   : %d\n"
-	      KERN_INFO "remaining      : %d",
-	      seg_sz, c_info->offset,
-	      seg_sz - c_info->offset);
-	TRACE_EXIT result;
-}                
-
-static int slow_seek_forward_until_error(const unsigned int distance,
-					 cmpr_info *c_info,
-					 zft_position *pos, 
-					 const zft_volinfo *volume,
-					 __u8 *buf)
-{
-	unsigned int remaining = distance;
-	int seg_sz;
-	int seg_pos;
-	int result;
-	TRACE_FUN(ft_t_flow);
-	
-	seg_pos = pos->seg_pos;
-	do {
-		TRACE_CATCH(seg_sz = zft_fetch_segment(seg_pos, buf, 
-						       FT_RD_AHEAD),);
-		/* now we have the contents of the actual segment in
-		 * the deblock buffer
-		 */
-		TRACE_CATCH(result = seek_in_segment(remaining, c_info, buf,
-						     seg_sz, seg_pos,volume),);
-		remaining        -= result;
-		pos->volume_pos  += result<<10;
-		pos->seg_pos      = seg_pos;
-		pos->seg_byte_pos = c_info->offset;
-		seg_pos ++;
-		if (seg_pos <= volume->end_seg && c_info->offset == seg_sz) {
-			pos->seg_pos ++;
-			pos->seg_byte_pos = 0;
-			c_info->offset = 0;
-		}
-		/*  Allow escape from this loop on signal!
-		 */
-		FT_SIGNAL_EXIT(_DONT_BLOCK);
-		TRACE(ft_t_noise, "\n"
-		      KERN_INFO "remaining:  %d\n"
-		      KERN_INFO "seg_pos:    %d\n"
-		      KERN_INFO "end_seg:    %d\n"
-		      KERN_INFO "result:     %d",
-		      remaining, seg_pos, volume->end_seg, result);  
-	} while (remaining > 0 && seg_pos <= volume->end_seg);
-	TRACE_EXIT 0;
-}
-
-/* return segment id of next segment containing valid data, -EIO otherwise
- */
-static int search_valid_segment(unsigned int segment,
-				const unsigned int end_seg,
-				const unsigned int max_foffs,
-				zft_position *pos,
-				cmpr_info *c_info,
-				const zft_volinfo *volume,
-				__u8 *buf)
-{
-	cmpr_info tmp_info;
-	int seg_sz;
-	TRACE_FUN(ft_t_flow);
-	
-	memset(&tmp_info, 0, sizeof(cmpr_info));
-	while (segment <= end_seg) {
-		FT_SIGNAL_EXIT(_DONT_BLOCK);
-		TRACE(ft_t_noise,
-		      "Searching readable segment between %d and %d",
-		      segment, end_seg);
-		seg_sz = zft_fetch_segment(segment, buf, FT_RD_AHEAD);
-		if ((seg_sz > 0) &&
-		    (get_cseg (&tmp_info, buf, seg_sz, volume) >= 0) &&
-		    (tmp_info.foffs != 0 || segment == volume->start_seg)) {
-			if ((tmp_info.foffs>>10) > max_foffs) {
-				TRACE_ABORT(-EIO, ft_t_noise, "\n"
-					    KERN_INFO "cseg.foff: %d\n"
-					    KERN_INFO "dest     : %d",
-					    (int)(tmp_info.foffs >> 10),
-					    max_foffs);
-			}
-			DUMP_CMPR_INFO(ft_t_noise, "", &tmp_info);
-			*c_info           = tmp_info;
-			pos->seg_pos      = segment;
-			pos->volume_pos   = c_info->foffs;
-			pos->seg_byte_pos = c_info->offset;
-			TRACE(ft_t_noise, "found segment at %d", segment);
-			TRACE_EXIT 0;
-		}
-		segment++;
-	}
-	TRACE_EXIT -EIO;
-}
-
-static int slow_seek_forward(unsigned int dest,
-			     cmpr_info *c_info,
-			     zft_position *pos,
-			     const zft_volinfo *volume,
-			     __u8 *buf)
-{
-	unsigned int distance;
-	int result = 0;
-	TRACE_FUN(ft_t_flow);
-		
-	distance = dest - (pos->volume_pos >> 10);
-	while ((distance > 0) &&
-	       (result = slow_seek_forward_until_error(distance,
-						       c_info,
-						       pos,
-						       volume,
-						       buf)) < 0) {
-		if (result == -EINTR) {
-			break;
-		}
-		TRACE(ft_t_noise, "seg_pos: %d", pos->seg_pos);
-		/* the failing segment is either pos->seg_pos or
-		 * pos->seg_pos + 1. There is no need to further try
-		 * that segment, because ftape_read_segment() already
-		 * has tried very much to read it. So we start with
-		 * following segment, which is pos->seg_pos + 1
-		 */
-		if(search_valid_segment(pos->seg_pos+1, volume->end_seg, dest,
-					pos, c_info,
-					volume, buf) < 0) {
-			TRACE(ft_t_noise, "search_valid_segment() failed");
-			result = -EIO;
-			break;
-		}
-		distance = dest - (pos->volume_pos >> 10);
-		result = 0;
-		TRACE(ft_t_noise, "segment: %d", pos->seg_pos);
-		/* found valid segment, retry the seek */
-	}
-	TRACE_EXIT result;
-}
-
-static int compute_seg_pos(const unsigned int dest,
-			   zft_position *pos,
-			   const zft_volinfo *volume)
-{
-	int segment;
-	int distance = dest - (pos->volume_pos >> 10);
-	unsigned int raw_size;
-	unsigned int virt_size;
-	unsigned int factor;
-	TRACE_FUN(ft_t_flow);
-
-	if (distance >= 0) {
-		raw_size  = volume->end_seg - pos->seg_pos + 1;
-		virt_size = ((unsigned int)(volume->size>>10) 
-			     - (unsigned int)(pos->volume_pos>>10)
-			     + FT_SECTORS_PER_SEGMENT - FT_ECC_SECTORS - 1);
-		virt_size /= FT_SECTORS_PER_SEGMENT - FT_ECC_SECTORS;
-		if (virt_size == 0 || raw_size == 0) {
-			TRACE_EXIT 0;
-		}
-		if (raw_size >= (1<<25)) {
-			factor = raw_size/(virt_size>>7);
-		} else {
-			factor = (raw_size<<7)/virt_size;
-		}
-		segment = distance/(FT_SECTORS_PER_SEGMENT-FT_ECC_SECTORS);
-		segment = (segment * factor)>>7;
-	} else {
-		raw_size  = pos->seg_pos - volume->start_seg + 1;
-		virt_size = ((unsigned int)(pos->volume_pos>>10)
-			     + FT_SECTORS_PER_SEGMENT - FT_ECC_SECTORS - 1);
-		virt_size /= FT_SECTORS_PER_SEGMENT - FT_ECC_SECTORS;
-		if (virt_size == 0 || raw_size == 0) {
-			TRACE_EXIT 0;
-		}
-		if (raw_size >= (1<<25)) {
-			factor = raw_size/(virt_size>>7);
-		} else {
-			factor = (raw_size<<7)/virt_size;
-		}
-		segment = distance/(FT_SECTORS_PER_SEGMENT-FT_ECC_SECTORS);
-	}
-	TRACE(ft_t_noise, "factor: %d/%d", factor, 1<<7);
-	TRACE_EXIT segment;
-}
-
-static struct zft_cmpr_ops cmpr_ops = {
-	zftc_write,
-	zftc_read,
-	zftc_seek,
-	zftc_lock,
-	zftc_reset,
-	zftc_cleanup
-};
-
-int zft_compressor_init(void)
-{
-	TRACE_FUN(ft_t_flow);
-	
-#ifdef MODULE
-	printk(KERN_INFO "zftape compressor v1.00a 970514 for " FTAPE_VERSION "\n");
-        if (TRACE_LEVEL >= ft_t_info) {
-		printk(
-KERN_INFO "(c) 1997 Claus-Justus Heine (claus@momo.math.rwth-aachen.de)\n"
-KERN_INFO "Compressor for zftape (lzrw3 algorithm)\n");
-        }
-#else /* !MODULE */
-	/* print a short no-nonsense boot message */
-	printk(KERN_INFO "zftape compressor v1.00a 970514\n");
-	printk(KERN_INFO "For use with " FTAPE_VERSION "\n");
-#endif /* MODULE */
-	TRACE(ft_t_info, "zft_compressor_init @ 0x%p", zft_compressor_init);
-	TRACE(ft_t_info, "installing compressor for zftape ...");
-	TRACE_CATCH(zft_cmpr_register(&cmpr_ops),);
-	TRACE_EXIT 0;
-}
-
-#ifdef MODULE
-
-MODULE_AUTHOR(
-	"(c) 1996, 1997 Claus-Justus Heine (claus@momo.math.rwth-aachen.de");
-MODULE_DESCRIPTION(
-"Compression routines for zftape. Uses the lzrw3 algorithm by Ross Williams");
-MODULE_LICENSE("GPL");
-
-/* Called by modules package when installing the driver
- */
-int init_module(void)
-{
-	return zft_compressor_init();
-}
-
-#endif /* MODULE */