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d3c12383c9
This commit changes the provider compress and decompress API to take ABD pointers instead of buffer pointers for both data source and destination. It then updates all providers to match. This doesn't actually change the providers to do chunked compression, just changes the API to allow such an update in the future. Helper macros are added to easily adapt the ABD functions to their buffer-based implementations. Sponsored-by: Klara, Inc. Sponsored-by: Wasabi Technology, Inc. Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
97 lines
2.6 KiB
C
97 lines
2.6 KiB
C
/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License (the "License").
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* You may not use this file except in compliance with the License.
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*
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* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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* or https://opensource.org/licenses/CDDL-1.0.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information: Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*/
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/*
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* Copyright 2009 Sun Microsystems, Inc. All rights reserved.
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* Use is subject to license terms.
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*/
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/*
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* Zero-length encoding. This is a fast and simple algorithm to eliminate
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* runs of zeroes. Each chunk of compressed data begins with a length byte, b.
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* If b < n (where n is the compression parameter) then the next b + 1 bytes
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* are literal values. If b >= n then the next (256 - b + 1) bytes are zero.
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*/
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#include <sys/types.h>
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#include <sys/sysmacros.h>
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#include <sys/zio_compress.h>
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static size_t
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zfs_zle_compress_buf(void *s_start, void *d_start, size_t s_len,
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size_t d_len, int n)
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{
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uchar_t *src = s_start;
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uchar_t *dst = d_start;
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uchar_t *s_end = src + s_len;
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uchar_t *d_end = dst + d_len;
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while (src < s_end && dst < d_end - 1) {
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uchar_t *first = src;
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uchar_t *len = dst++;
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if (src[0] == 0) {
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uchar_t *last = src + (256 - n);
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while (src < MIN(last, s_end) && src[0] == 0)
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src++;
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*len = src - first - 1 + n;
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} else {
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uchar_t *last = src + n;
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if (d_end - dst < n)
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break;
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while (src < MIN(last, s_end) - 1 && (src[0] | src[1]))
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*dst++ = *src++;
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if (src[0])
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*dst++ = *src++;
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*len = src - first - 1;
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}
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}
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return (src == s_end ? dst - (uchar_t *)d_start : s_len);
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}
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static int
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zfs_zle_decompress_buf(void *s_start, void *d_start, size_t s_len,
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size_t d_len, int n)
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{
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uchar_t *src = s_start;
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uchar_t *dst = d_start;
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uchar_t *s_end = src + s_len;
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uchar_t *d_end = dst + d_len;
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while (src < s_end && dst < d_end) {
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int len = 1 + *src++;
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if (len <= n) {
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if (src + len > s_end || dst + len > d_end)
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return (-1);
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while (len-- != 0)
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*dst++ = *src++;
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} else {
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len -= n;
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if (dst + len > d_end)
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return (-1);
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while (len-- != 0)
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*dst++ = 0;
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}
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}
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return (dst == d_end ? 0 : -1);
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}
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ZFS_COMPRESS_WRAP_DECL(zfs_zle_compress)
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ZFS_DECOMPRESS_WRAP_DECL(zfs_zle_decompress)
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