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-rw-r--r--drivers/staging/erofs/decompressor.c335
1 files changed, 0 insertions, 335 deletions
diff --git a/drivers/staging/erofs/decompressor.c b/drivers/staging/erofs/decompressor.c
deleted file mode 100644
index 1fb0abb98dff..000000000000
--- a/drivers/staging/erofs/decompressor.c
+++ /dev/null
@@ -1,335 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * linux/drivers/staging/erofs/decompressor.c
- *
- * Copyright (C) 2019 HUAWEI, Inc.
- * http://www.huawei.com/
- * Created by Gao Xiang <gaoxiang25@huawei.com>
- */
-#include "compress.h"
-#include <linux/lz4.h>
-
-#ifndef LZ4_DISTANCE_MAX /* history window size */
-#define LZ4_DISTANCE_MAX 65535 /* set to maximum value by default */
-#endif
-
-#define LZ4_MAX_DISTANCE_PAGES (DIV_ROUND_UP(LZ4_DISTANCE_MAX, PAGE_SIZE) + 1)
-#ifndef LZ4_DECOMPRESS_INPLACE_MARGIN
-#define LZ4_DECOMPRESS_INPLACE_MARGIN(srcsize) (((srcsize) >> 8) + 32)
-#endif
-
-struct z_erofs_decompressor {
- /*
- * if destpages have sparsed pages, fill them with bounce pages.
- * it also check whether destpages indicate continuous physical memory.
- */
- int (*prepare_destpages)(struct z_erofs_decompress_req *rq,
- struct list_head *pagepool);
- int (*decompress)(struct z_erofs_decompress_req *rq, u8 *out);
- char *name;
-};
-
-static int lz4_prepare_destpages(struct z_erofs_decompress_req *rq,
- struct list_head *pagepool)
-{
- const unsigned int nr =
- PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
- struct page *availables[LZ4_MAX_DISTANCE_PAGES] = { NULL };
- unsigned long bounced[DIV_ROUND_UP(LZ4_MAX_DISTANCE_PAGES,
- BITS_PER_LONG)] = { 0 };
- void *kaddr = NULL;
- unsigned int i, j, top;
-
- top = 0;
- for (i = j = 0; i < nr; ++i, ++j) {
- struct page *const page = rq->out[i];
- struct page *victim;
-
- if (j >= LZ4_MAX_DISTANCE_PAGES)
- j = 0;
-
- /* 'valid' bounced can only be tested after a complete round */
- if (test_bit(j, bounced)) {
- DBG_BUGON(i < LZ4_MAX_DISTANCE_PAGES);
- DBG_BUGON(top >= LZ4_MAX_DISTANCE_PAGES);
- availables[top++] = rq->out[i - LZ4_MAX_DISTANCE_PAGES];
- }
-
- if (page) {
- __clear_bit(j, bounced);
- if (kaddr) {
- if (kaddr + PAGE_SIZE == page_address(page))
- kaddr += PAGE_SIZE;
- else
- kaddr = NULL;
- } else if (!i) {
- kaddr = page_address(page);
- }
- continue;
- }
- kaddr = NULL;
- __set_bit(j, bounced);
-
- if (top) {
- victim = availables[--top];
- get_page(victim);
- } else {
- if (!list_empty(pagepool)) {
- victim = lru_to_page(pagepool);
- list_del(&victim->lru);
- DBG_BUGON(page_ref_count(victim) != 1);
- } else {
- victim = alloc_pages(GFP_KERNEL, 0);
- if (!victim)
- return -ENOMEM;
- }
- victim->mapping = Z_EROFS_MAPPING_STAGING;
- }
- rq->out[i] = victim;
- }
- return kaddr ? 1 : 0;
-}
-
-static void *generic_copy_inplace_data(struct z_erofs_decompress_req *rq,
- u8 *src, unsigned int pageofs_in)
-{
- /*
- * if in-place decompression is ongoing, those decompressed
- * pages should be copied in order to avoid being overlapped.
- */
- struct page **in = rq->in;
- u8 *const tmp = erofs_get_pcpubuf(0);
- u8 *tmpp = tmp;
- unsigned int inlen = rq->inputsize - pageofs_in;
- unsigned int count = min_t(uint, inlen, PAGE_SIZE - pageofs_in);
-
- while (tmpp < tmp + inlen) {
- if (!src)
- src = kmap_atomic(*in);
- memcpy(tmpp, src + pageofs_in, count);
- kunmap_atomic(src);
- src = NULL;
- tmpp += count;
- pageofs_in = 0;
- count = PAGE_SIZE;
- ++in;
- }
- return tmp;
-}
-
-static int lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
-{
- unsigned int inputmargin, inlen;
- u8 *src;
- bool copied, support_0padding;
- int ret;
-
- if (rq->inputsize > PAGE_SIZE)
- return -ENOTSUPP;
-
- src = kmap_atomic(*rq->in);
- inputmargin = 0;
- support_0padding = false;
-
- /* decompression inplace is only safe when 0padding is enabled */
- if (EROFS_SB(rq->sb)->requirements & EROFS_REQUIREMENT_LZ4_0PADDING) {
- support_0padding = true;
-
- while (!src[inputmargin & ~PAGE_MASK])
- if (!(++inputmargin & ~PAGE_MASK))
- break;
-
- if (inputmargin >= rq->inputsize) {
- kunmap_atomic(src);
- return -EIO;
- }
- }
-
- copied = false;
- inlen = rq->inputsize - inputmargin;
- if (rq->inplace_io) {
- const uint oend = (rq->pageofs_out +
- rq->outputsize) & ~PAGE_MASK;
- const uint nr = PAGE_ALIGN(rq->pageofs_out +
- rq->outputsize) >> PAGE_SHIFT;
-
- if (rq->partial_decoding || !support_0padding ||
- rq->out[nr - 1] != rq->in[0] ||
- rq->inputsize - oend <
- LZ4_DECOMPRESS_INPLACE_MARGIN(inlen)) {
- src = generic_copy_inplace_data(rq, src, inputmargin);
- inputmargin = 0;
- copied = true;
- }
- }
-
- ret = LZ4_decompress_safe_partial(src + inputmargin, out,
- inlen, rq->outputsize,
- rq->outputsize);
- if (ret < 0) {
- errln("%s, failed to decompress, in[%p, %u, %u] out[%p, %u]",
- __func__, src + inputmargin, inlen, inputmargin,
- out, rq->outputsize);
- WARN_ON(1);
- print_hex_dump(KERN_DEBUG, "[ in]: ", DUMP_PREFIX_OFFSET,
- 16, 1, src + inputmargin, inlen, true);
- print_hex_dump(KERN_DEBUG, "[out]: ", DUMP_PREFIX_OFFSET,
- 16, 1, out, rq->outputsize, true);
- ret = -EIO;
- }
-
- if (copied)
- erofs_put_pcpubuf(src);
- else
- kunmap_atomic(src);
- return ret;
-}
-
-static struct z_erofs_decompressor decompressors[] = {
- [Z_EROFS_COMPRESSION_SHIFTED] = {
- .name = "shifted"
- },
- [Z_EROFS_COMPRESSION_LZ4] = {
- .prepare_destpages = lz4_prepare_destpages,
- .decompress = lz4_decompress,
- .name = "lz4"
- },
-};
-
-static void copy_from_pcpubuf(struct page **out, const char *dst,
- unsigned short pageofs_out,
- unsigned int outputsize)
-{
- const char *end = dst + outputsize;
- const unsigned int righthalf = PAGE_SIZE - pageofs_out;
- const char *cur = dst - pageofs_out;
-
- while (cur < end) {
- struct page *const page = *out++;
-
- if (page) {
- char *buf = kmap_atomic(page);
-
- if (cur >= dst) {
- memcpy(buf, cur, min_t(uint, PAGE_SIZE,
- end - cur));
- } else {
- memcpy(buf + pageofs_out, cur + pageofs_out,
- min_t(uint, righthalf, end - cur));
- }
- kunmap_atomic(buf);
- }
- cur += PAGE_SIZE;
- }
-}
-
-static int decompress_generic(struct z_erofs_decompress_req *rq,
- struct list_head *pagepool)
-{
- const unsigned int nrpages_out =
- PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
- const struct z_erofs_decompressor *alg = decompressors + rq->alg;
- unsigned int dst_maptype;
- void *dst;
- int ret;
-
- if (nrpages_out == 1 && !rq->inplace_io) {
- DBG_BUGON(!*rq->out);
- dst = kmap_atomic(*rq->out);
- dst_maptype = 0;
- goto dstmap_out;
- }
-
- /*
- * For the case of small output size (especially much less
- * than PAGE_SIZE), memcpy the decompressed data rather than
- * compressed data is preferred.
- */
- if (rq->outputsize <= PAGE_SIZE * 7 / 8) {
- dst = erofs_get_pcpubuf(0);
- if (IS_ERR(dst))
- return PTR_ERR(dst);
-
- rq->inplace_io = false;
- ret = alg->decompress(rq, dst);
- if (!ret)
- copy_from_pcpubuf(rq->out, dst, rq->pageofs_out,
- rq->outputsize);
-
- erofs_put_pcpubuf(dst);
- return ret;
- }
-
- ret = alg->prepare_destpages(rq, pagepool);
- if (ret < 0) {
- return ret;
- } else if (ret) {
- dst = page_address(*rq->out);
- dst_maptype = 1;
- goto dstmap_out;
- }
-
- dst = erofs_vmap(rq->out, nrpages_out);
- if (!dst)
- return -ENOMEM;
- dst_maptype = 2;
-
-dstmap_out:
- ret = alg->decompress(rq, dst + rq->pageofs_out);
-
- if (!dst_maptype)
- kunmap_atomic(dst);
- else if (dst_maptype == 2)
- erofs_vunmap(dst, nrpages_out);
- return ret;
-}
-
-static int shifted_decompress(const struct z_erofs_decompress_req *rq,
- struct list_head *pagepool)
-{
- const unsigned int nrpages_out =
- PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
- const unsigned int righthalf = PAGE_SIZE - rq->pageofs_out;
- unsigned char *src, *dst;
-
- if (nrpages_out > 2) {
- DBG_BUGON(1);
- return -EIO;
- }
-
- if (rq->out[0] == *rq->in) {
- DBG_BUGON(nrpages_out != 1);
- return 0;
- }
-
- src = kmap_atomic(*rq->in);
- if (!rq->out[0]) {
- dst = NULL;
- } else {
- dst = kmap_atomic(rq->out[0]);
- memcpy(dst + rq->pageofs_out, src, righthalf);
- }
-
- if (rq->out[1] == *rq->in) {
- memmove(src, src + righthalf, rq->pageofs_out);
- } else if (nrpages_out == 2) {
- if (dst)
- kunmap_atomic(dst);
- DBG_BUGON(!rq->out[1]);
- dst = kmap_atomic(rq->out[1]);
- memcpy(dst, src + righthalf, rq->pageofs_out);
- }
- if (dst)
- kunmap_atomic(dst);
- kunmap_atomic(src);
- return 0;
-}
-
-int z_erofs_decompress(struct z_erofs_decompress_req *rq,
- struct list_head *pagepool)
-{
- if (rq->alg == Z_EROFS_COMPRESSION_SHIFTED)
- return shifted_decompress(rq, pagepool);
- return decompress_generic(rq, pagepool);
-}
-
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