147e4937aSGao Xiang // SPDX-License-Identifier: GPL-2.0-only 247e4937aSGao Xiang /* 347e4937aSGao Xiang * Copyright (C) 2019 HUAWEI, Inc. 447e4937aSGao Xiang * http://www.huawei.com/ 547e4937aSGao Xiang * Created by Gao Xiang <gaoxiang25@huawei.com> 647e4937aSGao Xiang */ 747e4937aSGao Xiang #include "compress.h" 847e4937aSGao Xiang #include <linux/module.h> 947e4937aSGao Xiang #include <linux/lz4.h> 1047e4937aSGao Xiang 1147e4937aSGao Xiang #ifndef LZ4_DISTANCE_MAX /* history window size */ 1247e4937aSGao Xiang #define LZ4_DISTANCE_MAX 65535 /* set to maximum value by default */ 1347e4937aSGao Xiang #endif 1447e4937aSGao Xiang 1547e4937aSGao Xiang #define LZ4_MAX_DISTANCE_PAGES (DIV_ROUND_UP(LZ4_DISTANCE_MAX, PAGE_SIZE) + 1) 1647e4937aSGao Xiang #ifndef LZ4_DECOMPRESS_INPLACE_MARGIN 1747e4937aSGao Xiang #define LZ4_DECOMPRESS_INPLACE_MARGIN(srcsize) (((srcsize) >> 8) + 32) 1847e4937aSGao Xiang #endif 1947e4937aSGao Xiang 2047e4937aSGao Xiang struct z_erofs_decompressor { 2147e4937aSGao Xiang /* 2247e4937aSGao Xiang * if destpages have sparsed pages, fill them with bounce pages. 2347e4937aSGao Xiang * it also check whether destpages indicate continuous physical memory. 2447e4937aSGao Xiang */ 2547e4937aSGao Xiang int (*prepare_destpages)(struct z_erofs_decompress_req *rq, 2647e4937aSGao Xiang struct list_head *pagepool); 2747e4937aSGao Xiang int (*decompress)(struct z_erofs_decompress_req *rq, u8 *out); 2847e4937aSGao Xiang char *name; 2947e4937aSGao Xiang }; 3047e4937aSGao Xiang 3147e4937aSGao Xiang static bool use_vmap; 3247e4937aSGao Xiang module_param(use_vmap, bool, 0444); 3347e4937aSGao Xiang MODULE_PARM_DESC(use_vmap, "Use vmap() instead of vm_map_ram() (default 0)"); 3447e4937aSGao Xiang 3599634bf3SGao Xiang static int z_erofs_lz4_prepare_destpages(struct z_erofs_decompress_req *rq, 3647e4937aSGao Xiang struct list_head *pagepool) 3747e4937aSGao Xiang { 3847e4937aSGao Xiang const unsigned int nr = 3947e4937aSGao Xiang PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT; 4047e4937aSGao Xiang struct page *availables[LZ4_MAX_DISTANCE_PAGES] = { NULL }; 4147e4937aSGao Xiang unsigned long bounced[DIV_ROUND_UP(LZ4_MAX_DISTANCE_PAGES, 4247e4937aSGao Xiang BITS_PER_LONG)] = { 0 }; 4347e4937aSGao Xiang void *kaddr = NULL; 4447e4937aSGao Xiang unsigned int i, j, top; 4547e4937aSGao Xiang 4647e4937aSGao Xiang top = 0; 4747e4937aSGao Xiang for (i = j = 0; i < nr; ++i, ++j) { 4847e4937aSGao Xiang struct page *const page = rq->out[i]; 4947e4937aSGao Xiang struct page *victim; 5047e4937aSGao Xiang 5147e4937aSGao Xiang if (j >= LZ4_MAX_DISTANCE_PAGES) 5247e4937aSGao Xiang j = 0; 5347e4937aSGao Xiang 5447e4937aSGao Xiang /* 'valid' bounced can only be tested after a complete round */ 5547e4937aSGao Xiang if (test_bit(j, bounced)) { 5647e4937aSGao Xiang DBG_BUGON(i < LZ4_MAX_DISTANCE_PAGES); 5747e4937aSGao Xiang DBG_BUGON(top >= LZ4_MAX_DISTANCE_PAGES); 5847e4937aSGao Xiang availables[top++] = rq->out[i - LZ4_MAX_DISTANCE_PAGES]; 5947e4937aSGao Xiang } 6047e4937aSGao Xiang 6147e4937aSGao Xiang if (page) { 6247e4937aSGao Xiang __clear_bit(j, bounced); 6347e4937aSGao Xiang if (kaddr) { 6447e4937aSGao Xiang if (kaddr + PAGE_SIZE == page_address(page)) 6547e4937aSGao Xiang kaddr += PAGE_SIZE; 6647e4937aSGao Xiang else 6747e4937aSGao Xiang kaddr = NULL; 6847e4937aSGao Xiang } else if (!i) { 6947e4937aSGao Xiang kaddr = page_address(page); 7047e4937aSGao Xiang } 7147e4937aSGao Xiang continue; 7247e4937aSGao Xiang } 7347e4937aSGao Xiang kaddr = NULL; 7447e4937aSGao Xiang __set_bit(j, bounced); 7547e4937aSGao Xiang 7647e4937aSGao Xiang if (top) { 7747e4937aSGao Xiang victim = availables[--top]; 7847e4937aSGao Xiang get_page(victim); 7947e4937aSGao Xiang } else { 8047e4937aSGao Xiang victim = erofs_allocpage(pagepool, GFP_KERNEL, false); 818d8a09b0SGao Xiang if (!victim) 8247e4937aSGao Xiang return -ENOMEM; 8347e4937aSGao Xiang victim->mapping = Z_EROFS_MAPPING_STAGING; 8447e4937aSGao Xiang } 8547e4937aSGao Xiang rq->out[i] = victim; 8647e4937aSGao Xiang } 8747e4937aSGao Xiang return kaddr ? 1 : 0; 8847e4937aSGao Xiang } 8947e4937aSGao Xiang 9047e4937aSGao Xiang static void *generic_copy_inplace_data(struct z_erofs_decompress_req *rq, 9147e4937aSGao Xiang u8 *src, unsigned int pageofs_in) 9247e4937aSGao Xiang { 9347e4937aSGao Xiang /* 9447e4937aSGao Xiang * if in-place decompression is ongoing, those decompressed 9547e4937aSGao Xiang * pages should be copied in order to avoid being overlapped. 9647e4937aSGao Xiang */ 9747e4937aSGao Xiang struct page **in = rq->in; 9847e4937aSGao Xiang u8 *const tmp = erofs_get_pcpubuf(0); 9947e4937aSGao Xiang u8 *tmpp = tmp; 10047e4937aSGao Xiang unsigned int inlen = rq->inputsize - pageofs_in; 10147e4937aSGao Xiang unsigned int count = min_t(uint, inlen, PAGE_SIZE - pageofs_in); 10247e4937aSGao Xiang 10347e4937aSGao Xiang while (tmpp < tmp + inlen) { 10447e4937aSGao Xiang if (!src) 10547e4937aSGao Xiang src = kmap_atomic(*in); 10647e4937aSGao Xiang memcpy(tmpp, src + pageofs_in, count); 10747e4937aSGao Xiang kunmap_atomic(src); 10847e4937aSGao Xiang src = NULL; 10947e4937aSGao Xiang tmpp += count; 11047e4937aSGao Xiang pageofs_in = 0; 11147e4937aSGao Xiang count = PAGE_SIZE; 11247e4937aSGao Xiang ++in; 11347e4937aSGao Xiang } 11447e4937aSGao Xiang return tmp; 11547e4937aSGao Xiang } 11647e4937aSGao Xiang 11799634bf3SGao Xiang static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out) 11847e4937aSGao Xiang { 11947e4937aSGao Xiang unsigned int inputmargin, inlen; 12047e4937aSGao Xiang u8 *src; 12147e4937aSGao Xiang bool copied, support_0padding; 12247e4937aSGao Xiang int ret; 12347e4937aSGao Xiang 12447e4937aSGao Xiang if (rq->inputsize > PAGE_SIZE) 12547e4937aSGao Xiang return -EOPNOTSUPP; 12647e4937aSGao Xiang 12747e4937aSGao Xiang src = kmap_atomic(*rq->in); 12847e4937aSGao Xiang inputmargin = 0; 12947e4937aSGao Xiang support_0padding = false; 13047e4937aSGao Xiang 13147e4937aSGao Xiang /* decompression inplace is only safe when 0padding is enabled */ 132426a9308SGao Xiang if (EROFS_SB(rq->sb)->feature_incompat & 133426a9308SGao Xiang EROFS_FEATURE_INCOMPAT_LZ4_0PADDING) { 13447e4937aSGao Xiang support_0padding = true; 13547e4937aSGao Xiang 13647e4937aSGao Xiang while (!src[inputmargin & ~PAGE_MASK]) 13747e4937aSGao Xiang if (!(++inputmargin & ~PAGE_MASK)) 13847e4937aSGao Xiang break; 13947e4937aSGao Xiang 14047e4937aSGao Xiang if (inputmargin >= rq->inputsize) { 14147e4937aSGao Xiang kunmap_atomic(src); 14247e4937aSGao Xiang return -EIO; 14347e4937aSGao Xiang } 14447e4937aSGao Xiang } 14547e4937aSGao Xiang 14647e4937aSGao Xiang copied = false; 14747e4937aSGao Xiang inlen = rq->inputsize - inputmargin; 14847e4937aSGao Xiang if (rq->inplace_io) { 14947e4937aSGao Xiang const uint oend = (rq->pageofs_out + 15047e4937aSGao Xiang rq->outputsize) & ~PAGE_MASK; 15147e4937aSGao Xiang const uint nr = PAGE_ALIGN(rq->pageofs_out + 15247e4937aSGao Xiang rq->outputsize) >> PAGE_SHIFT; 15347e4937aSGao Xiang 15447e4937aSGao Xiang if (rq->partial_decoding || !support_0padding || 15547e4937aSGao Xiang rq->out[nr - 1] != rq->in[0] || 15647e4937aSGao Xiang rq->inputsize - oend < 15747e4937aSGao Xiang LZ4_DECOMPRESS_INPLACE_MARGIN(inlen)) { 15847e4937aSGao Xiang src = generic_copy_inplace_data(rq, src, inputmargin); 15947e4937aSGao Xiang inputmargin = 0; 16047e4937aSGao Xiang copied = true; 16147e4937aSGao Xiang } 16247e4937aSGao Xiang } 16347e4937aSGao Xiang 16447e4937aSGao Xiang ret = LZ4_decompress_safe_partial(src + inputmargin, out, 16547e4937aSGao Xiang inlen, rq->outputsize, 16647e4937aSGao Xiang rq->outputsize); 16747e4937aSGao Xiang if (ret < 0) { 16847e4937aSGao Xiang errln("%s, failed to decompress, in[%p, %u, %u] out[%p, %u]", 16947e4937aSGao Xiang __func__, src + inputmargin, inlen, inputmargin, 17047e4937aSGao Xiang out, rq->outputsize); 17147e4937aSGao Xiang WARN_ON(1); 17247e4937aSGao Xiang print_hex_dump(KERN_DEBUG, "[ in]: ", DUMP_PREFIX_OFFSET, 17347e4937aSGao Xiang 16, 1, src + inputmargin, inlen, true); 17447e4937aSGao Xiang print_hex_dump(KERN_DEBUG, "[out]: ", DUMP_PREFIX_OFFSET, 17547e4937aSGao Xiang 16, 1, out, rq->outputsize, true); 17647e4937aSGao Xiang ret = -EIO; 17747e4937aSGao Xiang } 17847e4937aSGao Xiang 17947e4937aSGao Xiang if (copied) 18047e4937aSGao Xiang erofs_put_pcpubuf(src); 18147e4937aSGao Xiang else 18247e4937aSGao Xiang kunmap_atomic(src); 18347e4937aSGao Xiang return ret; 18447e4937aSGao Xiang } 18547e4937aSGao Xiang 18647e4937aSGao Xiang static struct z_erofs_decompressor decompressors[] = { 18747e4937aSGao Xiang [Z_EROFS_COMPRESSION_SHIFTED] = { 18847e4937aSGao Xiang .name = "shifted" 18947e4937aSGao Xiang }, 19047e4937aSGao Xiang [Z_EROFS_COMPRESSION_LZ4] = { 19199634bf3SGao Xiang .prepare_destpages = z_erofs_lz4_prepare_destpages, 19299634bf3SGao Xiang .decompress = z_erofs_lz4_decompress, 19347e4937aSGao Xiang .name = "lz4" 19447e4937aSGao Xiang }, 19547e4937aSGao Xiang }; 19647e4937aSGao Xiang 19747e4937aSGao Xiang static void copy_from_pcpubuf(struct page **out, const char *dst, 19847e4937aSGao Xiang unsigned short pageofs_out, 19947e4937aSGao Xiang unsigned int outputsize) 20047e4937aSGao Xiang { 20147e4937aSGao Xiang const char *end = dst + outputsize; 20247e4937aSGao Xiang const unsigned int righthalf = PAGE_SIZE - pageofs_out; 20347e4937aSGao Xiang const char *cur = dst - pageofs_out; 20447e4937aSGao Xiang 20547e4937aSGao Xiang while (cur < end) { 20647e4937aSGao Xiang struct page *const page = *out++; 20747e4937aSGao Xiang 20847e4937aSGao Xiang if (page) { 20947e4937aSGao Xiang char *buf = kmap_atomic(page); 21047e4937aSGao Xiang 21147e4937aSGao Xiang if (cur >= dst) { 21247e4937aSGao Xiang memcpy(buf, cur, min_t(uint, PAGE_SIZE, 21347e4937aSGao Xiang end - cur)); 21447e4937aSGao Xiang } else { 21547e4937aSGao Xiang memcpy(buf + pageofs_out, cur + pageofs_out, 21647e4937aSGao Xiang min_t(uint, righthalf, end - cur)); 21747e4937aSGao Xiang } 21847e4937aSGao Xiang kunmap_atomic(buf); 21947e4937aSGao Xiang } 22047e4937aSGao Xiang cur += PAGE_SIZE; 22147e4937aSGao Xiang } 22247e4937aSGao Xiang } 22347e4937aSGao Xiang 22447e4937aSGao Xiang static void *erofs_vmap(struct page **pages, unsigned int count) 22547e4937aSGao Xiang { 22647e4937aSGao Xiang int i = 0; 22747e4937aSGao Xiang 22847e4937aSGao Xiang if (use_vmap) 22947e4937aSGao Xiang return vmap(pages, count, VM_MAP, PAGE_KERNEL); 23047e4937aSGao Xiang 23147e4937aSGao Xiang while (1) { 23247e4937aSGao Xiang void *addr = vm_map_ram(pages, count, -1, PAGE_KERNEL); 23347e4937aSGao Xiang 23447e4937aSGao Xiang /* retry two more times (totally 3 times) */ 23547e4937aSGao Xiang if (addr || ++i >= 3) 23647e4937aSGao Xiang return addr; 23747e4937aSGao Xiang vm_unmap_aliases(); 23847e4937aSGao Xiang } 23947e4937aSGao Xiang return NULL; 24047e4937aSGao Xiang } 24147e4937aSGao Xiang 24247e4937aSGao Xiang static void erofs_vunmap(const void *mem, unsigned int count) 24347e4937aSGao Xiang { 24447e4937aSGao Xiang if (!use_vmap) 24547e4937aSGao Xiang vm_unmap_ram(mem, count); 24647e4937aSGao Xiang else 24747e4937aSGao Xiang vunmap(mem); 24847e4937aSGao Xiang } 24947e4937aSGao Xiang 25099634bf3SGao Xiang static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq, 25147e4937aSGao Xiang struct list_head *pagepool) 25247e4937aSGao Xiang { 25347e4937aSGao Xiang const unsigned int nrpages_out = 25447e4937aSGao Xiang PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT; 25547e4937aSGao Xiang const struct z_erofs_decompressor *alg = decompressors + rq->alg; 25647e4937aSGao Xiang unsigned int dst_maptype; 25747e4937aSGao Xiang void *dst; 25847e4937aSGao Xiang int ret; 25947e4937aSGao Xiang 26047e4937aSGao Xiang if (nrpages_out == 1 && !rq->inplace_io) { 26147e4937aSGao Xiang DBG_BUGON(!*rq->out); 26247e4937aSGao Xiang dst = kmap_atomic(*rq->out); 26347e4937aSGao Xiang dst_maptype = 0; 26447e4937aSGao Xiang goto dstmap_out; 26547e4937aSGao Xiang } 26647e4937aSGao Xiang 26747e4937aSGao Xiang /* 26847e4937aSGao Xiang * For the case of small output size (especially much less 26947e4937aSGao Xiang * than PAGE_SIZE), memcpy the decompressed data rather than 27047e4937aSGao Xiang * compressed data is preferred. 27147e4937aSGao Xiang */ 27247e4937aSGao Xiang if (rq->outputsize <= PAGE_SIZE * 7 / 8) { 27347e4937aSGao Xiang dst = erofs_get_pcpubuf(0); 27447e4937aSGao Xiang if (IS_ERR(dst)) 27547e4937aSGao Xiang return PTR_ERR(dst); 27647e4937aSGao Xiang 27747e4937aSGao Xiang rq->inplace_io = false; 27847e4937aSGao Xiang ret = alg->decompress(rq, dst); 27947e4937aSGao Xiang if (!ret) 28047e4937aSGao Xiang copy_from_pcpubuf(rq->out, dst, rq->pageofs_out, 28147e4937aSGao Xiang rq->outputsize); 28247e4937aSGao Xiang 28347e4937aSGao Xiang erofs_put_pcpubuf(dst); 28447e4937aSGao Xiang return ret; 28547e4937aSGao Xiang } 28647e4937aSGao Xiang 28747e4937aSGao Xiang ret = alg->prepare_destpages(rq, pagepool); 28847e4937aSGao Xiang if (ret < 0) { 28947e4937aSGao Xiang return ret; 29047e4937aSGao Xiang } else if (ret) { 29147e4937aSGao Xiang dst = page_address(*rq->out); 29247e4937aSGao Xiang dst_maptype = 1; 29347e4937aSGao Xiang goto dstmap_out; 29447e4937aSGao Xiang } 29547e4937aSGao Xiang 29647e4937aSGao Xiang dst = erofs_vmap(rq->out, nrpages_out); 29747e4937aSGao Xiang if (!dst) 29847e4937aSGao Xiang return -ENOMEM; 29947e4937aSGao Xiang dst_maptype = 2; 30047e4937aSGao Xiang 30147e4937aSGao Xiang dstmap_out: 30247e4937aSGao Xiang ret = alg->decompress(rq, dst + rq->pageofs_out); 30347e4937aSGao Xiang 30447e4937aSGao Xiang if (!dst_maptype) 30547e4937aSGao Xiang kunmap_atomic(dst); 30647e4937aSGao Xiang else if (dst_maptype == 2) 30747e4937aSGao Xiang erofs_vunmap(dst, nrpages_out); 30847e4937aSGao Xiang return ret; 30947e4937aSGao Xiang } 31047e4937aSGao Xiang 31199634bf3SGao Xiang static int z_erofs_shifted_transform(const struct z_erofs_decompress_req *rq, 31247e4937aSGao Xiang struct list_head *pagepool) 31347e4937aSGao Xiang { 31447e4937aSGao Xiang const unsigned int nrpages_out = 31547e4937aSGao Xiang PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT; 31647e4937aSGao Xiang const unsigned int righthalf = PAGE_SIZE - rq->pageofs_out; 31747e4937aSGao Xiang unsigned char *src, *dst; 31847e4937aSGao Xiang 31947e4937aSGao Xiang if (nrpages_out > 2) { 32047e4937aSGao Xiang DBG_BUGON(1); 32147e4937aSGao Xiang return -EIO; 32247e4937aSGao Xiang } 32347e4937aSGao Xiang 32447e4937aSGao Xiang if (rq->out[0] == *rq->in) { 32547e4937aSGao Xiang DBG_BUGON(nrpages_out != 1); 32647e4937aSGao Xiang return 0; 32747e4937aSGao Xiang } 32847e4937aSGao Xiang 32947e4937aSGao Xiang src = kmap_atomic(*rq->in); 33047e4937aSGao Xiang if (!rq->out[0]) { 33147e4937aSGao Xiang dst = NULL; 33247e4937aSGao Xiang } else { 33347e4937aSGao Xiang dst = kmap_atomic(rq->out[0]); 33447e4937aSGao Xiang memcpy(dst + rq->pageofs_out, src, righthalf); 33547e4937aSGao Xiang } 33647e4937aSGao Xiang 33747e4937aSGao Xiang if (rq->out[1] == *rq->in) { 33847e4937aSGao Xiang memmove(src, src + righthalf, rq->pageofs_out); 33947e4937aSGao Xiang } else if (nrpages_out == 2) { 34047e4937aSGao Xiang if (dst) 34147e4937aSGao Xiang kunmap_atomic(dst); 34247e4937aSGao Xiang DBG_BUGON(!rq->out[1]); 34347e4937aSGao Xiang dst = kmap_atomic(rq->out[1]); 34447e4937aSGao Xiang memcpy(dst, src + righthalf, rq->pageofs_out); 34547e4937aSGao Xiang } 34647e4937aSGao Xiang if (dst) 34747e4937aSGao Xiang kunmap_atomic(dst); 34847e4937aSGao Xiang kunmap_atomic(src); 34947e4937aSGao Xiang return 0; 35047e4937aSGao Xiang } 35147e4937aSGao Xiang 35247e4937aSGao Xiang int z_erofs_decompress(struct z_erofs_decompress_req *rq, 35347e4937aSGao Xiang struct list_head *pagepool) 35447e4937aSGao Xiang { 35547e4937aSGao Xiang if (rq->alg == Z_EROFS_COMPRESSION_SHIFTED) 35699634bf3SGao Xiang return z_erofs_shifted_transform(rq, pagepool); 35799634bf3SGao Xiang return z_erofs_decompress_generic(rq, pagepool); 35847e4937aSGao Xiang } 35947e4937aSGao Xiang 360