|
| 1 | +// SPDX-License-Identifier: GPL-2.0-or-later |
| 2 | +#include <linux/module.h> |
| 3 | +#include <linux/zlib.h> |
| 4 | +#include "compress.h" |
| 5 | + |
| 6 | +struct z_erofs_deflate { |
| 7 | + struct z_erofs_deflate *next; |
| 8 | + struct z_stream_s z; |
| 9 | + u8 bounce[PAGE_SIZE]; |
| 10 | +}; |
| 11 | + |
| 12 | +static DEFINE_SPINLOCK(z_erofs_deflate_lock); |
| 13 | +static unsigned int z_erofs_deflate_nstrms, z_erofs_deflate_avail_strms; |
| 14 | +static struct z_erofs_deflate *z_erofs_deflate_head; |
| 15 | +static DECLARE_WAIT_QUEUE_HEAD(z_erofs_deflate_wq); |
| 16 | + |
| 17 | +module_param_named(deflate_streams, z_erofs_deflate_nstrms, uint, 0444); |
| 18 | + |
| 19 | +void z_erofs_deflate_exit(void) |
| 20 | +{ |
| 21 | + /* there should be no running fs instance */ |
| 22 | + while (z_erofs_deflate_avail_strms) { |
| 23 | + struct z_erofs_deflate *strm; |
| 24 | + |
| 25 | + spin_lock(&z_erofs_deflate_lock); |
| 26 | + strm = z_erofs_deflate_head; |
| 27 | + if (!strm) { |
| 28 | + spin_unlock(&z_erofs_deflate_lock); |
| 29 | + continue; |
| 30 | + } |
| 31 | + z_erofs_deflate_head = NULL; |
| 32 | + spin_unlock(&z_erofs_deflate_lock); |
| 33 | + |
| 34 | + while (strm) { |
| 35 | + struct z_erofs_deflate *n = strm->next; |
| 36 | + |
| 37 | + vfree(strm->z.workspace); |
| 38 | + kfree(strm); |
| 39 | + --z_erofs_deflate_avail_strms; |
| 40 | + strm = n; |
| 41 | + } |
| 42 | + } |
| 43 | +} |
| 44 | + |
| 45 | +int __init z_erofs_deflate_init(void) |
| 46 | +{ |
| 47 | + /* by default, use # of possible CPUs instead */ |
| 48 | + if (!z_erofs_deflate_nstrms) |
| 49 | + z_erofs_deflate_nstrms = num_possible_cpus(); |
| 50 | + |
| 51 | + for (; z_erofs_deflate_avail_strms < z_erofs_deflate_nstrms; |
| 52 | + ++z_erofs_deflate_avail_strms) { |
| 53 | + struct z_erofs_deflate *strm; |
| 54 | + |
| 55 | + strm = kzalloc(sizeof(*strm), GFP_KERNEL); |
| 56 | + if (!strm) |
| 57 | + goto out_failed; |
| 58 | + |
| 59 | + /* XXX: in-kernel zlib cannot shrink windowbits currently */ |
| 60 | + strm->z.workspace = vmalloc(zlib_inflate_workspacesize()); |
| 61 | + if (!strm->z.workspace) { |
| 62 | + kfree(strm); |
| 63 | + goto out_failed; |
| 64 | + } |
| 65 | + |
| 66 | + spin_lock(&z_erofs_deflate_lock); |
| 67 | + strm->next = z_erofs_deflate_head; |
| 68 | + z_erofs_deflate_head = strm; |
| 69 | + spin_unlock(&z_erofs_deflate_lock); |
| 70 | + } |
| 71 | + return 0; |
| 72 | + |
| 73 | +out_failed: |
| 74 | + pr_err("failed to allocate zlib workspace\n"); |
| 75 | + z_erofs_deflate_exit(); |
| 76 | + return -ENOMEM; |
| 77 | +} |
| 78 | + |
| 79 | +int z_erofs_load_deflate_config(struct super_block *sb, |
| 80 | + struct erofs_super_block *dsb, |
| 81 | + struct z_erofs_deflate_cfgs *dfl, int size) |
| 82 | +{ |
| 83 | + if (!dfl || size < sizeof(struct z_erofs_deflate_cfgs)) { |
| 84 | + erofs_err(sb, "invalid deflate cfgs, size=%u", size); |
| 85 | + return -EINVAL; |
| 86 | + } |
| 87 | + |
| 88 | + if (dfl->windowbits > MAX_WBITS) { |
| 89 | + erofs_err(sb, "unsupported windowbits %u", dfl->windowbits); |
| 90 | + return -EOPNOTSUPP; |
| 91 | + } |
| 92 | + |
| 93 | + erofs_info(sb, "EXPERIMENTAL DEFLATE feature in use. Use at your own risk!"); |
| 94 | + return 0; |
| 95 | +} |
| 96 | + |
| 97 | +int z_erofs_deflate_decompress(struct z_erofs_decompress_req *rq, |
| 98 | + struct page **pagepool) |
| 99 | +{ |
| 100 | + const unsigned int nrpages_out = |
| 101 | + PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT; |
| 102 | + const unsigned int nrpages_in = |
| 103 | + PAGE_ALIGN(rq->inputsize) >> PAGE_SHIFT; |
| 104 | + struct super_block *sb = rq->sb; |
| 105 | + unsigned int insz, outsz, pofs; |
| 106 | + struct z_erofs_deflate *strm; |
| 107 | + u8 *kin, *kout = NULL; |
| 108 | + bool bounced = false; |
| 109 | + int no = -1, ni = 0, j = 0, zerr, err; |
| 110 | + |
| 111 | + /* 1. get the exact DEFLATE compressed size */ |
| 112 | + kin = kmap_local_page(*rq->in); |
| 113 | + err = z_erofs_fixup_insize(rq, kin + rq->pageofs_in, |
| 114 | + min_t(unsigned int, rq->inputsize, |
| 115 | + sb->s_blocksize - rq->pageofs_in)); |
| 116 | + if (err) { |
| 117 | + kunmap_local(kin); |
| 118 | + return err; |
| 119 | + } |
| 120 | + |
| 121 | + /* 2. get an available DEFLATE context */ |
| 122 | +again: |
| 123 | + spin_lock(&z_erofs_deflate_lock); |
| 124 | + strm = z_erofs_deflate_head; |
| 125 | + if (!strm) { |
| 126 | + spin_unlock(&z_erofs_deflate_lock); |
| 127 | + wait_event(z_erofs_deflate_wq, READ_ONCE(z_erofs_deflate_head)); |
| 128 | + goto again; |
| 129 | + } |
| 130 | + z_erofs_deflate_head = strm->next; |
| 131 | + spin_unlock(&z_erofs_deflate_lock); |
| 132 | + |
| 133 | + /* 3. multi-call decompress */ |
| 134 | + insz = rq->inputsize; |
| 135 | + outsz = rq->outputsize; |
| 136 | + zerr = zlib_inflateInit2(&strm->z, -MAX_WBITS); |
| 137 | + if (zerr != Z_OK) { |
| 138 | + err = -EIO; |
| 139 | + goto failed_zinit; |
| 140 | + } |
| 141 | + |
| 142 | + pofs = rq->pageofs_out; |
| 143 | + strm->z.avail_in = min_t(u32, insz, PAGE_SIZE - rq->pageofs_in); |
| 144 | + insz -= strm->z.avail_in; |
| 145 | + strm->z.next_in = kin + rq->pageofs_in; |
| 146 | + strm->z.avail_out = 0; |
| 147 | + |
| 148 | + while (1) { |
| 149 | + if (!strm->z.avail_out) { |
| 150 | + if (++no >= nrpages_out || !outsz) { |
| 151 | + erofs_err(sb, "insufficient space for decompressed data"); |
| 152 | + err = -EFSCORRUPTED; |
| 153 | + break; |
| 154 | + } |
| 155 | + |
| 156 | + if (kout) |
| 157 | + kunmap_local(kout); |
| 158 | + strm->z.avail_out = min_t(u32, outsz, PAGE_SIZE - pofs); |
| 159 | + outsz -= strm->z.avail_out; |
| 160 | + if (!rq->out[no]) { |
| 161 | + rq->out[no] = erofs_allocpage(pagepool, |
| 162 | + GFP_KERNEL | __GFP_NOFAIL); |
| 163 | + set_page_private(rq->out[no], |
| 164 | + Z_EROFS_SHORTLIVED_PAGE); |
| 165 | + } |
| 166 | + kout = kmap_local_page(rq->out[no]); |
| 167 | + strm->z.next_out = kout + pofs; |
| 168 | + pofs = 0; |
| 169 | + } |
| 170 | + |
| 171 | + if (!strm->z.avail_in && insz) { |
| 172 | + if (++ni >= nrpages_in) { |
| 173 | + erofs_err(sb, "invalid compressed data"); |
| 174 | + err = -EFSCORRUPTED; |
| 175 | + break; |
| 176 | + } |
| 177 | + |
| 178 | + if (kout) { /* unlike kmap(), take care of the orders */ |
| 179 | + j = strm->z.next_out - kout; |
| 180 | + kunmap_local(kout); |
| 181 | + } |
| 182 | + kunmap_local(kin); |
| 183 | + strm->z.avail_in = min_t(u32, insz, PAGE_SIZE); |
| 184 | + insz -= strm->z.avail_in; |
| 185 | + kin = kmap_local_page(rq->in[ni]); |
| 186 | + strm->z.next_in = kin; |
| 187 | + bounced = false; |
| 188 | + if (kout) { |
| 189 | + kout = kmap_local_page(rq->out[no]); |
| 190 | + strm->z.next_out = kout + j; |
| 191 | + } |
| 192 | + } |
| 193 | + |
| 194 | + /* |
| 195 | + * Handle overlapping: Use bounced buffer if the compressed |
| 196 | + * data is under processing; Or use short-lived pages from the |
| 197 | + * on-stack pagepool where pages share among the same request |
| 198 | + * and not _all_ inplace I/O pages are needed to be doubled. |
| 199 | + */ |
| 200 | + if (!bounced && rq->out[no] == rq->in[ni]) { |
| 201 | + memcpy(strm->bounce, strm->z.next_in, strm->z.avail_in); |
| 202 | + strm->z.next_in = strm->bounce; |
| 203 | + bounced = true; |
| 204 | + } |
| 205 | + |
| 206 | + for (j = ni + 1; j < nrpages_in; ++j) { |
| 207 | + struct page *tmppage; |
| 208 | + |
| 209 | + if (rq->out[no] != rq->in[j]) |
| 210 | + continue; |
| 211 | + |
| 212 | + DBG_BUGON(erofs_page_is_managed(EROFS_SB(sb), |
| 213 | + rq->in[j])); |
| 214 | + tmppage = erofs_allocpage(pagepool, |
| 215 | + GFP_KERNEL | __GFP_NOFAIL); |
| 216 | + set_page_private(tmppage, Z_EROFS_SHORTLIVED_PAGE); |
| 217 | + copy_highpage(tmppage, rq->in[j]); |
| 218 | + rq->in[j] = tmppage; |
| 219 | + } |
| 220 | + |
| 221 | + zerr = zlib_inflate(&strm->z, Z_SYNC_FLUSH); |
| 222 | + if (zerr != Z_OK || !(outsz + strm->z.avail_out)) { |
| 223 | + if (zerr == Z_OK && rq->partial_decoding) |
| 224 | + break; |
| 225 | + if (zerr == Z_STREAM_END && !outsz) |
| 226 | + break; |
| 227 | + erofs_err(sb, "failed to decompress %d in[%u] out[%u]", |
| 228 | + zerr, rq->inputsize, rq->outputsize); |
| 229 | + err = -EFSCORRUPTED; |
| 230 | + break; |
| 231 | + } |
| 232 | + } |
| 233 | + |
| 234 | + if (zlib_inflateEnd(&strm->z) != Z_OK && !err) |
| 235 | + err = -EIO; |
| 236 | + if (kout) |
| 237 | + kunmap_local(kout); |
| 238 | +failed_zinit: |
| 239 | + kunmap_local(kin); |
| 240 | + /* 4. push back DEFLATE stream context to the global list */ |
| 241 | + spin_lock(&z_erofs_deflate_lock); |
| 242 | + strm->next = z_erofs_deflate_head; |
| 243 | + z_erofs_deflate_head = strm; |
| 244 | + spin_unlock(&z_erofs_deflate_lock); |
| 245 | + wake_up(&z_erofs_deflate_wq); |
| 246 | + return err; |
| 247 | +} |
0 commit comments