1 // SPDX-License-Identifier: GPL-2.0-or-later 2 #include <linux/zlib.h> 3 #include "compress.h" 4 5 struct z_erofs_deflate { 6 struct z_erofs_deflate *next; 7 struct z_stream_s z; 8 u8 bounce[PAGE_SIZE]; 9 }; 10 11 static DEFINE_SPINLOCK(z_erofs_deflate_lock); 12 static unsigned int z_erofs_deflate_nstrms, z_erofs_deflate_avail_strms; 13 static struct z_erofs_deflate *z_erofs_deflate_head; 14 static DECLARE_WAIT_QUEUE_HEAD(z_erofs_deflate_wq); 15 16 module_param_named(deflate_streams, z_erofs_deflate_nstrms, uint, 0444); 17 18 void z_erofs_deflate_exit(void) 19 { 20 /* there should be no running fs instance */ 21 while (z_erofs_deflate_avail_strms) { 22 struct z_erofs_deflate *strm; 23 24 spin_lock(&z_erofs_deflate_lock); 25 strm = z_erofs_deflate_head; 26 if (!strm) { 27 spin_unlock(&z_erofs_deflate_lock); 28 continue; 29 } 30 z_erofs_deflate_head = NULL; 31 spin_unlock(&z_erofs_deflate_lock); 32 33 while (strm) { 34 struct z_erofs_deflate *n = strm->next; 35 36 vfree(strm->z.workspace); 37 kfree(strm); 38 --z_erofs_deflate_avail_strms; 39 strm = n; 40 } 41 } 42 } 43 44 int __init z_erofs_deflate_init(void) 45 { 46 /* by default, use # of possible CPUs instead */ 47 if (!z_erofs_deflate_nstrms) 48 z_erofs_deflate_nstrms = num_possible_cpus(); 49 50 for (; z_erofs_deflate_avail_strms < z_erofs_deflate_nstrms; 51 ++z_erofs_deflate_avail_strms) { 52 struct z_erofs_deflate *strm; 53 54 strm = kzalloc(sizeof(*strm), GFP_KERNEL); 55 if (!strm) 56 goto out_failed; 57 58 /* XXX: in-kernel zlib cannot shrink windowbits currently */ 59 strm->z.workspace = vmalloc(zlib_inflate_workspacesize()); 60 if (!strm->z.workspace) { 61 kfree(strm); 62 goto out_failed; 63 } 64 65 spin_lock(&z_erofs_deflate_lock); 66 strm->next = z_erofs_deflate_head; 67 z_erofs_deflate_head = strm; 68 spin_unlock(&z_erofs_deflate_lock); 69 } 70 return 0; 71 72 out_failed: 73 pr_err("failed to allocate zlib workspace\n"); 74 z_erofs_deflate_exit(); 75 return -ENOMEM; 76 } 77 78 int z_erofs_load_deflate_config(struct super_block *sb, 79 struct erofs_super_block *dsb, void *data, int size) 80 { 81 struct z_erofs_deflate_cfgs *dfl = data; 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 } 248