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 return 0; 50 } 51 52 int z_erofs_load_deflate_config(struct super_block *sb, 53 struct erofs_super_block *dsb, void *data, int size) 54 { 55 struct z_erofs_deflate_cfgs *dfl = data; 56 static DEFINE_MUTEX(deflate_resize_mutex); 57 static bool inited; 58 59 if (!dfl || size < sizeof(struct z_erofs_deflate_cfgs)) { 60 erofs_err(sb, "invalid deflate cfgs, size=%u", size); 61 return -EINVAL; 62 } 63 64 if (dfl->windowbits > MAX_WBITS) { 65 erofs_err(sb, "unsupported windowbits %u", dfl->windowbits); 66 return -EOPNOTSUPP; 67 } 68 mutex_lock(&deflate_resize_mutex); 69 if (!inited) { 70 for (; z_erofs_deflate_avail_strms < z_erofs_deflate_nstrms; 71 ++z_erofs_deflate_avail_strms) { 72 struct z_erofs_deflate *strm; 73 74 strm = kzalloc(sizeof(*strm), GFP_KERNEL); 75 if (!strm) 76 goto failed; 77 /* XXX: in-kernel zlib cannot customize windowbits */ 78 strm->z.workspace = vmalloc(zlib_inflate_workspacesize()); 79 if (!strm->z.workspace) { 80 kfree(strm); 81 goto failed; 82 } 83 84 spin_lock(&z_erofs_deflate_lock); 85 strm->next = z_erofs_deflate_head; 86 z_erofs_deflate_head = strm; 87 spin_unlock(&z_erofs_deflate_lock); 88 } 89 inited = true; 90 } 91 mutex_unlock(&deflate_resize_mutex); 92 erofs_info(sb, "EXPERIMENTAL DEFLATE feature in use. Use at your own risk!"); 93 return 0; 94 failed: 95 mutex_unlock(&deflate_resize_mutex); 96 z_erofs_deflate_exit(); 97 return -ENOMEM; 98 } 99 100 int z_erofs_deflate_decompress(struct z_erofs_decompress_req *rq, 101 struct page **pgpl) 102 { 103 const unsigned int nrpages_out = 104 PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT; 105 const unsigned int nrpages_in = 106 PAGE_ALIGN(rq->inputsize) >> PAGE_SHIFT; 107 struct super_block *sb = rq->sb; 108 unsigned int insz, outsz, pofs; 109 struct z_erofs_deflate *strm; 110 u8 *kin, *kout = NULL; 111 bool bounced = false; 112 int no = -1, ni = 0, j = 0, zerr, err; 113 114 /* 1. get the exact DEFLATE compressed size */ 115 kin = kmap_local_page(*rq->in); 116 err = z_erofs_fixup_insize(rq, kin + rq->pageofs_in, 117 min_t(unsigned int, rq->inputsize, 118 sb->s_blocksize - rq->pageofs_in)); 119 if (err) { 120 kunmap_local(kin); 121 return err; 122 } 123 124 /* 2. get an available DEFLATE context */ 125 again: 126 spin_lock(&z_erofs_deflate_lock); 127 strm = z_erofs_deflate_head; 128 if (!strm) { 129 spin_unlock(&z_erofs_deflate_lock); 130 wait_event(z_erofs_deflate_wq, READ_ONCE(z_erofs_deflate_head)); 131 goto again; 132 } 133 z_erofs_deflate_head = strm->next; 134 spin_unlock(&z_erofs_deflate_lock); 135 136 /* 3. multi-call decompress */ 137 insz = rq->inputsize; 138 outsz = rq->outputsize; 139 zerr = zlib_inflateInit2(&strm->z, -MAX_WBITS); 140 if (zerr != Z_OK) { 141 err = -EIO; 142 goto failed_zinit; 143 } 144 145 pofs = rq->pageofs_out; 146 strm->z.avail_in = min_t(u32, insz, PAGE_SIZE - rq->pageofs_in); 147 insz -= strm->z.avail_in; 148 strm->z.next_in = kin + rq->pageofs_in; 149 strm->z.avail_out = 0; 150 151 while (1) { 152 if (!strm->z.avail_out) { 153 if (++no >= nrpages_out || !outsz) { 154 erofs_err(sb, "insufficient space for decompressed data"); 155 err = -EFSCORRUPTED; 156 break; 157 } 158 159 if (kout) 160 kunmap_local(kout); 161 strm->z.avail_out = min_t(u32, outsz, PAGE_SIZE - pofs); 162 outsz -= strm->z.avail_out; 163 if (!rq->out[no]) { 164 rq->out[no] = erofs_allocpage(pgpl, rq->gfp); 165 if (!rq->out[no]) { 166 kout = NULL; 167 err = -ENOMEM; 168 break; 169 } 170 set_page_private(rq->out[no], 171 Z_EROFS_SHORTLIVED_PAGE); 172 } 173 kout = kmap_local_page(rq->out[no]); 174 strm->z.next_out = kout + pofs; 175 pofs = 0; 176 } 177 178 if (!strm->z.avail_in && insz) { 179 if (++ni >= nrpages_in) { 180 erofs_err(sb, "invalid compressed data"); 181 err = -EFSCORRUPTED; 182 break; 183 } 184 185 if (kout) { /* unlike kmap(), take care of the orders */ 186 j = strm->z.next_out - kout; 187 kunmap_local(kout); 188 } 189 kunmap_local(kin); 190 strm->z.avail_in = min_t(u32, insz, PAGE_SIZE); 191 insz -= strm->z.avail_in; 192 kin = kmap_local_page(rq->in[ni]); 193 strm->z.next_in = kin; 194 bounced = false; 195 if (kout) { 196 kout = kmap_local_page(rq->out[no]); 197 strm->z.next_out = kout + j; 198 } 199 } 200 201 /* 202 * Handle overlapping: Use bounced buffer if the compressed 203 * data is under processing; Or use short-lived pages from the 204 * on-stack pagepool where pages share among the same request 205 * and not _all_ inplace I/O pages are needed to be doubled. 206 */ 207 if (!bounced && rq->out[no] == rq->in[ni]) { 208 memcpy(strm->bounce, strm->z.next_in, strm->z.avail_in); 209 strm->z.next_in = strm->bounce; 210 bounced = true; 211 } 212 213 for (j = ni + 1; j < nrpages_in; ++j) { 214 struct page *tmppage; 215 216 if (rq->out[no] != rq->in[j]) 217 continue; 218 tmppage = erofs_allocpage(pgpl, rq->gfp); 219 if (!tmppage) { 220 err = -ENOMEM; 221 goto failed; 222 } 223 set_page_private(tmppage, Z_EROFS_SHORTLIVED_PAGE); 224 copy_highpage(tmppage, rq->in[j]); 225 rq->in[j] = tmppage; 226 } 227 228 zerr = zlib_inflate(&strm->z, Z_SYNC_FLUSH); 229 if (zerr != Z_OK || !(outsz + strm->z.avail_out)) { 230 if (zerr == Z_OK && rq->partial_decoding) 231 break; 232 if (zerr == Z_STREAM_END && !outsz) 233 break; 234 erofs_err(sb, "failed to decompress %d in[%u] out[%u]", 235 zerr, rq->inputsize, rq->outputsize); 236 err = -EFSCORRUPTED; 237 break; 238 } 239 } 240 failed: 241 if (zlib_inflateEnd(&strm->z) != Z_OK && !err) 242 err = -EIO; 243 if (kout) 244 kunmap_local(kout); 245 failed_zinit: 246 kunmap_local(kin); 247 /* 4. push back DEFLATE stream context to the global list */ 248 spin_lock(&z_erofs_deflate_lock); 249 strm->next = z_erofs_deflate_head; 250 z_erofs_deflate_head = strm; 251 spin_unlock(&z_erofs_deflate_lock); 252 wake_up(&z_erofs_deflate_wq); 253 return err; 254 } 255