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