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