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
z_erofs_deflate_exit(void)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
z_erofs_deflate_init(void)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
z_erofs_load_deflate_config(struct super_block * sb,struct erofs_super_block * dsb,void * data,int size)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
z_erofs_deflate_decompress(struct z_erofs_decompress_req * rq,struct page ** pagepool)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