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