1 // SPDX-License-Identifier: GPL-2.0 1 // SPDX-License-Identifier: GPL-2.0
2 // Author: Kirill Smelkov (kirr@nexedi.com) 2 // Author: Kirill Smelkov (kirr@nexedi.com)
3 // 3 //
4 // Search for stream-like files that are using 4 // Search for stream-like files that are using nonseekable_open and convert
5 // them to stream_open. A stream-like file is 5 // them to stream_open. A stream-like file is a file that does not use ppos in
6 // its read and write. Rationale for the conve 6 // its read and write. Rationale for the conversion is to avoid deadlock in
7 // between read and write. 7 // between read and write.
8 8
9 virtual report 9 virtual report
10 virtual patch 10 virtual patch
11 virtual explain // explain decisions in the p 11 virtual explain // explain decisions in the patch (SPFLAGS="-D explain")
12 12
13 // stream-like reader & writer - ones that do 13 // stream-like reader & writer - ones that do not depend on f_pos.
14 @ stream_reader @ 14 @ stream_reader @
15 identifier readstream, ppos; 15 identifier readstream, ppos;
16 identifier f, buf, len; 16 identifier f, buf, len;
17 type loff_t; 17 type loff_t;
18 @@ 18 @@
19 ssize_t readstream(struct file *f, char *buf 19 ssize_t readstream(struct file *f, char *buf, size_t len, loff_t *ppos)
20 { 20 {
21 ... when != ppos 21 ... when != ppos
22 } 22 }
23 23
24 @ stream_writer @ 24 @ stream_writer @
25 identifier writestream, ppos; 25 identifier writestream, ppos;
26 identifier f, buf, len; 26 identifier f, buf, len;
27 type loff_t; 27 type loff_t;
28 @@ 28 @@
29 ssize_t writestream(struct file *f, const ch 29 ssize_t writestream(struct file *f, const char *buf, size_t len, loff_t *ppos)
30 { 30 {
31 ... when != ppos 31 ... when != ppos
32 } 32 }
33 33
34 34
35 // a function that blocks 35 // a function that blocks
36 @ blocks @ 36 @ blocks @
37 identifier block_f; 37 identifier block_f;
38 identifier wait =~ "^wait_.*"; 38 identifier wait =~ "^wait_.*";
39 @@ 39 @@
40 block_f(...) { 40 block_f(...) {
41 ... when exists 41 ... when exists
42 wait(...) 42 wait(...)
43 ... when exists 43 ... when exists
44 } 44 }
45 45
46 // stream_reader that can block inside. 46 // stream_reader that can block inside.
47 // 47 //
48 // XXX wait_* can be called not directly from 48 // XXX wait_* can be called not directly from current function (e.g. func -> f -> g -> wait())
49 // XXX currently reader_blocks supports only d 49 // XXX currently reader_blocks supports only direct and 1-level indirect cases.
50 @ reader_blocks_direct @ 50 @ reader_blocks_direct @
51 identifier stream_reader.readstream; 51 identifier stream_reader.readstream;
52 identifier wait =~ "^wait_.*"; 52 identifier wait =~ "^wait_.*";
53 @@ 53 @@
54 readstream(...) 54 readstream(...)
55 { 55 {
56 ... when exists 56 ... when exists
57 wait(...) 57 wait(...)
58 ... when exists 58 ... when exists
59 } 59 }
60 60
61 @ reader_blocks_1 @ 61 @ reader_blocks_1 @
62 identifier stream_reader.readstream; 62 identifier stream_reader.readstream;
63 identifier blocks.block_f; 63 identifier blocks.block_f;
64 @@ 64 @@
65 readstream(...) 65 readstream(...)
66 { 66 {
67 ... when exists 67 ... when exists
68 block_f(...) 68 block_f(...)
69 ... when exists 69 ... when exists
70 } 70 }
71 71
72 @ reader_blocks depends on reader_blocks_direc 72 @ reader_blocks depends on reader_blocks_direct || reader_blocks_1 @
73 identifier stream_reader.readstream; 73 identifier stream_reader.readstream;
74 @@ 74 @@
75 readstream(...) { 75 readstream(...) {
76 ... 76 ...
77 } 77 }
78 78
79 79
80 // file_operations + whether they have _any_ . 80 // file_operations + whether they have _any_ .read, .write, .llseek ... at all.
81 // 81 //
82 // XXX add support for file_operations xxx[N] 82 // XXX add support for file_operations xxx[N] = ... (sound/core/pcm_native.c)
83 @ fops0 @ 83 @ fops0 @
84 identifier fops; 84 identifier fops;
85 @@ 85 @@
86 struct file_operations fops = { 86 struct file_operations fops = {
87 ... 87 ...
88 }; 88 };
89 89
90 @ has_read @ 90 @ has_read @
91 identifier fops0.fops; 91 identifier fops0.fops;
92 identifier read_f; 92 identifier read_f;
93 @@ 93 @@
94 struct file_operations fops = { 94 struct file_operations fops = {
95 .read = read_f, 95 .read = read_f,
96 }; 96 };
97 97
98 @ has_read_iter @ 98 @ has_read_iter @
99 identifier fops0.fops; 99 identifier fops0.fops;
100 identifier read_iter_f; 100 identifier read_iter_f;
101 @@ 101 @@
102 struct file_operations fops = { 102 struct file_operations fops = {
103 .read_iter = read_iter_f, 103 .read_iter = read_iter_f,
104 }; 104 };
105 105
106 @ has_write @ 106 @ has_write @
107 identifier fops0.fops; 107 identifier fops0.fops;
108 identifier write_f; 108 identifier write_f;
109 @@ 109 @@
110 struct file_operations fops = { 110 struct file_operations fops = {
111 .write = write_f, 111 .write = write_f,
112 }; 112 };
113 113
114 @ has_write_iter @ 114 @ has_write_iter @
115 identifier fops0.fops; 115 identifier fops0.fops;
116 identifier write_iter_f; 116 identifier write_iter_f;
117 @@ 117 @@
118 struct file_operations fops = { 118 struct file_operations fops = {
119 .write_iter = write_iter_f, 119 .write_iter = write_iter_f,
120 }; 120 };
121 121
122 @ has_llseek @ 122 @ has_llseek @
123 identifier fops0.fops; 123 identifier fops0.fops;
124 identifier llseek_f; 124 identifier llseek_f;
125 @@ 125 @@
126 struct file_operations fops = { 126 struct file_operations fops = {
127 .llseek = llseek_f, 127 .llseek = llseek_f,
128 }; 128 };
129 129
130 @ has_no_llseek @ 130 @ has_no_llseek @
131 identifier fops0.fops; 131 identifier fops0.fops;
132 @@ 132 @@
133 struct file_operations fops = { 133 struct file_operations fops = {
134 }; 134 };
135 135
136 @ has_noop_llseek @ 136 @ has_noop_llseek @
137 identifier fops0.fops; 137 identifier fops0.fops;
138 @@ 138 @@
139 struct file_operations fops = { 139 struct file_operations fops = {
140 .llseek = noop_llseek, 140 .llseek = noop_llseek,
141 }; 141 };
142 142
143 @ has_mmap @ 143 @ has_mmap @
144 identifier fops0.fops; 144 identifier fops0.fops;
145 identifier mmap_f; 145 identifier mmap_f;
146 @@ 146 @@
147 struct file_operations fops = { 147 struct file_operations fops = {
148 .mmap = mmap_f, 148 .mmap = mmap_f,
149 }; 149 };
150 150
151 @ has_copy_file_range @ 151 @ has_copy_file_range @
152 identifier fops0.fops; 152 identifier fops0.fops;
153 identifier copy_file_range_f; 153 identifier copy_file_range_f;
154 @@ 154 @@
155 struct file_operations fops = { 155 struct file_operations fops = {
156 .copy_file_range = copy_file_range_f, 156 .copy_file_range = copy_file_range_f,
157 }; 157 };
158 158
159 @ has_remap_file_range @ 159 @ has_remap_file_range @
160 identifier fops0.fops; 160 identifier fops0.fops;
161 identifier remap_file_range_f; 161 identifier remap_file_range_f;
162 @@ 162 @@
163 struct file_operations fops = { 163 struct file_operations fops = {
164 .remap_file_range = remap_file_range_f, 164 .remap_file_range = remap_file_range_f,
165 }; 165 };
166 166
167 @ has_splice_read @ 167 @ has_splice_read @
168 identifier fops0.fops; 168 identifier fops0.fops;
169 identifier splice_read_f; 169 identifier splice_read_f;
170 @@ 170 @@
171 struct file_operations fops = { 171 struct file_operations fops = {
172 .splice_read = splice_read_f, 172 .splice_read = splice_read_f,
173 }; 173 };
174 174
175 @ has_splice_write @ 175 @ has_splice_write @
176 identifier fops0.fops; 176 identifier fops0.fops;
177 identifier splice_write_f; 177 identifier splice_write_f;
178 @@ 178 @@
179 struct file_operations fops = { 179 struct file_operations fops = {
180 .splice_write = splice_write_f, 180 .splice_write = splice_write_f,
181 }; 181 };
182 182
183 183
184 // file_operations that is candidate for strea 184 // file_operations that is candidate for stream_open conversion - it does not
185 // use mmap and other methods that assume @off 185 // use mmap and other methods that assume @offset access to file.
186 // 186 //
187 // XXX for simplicity require no .{read/write} 187 // XXX for simplicity require no .{read/write}_iter and no .splice_{read/write} for now.
188 // XXX maybe_steam.fops cannot be used in othe 188 // XXX maybe_steam.fops cannot be used in other rules - it gives "bad rule maybe_stream or bad variable fops".
189 @ maybe_stream depends on (!has_llseek || has_ 189 @ maybe_stream depends on (!has_llseek || has_no_llseek || has_noop_llseek) && !has_mmap && !has_copy_file_range && !has_remap_file_range && !has_read_iter && !has_write_iter && !has_splice_read && !has_splice_write @
190 identifier fops0.fops; 190 identifier fops0.fops;
191 @@ 191 @@
192 struct file_operations fops = { 192 struct file_operations fops = {
193 }; 193 };
194 194
195 195
196 // ---- conversions ---- 196 // ---- conversions ----
197 197
198 // XXX .open = nonseekable_open -> .open = str 198 // XXX .open = nonseekable_open -> .open = stream_open
199 // XXX .open = func -> openfunc -> nonseekable 199 // XXX .open = func -> openfunc -> nonseekable_open
200 200
201 // read & write 201 // read & write
202 // 202 //
203 // if both are used in the same file_operation 203 // if both are used in the same file_operations together with an opener -
204 // under that conditions we can use stream_ope 204 // under that conditions we can use stream_open instead of nonseekable_open.
205 @ fops_rw depends on maybe_stream @ 205 @ fops_rw depends on maybe_stream @
206 identifier fops0.fops, openfunc; 206 identifier fops0.fops, openfunc;
207 identifier stream_reader.readstream; 207 identifier stream_reader.readstream;
208 identifier stream_writer.writestream; 208 identifier stream_writer.writestream;
209 @@ 209 @@
210 struct file_operations fops = { 210 struct file_operations fops = {
211 .open = openfunc, 211 .open = openfunc,
212 .read = readstream, 212 .read = readstream,
213 .write = writestream, 213 .write = writestream,
214 }; 214 };
215 215
216 @ report_rw depends on report @ 216 @ report_rw depends on report @
217 identifier fops_rw.openfunc; 217 identifier fops_rw.openfunc;
218 position p1; 218 position p1;
219 @@ 219 @@
220 openfunc(...) { 220 openfunc(...) {
221 <... 221 <...
222 nonseekable_open@p1 222 nonseekable_open@p1
223 ...> 223 ...>
224 } 224 }
225 225
226 @ script:python depends on report && reader_bl 226 @ script:python depends on report && reader_blocks @
227 fops << fops0.fops; 227 fops << fops0.fops;
228 p << report_rw.p1; 228 p << report_rw.p1;
229 @@ 229 @@
230 coccilib.report.print_report(p[0], 230 coccilib.report.print_report(p[0],
231 "ERROR: %s: .read() can deadlock .write(); c 231 "ERROR: %s: .read() can deadlock .write(); change nonseekable_open -> stream_open to fix." % (fops,))
232 232
233 @ script:python depends on report && !reader_b 233 @ script:python depends on report && !reader_blocks @
234 fops << fops0.fops; 234 fops << fops0.fops;
235 p << report_rw.p1; 235 p << report_rw.p1;
236 @@ 236 @@
237 coccilib.report.print_report(p[0], 237 coccilib.report.print_report(p[0],
238 "WARNING: %s: .read() and .write() have stre 238 "WARNING: %s: .read() and .write() have stream semantic; safe to change nonseekable_open -> stream_open." % (fops,))
239 239
240 240
241 @ explain_rw_deadlocked depends on explain && 241 @ explain_rw_deadlocked depends on explain && reader_blocks @
242 identifier fops_rw.openfunc; 242 identifier fops_rw.openfunc;
243 @@ 243 @@
244 openfunc(...) { 244 openfunc(...) {
245 <... 245 <...
246 - nonseekable_open 246 - nonseekable_open
247 + nonseekable_open /* read & write (was dea 247 + nonseekable_open /* read & write (was deadlock) */
248 ...> 248 ...>
249 } 249 }
250 250
251 251
252 @ explain_rw_nodeadlock depends on explain && 252 @ explain_rw_nodeadlock depends on explain && !reader_blocks @
253 identifier fops_rw.openfunc; 253 identifier fops_rw.openfunc;
254 @@ 254 @@
255 openfunc(...) { 255 openfunc(...) {
256 <... 256 <...
257 - nonseekable_open 257 - nonseekable_open
258 + nonseekable_open /* read & write (no dire 258 + nonseekable_open /* read & write (no direct deadlock) */
259 ...> 259 ...>
260 } 260 }
261 261
262 @ patch_rw depends on patch @ 262 @ patch_rw depends on patch @
263 identifier fops_rw.openfunc; 263 identifier fops_rw.openfunc;
264 @@ 264 @@
265 openfunc(...) { 265 openfunc(...) {
266 <... 266 <...
267 - nonseekable_open 267 - nonseekable_open
268 + stream_open 268 + stream_open
269 ...> 269 ...>
270 } 270 }
271 271
272 272
273 // read, but not write 273 // read, but not write
274 @ fops_r depends on maybe_stream && !has_write 274 @ fops_r depends on maybe_stream && !has_write @
275 identifier fops0.fops, openfunc; 275 identifier fops0.fops, openfunc;
276 identifier stream_reader.readstream; 276 identifier stream_reader.readstream;
277 @@ 277 @@
278 struct file_operations fops = { 278 struct file_operations fops = {
279 .open = openfunc, 279 .open = openfunc,
280 .read = readstream, 280 .read = readstream,
281 }; 281 };
282 282
283 @ report_r depends on report @ 283 @ report_r depends on report @
284 identifier fops_r.openfunc; 284 identifier fops_r.openfunc;
285 position p1; 285 position p1;
286 @@ 286 @@
287 openfunc(...) { 287 openfunc(...) {
288 <... 288 <...
289 nonseekable_open@p1 289 nonseekable_open@p1
290 ...> 290 ...>
291 } 291 }
292 292
293 @ script:python depends on report @ 293 @ script:python depends on report @
294 fops << fops0.fops; 294 fops << fops0.fops;
295 p << report_r.p1; 295 p << report_r.p1;
296 @@ 296 @@
297 coccilib.report.print_report(p[0], 297 coccilib.report.print_report(p[0],
298 "WARNING: %s: .read() has stream semantic; s 298 "WARNING: %s: .read() has stream semantic; safe to change nonseekable_open -> stream_open." % (fops,))
299 299
300 @ explain_r depends on explain @ 300 @ explain_r depends on explain @
301 identifier fops_r.openfunc; 301 identifier fops_r.openfunc;
302 @@ 302 @@
303 openfunc(...) { 303 openfunc(...) {
304 <... 304 <...
305 - nonseekable_open 305 - nonseekable_open
306 + nonseekable_open /* read only */ 306 + nonseekable_open /* read only */
307 ...> 307 ...>
308 } 308 }
309 309
310 @ patch_r depends on patch @ 310 @ patch_r depends on patch @
311 identifier fops_r.openfunc; 311 identifier fops_r.openfunc;
312 @@ 312 @@
313 openfunc(...) { 313 openfunc(...) {
314 <... 314 <...
315 - nonseekable_open 315 - nonseekable_open
316 + stream_open 316 + stream_open
317 ...> 317 ...>
318 } 318 }
319 319
320 320
321 // write, but not read 321 // write, but not read
322 @ fops_w depends on maybe_stream && !has_read 322 @ fops_w depends on maybe_stream && !has_read @
323 identifier fops0.fops, openfunc; 323 identifier fops0.fops, openfunc;
324 identifier stream_writer.writestream; 324 identifier stream_writer.writestream;
325 @@ 325 @@
326 struct file_operations fops = { 326 struct file_operations fops = {
327 .open = openfunc, 327 .open = openfunc,
328 .write = writestream, 328 .write = writestream,
329 }; 329 };
330 330
331 @ report_w depends on report @ 331 @ report_w depends on report @
332 identifier fops_w.openfunc; 332 identifier fops_w.openfunc;
333 position p1; 333 position p1;
334 @@ 334 @@
335 openfunc(...) { 335 openfunc(...) {
336 <... 336 <...
337 nonseekable_open@p1 337 nonseekable_open@p1
338 ...> 338 ...>
339 } 339 }
340 340
341 @ script:python depends on report @ 341 @ script:python depends on report @
342 fops << fops0.fops; 342 fops << fops0.fops;
343 p << report_w.p1; 343 p << report_w.p1;
344 @@ 344 @@
345 coccilib.report.print_report(p[0], 345 coccilib.report.print_report(p[0],
346 "WARNING: %s: .write() has stream semantic; 346 "WARNING: %s: .write() has stream semantic; safe to change nonseekable_open -> stream_open." % (fops,))
347 347
348 @ explain_w depends on explain @ 348 @ explain_w depends on explain @
349 identifier fops_w.openfunc; 349 identifier fops_w.openfunc;
350 @@ 350 @@
351 openfunc(...) { 351 openfunc(...) {
352 <... 352 <...
353 - nonseekable_open 353 - nonseekable_open
354 + nonseekable_open /* write only */ 354 + nonseekable_open /* write only */
355 ...> 355 ...>
356 } 356 }
357 357
358 @ patch_w depends on patch @ 358 @ patch_w depends on patch @
359 identifier fops_w.openfunc; 359 identifier fops_w.openfunc;
360 @@ 360 @@
361 openfunc(...) { 361 openfunc(...) {
362 <... 362 <...
363 - nonseekable_open 363 - nonseekable_open
364 + stream_open 364 + stream_open
365 ...> 365 ...>
366 } 366 }
367 367
368 368
369 // no read, no write - don't change anything 369 // no read, no write - don't change anything
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