Commit | Line | Data |
---|---|---|
306b0c95 | 1 | /* |
f1e3cfff | 2 | * Compressed RAM block device |
306b0c95 | 3 | * |
1130ebba | 4 | * Copyright (C) 2008, 2009, 2010 Nitin Gupta |
7bfb3de8 | 5 | * 2012, 2013 Minchan Kim |
306b0c95 NG |
6 | * |
7 | * This code is released using a dual license strategy: BSD/GPL | |
8 | * You can choose the licence that better fits your requirements. | |
9 | * | |
10 | * Released under the terms of 3-clause BSD License | |
11 | * Released under the terms of GNU General Public License Version 2.0 | |
12 | * | |
306b0c95 NG |
13 | */ |
14 | ||
f1e3cfff | 15 | #define KMSG_COMPONENT "zram" |
306b0c95 NG |
16 | #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt |
17 | ||
18 | #include <linux/module.h> | |
19 | #include <linux/kernel.h> | |
8946a086 | 20 | #include <linux/bio.h> |
306b0c95 NG |
21 | #include <linux/bitops.h> |
22 | #include <linux/blkdev.h> | |
23 | #include <linux/buffer_head.h> | |
24 | #include <linux/device.h> | |
25 | #include <linux/genhd.h> | |
26 | #include <linux/highmem.h> | |
5a0e3ad6 | 27 | #include <linux/slab.h> |
306b0c95 | 28 | #include <linux/string.h> |
306b0c95 | 29 | #include <linux/vmalloc.h> |
fcfa8d95 | 30 | #include <linux/err.h> |
85508ec6 | 31 | #include <linux/idr.h> |
6566d1a3 | 32 | #include <linux/sysfs.h> |
306b0c95 | 33 | |
16a4bfb9 | 34 | #include "zram_drv.h" |
306b0c95 | 35 | |
85508ec6 | 36 | static DEFINE_IDR(zram_index_idr); |
6566d1a3 SS |
37 | /* idr index must be protected */ |
38 | static DEFINE_MUTEX(zram_index_mutex); | |
39 | ||
f1e3cfff | 40 | static int zram_major; |
b7ca232e | 41 | static const char *default_compressor = "lzo"; |
306b0c95 | 42 | |
306b0c95 | 43 | /* Module params (documentation at end) */ |
ca3d70bd | 44 | static unsigned int num_devices = 1; |
33863c21 | 45 | |
8f7d282c SS |
46 | static inline void deprecated_attr_warn(const char *name) |
47 | { | |
48 | pr_warn_once("%d (%s) Attribute %s (and others) will be removed. %s\n", | |
49 | task_pid_nr(current), | |
50 | current->comm, | |
51 | name, | |
52 | "See zram documentation."); | |
53 | } | |
54 | ||
a68eb3b6 | 55 | #define ZRAM_ATTR_RO(name) \ |
3bca3ef7 | 56 | static ssize_t name##_show(struct device *d, \ |
a68eb3b6 SS |
57 | struct device_attribute *attr, char *b) \ |
58 | { \ | |
59 | struct zram *zram = dev_to_zram(d); \ | |
8f7d282c SS |
60 | \ |
61 | deprecated_attr_warn(__stringify(name)); \ | |
56b4e8cb | 62 | return scnprintf(b, PAGE_SIZE, "%llu\n", \ |
a68eb3b6 SS |
63 | (u64)atomic64_read(&zram->stats.name)); \ |
64 | } \ | |
083914ea | 65 | static DEVICE_ATTR_RO(name); |
a68eb3b6 | 66 | |
08eee69f | 67 | static inline bool init_done(struct zram *zram) |
be2d1d56 | 68 | { |
08eee69f | 69 | return zram->disksize; |
be2d1d56 SS |
70 | } |
71 | ||
9b3bb7ab SS |
72 | static inline struct zram *dev_to_zram(struct device *dev) |
73 | { | |
74 | return (struct zram *)dev_to_disk(dev)->private_data; | |
75 | } | |
76 | ||
b31177f2 | 77 | /* flag operations require table entry bit_spin_lock() being held */ |
522698d7 SS |
78 | static int zram_test_flag(struct zram_meta *meta, u32 index, |
79 | enum zram_pageflags flag) | |
99ebbd30 | 80 | { |
522698d7 SS |
81 | return meta->table[index].value & BIT(flag); |
82 | } | |
99ebbd30 | 83 | |
522698d7 SS |
84 | static void zram_set_flag(struct zram_meta *meta, u32 index, |
85 | enum zram_pageflags flag) | |
86 | { | |
87 | meta->table[index].value |= BIT(flag); | |
88 | } | |
99ebbd30 | 89 | |
522698d7 SS |
90 | static void zram_clear_flag(struct zram_meta *meta, u32 index, |
91 | enum zram_pageflags flag) | |
92 | { | |
93 | meta->table[index].value &= ~BIT(flag); | |
94 | } | |
99ebbd30 | 95 | |
522698d7 SS |
96 | static size_t zram_get_obj_size(struct zram_meta *meta, u32 index) |
97 | { | |
98 | return meta->table[index].value & (BIT(ZRAM_FLAG_SHIFT) - 1); | |
99ebbd30 AM |
99 | } |
100 | ||
522698d7 SS |
101 | static void zram_set_obj_size(struct zram_meta *meta, |
102 | u32 index, size_t size) | |
9b3bb7ab | 103 | { |
522698d7 | 104 | unsigned long flags = meta->table[index].value >> ZRAM_FLAG_SHIFT; |
9b3bb7ab | 105 | |
522698d7 SS |
106 | meta->table[index].value = (flags << ZRAM_FLAG_SHIFT) | size; |
107 | } | |
108 | ||
1c53e0d2 | 109 | static inline bool is_partial_io(struct bio_vec *bvec) |
522698d7 SS |
110 | { |
111 | return bvec->bv_len != PAGE_SIZE; | |
112 | } | |
113 | ||
114 | /* | |
115 | * Check if request is within bounds and aligned on zram logical blocks. | |
116 | */ | |
1c53e0d2 | 117 | static inline bool valid_io_request(struct zram *zram, |
522698d7 SS |
118 | sector_t start, unsigned int size) |
119 | { | |
120 | u64 end, bound; | |
121 | ||
122 | /* unaligned request */ | |
123 | if (unlikely(start & (ZRAM_SECTOR_PER_LOGICAL_BLOCK - 1))) | |
1c53e0d2 | 124 | return false; |
522698d7 | 125 | if (unlikely(size & (ZRAM_LOGICAL_BLOCK_SIZE - 1))) |
1c53e0d2 | 126 | return false; |
522698d7 SS |
127 | |
128 | end = start + (size >> SECTOR_SHIFT); | |
129 | bound = zram->disksize >> SECTOR_SHIFT; | |
130 | /* out of range range */ | |
131 | if (unlikely(start >= bound || end > bound || start > end)) | |
1c53e0d2 | 132 | return false; |
522698d7 SS |
133 | |
134 | /* I/O request is valid */ | |
1c53e0d2 | 135 | return true; |
522698d7 SS |
136 | } |
137 | ||
138 | static void update_position(u32 *index, int *offset, struct bio_vec *bvec) | |
139 | { | |
140 | if (*offset + bvec->bv_len >= PAGE_SIZE) | |
141 | (*index)++; | |
142 | *offset = (*offset + bvec->bv_len) % PAGE_SIZE; | |
143 | } | |
144 | ||
145 | static inline void update_used_max(struct zram *zram, | |
146 | const unsigned long pages) | |
147 | { | |
148 | unsigned long old_max, cur_max; | |
149 | ||
150 | old_max = atomic_long_read(&zram->stats.max_used_pages); | |
151 | ||
152 | do { | |
153 | cur_max = old_max; | |
154 | if (pages > cur_max) | |
155 | old_max = atomic_long_cmpxchg( | |
156 | &zram->stats.max_used_pages, cur_max, pages); | |
157 | } while (old_max != cur_max); | |
158 | } | |
159 | ||
1c53e0d2 | 160 | static bool page_zero_filled(void *ptr) |
522698d7 SS |
161 | { |
162 | unsigned int pos; | |
163 | unsigned long *page; | |
164 | ||
165 | page = (unsigned long *)ptr; | |
166 | ||
167 | for (pos = 0; pos != PAGE_SIZE / sizeof(*page); pos++) { | |
168 | if (page[pos]) | |
1c53e0d2 | 169 | return false; |
522698d7 SS |
170 | } |
171 | ||
1c53e0d2 | 172 | return true; |
522698d7 SS |
173 | } |
174 | ||
175 | static void handle_zero_page(struct bio_vec *bvec) | |
176 | { | |
177 | struct page *page = bvec->bv_page; | |
178 | void *user_mem; | |
179 | ||
180 | user_mem = kmap_atomic(page); | |
181 | if (is_partial_io(bvec)) | |
182 | memset(user_mem + bvec->bv_offset, 0, bvec->bv_len); | |
183 | else | |
184 | clear_page(user_mem); | |
185 | kunmap_atomic(user_mem); | |
186 | ||
187 | flush_dcache_page(page); | |
9b3bb7ab SS |
188 | } |
189 | ||
190 | static ssize_t initstate_show(struct device *dev, | |
191 | struct device_attribute *attr, char *buf) | |
192 | { | |
a68eb3b6 | 193 | u32 val; |
9b3bb7ab SS |
194 | struct zram *zram = dev_to_zram(dev); |
195 | ||
a68eb3b6 SS |
196 | down_read(&zram->init_lock); |
197 | val = init_done(zram); | |
198 | up_read(&zram->init_lock); | |
9b3bb7ab | 199 | |
56b4e8cb | 200 | return scnprintf(buf, PAGE_SIZE, "%u\n", val); |
9b3bb7ab SS |
201 | } |
202 | ||
522698d7 SS |
203 | static ssize_t disksize_show(struct device *dev, |
204 | struct device_attribute *attr, char *buf) | |
205 | { | |
206 | struct zram *zram = dev_to_zram(dev); | |
207 | ||
208 | return scnprintf(buf, PAGE_SIZE, "%llu\n", zram->disksize); | |
209 | } | |
210 | ||
9b3bb7ab SS |
211 | static ssize_t orig_data_size_show(struct device *dev, |
212 | struct device_attribute *attr, char *buf) | |
213 | { | |
214 | struct zram *zram = dev_to_zram(dev); | |
215 | ||
8f7d282c | 216 | deprecated_attr_warn("orig_data_size"); |
56b4e8cb | 217 | return scnprintf(buf, PAGE_SIZE, "%llu\n", |
90a7806e | 218 | (u64)(atomic64_read(&zram->stats.pages_stored)) << PAGE_SHIFT); |
9b3bb7ab SS |
219 | } |
220 | ||
9b3bb7ab SS |
221 | static ssize_t mem_used_total_show(struct device *dev, |
222 | struct device_attribute *attr, char *buf) | |
223 | { | |
224 | u64 val = 0; | |
225 | struct zram *zram = dev_to_zram(dev); | |
9b3bb7ab | 226 | |
8f7d282c | 227 | deprecated_attr_warn("mem_used_total"); |
9b3bb7ab | 228 | down_read(&zram->init_lock); |
5a99e95b WY |
229 | if (init_done(zram)) { |
230 | struct zram_meta *meta = zram->meta; | |
722cdc17 | 231 | val = zs_get_total_pages(meta->mem_pool); |
5a99e95b | 232 | } |
9b3bb7ab SS |
233 | up_read(&zram->init_lock); |
234 | ||
722cdc17 | 235 | return scnprintf(buf, PAGE_SIZE, "%llu\n", val << PAGE_SHIFT); |
9b3bb7ab SS |
236 | } |
237 | ||
9ada9da9 MK |
238 | static ssize_t mem_limit_show(struct device *dev, |
239 | struct device_attribute *attr, char *buf) | |
240 | { | |
241 | u64 val; | |
242 | struct zram *zram = dev_to_zram(dev); | |
243 | ||
8f7d282c | 244 | deprecated_attr_warn("mem_limit"); |
9ada9da9 MK |
245 | down_read(&zram->init_lock); |
246 | val = zram->limit_pages; | |
247 | up_read(&zram->init_lock); | |
248 | ||
249 | return scnprintf(buf, PAGE_SIZE, "%llu\n", val << PAGE_SHIFT); | |
250 | } | |
251 | ||
252 | static ssize_t mem_limit_store(struct device *dev, | |
253 | struct device_attribute *attr, const char *buf, size_t len) | |
254 | { | |
255 | u64 limit; | |
256 | char *tmp; | |
257 | struct zram *zram = dev_to_zram(dev); | |
258 | ||
259 | limit = memparse(buf, &tmp); | |
260 | if (buf == tmp) /* no chars parsed, invalid input */ | |
261 | return -EINVAL; | |
262 | ||
263 | down_write(&zram->init_lock); | |
264 | zram->limit_pages = PAGE_ALIGN(limit) >> PAGE_SHIFT; | |
265 | up_write(&zram->init_lock); | |
266 | ||
267 | return len; | |
268 | } | |
269 | ||
461a8eee MK |
270 | static ssize_t mem_used_max_show(struct device *dev, |
271 | struct device_attribute *attr, char *buf) | |
272 | { | |
273 | u64 val = 0; | |
274 | struct zram *zram = dev_to_zram(dev); | |
275 | ||
8f7d282c | 276 | deprecated_attr_warn("mem_used_max"); |
461a8eee MK |
277 | down_read(&zram->init_lock); |
278 | if (init_done(zram)) | |
279 | val = atomic_long_read(&zram->stats.max_used_pages); | |
280 | up_read(&zram->init_lock); | |
281 | ||
282 | return scnprintf(buf, PAGE_SIZE, "%llu\n", val << PAGE_SHIFT); | |
283 | } | |
284 | ||
285 | static ssize_t mem_used_max_store(struct device *dev, | |
286 | struct device_attribute *attr, const char *buf, size_t len) | |
287 | { | |
288 | int err; | |
289 | unsigned long val; | |
290 | struct zram *zram = dev_to_zram(dev); | |
461a8eee MK |
291 | |
292 | err = kstrtoul(buf, 10, &val); | |
293 | if (err || val != 0) | |
294 | return -EINVAL; | |
295 | ||
296 | down_read(&zram->init_lock); | |
5a99e95b WY |
297 | if (init_done(zram)) { |
298 | struct zram_meta *meta = zram->meta; | |
461a8eee MK |
299 | atomic_long_set(&zram->stats.max_used_pages, |
300 | zs_get_total_pages(meta->mem_pool)); | |
5a99e95b | 301 | } |
461a8eee MK |
302 | up_read(&zram->init_lock); |
303 | ||
304 | return len; | |
305 | } | |
306 | ||
43209ea2 SS |
307 | /* |
308 | * We switched to per-cpu streams and this attr is not needed anymore. | |
309 | * However, we will keep it around for some time, because: | |
310 | * a) we may revert per-cpu streams in the future | |
311 | * b) it's visible to user space and we need to follow our 2 years | |
312 | * retirement rule; but we already have a number of 'soon to be | |
313 | * altered' attrs, so max_comp_streams need to wait for the next | |
314 | * layoff cycle. | |
315 | */ | |
522698d7 SS |
316 | static ssize_t max_comp_streams_show(struct device *dev, |
317 | struct device_attribute *attr, char *buf) | |
318 | { | |
43209ea2 | 319 | return scnprintf(buf, PAGE_SIZE, "%d\n", num_online_cpus()); |
522698d7 SS |
320 | } |
321 | ||
beca3ec7 SS |
322 | static ssize_t max_comp_streams_store(struct device *dev, |
323 | struct device_attribute *attr, const char *buf, size_t len) | |
324 | { | |
43209ea2 | 325 | return len; |
beca3ec7 SS |
326 | } |
327 | ||
e46b8a03 SS |
328 | static ssize_t comp_algorithm_show(struct device *dev, |
329 | struct device_attribute *attr, char *buf) | |
330 | { | |
331 | size_t sz; | |
332 | struct zram *zram = dev_to_zram(dev); | |
333 | ||
334 | down_read(&zram->init_lock); | |
335 | sz = zcomp_available_show(zram->compressor, buf); | |
336 | up_read(&zram->init_lock); | |
337 | ||
338 | return sz; | |
339 | } | |
340 | ||
341 | static ssize_t comp_algorithm_store(struct device *dev, | |
342 | struct device_attribute *attr, const char *buf, size_t len) | |
343 | { | |
344 | struct zram *zram = dev_to_zram(dev); | |
415403be | 345 | char compressor[CRYPTO_MAX_ALG_NAME]; |
4bbacd51 SS |
346 | size_t sz; |
347 | ||
415403be SS |
348 | strlcpy(compressor, buf, sizeof(compressor)); |
349 | /* ignore trailing newline */ | |
350 | sz = strlen(compressor); | |
351 | if (sz > 0 && compressor[sz - 1] == '\n') | |
352 | compressor[sz - 1] = 0x00; | |
353 | ||
354 | if (!zcomp_available_algorithm(compressor)) | |
1d5b43bf LH |
355 | return -EINVAL; |
356 | ||
e46b8a03 SS |
357 | down_write(&zram->init_lock); |
358 | if (init_done(zram)) { | |
359 | up_write(&zram->init_lock); | |
360 | pr_info("Can't change algorithm for initialized device\n"); | |
361 | return -EBUSY; | |
362 | } | |
4bbacd51 | 363 | |
415403be | 364 | strlcpy(zram->compressor, compressor, sizeof(compressor)); |
e46b8a03 SS |
365 | up_write(&zram->init_lock); |
366 | return len; | |
367 | } | |
368 | ||
522698d7 SS |
369 | static ssize_t compact_store(struct device *dev, |
370 | struct device_attribute *attr, const char *buf, size_t len) | |
306b0c95 | 371 | { |
522698d7 SS |
372 | struct zram *zram = dev_to_zram(dev); |
373 | struct zram_meta *meta; | |
306b0c95 | 374 | |
522698d7 SS |
375 | down_read(&zram->init_lock); |
376 | if (!init_done(zram)) { | |
377 | up_read(&zram->init_lock); | |
378 | return -EINVAL; | |
379 | } | |
306b0c95 | 380 | |
522698d7 | 381 | meta = zram->meta; |
7d3f3938 | 382 | zs_compact(meta->mem_pool); |
522698d7 | 383 | up_read(&zram->init_lock); |
d2d5e762 | 384 | |
522698d7 | 385 | return len; |
d2d5e762 WY |
386 | } |
387 | ||
522698d7 SS |
388 | static ssize_t io_stat_show(struct device *dev, |
389 | struct device_attribute *attr, char *buf) | |
d2d5e762 | 390 | { |
522698d7 SS |
391 | struct zram *zram = dev_to_zram(dev); |
392 | ssize_t ret; | |
d2d5e762 | 393 | |
522698d7 SS |
394 | down_read(&zram->init_lock); |
395 | ret = scnprintf(buf, PAGE_SIZE, | |
396 | "%8llu %8llu %8llu %8llu\n", | |
397 | (u64)atomic64_read(&zram->stats.failed_reads), | |
398 | (u64)atomic64_read(&zram->stats.failed_writes), | |
399 | (u64)atomic64_read(&zram->stats.invalid_io), | |
400 | (u64)atomic64_read(&zram->stats.notify_free)); | |
401 | up_read(&zram->init_lock); | |
306b0c95 | 402 | |
522698d7 | 403 | return ret; |
9b3bb7ab SS |
404 | } |
405 | ||
522698d7 SS |
406 | static ssize_t mm_stat_show(struct device *dev, |
407 | struct device_attribute *attr, char *buf) | |
9b3bb7ab | 408 | { |
522698d7 | 409 | struct zram *zram = dev_to_zram(dev); |
7d3f3938 | 410 | struct zs_pool_stats pool_stats; |
522698d7 SS |
411 | u64 orig_size, mem_used = 0; |
412 | long max_used; | |
413 | ssize_t ret; | |
a539c72a | 414 | |
7d3f3938 SS |
415 | memset(&pool_stats, 0x00, sizeof(struct zs_pool_stats)); |
416 | ||
522698d7 | 417 | down_read(&zram->init_lock); |
7d3f3938 | 418 | if (init_done(zram)) { |
522698d7 | 419 | mem_used = zs_get_total_pages(zram->meta->mem_pool); |
7d3f3938 SS |
420 | zs_pool_stats(zram->meta->mem_pool, &pool_stats); |
421 | } | |
9b3bb7ab | 422 | |
522698d7 SS |
423 | orig_size = atomic64_read(&zram->stats.pages_stored); |
424 | max_used = atomic_long_read(&zram->stats.max_used_pages); | |
9b3bb7ab | 425 | |
522698d7 | 426 | ret = scnprintf(buf, PAGE_SIZE, |
7d3f3938 | 427 | "%8llu %8llu %8llu %8lu %8ld %8llu %8lu\n", |
522698d7 SS |
428 | orig_size << PAGE_SHIFT, |
429 | (u64)atomic64_read(&zram->stats.compr_data_size), | |
430 | mem_used << PAGE_SHIFT, | |
431 | zram->limit_pages << PAGE_SHIFT, | |
432 | max_used << PAGE_SHIFT, | |
433 | (u64)atomic64_read(&zram->stats.zero_pages), | |
860c707d | 434 | pool_stats.pages_compacted); |
522698d7 | 435 | up_read(&zram->init_lock); |
9b3bb7ab | 436 | |
522698d7 SS |
437 | return ret; |
438 | } | |
439 | ||
623e47fc SS |
440 | static ssize_t debug_stat_show(struct device *dev, |
441 | struct device_attribute *attr, char *buf) | |
442 | { | |
443 | int version = 1; | |
444 | struct zram *zram = dev_to_zram(dev); | |
445 | ssize_t ret; | |
446 | ||
447 | down_read(&zram->init_lock); | |
448 | ret = scnprintf(buf, PAGE_SIZE, | |
449 | "version: %d\n%8llu\n", | |
450 | version, | |
451 | (u64)atomic64_read(&zram->stats.writestall)); | |
452 | up_read(&zram->init_lock); | |
453 | ||
454 | return ret; | |
455 | } | |
456 | ||
522698d7 SS |
457 | static DEVICE_ATTR_RO(io_stat); |
458 | static DEVICE_ATTR_RO(mm_stat); | |
623e47fc | 459 | static DEVICE_ATTR_RO(debug_stat); |
522698d7 SS |
460 | ZRAM_ATTR_RO(num_reads); |
461 | ZRAM_ATTR_RO(num_writes); | |
462 | ZRAM_ATTR_RO(failed_reads); | |
463 | ZRAM_ATTR_RO(failed_writes); | |
464 | ZRAM_ATTR_RO(invalid_io); | |
465 | ZRAM_ATTR_RO(notify_free); | |
466 | ZRAM_ATTR_RO(zero_pages); | |
467 | ZRAM_ATTR_RO(compr_data_size); | |
468 | ||
469 | static inline bool zram_meta_get(struct zram *zram) | |
470 | { | |
471 | if (atomic_inc_not_zero(&zram->refcount)) | |
472 | return true; | |
473 | return false; | |
474 | } | |
475 | ||
476 | static inline void zram_meta_put(struct zram *zram) | |
477 | { | |
478 | atomic_dec(&zram->refcount); | |
479 | } | |
480 | ||
481 | static void zram_meta_free(struct zram_meta *meta, u64 disksize) | |
482 | { | |
483 | size_t num_pages = disksize >> PAGE_SHIFT; | |
484 | size_t index; | |
1fec1172 GM |
485 | |
486 | /* Free all pages that are still in this zram device */ | |
487 | for (index = 0; index < num_pages; index++) { | |
488 | unsigned long handle = meta->table[index].handle; | |
489 | ||
490 | if (!handle) | |
491 | continue; | |
492 | ||
493 | zs_free(meta->mem_pool, handle); | |
494 | } | |
495 | ||
9b3bb7ab | 496 | zs_destroy_pool(meta->mem_pool); |
9b3bb7ab SS |
497 | vfree(meta->table); |
498 | kfree(meta); | |
499 | } | |
500 | ||
4ce321f5 | 501 | static struct zram_meta *zram_meta_alloc(char *pool_name, u64 disksize) |
9b3bb7ab SS |
502 | { |
503 | size_t num_pages; | |
504 | struct zram_meta *meta = kmalloc(sizeof(*meta), GFP_KERNEL); | |
b8179958 | 505 | |
9b3bb7ab | 506 | if (!meta) |
b8179958 | 507 | return NULL; |
9b3bb7ab | 508 | |
9b3bb7ab SS |
509 | num_pages = disksize >> PAGE_SHIFT; |
510 | meta->table = vzalloc(num_pages * sizeof(*meta->table)); | |
511 | if (!meta->table) { | |
512 | pr_err("Error allocating zram address table\n"); | |
b8179958 | 513 | goto out_error; |
9b3bb7ab SS |
514 | } |
515 | ||
d0d8da2d | 516 | meta->mem_pool = zs_create_pool(pool_name); |
9b3bb7ab SS |
517 | if (!meta->mem_pool) { |
518 | pr_err("Error creating memory pool\n"); | |
b8179958 | 519 | goto out_error; |
9b3bb7ab SS |
520 | } |
521 | ||
522 | return meta; | |
523 | ||
b8179958 | 524 | out_error: |
9b3bb7ab | 525 | vfree(meta->table); |
9b3bb7ab | 526 | kfree(meta); |
b8179958 | 527 | return NULL; |
9b3bb7ab SS |
528 | } |
529 | ||
d2d5e762 WY |
530 | /* |
531 | * To protect concurrent access to the same index entry, | |
532 | * caller should hold this table index entry's bit_spinlock to | |
533 | * indicate this index entry is accessing. | |
534 | */ | |
f1e3cfff | 535 | static void zram_free_page(struct zram *zram, size_t index) |
306b0c95 | 536 | { |
8b3cc3ed MK |
537 | struct zram_meta *meta = zram->meta; |
538 | unsigned long handle = meta->table[index].handle; | |
306b0c95 | 539 | |
fd1a30de | 540 | if (unlikely(!handle)) { |
2e882281 NG |
541 | /* |
542 | * No memory is allocated for zero filled pages. | |
543 | * Simply clear zero page flag. | |
544 | */ | |
8b3cc3ed MK |
545 | if (zram_test_flag(meta, index, ZRAM_ZERO)) { |
546 | zram_clear_flag(meta, index, ZRAM_ZERO); | |
90a7806e | 547 | atomic64_dec(&zram->stats.zero_pages); |
306b0c95 NG |
548 | } |
549 | return; | |
550 | } | |
551 | ||
8b3cc3ed | 552 | zs_free(meta->mem_pool, handle); |
306b0c95 | 553 | |
d2d5e762 WY |
554 | atomic64_sub(zram_get_obj_size(meta, index), |
555 | &zram->stats.compr_data_size); | |
90a7806e | 556 | atomic64_dec(&zram->stats.pages_stored); |
306b0c95 | 557 | |
8b3cc3ed | 558 | meta->table[index].handle = 0; |
d2d5e762 | 559 | zram_set_obj_size(meta, index, 0); |
306b0c95 NG |
560 | } |
561 | ||
37b51fdd | 562 | static int zram_decompress_page(struct zram *zram, char *mem, u32 index) |
306b0c95 | 563 | { |
b7ca232e | 564 | int ret = 0; |
37b51fdd | 565 | unsigned char *cmem; |
8b3cc3ed | 566 | struct zram_meta *meta = zram->meta; |
92967471 | 567 | unsigned long handle; |
ebaf9ab5 | 568 | unsigned int size; |
92967471 | 569 | |
d2d5e762 | 570 | bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value); |
92967471 | 571 | handle = meta->table[index].handle; |
d2d5e762 | 572 | size = zram_get_obj_size(meta, index); |
306b0c95 | 573 | |
8b3cc3ed | 574 | if (!handle || zram_test_flag(meta, index, ZRAM_ZERO)) { |
d2d5e762 | 575 | bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value); |
42e99bd9 | 576 | clear_page(mem); |
8c921b2b JM |
577 | return 0; |
578 | } | |
306b0c95 | 579 | |
8b3cc3ed | 580 | cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_RO); |
ebaf9ab5 | 581 | if (size == PAGE_SIZE) { |
42e99bd9 | 582 | copy_page(mem, cmem); |
ebaf9ab5 SS |
583 | } else { |
584 | struct zcomp_strm *zstrm = zcomp_stream_get(zram->comp); | |
585 | ||
586 | ret = zcomp_decompress(zstrm, cmem, size, mem); | |
587 | zcomp_stream_put(zram->comp); | |
588 | } | |
8b3cc3ed | 589 | zs_unmap_object(meta->mem_pool, handle); |
d2d5e762 | 590 | bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value); |
a1dd52af | 591 | |
8c921b2b | 592 | /* Should NEVER happen. Return bio error if it does. */ |
b7ca232e | 593 | if (unlikely(ret)) { |
8c921b2b | 594 | pr_err("Decompression failed! err=%d, page=%u\n", ret, index); |
8c921b2b | 595 | return ret; |
a1dd52af | 596 | } |
306b0c95 | 597 | |
8c921b2b | 598 | return 0; |
306b0c95 NG |
599 | } |
600 | ||
37b51fdd | 601 | static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec, |
b627cff3 | 602 | u32 index, int offset) |
924bd88d JM |
603 | { |
604 | int ret; | |
37b51fdd SS |
605 | struct page *page; |
606 | unsigned char *user_mem, *uncmem = NULL; | |
8b3cc3ed | 607 | struct zram_meta *meta = zram->meta; |
37b51fdd SS |
608 | page = bvec->bv_page; |
609 | ||
d2d5e762 | 610 | bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value); |
8b3cc3ed MK |
611 | if (unlikely(!meta->table[index].handle) || |
612 | zram_test_flag(meta, index, ZRAM_ZERO)) { | |
d2d5e762 | 613 | bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value); |
37b51fdd | 614 | handle_zero_page(bvec); |
924bd88d JM |
615 | return 0; |
616 | } | |
d2d5e762 | 617 | bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value); |
924bd88d | 618 | |
37b51fdd SS |
619 | if (is_partial_io(bvec)) |
620 | /* Use a temporary buffer to decompress the page */ | |
7e5a5104 MK |
621 | uncmem = kmalloc(PAGE_SIZE, GFP_NOIO); |
622 | ||
623 | user_mem = kmap_atomic(page); | |
624 | if (!is_partial_io(bvec)) | |
37b51fdd SS |
625 | uncmem = user_mem; |
626 | ||
627 | if (!uncmem) { | |
70864969 | 628 | pr_err("Unable to allocate temp memory\n"); |
37b51fdd SS |
629 | ret = -ENOMEM; |
630 | goto out_cleanup; | |
631 | } | |
924bd88d | 632 | |
37b51fdd | 633 | ret = zram_decompress_page(zram, uncmem, index); |
924bd88d | 634 | /* Should NEVER happen. Return bio error if it does. */ |
b7ca232e | 635 | if (unlikely(ret)) |
37b51fdd | 636 | goto out_cleanup; |
924bd88d | 637 | |
37b51fdd SS |
638 | if (is_partial_io(bvec)) |
639 | memcpy(user_mem + bvec->bv_offset, uncmem + offset, | |
640 | bvec->bv_len); | |
641 | ||
642 | flush_dcache_page(page); | |
643 | ret = 0; | |
644 | out_cleanup: | |
645 | kunmap_atomic(user_mem); | |
646 | if (is_partial_io(bvec)) | |
647 | kfree(uncmem); | |
648 | return ret; | |
924bd88d JM |
649 | } |
650 | ||
651 | static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, | |
652 | int offset) | |
306b0c95 | 653 | { |
397c6066 | 654 | int ret = 0; |
ebaf9ab5 | 655 | unsigned int clen; |
da9556a2 | 656 | unsigned long handle = 0; |
130f315a | 657 | struct page *page; |
924bd88d | 658 | unsigned char *user_mem, *cmem, *src, *uncmem = NULL; |
8b3cc3ed | 659 | struct zram_meta *meta = zram->meta; |
17162f41 | 660 | struct zcomp_strm *zstrm = NULL; |
461a8eee | 661 | unsigned long alloced_pages; |
306b0c95 | 662 | |
8c921b2b | 663 | page = bvec->bv_page; |
924bd88d JM |
664 | if (is_partial_io(bvec)) { |
665 | /* | |
666 | * This is a partial IO. We need to read the full page | |
667 | * before to write the changes. | |
668 | */ | |
7e5a5104 | 669 | uncmem = kmalloc(PAGE_SIZE, GFP_NOIO); |
924bd88d | 670 | if (!uncmem) { |
924bd88d JM |
671 | ret = -ENOMEM; |
672 | goto out; | |
673 | } | |
37b51fdd | 674 | ret = zram_decompress_page(zram, uncmem, index); |
397c6066 | 675 | if (ret) |
924bd88d | 676 | goto out; |
924bd88d JM |
677 | } |
678 | ||
da9556a2 | 679 | compress_again: |
ba82fe2e | 680 | user_mem = kmap_atomic(page); |
397c6066 | 681 | if (is_partial_io(bvec)) { |
924bd88d JM |
682 | memcpy(uncmem + offset, user_mem + bvec->bv_offset, |
683 | bvec->bv_len); | |
397c6066 NG |
684 | kunmap_atomic(user_mem); |
685 | user_mem = NULL; | |
686 | } else { | |
924bd88d | 687 | uncmem = user_mem; |
397c6066 | 688 | } |
924bd88d JM |
689 | |
690 | if (page_zero_filled(uncmem)) { | |
c4065152 WY |
691 | if (user_mem) |
692 | kunmap_atomic(user_mem); | |
f40ac2ae | 693 | /* Free memory associated with this sector now. */ |
d2d5e762 | 694 | bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value); |
f40ac2ae | 695 | zram_free_page(zram, index); |
92967471 | 696 | zram_set_flag(meta, index, ZRAM_ZERO); |
d2d5e762 | 697 | bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value); |
f40ac2ae | 698 | |
90a7806e | 699 | atomic64_inc(&zram->stats.zero_pages); |
924bd88d JM |
700 | ret = 0; |
701 | goto out; | |
8c921b2b | 702 | } |
306b0c95 | 703 | |
2aea8493 | 704 | zstrm = zcomp_stream_get(zram->comp); |
ebaf9ab5 | 705 | ret = zcomp_compress(zstrm, uncmem, &clen); |
397c6066 NG |
706 | if (!is_partial_io(bvec)) { |
707 | kunmap_atomic(user_mem); | |
708 | user_mem = NULL; | |
709 | uncmem = NULL; | |
710 | } | |
306b0c95 | 711 | |
b7ca232e | 712 | if (unlikely(ret)) { |
8c921b2b | 713 | pr_err("Compression failed! err=%d\n", ret); |
924bd88d | 714 | goto out; |
8c921b2b | 715 | } |
da9556a2 | 716 | |
b7ca232e | 717 | src = zstrm->buffer; |
c8f2f0db | 718 | if (unlikely(clen > max_zpage_size)) { |
c8f2f0db | 719 | clen = PAGE_SIZE; |
397c6066 NG |
720 | if (is_partial_io(bvec)) |
721 | src = uncmem; | |
c8f2f0db | 722 | } |
a1dd52af | 723 | |
da9556a2 SS |
724 | /* |
725 | * handle allocation has 2 paths: | |
726 | * a) fast path is executed with preemption disabled (for | |
727 | * per-cpu streams) and has __GFP_DIRECT_RECLAIM bit clear, | |
728 | * since we can't sleep; | |
729 | * b) slow path enables preemption and attempts to allocate | |
730 | * the page with __GFP_DIRECT_RECLAIM bit set. we have to | |
731 | * put per-cpu compression stream and, thus, to re-do | |
732 | * the compression once handle is allocated. | |
733 | * | |
734 | * if we have a 'non-null' handle here then we are coming | |
735 | * from the slow path and handle has already been allocated. | |
736 | */ | |
737 | if (!handle) | |
738 | handle = zs_malloc(meta->mem_pool, clen, | |
739 | __GFP_KSWAPD_RECLAIM | | |
740 | __GFP_NOWARN | | |
9bc482d3 MK |
741 | __GFP_HIGHMEM | |
742 | __GFP_MOVABLE); | |
fd1a30de | 743 | if (!handle) { |
2aea8493 | 744 | zcomp_stream_put(zram->comp); |
da9556a2 SS |
745 | zstrm = NULL; |
746 | ||
623e47fc SS |
747 | atomic64_inc(&zram->stats.writestall); |
748 | ||
da9556a2 | 749 | handle = zs_malloc(meta->mem_pool, clen, |
9bc482d3 MK |
750 | GFP_NOIO | __GFP_HIGHMEM | |
751 | __GFP_MOVABLE); | |
da9556a2 SS |
752 | if (handle) |
753 | goto compress_again; | |
754 | ||
ebaf9ab5 | 755 | pr_err("Error allocating memory for compressed page: %u, size=%u\n", |
596b3dd4 | 756 | index, clen); |
924bd88d JM |
757 | ret = -ENOMEM; |
758 | goto out; | |
8c921b2b | 759 | } |
9ada9da9 | 760 | |
461a8eee | 761 | alloced_pages = zs_get_total_pages(meta->mem_pool); |
12372755 SS |
762 | update_used_max(zram, alloced_pages); |
763 | ||
461a8eee | 764 | if (zram->limit_pages && alloced_pages > zram->limit_pages) { |
9ada9da9 MK |
765 | zs_free(meta->mem_pool, handle); |
766 | ret = -ENOMEM; | |
767 | goto out; | |
768 | } | |
769 | ||
8b3cc3ed | 770 | cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_WO); |
306b0c95 | 771 | |
42e99bd9 | 772 | if ((clen == PAGE_SIZE) && !is_partial_io(bvec)) { |
397c6066 | 773 | src = kmap_atomic(page); |
42e99bd9 | 774 | copy_page(cmem, src); |
397c6066 | 775 | kunmap_atomic(src); |
42e99bd9 JL |
776 | } else { |
777 | memcpy(cmem, src, clen); | |
778 | } | |
306b0c95 | 779 | |
2aea8493 | 780 | zcomp_stream_put(zram->comp); |
17162f41 | 781 | zstrm = NULL; |
8b3cc3ed | 782 | zs_unmap_object(meta->mem_pool, handle); |
fd1a30de | 783 | |
f40ac2ae SS |
784 | /* |
785 | * Free memory associated with this sector | |
786 | * before overwriting unused sectors. | |
787 | */ | |
d2d5e762 | 788 | bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value); |
f40ac2ae SS |
789 | zram_free_page(zram, index); |
790 | ||
8b3cc3ed | 791 | meta->table[index].handle = handle; |
d2d5e762 WY |
792 | zram_set_obj_size(meta, index, clen); |
793 | bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value); | |
306b0c95 | 794 | |
8c921b2b | 795 | /* Update stats */ |
90a7806e SS |
796 | atomic64_add(clen, &zram->stats.compr_data_size); |
797 | atomic64_inc(&zram->stats.pages_stored); | |
924bd88d | 798 | out: |
17162f41 | 799 | if (zstrm) |
2aea8493 | 800 | zcomp_stream_put(zram->comp); |
397c6066 NG |
801 | if (is_partial_io(bvec)) |
802 | kfree(uncmem); | |
924bd88d | 803 | return ret; |
8c921b2b JM |
804 | } |
805 | ||
f4659d8e JK |
806 | /* |
807 | * zram_bio_discard - handler on discard request | |
808 | * @index: physical block index in PAGE_SIZE units | |
809 | * @offset: byte offset within physical block | |
810 | */ | |
811 | static void zram_bio_discard(struct zram *zram, u32 index, | |
812 | int offset, struct bio *bio) | |
813 | { | |
814 | size_t n = bio->bi_iter.bi_size; | |
d2d5e762 | 815 | struct zram_meta *meta = zram->meta; |
f4659d8e JK |
816 | |
817 | /* | |
818 | * zram manages data in physical block size units. Because logical block | |
819 | * size isn't identical with physical block size on some arch, we | |
820 | * could get a discard request pointing to a specific offset within a | |
821 | * certain physical block. Although we can handle this request by | |
822 | * reading that physiclal block and decompressing and partially zeroing | |
823 | * and re-compressing and then re-storing it, this isn't reasonable | |
824 | * because our intent with a discard request is to save memory. So | |
825 | * skipping this logical block is appropriate here. | |
826 | */ | |
827 | if (offset) { | |
38515c73 | 828 | if (n <= (PAGE_SIZE - offset)) |
f4659d8e JK |
829 | return; |
830 | ||
38515c73 | 831 | n -= (PAGE_SIZE - offset); |
f4659d8e JK |
832 | index++; |
833 | } | |
834 | ||
835 | while (n >= PAGE_SIZE) { | |
d2d5e762 | 836 | bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value); |
f4659d8e | 837 | zram_free_page(zram, index); |
d2d5e762 | 838 | bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value); |
015254da | 839 | atomic64_inc(&zram->stats.notify_free); |
f4659d8e JK |
840 | index++; |
841 | n -= PAGE_SIZE; | |
842 | } | |
843 | } | |
844 | ||
522698d7 | 845 | static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index, |
c11f0c0b | 846 | int offset, bool is_write) |
9b3bb7ab | 847 | { |
522698d7 | 848 | unsigned long start_time = jiffies; |
c11f0c0b | 849 | int rw_acct = is_write ? REQ_OP_WRITE : REQ_OP_READ; |
9b3bb7ab | 850 | int ret; |
9b3bb7ab | 851 | |
c11f0c0b | 852 | generic_start_io_acct(rw_acct, bvec->bv_len >> SECTOR_SHIFT, |
522698d7 | 853 | &zram->disk->part0); |
46a51c80 | 854 | |
c11f0c0b | 855 | if (!is_write) { |
522698d7 SS |
856 | atomic64_inc(&zram->stats.num_reads); |
857 | ret = zram_bvec_read(zram, bvec, index, offset); | |
858 | } else { | |
859 | atomic64_inc(&zram->stats.num_writes); | |
860 | ret = zram_bvec_write(zram, bvec, index, offset); | |
1b672224 | 861 | } |
9b3bb7ab | 862 | |
c11f0c0b | 863 | generic_end_io_acct(rw_acct, &zram->disk->part0, start_time); |
9b3bb7ab | 864 | |
522698d7 | 865 | if (unlikely(ret)) { |
c11f0c0b | 866 | if (!is_write) |
522698d7 SS |
867 | atomic64_inc(&zram->stats.failed_reads); |
868 | else | |
869 | atomic64_inc(&zram->stats.failed_writes); | |
1b672224 | 870 | } |
9b3bb7ab | 871 | |
1b672224 | 872 | return ret; |
8c921b2b JM |
873 | } |
874 | ||
be257c61 | 875 | static void __zram_make_request(struct zram *zram, struct bio *bio) |
8c921b2b | 876 | { |
abf54548 | 877 | int offset; |
8c921b2b | 878 | u32 index; |
7988613b KO |
879 | struct bio_vec bvec; |
880 | struct bvec_iter iter; | |
8c921b2b | 881 | |
4f024f37 KO |
882 | index = bio->bi_iter.bi_sector >> SECTORS_PER_PAGE_SHIFT; |
883 | offset = (bio->bi_iter.bi_sector & | |
884 | (SECTORS_PER_PAGE - 1)) << SECTOR_SHIFT; | |
8c921b2b | 885 | |
95fe6c1a | 886 | if (unlikely(bio_op(bio) == REQ_OP_DISCARD)) { |
f4659d8e | 887 | zram_bio_discard(zram, index, offset, bio); |
4246a0b6 | 888 | bio_endio(bio); |
f4659d8e JK |
889 | return; |
890 | } | |
891 | ||
7988613b | 892 | bio_for_each_segment(bvec, bio, iter) { |
924bd88d JM |
893 | int max_transfer_size = PAGE_SIZE - offset; |
894 | ||
7988613b | 895 | if (bvec.bv_len > max_transfer_size) { |
924bd88d JM |
896 | /* |
897 | * zram_bvec_rw() can only make operation on a single | |
898 | * zram page. Split the bio vector. | |
899 | */ | |
900 | struct bio_vec bv; | |
901 | ||
7988613b | 902 | bv.bv_page = bvec.bv_page; |
924bd88d | 903 | bv.bv_len = max_transfer_size; |
7988613b | 904 | bv.bv_offset = bvec.bv_offset; |
924bd88d | 905 | |
abf54548 | 906 | if (zram_bvec_rw(zram, &bv, index, offset, |
c11f0c0b | 907 | op_is_write(bio_op(bio))) < 0) |
924bd88d JM |
908 | goto out; |
909 | ||
7988613b | 910 | bv.bv_len = bvec.bv_len - max_transfer_size; |
924bd88d | 911 | bv.bv_offset += max_transfer_size; |
abf54548 | 912 | if (zram_bvec_rw(zram, &bv, index + 1, 0, |
c11f0c0b | 913 | op_is_write(bio_op(bio))) < 0) |
924bd88d JM |
914 | goto out; |
915 | } else | |
abf54548 | 916 | if (zram_bvec_rw(zram, &bvec, index, offset, |
c11f0c0b | 917 | op_is_write(bio_op(bio))) < 0) |
924bd88d JM |
918 | goto out; |
919 | ||
7988613b | 920 | update_position(&index, &offset, &bvec); |
a1dd52af | 921 | } |
306b0c95 | 922 | |
4246a0b6 | 923 | bio_endio(bio); |
7d7854b4 | 924 | return; |
306b0c95 NG |
925 | |
926 | out: | |
306b0c95 | 927 | bio_io_error(bio); |
306b0c95 NG |
928 | } |
929 | ||
306b0c95 | 930 | /* |
f1e3cfff | 931 | * Handler function for all zram I/O requests. |
306b0c95 | 932 | */ |
dece1635 | 933 | static blk_qc_t zram_make_request(struct request_queue *queue, struct bio *bio) |
306b0c95 | 934 | { |
f1e3cfff | 935 | struct zram *zram = queue->queuedata; |
306b0c95 | 936 | |
08eee69f | 937 | if (unlikely(!zram_meta_get(zram))) |
3de738cd | 938 | goto error; |
0900beae | 939 | |
54efd50b KO |
940 | blk_queue_split(queue, &bio, queue->bio_split); |
941 | ||
54850e73 | 942 | if (!valid_io_request(zram, bio->bi_iter.bi_sector, |
943 | bio->bi_iter.bi_size)) { | |
da5cc7d3 | 944 | atomic64_inc(&zram->stats.invalid_io); |
08eee69f | 945 | goto put_zram; |
6642a67c JM |
946 | } |
947 | ||
be257c61 | 948 | __zram_make_request(zram, bio); |
08eee69f | 949 | zram_meta_put(zram); |
dece1635 | 950 | return BLK_QC_T_NONE; |
08eee69f MK |
951 | put_zram: |
952 | zram_meta_put(zram); | |
0900beae JM |
953 | error: |
954 | bio_io_error(bio); | |
dece1635 | 955 | return BLK_QC_T_NONE; |
306b0c95 NG |
956 | } |
957 | ||
2ccbec05 NG |
958 | static void zram_slot_free_notify(struct block_device *bdev, |
959 | unsigned long index) | |
107c161b | 960 | { |
f1e3cfff | 961 | struct zram *zram; |
f614a9f4 | 962 | struct zram_meta *meta; |
107c161b | 963 | |
f1e3cfff | 964 | zram = bdev->bd_disk->private_data; |
f614a9f4 | 965 | meta = zram->meta; |
a0c516cb | 966 | |
d2d5e762 | 967 | bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value); |
f614a9f4 | 968 | zram_free_page(zram, index); |
d2d5e762 | 969 | bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value); |
f614a9f4 | 970 | atomic64_inc(&zram->stats.notify_free); |
107c161b NG |
971 | } |
972 | ||
8c7f0102 | 973 | static int zram_rw_page(struct block_device *bdev, sector_t sector, |
c11f0c0b | 974 | struct page *page, bool is_write) |
8c7f0102 | 975 | { |
08eee69f | 976 | int offset, err = -EIO; |
8c7f0102 | 977 | u32 index; |
978 | struct zram *zram; | |
979 | struct bio_vec bv; | |
980 | ||
981 | zram = bdev->bd_disk->private_data; | |
08eee69f MK |
982 | if (unlikely(!zram_meta_get(zram))) |
983 | goto out; | |
984 | ||
8c7f0102 | 985 | if (!valid_io_request(zram, sector, PAGE_SIZE)) { |
986 | atomic64_inc(&zram->stats.invalid_io); | |
08eee69f MK |
987 | err = -EINVAL; |
988 | goto put_zram; | |
8c7f0102 | 989 | } |
990 | ||
991 | index = sector >> SECTORS_PER_PAGE_SHIFT; | |
992 | offset = sector & (SECTORS_PER_PAGE - 1) << SECTOR_SHIFT; | |
993 | ||
994 | bv.bv_page = page; | |
995 | bv.bv_len = PAGE_SIZE; | |
996 | bv.bv_offset = 0; | |
997 | ||
c11f0c0b | 998 | err = zram_bvec_rw(zram, &bv, index, offset, is_write); |
08eee69f MK |
999 | put_zram: |
1000 | zram_meta_put(zram); | |
1001 | out: | |
8c7f0102 | 1002 | /* |
1003 | * If I/O fails, just return error(ie, non-zero) without | |
1004 | * calling page_endio. | |
1005 | * It causes resubmit the I/O with bio request by upper functions | |
1006 | * of rw_page(e.g., swap_readpage, __swap_writepage) and | |
1007 | * bio->bi_end_io does things to handle the error | |
1008 | * (e.g., SetPageError, set_page_dirty and extra works). | |
1009 | */ | |
1010 | if (err == 0) | |
c11f0c0b | 1011 | page_endio(page, is_write, 0); |
8c7f0102 | 1012 | return err; |
1013 | } | |
1014 | ||
522698d7 SS |
1015 | static void zram_reset_device(struct zram *zram) |
1016 | { | |
1017 | struct zram_meta *meta; | |
1018 | struct zcomp *comp; | |
1019 | u64 disksize; | |
306b0c95 | 1020 | |
522698d7 | 1021 | down_write(&zram->init_lock); |
9b3bb7ab | 1022 | |
522698d7 SS |
1023 | zram->limit_pages = 0; |
1024 | ||
1025 | if (!init_done(zram)) { | |
1026 | up_write(&zram->init_lock); | |
1027 | return; | |
1028 | } | |
1029 | ||
1030 | meta = zram->meta; | |
1031 | comp = zram->comp; | |
1032 | disksize = zram->disksize; | |
1033 | /* | |
1034 | * Refcount will go down to 0 eventually and r/w handler | |
1035 | * cannot handle further I/O so it will bail out by | |
1036 | * check zram_meta_get. | |
1037 | */ | |
1038 | zram_meta_put(zram); | |
1039 | /* | |
1040 | * We want to free zram_meta in process context to avoid | |
1041 | * deadlock between reclaim path and any other locks. | |
1042 | */ | |
1043 | wait_event(zram->io_done, atomic_read(&zram->refcount) == 0); | |
1044 | ||
1045 | /* Reset stats */ | |
1046 | memset(&zram->stats, 0, sizeof(zram->stats)); | |
1047 | zram->disksize = 0; | |
522698d7 SS |
1048 | |
1049 | set_capacity(zram->disk, 0); | |
1050 | part_stat_set_all(&zram->disk->part0, 0); | |
1051 | ||
1052 | up_write(&zram->init_lock); | |
1053 | /* I/O operation under all of CPU are done so let's free */ | |
1054 | zram_meta_free(meta, disksize); | |
1055 | zcomp_destroy(comp); | |
1056 | } | |
1057 | ||
1058 | static ssize_t disksize_store(struct device *dev, | |
1059 | struct device_attribute *attr, const char *buf, size_t len) | |
2f6a3bed | 1060 | { |
522698d7 SS |
1061 | u64 disksize; |
1062 | struct zcomp *comp; | |
1063 | struct zram_meta *meta; | |
2f6a3bed | 1064 | struct zram *zram = dev_to_zram(dev); |
522698d7 | 1065 | int err; |
2f6a3bed | 1066 | |
522698d7 SS |
1067 | disksize = memparse(buf, NULL); |
1068 | if (!disksize) | |
1069 | return -EINVAL; | |
2f6a3bed | 1070 | |
522698d7 | 1071 | disksize = PAGE_ALIGN(disksize); |
4ce321f5 | 1072 | meta = zram_meta_alloc(zram->disk->disk_name, disksize); |
522698d7 SS |
1073 | if (!meta) |
1074 | return -ENOMEM; | |
1075 | ||
da9556a2 | 1076 | comp = zcomp_create(zram->compressor); |
522698d7 | 1077 | if (IS_ERR(comp)) { |
70864969 | 1078 | pr_err("Cannot initialise %s compressing backend\n", |
522698d7 SS |
1079 | zram->compressor); |
1080 | err = PTR_ERR(comp); | |
1081 | goto out_free_meta; | |
1082 | } | |
1083 | ||
1084 | down_write(&zram->init_lock); | |
1085 | if (init_done(zram)) { | |
1086 | pr_info("Cannot change disksize for initialized device\n"); | |
1087 | err = -EBUSY; | |
1088 | goto out_destroy_comp; | |
1089 | } | |
1090 | ||
1091 | init_waitqueue_head(&zram->io_done); | |
1092 | atomic_set(&zram->refcount, 1); | |
1093 | zram->meta = meta; | |
1094 | zram->comp = comp; | |
1095 | zram->disksize = disksize; | |
1096 | set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT); | |
1097 | up_write(&zram->init_lock); | |
1098 | ||
1099 | /* | |
1100 | * Revalidate disk out of the init_lock to avoid lockdep splat. | |
1101 | * It's okay because disk's capacity is protected by init_lock | |
1102 | * so that revalidate_disk always sees up-to-date capacity. | |
1103 | */ | |
1104 | revalidate_disk(zram->disk); | |
1105 | ||
1106 | return len; | |
1107 | ||
1108 | out_destroy_comp: | |
1109 | up_write(&zram->init_lock); | |
1110 | zcomp_destroy(comp); | |
1111 | out_free_meta: | |
1112 | zram_meta_free(meta, disksize); | |
1113 | return err; | |
2f6a3bed SS |
1114 | } |
1115 | ||
522698d7 SS |
1116 | static ssize_t reset_store(struct device *dev, |
1117 | struct device_attribute *attr, const char *buf, size_t len) | |
4f2109f6 | 1118 | { |
522698d7 SS |
1119 | int ret; |
1120 | unsigned short do_reset; | |
1121 | struct zram *zram; | |
1122 | struct block_device *bdev; | |
4f2109f6 | 1123 | |
f405c445 SS |
1124 | ret = kstrtou16(buf, 10, &do_reset); |
1125 | if (ret) | |
1126 | return ret; | |
1127 | ||
1128 | if (!do_reset) | |
1129 | return -EINVAL; | |
1130 | ||
522698d7 SS |
1131 | zram = dev_to_zram(dev); |
1132 | bdev = bdget_disk(zram->disk, 0); | |
522698d7 SS |
1133 | if (!bdev) |
1134 | return -ENOMEM; | |
4f2109f6 | 1135 | |
522698d7 | 1136 | mutex_lock(&bdev->bd_mutex); |
f405c445 SS |
1137 | /* Do not reset an active device or claimed device */ |
1138 | if (bdev->bd_openers || zram->claim) { | |
1139 | mutex_unlock(&bdev->bd_mutex); | |
1140 | bdput(bdev); | |
1141 | return -EBUSY; | |
522698d7 SS |
1142 | } |
1143 | ||
f405c445 SS |
1144 | /* From now on, anyone can't open /dev/zram[0-9] */ |
1145 | zram->claim = true; | |
1146 | mutex_unlock(&bdev->bd_mutex); | |
522698d7 | 1147 | |
f405c445 | 1148 | /* Make sure all the pending I/O are finished */ |
522698d7 SS |
1149 | fsync_bdev(bdev); |
1150 | zram_reset_device(zram); | |
522698d7 SS |
1151 | revalidate_disk(zram->disk); |
1152 | bdput(bdev); | |
1153 | ||
f405c445 SS |
1154 | mutex_lock(&bdev->bd_mutex); |
1155 | zram->claim = false; | |
1156 | mutex_unlock(&bdev->bd_mutex); | |
1157 | ||
522698d7 | 1158 | return len; |
f405c445 SS |
1159 | } |
1160 | ||
1161 | static int zram_open(struct block_device *bdev, fmode_t mode) | |
1162 | { | |
1163 | int ret = 0; | |
1164 | struct zram *zram; | |
1165 | ||
1166 | WARN_ON(!mutex_is_locked(&bdev->bd_mutex)); | |
1167 | ||
1168 | zram = bdev->bd_disk->private_data; | |
1169 | /* zram was claimed to reset so open request fails */ | |
1170 | if (zram->claim) | |
1171 | ret = -EBUSY; | |
4f2109f6 SS |
1172 | |
1173 | return ret; | |
1174 | } | |
1175 | ||
522698d7 | 1176 | static const struct block_device_operations zram_devops = { |
f405c445 | 1177 | .open = zram_open, |
522698d7 SS |
1178 | .swap_slot_free_notify = zram_slot_free_notify, |
1179 | .rw_page = zram_rw_page, | |
1180 | .owner = THIS_MODULE | |
1181 | }; | |
1182 | ||
1183 | static DEVICE_ATTR_WO(compact); | |
1184 | static DEVICE_ATTR_RW(disksize); | |
1185 | static DEVICE_ATTR_RO(initstate); | |
1186 | static DEVICE_ATTR_WO(reset); | |
1187 | static DEVICE_ATTR_RO(orig_data_size); | |
1188 | static DEVICE_ATTR_RO(mem_used_total); | |
1189 | static DEVICE_ATTR_RW(mem_limit); | |
1190 | static DEVICE_ATTR_RW(mem_used_max); | |
1191 | static DEVICE_ATTR_RW(max_comp_streams); | |
1192 | static DEVICE_ATTR_RW(comp_algorithm); | |
a68eb3b6 | 1193 | |
9b3bb7ab SS |
1194 | static struct attribute *zram_disk_attrs[] = { |
1195 | &dev_attr_disksize.attr, | |
1196 | &dev_attr_initstate.attr, | |
1197 | &dev_attr_reset.attr, | |
1198 | &dev_attr_num_reads.attr, | |
1199 | &dev_attr_num_writes.attr, | |
64447249 SS |
1200 | &dev_attr_failed_reads.attr, |
1201 | &dev_attr_failed_writes.attr, | |
99ebbd30 | 1202 | &dev_attr_compact.attr, |
9b3bb7ab SS |
1203 | &dev_attr_invalid_io.attr, |
1204 | &dev_attr_notify_free.attr, | |
1205 | &dev_attr_zero_pages.attr, | |
1206 | &dev_attr_orig_data_size.attr, | |
1207 | &dev_attr_compr_data_size.attr, | |
1208 | &dev_attr_mem_used_total.attr, | |
9ada9da9 | 1209 | &dev_attr_mem_limit.attr, |
461a8eee | 1210 | &dev_attr_mem_used_max.attr, |
beca3ec7 | 1211 | &dev_attr_max_comp_streams.attr, |
e46b8a03 | 1212 | &dev_attr_comp_algorithm.attr, |
2f6a3bed | 1213 | &dev_attr_io_stat.attr, |
4f2109f6 | 1214 | &dev_attr_mm_stat.attr, |
623e47fc | 1215 | &dev_attr_debug_stat.attr, |
9b3bb7ab SS |
1216 | NULL, |
1217 | }; | |
1218 | ||
1219 | static struct attribute_group zram_disk_attr_group = { | |
1220 | .attrs = zram_disk_attrs, | |
1221 | }; | |
1222 | ||
92ff1528 SS |
1223 | /* |
1224 | * Allocate and initialize new zram device. the function returns | |
1225 | * '>= 0' device_id upon success, and negative value otherwise. | |
1226 | */ | |
1227 | static int zram_add(void) | |
306b0c95 | 1228 | { |
85508ec6 | 1229 | struct zram *zram; |
ee980160 | 1230 | struct request_queue *queue; |
92ff1528 | 1231 | int ret, device_id; |
85508ec6 SS |
1232 | |
1233 | zram = kzalloc(sizeof(struct zram), GFP_KERNEL); | |
1234 | if (!zram) | |
1235 | return -ENOMEM; | |
1236 | ||
92ff1528 | 1237 | ret = idr_alloc(&zram_index_idr, zram, 0, 0, GFP_KERNEL); |
85508ec6 SS |
1238 | if (ret < 0) |
1239 | goto out_free_dev; | |
92ff1528 | 1240 | device_id = ret; |
de1a21a0 | 1241 | |
0900beae | 1242 | init_rwsem(&zram->init_lock); |
306b0c95 | 1243 | |
ee980160 SS |
1244 | queue = blk_alloc_queue(GFP_KERNEL); |
1245 | if (!queue) { | |
306b0c95 NG |
1246 | pr_err("Error allocating disk queue for device %d\n", |
1247 | device_id); | |
85508ec6 SS |
1248 | ret = -ENOMEM; |
1249 | goto out_free_idr; | |
306b0c95 NG |
1250 | } |
1251 | ||
ee980160 | 1252 | blk_queue_make_request(queue, zram_make_request); |
306b0c95 | 1253 | |
85508ec6 | 1254 | /* gendisk structure */ |
f1e3cfff NG |
1255 | zram->disk = alloc_disk(1); |
1256 | if (!zram->disk) { | |
70864969 | 1257 | pr_err("Error allocating disk structure for device %d\n", |
306b0c95 | 1258 | device_id); |
201c7b72 | 1259 | ret = -ENOMEM; |
39a9b8ac | 1260 | goto out_free_queue; |
306b0c95 NG |
1261 | } |
1262 | ||
f1e3cfff NG |
1263 | zram->disk->major = zram_major; |
1264 | zram->disk->first_minor = device_id; | |
1265 | zram->disk->fops = &zram_devops; | |
ee980160 SS |
1266 | zram->disk->queue = queue; |
1267 | zram->disk->queue->queuedata = zram; | |
f1e3cfff NG |
1268 | zram->disk->private_data = zram; |
1269 | snprintf(zram->disk->disk_name, 16, "zram%d", device_id); | |
306b0c95 | 1270 | |
33863c21 | 1271 | /* Actual capacity set using syfs (/sys/block/zram<id>/disksize */ |
f1e3cfff | 1272 | set_capacity(zram->disk, 0); |
b67d1ec1 SS |
1273 | /* zram devices sort of resembles non-rotational disks */ |
1274 | queue_flag_set_unlocked(QUEUE_FLAG_NONROT, zram->disk->queue); | |
b277da0a | 1275 | queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, zram->disk->queue); |
a1dd52af NG |
1276 | /* |
1277 | * To ensure that we always get PAGE_SIZE aligned | |
1278 | * and n*PAGE_SIZED sized I/O requests. | |
1279 | */ | |
f1e3cfff | 1280 | blk_queue_physical_block_size(zram->disk->queue, PAGE_SIZE); |
7b19b8d4 RJ |
1281 | blk_queue_logical_block_size(zram->disk->queue, |
1282 | ZRAM_LOGICAL_BLOCK_SIZE); | |
f1e3cfff NG |
1283 | blk_queue_io_min(zram->disk->queue, PAGE_SIZE); |
1284 | blk_queue_io_opt(zram->disk->queue, PAGE_SIZE); | |
f4659d8e | 1285 | zram->disk->queue->limits.discard_granularity = PAGE_SIZE; |
2bb4cd5c | 1286 | blk_queue_max_discard_sectors(zram->disk->queue, UINT_MAX); |
f4659d8e JK |
1287 | /* |
1288 | * zram_bio_discard() will clear all logical blocks if logical block | |
1289 | * size is identical with physical block size(PAGE_SIZE). But if it is | |
1290 | * different, we will skip discarding some parts of logical blocks in | |
1291 | * the part of the request range which isn't aligned to physical block | |
1292 | * size. So we can't ensure that all discarded logical blocks are | |
1293 | * zeroed. | |
1294 | */ | |
1295 | if (ZRAM_LOGICAL_BLOCK_SIZE == PAGE_SIZE) | |
1296 | zram->disk->queue->limits.discard_zeroes_data = 1; | |
1297 | else | |
1298 | zram->disk->queue->limits.discard_zeroes_data = 0; | |
1299 | queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, zram->disk->queue); | |
5d83d5a0 | 1300 | |
f1e3cfff | 1301 | add_disk(zram->disk); |
306b0c95 | 1302 | |
33863c21 NG |
1303 | ret = sysfs_create_group(&disk_to_dev(zram->disk)->kobj, |
1304 | &zram_disk_attr_group); | |
1305 | if (ret < 0) { | |
70864969 SS |
1306 | pr_err("Error creating sysfs group for device %d\n", |
1307 | device_id); | |
39a9b8ac | 1308 | goto out_free_disk; |
33863c21 | 1309 | } |
e46b8a03 | 1310 | strlcpy(zram->compressor, default_compressor, sizeof(zram->compressor)); |
be2d1d56 | 1311 | zram->meta = NULL; |
d12b63c9 SS |
1312 | |
1313 | pr_info("Added device: %s\n", zram->disk->disk_name); | |
92ff1528 | 1314 | return device_id; |
de1a21a0 | 1315 | |
39a9b8ac JL |
1316 | out_free_disk: |
1317 | del_gendisk(zram->disk); | |
1318 | put_disk(zram->disk); | |
1319 | out_free_queue: | |
ee980160 | 1320 | blk_cleanup_queue(queue); |
85508ec6 SS |
1321 | out_free_idr: |
1322 | idr_remove(&zram_index_idr, device_id); | |
1323 | out_free_dev: | |
1324 | kfree(zram); | |
de1a21a0 | 1325 | return ret; |
306b0c95 NG |
1326 | } |
1327 | ||
6566d1a3 | 1328 | static int zram_remove(struct zram *zram) |
306b0c95 | 1329 | { |
6566d1a3 SS |
1330 | struct block_device *bdev; |
1331 | ||
1332 | bdev = bdget_disk(zram->disk, 0); | |
1333 | if (!bdev) | |
1334 | return -ENOMEM; | |
1335 | ||
1336 | mutex_lock(&bdev->bd_mutex); | |
1337 | if (bdev->bd_openers || zram->claim) { | |
1338 | mutex_unlock(&bdev->bd_mutex); | |
1339 | bdput(bdev); | |
1340 | return -EBUSY; | |
1341 | } | |
1342 | ||
1343 | zram->claim = true; | |
1344 | mutex_unlock(&bdev->bd_mutex); | |
1345 | ||
85508ec6 SS |
1346 | /* |
1347 | * Remove sysfs first, so no one will perform a disksize | |
6566d1a3 SS |
1348 | * store while we destroy the devices. This also helps during |
1349 | * hot_remove -- zram_reset_device() is the last holder of | |
1350 | * ->init_lock, no later/concurrent disksize_store() or any | |
1351 | * other sysfs handlers are possible. | |
85508ec6 SS |
1352 | */ |
1353 | sysfs_remove_group(&disk_to_dev(zram->disk)->kobj, | |
1354 | &zram_disk_attr_group); | |
306b0c95 | 1355 | |
6566d1a3 SS |
1356 | /* Make sure all the pending I/O are finished */ |
1357 | fsync_bdev(bdev); | |
85508ec6 | 1358 | zram_reset_device(zram); |
6566d1a3 SS |
1359 | bdput(bdev); |
1360 | ||
1361 | pr_info("Removed device: %s\n", zram->disk->disk_name); | |
1362 | ||
85508ec6 SS |
1363 | blk_cleanup_queue(zram->disk->queue); |
1364 | del_gendisk(zram->disk); | |
1365 | put_disk(zram->disk); | |
1366 | kfree(zram); | |
6566d1a3 SS |
1367 | return 0; |
1368 | } | |
1369 | ||
1370 | /* zram-control sysfs attributes */ | |
1371 | static ssize_t hot_add_show(struct class *class, | |
1372 | struct class_attribute *attr, | |
1373 | char *buf) | |
1374 | { | |
1375 | int ret; | |
1376 | ||
1377 | mutex_lock(&zram_index_mutex); | |
1378 | ret = zram_add(); | |
1379 | mutex_unlock(&zram_index_mutex); | |
1380 | ||
1381 | if (ret < 0) | |
1382 | return ret; | |
1383 | return scnprintf(buf, PAGE_SIZE, "%d\n", ret); | |
1384 | } | |
1385 | ||
1386 | static ssize_t hot_remove_store(struct class *class, | |
1387 | struct class_attribute *attr, | |
1388 | const char *buf, | |
1389 | size_t count) | |
1390 | { | |
1391 | struct zram *zram; | |
1392 | int ret, dev_id; | |
1393 | ||
1394 | /* dev_id is gendisk->first_minor, which is `int' */ | |
1395 | ret = kstrtoint(buf, 10, &dev_id); | |
1396 | if (ret) | |
1397 | return ret; | |
1398 | if (dev_id < 0) | |
1399 | return -EINVAL; | |
1400 | ||
1401 | mutex_lock(&zram_index_mutex); | |
1402 | ||
1403 | zram = idr_find(&zram_index_idr, dev_id); | |
17ec4cd9 | 1404 | if (zram) { |
6566d1a3 | 1405 | ret = zram_remove(zram); |
17ec4cd9 JM |
1406 | idr_remove(&zram_index_idr, dev_id); |
1407 | } else { | |
6566d1a3 | 1408 | ret = -ENODEV; |
17ec4cd9 | 1409 | } |
6566d1a3 SS |
1410 | |
1411 | mutex_unlock(&zram_index_mutex); | |
1412 | return ret ? ret : count; | |
85508ec6 | 1413 | } |
a096cafc | 1414 | |
6566d1a3 SS |
1415 | static struct class_attribute zram_control_class_attrs[] = { |
1416 | __ATTR_RO(hot_add), | |
1417 | __ATTR_WO(hot_remove), | |
1418 | __ATTR_NULL, | |
1419 | }; | |
1420 | ||
1421 | static struct class zram_control_class = { | |
1422 | .name = "zram-control", | |
1423 | .owner = THIS_MODULE, | |
1424 | .class_attrs = zram_control_class_attrs, | |
1425 | }; | |
1426 | ||
85508ec6 SS |
1427 | static int zram_remove_cb(int id, void *ptr, void *data) |
1428 | { | |
1429 | zram_remove(ptr); | |
1430 | return 0; | |
1431 | } | |
a096cafc | 1432 | |
85508ec6 SS |
1433 | static void destroy_devices(void) |
1434 | { | |
6566d1a3 | 1435 | class_unregister(&zram_control_class); |
85508ec6 SS |
1436 | idr_for_each(&zram_index_idr, &zram_remove_cb, NULL); |
1437 | idr_destroy(&zram_index_idr); | |
a096cafc | 1438 | unregister_blkdev(zram_major, "zram"); |
306b0c95 NG |
1439 | } |
1440 | ||
f1e3cfff | 1441 | static int __init zram_init(void) |
306b0c95 | 1442 | { |
92ff1528 | 1443 | int ret; |
306b0c95 | 1444 | |
6566d1a3 SS |
1445 | ret = class_register(&zram_control_class); |
1446 | if (ret) { | |
70864969 | 1447 | pr_err("Unable to register zram-control class\n"); |
6566d1a3 SS |
1448 | return ret; |
1449 | } | |
1450 | ||
f1e3cfff NG |
1451 | zram_major = register_blkdev(0, "zram"); |
1452 | if (zram_major <= 0) { | |
70864969 | 1453 | pr_err("Unable to get major number\n"); |
6566d1a3 | 1454 | class_unregister(&zram_control_class); |
a096cafc | 1455 | return -EBUSY; |
306b0c95 NG |
1456 | } |
1457 | ||
92ff1528 | 1458 | while (num_devices != 0) { |
6566d1a3 | 1459 | mutex_lock(&zram_index_mutex); |
92ff1528 | 1460 | ret = zram_add(); |
6566d1a3 | 1461 | mutex_unlock(&zram_index_mutex); |
92ff1528 | 1462 | if (ret < 0) |
a096cafc | 1463 | goto out_error; |
92ff1528 | 1464 | num_devices--; |
de1a21a0 NG |
1465 | } |
1466 | ||
306b0c95 | 1467 | return 0; |
de1a21a0 | 1468 | |
a096cafc | 1469 | out_error: |
85508ec6 | 1470 | destroy_devices(); |
306b0c95 NG |
1471 | return ret; |
1472 | } | |
1473 | ||
f1e3cfff | 1474 | static void __exit zram_exit(void) |
306b0c95 | 1475 | { |
85508ec6 | 1476 | destroy_devices(); |
306b0c95 NG |
1477 | } |
1478 | ||
f1e3cfff NG |
1479 | module_init(zram_init); |
1480 | module_exit(zram_exit); | |
306b0c95 | 1481 | |
9b3bb7ab | 1482 | module_param(num_devices, uint, 0); |
c3cdb40e | 1483 | MODULE_PARM_DESC(num_devices, "Number of pre-created zram devices"); |
9b3bb7ab | 1484 | |
306b0c95 NG |
1485 | MODULE_LICENSE("Dual BSD/GPL"); |
1486 | MODULE_AUTHOR("Nitin Gupta <ngupta@vflare.org>"); | |
f1e3cfff | 1487 | MODULE_DESCRIPTION("Compressed RAM Block Device"); |