1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * (C) 2001 Clemson University and The University of Chicago
4 *
5 * See COPYING in top-level directory.
6 */
7 #include "protocol.h"
8 #include "orangefs-kernel.h"
9 #include "orangefs-bufmap.h"
10
11 struct slot_map {
12 int c;
13 wait_queue_head_t q;
14 int count;
15 unsigned long *map;
16 };
17
18 static struct slot_map rw_map = {
19 .c = -1,
20 .q = __WAIT_QUEUE_HEAD_INITIALIZER(rw_map.q)
21 };
22 static struct slot_map readdir_map = {
23 .c = -1,
24 .q = __WAIT_QUEUE_HEAD_INITIALIZER(readdir_map.q)
25 };
26
27
install(struct slot_map * m,int count,unsigned long * map)28 static void install(struct slot_map *m, int count, unsigned long *map)
29 {
30 spin_lock(&m->q.lock);
31 m->c = m->count = count;
32 m->map = map;
33 wake_up_all_locked(&m->q);
34 spin_unlock(&m->q.lock);
35 }
36
mark_killed(struct slot_map * m)37 static void mark_killed(struct slot_map *m)
38 {
39 spin_lock(&m->q.lock);
40 m->c -= m->count + 1;
41 spin_unlock(&m->q.lock);
42 }
43
run_down(struct slot_map * m)44 static void run_down(struct slot_map *m)
45 {
46 DEFINE_WAIT(wait);
47 spin_lock(&m->q.lock);
48 if (m->c != -1) {
49 for (;;) {
50 if (likely(list_empty(&wait.entry)))
51 __add_wait_queue_entry_tail(&m->q, &wait);
52 set_current_state(TASK_UNINTERRUPTIBLE);
53
54 if (m->c == -1)
55 break;
56
57 spin_unlock(&m->q.lock);
58 schedule();
59 spin_lock(&m->q.lock);
60 }
61 __remove_wait_queue(&m->q, &wait);
62 __set_current_state(TASK_RUNNING);
63 }
64 m->map = NULL;
65 spin_unlock(&m->q.lock);
66 }
67
put(struct slot_map * m,int slot)68 static void put(struct slot_map *m, int slot)
69 {
70 int v;
71 spin_lock(&m->q.lock);
72 __clear_bit(slot, m->map);
73 v = ++m->c;
74 if (v > 0)
75 wake_up_locked(&m->q);
76 if (unlikely(v == -1)) /* finished dying */
77 wake_up_all_locked(&m->q);
78 spin_unlock(&m->q.lock);
79 }
80
wait_for_free(struct slot_map * m)81 static int wait_for_free(struct slot_map *m)
82 {
83 long left = slot_timeout_secs * HZ;
84 DEFINE_WAIT(wait);
85
86 do {
87 long n = left, t;
88 if (likely(list_empty(&wait.entry)))
89 __add_wait_queue_entry_tail_exclusive(&m->q, &wait);
90 set_current_state(TASK_INTERRUPTIBLE);
91
92 if (m->c > 0)
93 break;
94
95 if (m->c < 0) {
96 /* we are waiting for map to be installed */
97 /* it would better be there soon, or we go away */
98 if (n > ORANGEFS_BUFMAP_WAIT_TIMEOUT_SECS * HZ)
99 n = ORANGEFS_BUFMAP_WAIT_TIMEOUT_SECS * HZ;
100 }
101 spin_unlock(&m->q.lock);
102 t = schedule_timeout(n);
103 spin_lock(&m->q.lock);
104 if (unlikely(!t) && n != left && m->c < 0)
105 left = t;
106 else
107 left = t + (left - n);
108 if (signal_pending(current))
109 left = -EINTR;
110 } while (left > 0);
111
112 if (!list_empty(&wait.entry))
113 list_del(&wait.entry);
114 else if (left <= 0 && waitqueue_active(&m->q))
115 __wake_up_locked_key(&m->q, TASK_INTERRUPTIBLE, NULL);
116 __set_current_state(TASK_RUNNING);
117
118 if (likely(left > 0))
119 return 0;
120
121 return left < 0 ? -EINTR : -ETIMEDOUT;
122 }
123
get(struct slot_map * m)124 static int get(struct slot_map *m)
125 {
126 int res = 0;
127 spin_lock(&m->q.lock);
128 if (unlikely(m->c <= 0))
129 res = wait_for_free(m);
130 if (likely(!res)) {
131 m->c--;
132 res = find_first_zero_bit(m->map, m->count);
133 __set_bit(res, m->map);
134 }
135 spin_unlock(&m->q.lock);
136 return res;
137 }
138
139 /* used to describe mapped buffers */
140 struct orangefs_bufmap_desc {
141 void __user *uaddr; /* user space address pointer */
142 struct page **page_array; /* array of mapped pages */
143 int array_count; /* size of above arrays */
144 struct list_head list_link;
145 };
146
147 static struct orangefs_bufmap {
148 int desc_size;
149 int desc_shift;
150 int desc_count;
151 int total_size;
152 int page_count;
153
154 struct page **page_array;
155 struct orangefs_bufmap_desc *desc_array;
156
157 /* array to track usage of buffer descriptors */
158 unsigned long *buffer_index_array;
159
160 /* array to track usage of buffer descriptors for readdir */
161 #define N DIV_ROUND_UP(ORANGEFS_READDIR_DEFAULT_DESC_COUNT, BITS_PER_LONG)
162 unsigned long readdir_index_array[N];
163 #undef N
164 } *__orangefs_bufmap;
165
166 static DEFINE_SPINLOCK(orangefs_bufmap_lock);
167
168 static void
orangefs_bufmap_unmap(struct orangefs_bufmap * bufmap)169 orangefs_bufmap_unmap(struct orangefs_bufmap *bufmap)
170 {
171 unpin_user_pages(bufmap->page_array, bufmap->page_count);
172 }
173
174 static void
orangefs_bufmap_free(struct orangefs_bufmap * bufmap)175 orangefs_bufmap_free(struct orangefs_bufmap *bufmap)
176 {
177 kfree(bufmap->page_array);
178 kfree(bufmap->desc_array);
179 bitmap_free(bufmap->buffer_index_array);
180 kfree(bufmap);
181 }
182
183 /*
184 * XXX: Can the size and shift change while the caller gives up the
185 * XXX: lock between calling this and doing something useful?
186 */
187
orangefs_bufmap_size_query(void)188 int orangefs_bufmap_size_query(void)
189 {
190 struct orangefs_bufmap *bufmap;
191 int size = 0;
192 spin_lock(&orangefs_bufmap_lock);
193 bufmap = __orangefs_bufmap;
194 if (bufmap)
195 size = bufmap->desc_size;
196 spin_unlock(&orangefs_bufmap_lock);
197 return size;
198 }
199
orangefs_bufmap_shift_query(void)200 int orangefs_bufmap_shift_query(void)
201 {
202 struct orangefs_bufmap *bufmap;
203 int shift = 0;
204 spin_lock(&orangefs_bufmap_lock);
205 bufmap = __orangefs_bufmap;
206 if (bufmap)
207 shift = bufmap->desc_shift;
208 spin_unlock(&orangefs_bufmap_lock);
209 return shift;
210 }
211
212 static DECLARE_WAIT_QUEUE_HEAD(bufmap_waitq);
213 static DECLARE_WAIT_QUEUE_HEAD(readdir_waitq);
214
215 static struct orangefs_bufmap *
orangefs_bufmap_alloc(struct ORANGEFS_dev_map_desc * user_desc)216 orangefs_bufmap_alloc(struct ORANGEFS_dev_map_desc *user_desc)
217 {
218 struct orangefs_bufmap *bufmap;
219
220 bufmap = kzalloc(sizeof(*bufmap), GFP_KERNEL);
221 if (!bufmap)
222 goto out;
223
224 bufmap->total_size = user_desc->total_size;
225 bufmap->desc_count = user_desc->count;
226 bufmap->desc_size = user_desc->size;
227 bufmap->desc_shift = ilog2(bufmap->desc_size);
228
229 bufmap->buffer_index_array = bitmap_zalloc(bufmap->desc_count, GFP_KERNEL);
230 if (!bufmap->buffer_index_array)
231 goto out_free_bufmap;
232
233 bufmap->desc_array =
234 kcalloc(bufmap->desc_count, sizeof(struct orangefs_bufmap_desc),
235 GFP_KERNEL);
236 if (!bufmap->desc_array)
237 goto out_free_index_array;
238
239 bufmap->page_count = bufmap->total_size / PAGE_SIZE;
240
241 /* allocate storage to track our page mappings */
242 bufmap->page_array =
243 kcalloc(bufmap->page_count, sizeof(struct page *), GFP_KERNEL);
244 if (!bufmap->page_array)
245 goto out_free_desc_array;
246
247 return bufmap;
248
249 out_free_desc_array:
250 kfree(bufmap->desc_array);
251 out_free_index_array:
252 bitmap_free(bufmap->buffer_index_array);
253 out_free_bufmap:
254 kfree(bufmap);
255 out:
256 return NULL;
257 }
258
259 static int
orangefs_bufmap_map(struct orangefs_bufmap * bufmap,struct ORANGEFS_dev_map_desc * user_desc)260 orangefs_bufmap_map(struct orangefs_bufmap *bufmap,
261 struct ORANGEFS_dev_map_desc *user_desc)
262 {
263 int pages_per_desc = bufmap->desc_size / PAGE_SIZE;
264 int offset = 0, ret, i;
265
266 /* map the pages */
267 ret = pin_user_pages_fast((unsigned long)user_desc->ptr,
268 bufmap->page_count, FOLL_WRITE, bufmap->page_array);
269
270 if (ret < 0)
271 return ret;
272
273 if (ret != bufmap->page_count) {
274 gossip_err("orangefs error: asked for %d pages, only got %d.\n",
275 bufmap->page_count, ret);
276
277 for (i = 0; i < ret; i++)
278 unpin_user_page(bufmap->page_array[i]);
279 return -ENOMEM;
280 }
281
282 /*
283 * ideally we want to get kernel space pointers for each page, but
284 * we can't kmap that many pages at once if highmem is being used.
285 * so instead, we just kmap/kunmap the page address each time the
286 * kaddr is needed.
287 */
288 for (i = 0; i < bufmap->page_count; i++)
289 flush_dcache_page(bufmap->page_array[i]);
290
291 /* build a list of available descriptors */
292 for (offset = 0, i = 0; i < bufmap->desc_count; i++) {
293 bufmap->desc_array[i].page_array = &bufmap->page_array[offset];
294 bufmap->desc_array[i].array_count = pages_per_desc;
295 bufmap->desc_array[i].uaddr =
296 (user_desc->ptr + (i * pages_per_desc * PAGE_SIZE));
297 offset += pages_per_desc;
298 }
299
300 return 0;
301 }
302
303 /*
304 * orangefs_bufmap_initialize()
305 *
306 * initializes the mapped buffer interface
307 *
308 * returns 0 on success, -errno on failure
309 */
orangefs_bufmap_initialize(struct ORANGEFS_dev_map_desc * user_desc)310 int orangefs_bufmap_initialize(struct ORANGEFS_dev_map_desc *user_desc)
311 {
312 struct orangefs_bufmap *bufmap;
313 int ret = -EINVAL;
314
315 gossip_debug(GOSSIP_BUFMAP_DEBUG,
316 "orangefs_bufmap_initialize: called (ptr ("
317 "%p) sz (%d) cnt(%d).\n",
318 user_desc->ptr,
319 user_desc->size,
320 user_desc->count);
321
322 if (user_desc->total_size < 0 ||
323 user_desc->size < 0 ||
324 user_desc->count < 0)
325 goto out;
326
327 /*
328 * sanity check alignment and size of buffer that caller wants to
329 * work with
330 */
331 if (PAGE_ALIGN((unsigned long)user_desc->ptr) !=
332 (unsigned long)user_desc->ptr) {
333 gossip_err("orangefs error: memory alignment (front). %p\n",
334 user_desc->ptr);
335 goto out;
336 }
337
338 if (PAGE_ALIGN(((unsigned long)user_desc->ptr + user_desc->total_size))
339 != (unsigned long)(user_desc->ptr + user_desc->total_size)) {
340 gossip_err("orangefs error: memory alignment (back).(%p + %d)\n",
341 user_desc->ptr,
342 user_desc->total_size);
343 goto out;
344 }
345
346 if (user_desc->total_size != (user_desc->size * user_desc->count)) {
347 gossip_err("orangefs error: user provided an oddly sized buffer: (%d, %d, %d)\n",
348 user_desc->total_size,
349 user_desc->size,
350 user_desc->count);
351 goto out;
352 }
353
354 if ((user_desc->size % PAGE_SIZE) != 0) {
355 gossip_err("orangefs error: bufmap size not page size divisible (%d).\n",
356 user_desc->size);
357 goto out;
358 }
359
360 ret = -ENOMEM;
361 bufmap = orangefs_bufmap_alloc(user_desc);
362 if (!bufmap)
363 goto out;
364
365 ret = orangefs_bufmap_map(bufmap, user_desc);
366 if (ret)
367 goto out_free_bufmap;
368
369
370 spin_lock(&orangefs_bufmap_lock);
371 if (__orangefs_bufmap) {
372 spin_unlock(&orangefs_bufmap_lock);
373 gossip_err("orangefs: error: bufmap already initialized.\n");
374 ret = -EINVAL;
375 goto out_unmap_bufmap;
376 }
377 __orangefs_bufmap = bufmap;
378 install(&rw_map,
379 bufmap->desc_count,
380 bufmap->buffer_index_array);
381 install(&readdir_map,
382 ORANGEFS_READDIR_DEFAULT_DESC_COUNT,
383 bufmap->readdir_index_array);
384 spin_unlock(&orangefs_bufmap_lock);
385
386 gossip_debug(GOSSIP_BUFMAP_DEBUG,
387 "orangefs_bufmap_initialize: exiting normally\n");
388 return 0;
389
390 out_unmap_bufmap:
391 orangefs_bufmap_unmap(bufmap);
392 out_free_bufmap:
393 orangefs_bufmap_free(bufmap);
394 out:
395 return ret;
396 }
397
398 /*
399 * orangefs_bufmap_finalize()
400 *
401 * shuts down the mapped buffer interface and releases any resources
402 * associated with it
403 *
404 * no return value
405 */
orangefs_bufmap_finalize(void)406 void orangefs_bufmap_finalize(void)
407 {
408 struct orangefs_bufmap *bufmap = __orangefs_bufmap;
409 if (!bufmap)
410 return;
411 gossip_debug(GOSSIP_BUFMAP_DEBUG, "orangefs_bufmap_finalize: called\n");
412 mark_killed(&rw_map);
413 mark_killed(&readdir_map);
414 gossip_debug(GOSSIP_BUFMAP_DEBUG,
415 "orangefs_bufmap_finalize: exiting normally\n");
416 }
417
orangefs_bufmap_run_down(void)418 void orangefs_bufmap_run_down(void)
419 {
420 struct orangefs_bufmap *bufmap = __orangefs_bufmap;
421 if (!bufmap)
422 return;
423 run_down(&rw_map);
424 run_down(&readdir_map);
425 spin_lock(&orangefs_bufmap_lock);
426 __orangefs_bufmap = NULL;
427 spin_unlock(&orangefs_bufmap_lock);
428 orangefs_bufmap_unmap(bufmap);
429 orangefs_bufmap_free(bufmap);
430 }
431
432 /*
433 * orangefs_bufmap_get()
434 *
435 * gets a free mapped buffer descriptor, will sleep until one becomes
436 * available if necessary
437 *
438 * returns slot on success, -errno on failure
439 */
orangefs_bufmap_get(void)440 int orangefs_bufmap_get(void)
441 {
442 return get(&rw_map);
443 }
444
445 /*
446 * orangefs_bufmap_put()
447 *
448 * returns a mapped buffer descriptor to the collection
449 *
450 * no return value
451 */
orangefs_bufmap_put(int buffer_index)452 void orangefs_bufmap_put(int buffer_index)
453 {
454 put(&rw_map, buffer_index);
455 }
456
457 /*
458 * orangefs_readdir_index_get()
459 *
460 * gets a free descriptor, will sleep until one becomes
461 * available if necessary.
462 * Although the readdir buffers are not mapped into kernel space
463 * we could do that at a later point of time. Regardless, these
464 * indices are used by the client-core.
465 *
466 * returns slot on success, -errno on failure
467 */
orangefs_readdir_index_get(void)468 int orangefs_readdir_index_get(void)
469 {
470 return get(&readdir_map);
471 }
472
orangefs_readdir_index_put(int buffer_index)473 void orangefs_readdir_index_put(int buffer_index)
474 {
475 put(&readdir_map, buffer_index);
476 }
477
478 /*
479 * we've been handed an iovec, we need to copy it to
480 * the shared memory descriptor at "buffer_index".
481 */
orangefs_bufmap_copy_from_iovec(struct iov_iter * iter,int buffer_index,size_t size)482 int orangefs_bufmap_copy_from_iovec(struct iov_iter *iter,
483 int buffer_index,
484 size_t size)
485 {
486 struct orangefs_bufmap_desc *to;
487 int i;
488
489 gossip_debug(GOSSIP_BUFMAP_DEBUG,
490 "%s: buffer_index:%d: size:%zu:\n",
491 __func__, buffer_index, size);
492
493 to = &__orangefs_bufmap->desc_array[buffer_index];
494 for (i = 0; size; i++) {
495 struct page *page = to->page_array[i];
496 size_t n = size;
497 if (n > PAGE_SIZE)
498 n = PAGE_SIZE;
499 if (copy_page_from_iter(page, 0, n, iter) != n)
500 return -EFAULT;
501 size -= n;
502 }
503 return 0;
504 }
505
506 /*
507 * we've been handed an iovec, we need to fill it from
508 * the shared memory descriptor at "buffer_index".
509 */
orangefs_bufmap_copy_to_iovec(struct iov_iter * iter,int buffer_index,size_t size)510 int orangefs_bufmap_copy_to_iovec(struct iov_iter *iter,
511 int buffer_index,
512 size_t size)
513 {
514 struct orangefs_bufmap_desc *from;
515 int i;
516
517 from = &__orangefs_bufmap->desc_array[buffer_index];
518 gossip_debug(GOSSIP_BUFMAP_DEBUG,
519 "%s: buffer_index:%d: size:%zu:\n",
520 __func__, buffer_index, size);
521
522
523 for (i = 0; size; i++) {
524 struct page *page = from->page_array[i];
525 size_t n = size;
526 if (n > PAGE_SIZE)
527 n = PAGE_SIZE;
528 n = copy_page_to_iter(page, 0, n, iter);
529 if (!n)
530 return -EFAULT;
531 size -= n;
532 }
533 return 0;
534 }
535
orangefs_bufmap_page_fill(void * page_to,int buffer_index,int slot_index)536 void orangefs_bufmap_page_fill(void *page_to,
537 int buffer_index,
538 int slot_index)
539 {
540 struct orangefs_bufmap_desc *from;
541 void *page_from;
542
543 from = &__orangefs_bufmap->desc_array[buffer_index];
544 page_from = kmap_atomic(from->page_array[slot_index]);
545 memcpy(page_to, page_from, PAGE_SIZE);
546 kunmap_atomic(page_from);
547 }
548