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 int i;
172
173 for (i = 0; i < bufmap->page_count; i++)
174 put_page(bufmap->page_array[i]);
175 }
176
177 static void
orangefs_bufmap_free(struct orangefs_bufmap * bufmap)178 orangefs_bufmap_free(struct orangefs_bufmap *bufmap)
179 {
180 kfree(bufmap->page_array);
181 kfree(bufmap->desc_array);
182 kfree(bufmap->buffer_index_array);
183 kfree(bufmap);
184 }
185
186 /*
187 * XXX: Can the size and shift change while the caller gives up the
188 * XXX: lock between calling this and doing something useful?
189 */
190
orangefs_bufmap_size_query(void)191 int orangefs_bufmap_size_query(void)
192 {
193 struct orangefs_bufmap *bufmap;
194 int size = 0;
195 spin_lock(&orangefs_bufmap_lock);
196 bufmap = __orangefs_bufmap;
197 if (bufmap)
198 size = bufmap->desc_size;
199 spin_unlock(&orangefs_bufmap_lock);
200 return size;
201 }
202
orangefs_bufmap_shift_query(void)203 int orangefs_bufmap_shift_query(void)
204 {
205 struct orangefs_bufmap *bufmap;
206 int shift = 0;
207 spin_lock(&orangefs_bufmap_lock);
208 bufmap = __orangefs_bufmap;
209 if (bufmap)
210 shift = bufmap->desc_shift;
211 spin_unlock(&orangefs_bufmap_lock);
212 return shift;
213 }
214
215 static DECLARE_WAIT_QUEUE_HEAD(bufmap_waitq);
216 static DECLARE_WAIT_QUEUE_HEAD(readdir_waitq);
217
218 static struct orangefs_bufmap *
orangefs_bufmap_alloc(struct ORANGEFS_dev_map_desc * user_desc)219 orangefs_bufmap_alloc(struct ORANGEFS_dev_map_desc *user_desc)
220 {
221 struct orangefs_bufmap *bufmap;
222
223 bufmap = kzalloc(sizeof(*bufmap), GFP_KERNEL);
224 if (!bufmap)
225 goto out;
226
227 bufmap->total_size = user_desc->total_size;
228 bufmap->desc_count = user_desc->count;
229 bufmap->desc_size = user_desc->size;
230 bufmap->desc_shift = ilog2(bufmap->desc_size);
231
232 bufmap->buffer_index_array =
233 kzalloc(DIV_ROUND_UP(bufmap->desc_count, BITS_PER_LONG), GFP_KERNEL);
234 if (!bufmap->buffer_index_array)
235 goto out_free_bufmap;
236
237 bufmap->desc_array =
238 kcalloc(bufmap->desc_count, sizeof(struct orangefs_bufmap_desc),
239 GFP_KERNEL);
240 if (!bufmap->desc_array)
241 goto out_free_index_array;
242
243 bufmap->page_count = bufmap->total_size / PAGE_SIZE;
244
245 /* allocate storage to track our page mappings */
246 bufmap->page_array =
247 kcalloc(bufmap->page_count, sizeof(struct page *), GFP_KERNEL);
248 if (!bufmap->page_array)
249 goto out_free_desc_array;
250
251 return bufmap;
252
253 out_free_desc_array:
254 kfree(bufmap->desc_array);
255 out_free_index_array:
256 kfree(bufmap->buffer_index_array);
257 out_free_bufmap:
258 kfree(bufmap);
259 out:
260 return NULL;
261 }
262
263 static int
orangefs_bufmap_map(struct orangefs_bufmap * bufmap,struct ORANGEFS_dev_map_desc * user_desc)264 orangefs_bufmap_map(struct orangefs_bufmap *bufmap,
265 struct ORANGEFS_dev_map_desc *user_desc)
266 {
267 int pages_per_desc = bufmap->desc_size / PAGE_SIZE;
268 int offset = 0, ret, i;
269
270 /* map the pages */
271 ret = get_user_pages_fast((unsigned long)user_desc->ptr,
272 bufmap->page_count, FOLL_WRITE, bufmap->page_array);
273
274 if (ret < 0)
275 return ret;
276
277 if (ret != bufmap->page_count) {
278 gossip_err("orangefs error: asked for %d pages, only got %d.\n",
279 bufmap->page_count, ret);
280
281 for (i = 0; i < ret; i++) {
282 SetPageError(bufmap->page_array[i]);
283 put_page(bufmap->page_array[i]);
284 }
285 return -ENOMEM;
286 }
287
288 /*
289 * ideally we want to get kernel space pointers for each page, but
290 * we can't kmap that many pages at once if highmem is being used.
291 * so instead, we just kmap/kunmap the page address each time the
292 * kaddr is needed.
293 */
294 for (i = 0; i < bufmap->page_count; i++)
295 flush_dcache_page(bufmap->page_array[i]);
296
297 /* build a list of available descriptors */
298 for (offset = 0, i = 0; i < bufmap->desc_count; i++) {
299 bufmap->desc_array[i].page_array = &bufmap->page_array[offset];
300 bufmap->desc_array[i].array_count = pages_per_desc;
301 bufmap->desc_array[i].uaddr =
302 (user_desc->ptr + (i * pages_per_desc * PAGE_SIZE));
303 offset += pages_per_desc;
304 }
305
306 return 0;
307 }
308
309 /*
310 * orangefs_bufmap_initialize()
311 *
312 * initializes the mapped buffer interface
313 *
314 * returns 0 on success, -errno on failure
315 */
orangefs_bufmap_initialize(struct ORANGEFS_dev_map_desc * user_desc)316 int orangefs_bufmap_initialize(struct ORANGEFS_dev_map_desc *user_desc)
317 {
318 struct orangefs_bufmap *bufmap;
319 int ret = -EINVAL;
320
321 gossip_debug(GOSSIP_BUFMAP_DEBUG,
322 "orangefs_bufmap_initialize: called (ptr ("
323 "%p) sz (%d) cnt(%d).\n",
324 user_desc->ptr,
325 user_desc->size,
326 user_desc->count);
327
328 if (user_desc->total_size < 0 ||
329 user_desc->size < 0 ||
330 user_desc->count < 0)
331 goto out;
332
333 /*
334 * sanity check alignment and size of buffer that caller wants to
335 * work with
336 */
337 if (PAGE_ALIGN((unsigned long)user_desc->ptr) !=
338 (unsigned long)user_desc->ptr) {
339 gossip_err("orangefs error: memory alignment (front). %p\n",
340 user_desc->ptr);
341 goto out;
342 }
343
344 if (PAGE_ALIGN(((unsigned long)user_desc->ptr + user_desc->total_size))
345 != (unsigned long)(user_desc->ptr + user_desc->total_size)) {
346 gossip_err("orangefs error: memory alignment (back).(%p + %d)\n",
347 user_desc->ptr,
348 user_desc->total_size);
349 goto out;
350 }
351
352 if (user_desc->total_size != (user_desc->size * user_desc->count)) {
353 gossip_err("orangefs error: user provided an oddly sized buffer: (%d, %d, %d)\n",
354 user_desc->total_size,
355 user_desc->size,
356 user_desc->count);
357 goto out;
358 }
359
360 if ((user_desc->size % PAGE_SIZE) != 0) {
361 gossip_err("orangefs error: bufmap size not page size divisible (%d).\n",
362 user_desc->size);
363 goto out;
364 }
365
366 ret = -ENOMEM;
367 bufmap = orangefs_bufmap_alloc(user_desc);
368 if (!bufmap)
369 goto out;
370
371 ret = orangefs_bufmap_map(bufmap, user_desc);
372 if (ret)
373 goto out_free_bufmap;
374
375
376 spin_lock(&orangefs_bufmap_lock);
377 if (__orangefs_bufmap) {
378 spin_unlock(&orangefs_bufmap_lock);
379 gossip_err("orangefs: error: bufmap already initialized.\n");
380 ret = -EINVAL;
381 goto out_unmap_bufmap;
382 }
383 __orangefs_bufmap = bufmap;
384 install(&rw_map,
385 bufmap->desc_count,
386 bufmap->buffer_index_array);
387 install(&readdir_map,
388 ORANGEFS_READDIR_DEFAULT_DESC_COUNT,
389 bufmap->readdir_index_array);
390 spin_unlock(&orangefs_bufmap_lock);
391
392 gossip_debug(GOSSIP_BUFMAP_DEBUG,
393 "orangefs_bufmap_initialize: exiting normally\n");
394 return 0;
395
396 out_unmap_bufmap:
397 orangefs_bufmap_unmap(bufmap);
398 out_free_bufmap:
399 orangefs_bufmap_free(bufmap);
400 out:
401 return ret;
402 }
403
404 /*
405 * orangefs_bufmap_finalize()
406 *
407 * shuts down the mapped buffer interface and releases any resources
408 * associated with it
409 *
410 * no return value
411 */
orangefs_bufmap_finalize(void)412 void orangefs_bufmap_finalize(void)
413 {
414 struct orangefs_bufmap *bufmap = __orangefs_bufmap;
415 if (!bufmap)
416 return;
417 gossip_debug(GOSSIP_BUFMAP_DEBUG, "orangefs_bufmap_finalize: called\n");
418 mark_killed(&rw_map);
419 mark_killed(&readdir_map);
420 gossip_debug(GOSSIP_BUFMAP_DEBUG,
421 "orangefs_bufmap_finalize: exiting normally\n");
422 }
423
orangefs_bufmap_run_down(void)424 void orangefs_bufmap_run_down(void)
425 {
426 struct orangefs_bufmap *bufmap = __orangefs_bufmap;
427 if (!bufmap)
428 return;
429 run_down(&rw_map);
430 run_down(&readdir_map);
431 spin_lock(&orangefs_bufmap_lock);
432 __orangefs_bufmap = NULL;
433 spin_unlock(&orangefs_bufmap_lock);
434 orangefs_bufmap_unmap(bufmap);
435 orangefs_bufmap_free(bufmap);
436 }
437
438 /*
439 * orangefs_bufmap_get()
440 *
441 * gets a free mapped buffer descriptor, will sleep until one becomes
442 * available if necessary
443 *
444 * returns slot on success, -errno on failure
445 */
orangefs_bufmap_get(void)446 int orangefs_bufmap_get(void)
447 {
448 return get(&rw_map);
449 }
450
451 /*
452 * orangefs_bufmap_put()
453 *
454 * returns a mapped buffer descriptor to the collection
455 *
456 * no return value
457 */
orangefs_bufmap_put(int buffer_index)458 void orangefs_bufmap_put(int buffer_index)
459 {
460 put(&rw_map, buffer_index);
461 }
462
463 /*
464 * orangefs_readdir_index_get()
465 *
466 * gets a free descriptor, will sleep until one becomes
467 * available if necessary.
468 * Although the readdir buffers are not mapped into kernel space
469 * we could do that at a later point of time. Regardless, these
470 * indices are used by the client-core.
471 *
472 * returns slot on success, -errno on failure
473 */
orangefs_readdir_index_get(void)474 int orangefs_readdir_index_get(void)
475 {
476 return get(&readdir_map);
477 }
478
orangefs_readdir_index_put(int buffer_index)479 void orangefs_readdir_index_put(int buffer_index)
480 {
481 put(&readdir_map, buffer_index);
482 }
483
484 /*
485 * we've been handed an iovec, we need to copy it to
486 * the shared memory descriptor at "buffer_index".
487 */
orangefs_bufmap_copy_from_iovec(struct iov_iter * iter,int buffer_index,size_t size)488 int orangefs_bufmap_copy_from_iovec(struct iov_iter *iter,
489 int buffer_index,
490 size_t size)
491 {
492 struct orangefs_bufmap_desc *to;
493 int i;
494
495 gossip_debug(GOSSIP_BUFMAP_DEBUG,
496 "%s: buffer_index:%d: size:%zu:\n",
497 __func__, buffer_index, size);
498
499 to = &__orangefs_bufmap->desc_array[buffer_index];
500 for (i = 0; size; i++) {
501 struct page *page = to->page_array[i];
502 size_t n = size;
503 if (n > PAGE_SIZE)
504 n = PAGE_SIZE;
505 if (copy_page_from_iter(page, 0, n, iter) != n)
506 return -EFAULT;
507 size -= n;
508 }
509 return 0;
510 }
511
512 /*
513 * we've been handed an iovec, we need to fill it from
514 * the shared memory descriptor at "buffer_index".
515 */
orangefs_bufmap_copy_to_iovec(struct iov_iter * iter,int buffer_index,size_t size)516 int orangefs_bufmap_copy_to_iovec(struct iov_iter *iter,
517 int buffer_index,
518 size_t size)
519 {
520 struct orangefs_bufmap_desc *from;
521 int i;
522
523 from = &__orangefs_bufmap->desc_array[buffer_index];
524 gossip_debug(GOSSIP_BUFMAP_DEBUG,
525 "%s: buffer_index:%d: size:%zu:\n",
526 __func__, buffer_index, size);
527
528
529 for (i = 0; size; i++) {
530 struct page *page = from->page_array[i];
531 size_t n = size;
532 if (n > PAGE_SIZE)
533 n = PAGE_SIZE;
534 n = copy_page_to_iter(page, 0, n, iter);
535 if (!n)
536 return -EFAULT;
537 size -= n;
538 }
539 return 0;
540 }
541
orangefs_bufmap_page_fill(void * page_to,int buffer_index,int slot_index)542 void orangefs_bufmap_page_fill(void *page_to,
543 int buffer_index,
544 int slot_index)
545 {
546 struct orangefs_bufmap_desc *from;
547 void *page_from;
548
549 from = &__orangefs_bufmap->desc_array[buffer_index];
550 page_from = kmap_atomic(from->page_array[slot_index]);
551 memcpy(page_to, page_from, PAGE_SIZE);
552 kunmap_atomic(page_from);
553 }
554