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