GNU Linux-libre 4.19.211-gnu1
[releases.git] / fs / orangefs / orangefs-bufmap.c
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
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
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
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
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
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 (unlikely(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
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
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
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
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
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 *
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
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, 1, 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  */
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  */
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
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  */
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  */
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  */
474 int orangefs_readdir_index_get(void)
475 {
476         return get(&readdir_map);
477 }
478
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  */
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  */
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 }