Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
[platform/kernel/linux-starfive.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 (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         unpin_user_pages(bufmap->page_array, bufmap->page_count);
172 }
173
174 static void
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
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 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 *
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
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                         SetPageError(bufmap->page_array[i]);
279                         unpin_user_page(bufmap->page_array[i]);
280                 }
281                 return -ENOMEM;
282         }
283
284         /*
285          * ideally we want to get kernel space pointers for each page, but
286          * we can't kmap that many pages at once if highmem is being used.
287          * so instead, we just kmap/kunmap the page address each time the
288          * kaddr is needed.
289          */
290         for (i = 0; i < bufmap->page_count; i++)
291                 flush_dcache_page(bufmap->page_array[i]);
292
293         /* build a list of available descriptors */
294         for (offset = 0, i = 0; i < bufmap->desc_count; i++) {
295                 bufmap->desc_array[i].page_array = &bufmap->page_array[offset];
296                 bufmap->desc_array[i].array_count = pages_per_desc;
297                 bufmap->desc_array[i].uaddr =
298                     (user_desc->ptr + (i * pages_per_desc * PAGE_SIZE));
299                 offset += pages_per_desc;
300         }
301
302         return 0;
303 }
304
305 /*
306  * orangefs_bufmap_initialize()
307  *
308  * initializes the mapped buffer interface
309  *
310  * returns 0 on success, -errno on failure
311  */
312 int orangefs_bufmap_initialize(struct ORANGEFS_dev_map_desc *user_desc)
313 {
314         struct orangefs_bufmap *bufmap;
315         int ret = -EINVAL;
316
317         gossip_debug(GOSSIP_BUFMAP_DEBUG,
318                      "orangefs_bufmap_initialize: called (ptr ("
319                      "%p) sz (%d) cnt(%d).\n",
320                      user_desc->ptr,
321                      user_desc->size,
322                      user_desc->count);
323
324         if (user_desc->total_size < 0 ||
325             user_desc->size < 0 ||
326             user_desc->count < 0)
327                 goto out;
328
329         /*
330          * sanity check alignment and size of buffer that caller wants to
331          * work with
332          */
333         if (PAGE_ALIGN((unsigned long)user_desc->ptr) !=
334             (unsigned long)user_desc->ptr) {
335                 gossip_err("orangefs error: memory alignment (front). %p\n",
336                            user_desc->ptr);
337                 goto out;
338         }
339
340         if (PAGE_ALIGN(((unsigned long)user_desc->ptr + user_desc->total_size))
341             != (unsigned long)(user_desc->ptr + user_desc->total_size)) {
342                 gossip_err("orangefs error: memory alignment (back).(%p + %d)\n",
343                            user_desc->ptr,
344                            user_desc->total_size);
345                 goto out;
346         }
347
348         if (user_desc->total_size != (user_desc->size * user_desc->count)) {
349                 gossip_err("orangefs error: user provided an oddly sized buffer: (%d, %d, %d)\n",
350                            user_desc->total_size,
351                            user_desc->size,
352                            user_desc->count);
353                 goto out;
354         }
355
356         if ((user_desc->size % PAGE_SIZE) != 0) {
357                 gossip_err("orangefs error: bufmap size not page size divisible (%d).\n",
358                            user_desc->size);
359                 goto out;
360         }
361
362         ret = -ENOMEM;
363         bufmap = orangefs_bufmap_alloc(user_desc);
364         if (!bufmap)
365                 goto out;
366
367         ret = orangefs_bufmap_map(bufmap, user_desc);
368         if (ret)
369                 goto out_free_bufmap;
370
371
372         spin_lock(&orangefs_bufmap_lock);
373         if (__orangefs_bufmap) {
374                 spin_unlock(&orangefs_bufmap_lock);
375                 gossip_err("orangefs: error: bufmap already initialized.\n");
376                 ret = -EINVAL;
377                 goto out_unmap_bufmap;
378         }
379         __orangefs_bufmap = bufmap;
380         install(&rw_map,
381                 bufmap->desc_count,
382                 bufmap->buffer_index_array);
383         install(&readdir_map,
384                 ORANGEFS_READDIR_DEFAULT_DESC_COUNT,
385                 bufmap->readdir_index_array);
386         spin_unlock(&orangefs_bufmap_lock);
387
388         gossip_debug(GOSSIP_BUFMAP_DEBUG,
389                      "orangefs_bufmap_initialize: exiting normally\n");
390         return 0;
391
392 out_unmap_bufmap:
393         orangefs_bufmap_unmap(bufmap);
394 out_free_bufmap:
395         orangefs_bufmap_free(bufmap);
396 out:
397         return ret;
398 }
399
400 /*
401  * orangefs_bufmap_finalize()
402  *
403  * shuts down the mapped buffer interface and releases any resources
404  * associated with it
405  *
406  * no return value
407  */
408 void orangefs_bufmap_finalize(void)
409 {
410         struct orangefs_bufmap *bufmap = __orangefs_bufmap;
411         if (!bufmap)
412                 return;
413         gossip_debug(GOSSIP_BUFMAP_DEBUG, "orangefs_bufmap_finalize: called\n");
414         mark_killed(&rw_map);
415         mark_killed(&readdir_map);
416         gossip_debug(GOSSIP_BUFMAP_DEBUG,
417                      "orangefs_bufmap_finalize: exiting normally\n");
418 }
419
420 void orangefs_bufmap_run_down(void)
421 {
422         struct orangefs_bufmap *bufmap = __orangefs_bufmap;
423         if (!bufmap)
424                 return;
425         run_down(&rw_map);
426         run_down(&readdir_map);
427         spin_lock(&orangefs_bufmap_lock);
428         __orangefs_bufmap = NULL;
429         spin_unlock(&orangefs_bufmap_lock);
430         orangefs_bufmap_unmap(bufmap);
431         orangefs_bufmap_free(bufmap);
432 }
433
434 /*
435  * orangefs_bufmap_get()
436  *
437  * gets a free mapped buffer descriptor, will sleep until one becomes
438  * available if necessary
439  *
440  * returns slot on success, -errno on failure
441  */
442 int orangefs_bufmap_get(void)
443 {
444         return get(&rw_map);
445 }
446
447 /*
448  * orangefs_bufmap_put()
449  *
450  * returns a mapped buffer descriptor to the collection
451  *
452  * no return value
453  */
454 void orangefs_bufmap_put(int buffer_index)
455 {
456         put(&rw_map, buffer_index);
457 }
458
459 /*
460  * orangefs_readdir_index_get()
461  *
462  * gets a free descriptor, will sleep until one becomes
463  * available if necessary.
464  * Although the readdir buffers are not mapped into kernel space
465  * we could do that at a later point of time. Regardless, these
466  * indices are used by the client-core.
467  *
468  * returns slot on success, -errno on failure
469  */
470 int orangefs_readdir_index_get(void)
471 {
472         return get(&readdir_map);
473 }
474
475 void orangefs_readdir_index_put(int buffer_index)
476 {
477         put(&readdir_map, buffer_index);
478 }
479
480 /*
481  * we've been handed an iovec, we need to copy it to
482  * the shared memory descriptor at "buffer_index".
483  */
484 int orangefs_bufmap_copy_from_iovec(struct iov_iter *iter,
485                                 int buffer_index,
486                                 size_t size)
487 {
488         struct orangefs_bufmap_desc *to;
489         int i;
490
491         gossip_debug(GOSSIP_BUFMAP_DEBUG,
492                      "%s: buffer_index:%d: size:%zu:\n",
493                      __func__, buffer_index, size);
494
495         to = &__orangefs_bufmap->desc_array[buffer_index];
496         for (i = 0; size; i++) {
497                 struct page *page = to->page_array[i];
498                 size_t n = size;
499                 if (n > PAGE_SIZE)
500                         n = PAGE_SIZE;
501                 if (copy_page_from_iter(page, 0, n, iter) != n)
502                         return -EFAULT;
503                 size -= n;
504         }
505         return 0;
506 }
507
508 /*
509  * we've been handed an iovec, we need to fill it from
510  * the shared memory descriptor at "buffer_index".
511  */
512 int orangefs_bufmap_copy_to_iovec(struct iov_iter *iter,
513                                     int buffer_index,
514                                     size_t size)
515 {
516         struct orangefs_bufmap_desc *from;
517         int i;
518
519         from = &__orangefs_bufmap->desc_array[buffer_index];
520         gossip_debug(GOSSIP_BUFMAP_DEBUG,
521                      "%s: buffer_index:%d: size:%zu:\n",
522                      __func__, buffer_index, size);
523
524
525         for (i = 0; size; i++) {
526                 struct page *page = from->page_array[i];
527                 size_t n = size;
528                 if (n > PAGE_SIZE)
529                         n = PAGE_SIZE;
530                 n = copy_page_to_iter(page, 0, n, iter);
531                 if (!n)
532                         return -EFAULT;
533                 size -= n;
534         }
535         return 0;
536 }
537
538 void orangefs_bufmap_page_fill(void *page_to,
539                                 int buffer_index,
540                                 int slot_index)
541 {
542         struct orangefs_bufmap_desc *from;
543         void *page_from;
544
545         from = &__orangefs_bufmap->desc_array[buffer_index];
546         page_from = kmap_atomic(from->page_array[slot_index]);
547         memcpy(page_to, page_from, PAGE_SIZE);
548         kunmap_atomic(page_from);
549 }