GNU Linux-libre 4.9.308-gnu1
[releases.git] / fs / orangefs / orangefs-bufmap.c
1 /*
2  * (C) 2001 Clemson University and The University of Chicago
3  *
4  * See COPYING in top-level directory.
5  */
6 #include "protocol.h"
7 #include "orangefs-kernel.h"
8 #include "orangefs-bufmap.h"
9
10 struct slot_map {
11         int c;
12         wait_queue_head_t q;
13         int count;
14         unsigned long *map;
15 };
16
17 static struct slot_map rw_map = {
18         .c = -1,
19         .q = __WAIT_QUEUE_HEAD_INITIALIZER(rw_map.q)
20 };
21 static struct slot_map readdir_map = {
22         .c = -1,
23         .q = __WAIT_QUEUE_HEAD_INITIALIZER(readdir_map.q)
24 };
25
26
27 static void install(struct slot_map *m, int count, unsigned long *map)
28 {
29         spin_lock(&m->q.lock);
30         m->c = m->count = count;
31         m->map = map;
32         wake_up_all_locked(&m->q);
33         spin_unlock(&m->q.lock);
34 }
35
36 static void mark_killed(struct slot_map *m)
37 {
38         spin_lock(&m->q.lock);
39         m->c -= m->count + 1;
40         spin_unlock(&m->q.lock);
41 }
42
43 static void run_down(struct slot_map *m)
44 {
45         DEFINE_WAIT(wait);
46         spin_lock(&m->q.lock);
47         if (m->c != -1) {
48                 for (;;) {
49                         if (likely(list_empty(&wait.task_list)))
50                                 __add_wait_queue_tail(&m->q, &wait);
51                         set_current_state(TASK_UNINTERRUPTIBLE);
52
53                         if (m->c == -1)
54                                 break;
55
56                         spin_unlock(&m->q.lock);
57                         schedule();
58                         spin_lock(&m->q.lock);
59                 }
60                 __remove_wait_queue(&m->q, &wait);
61                 __set_current_state(TASK_RUNNING);
62         }
63         m->map = NULL;
64         spin_unlock(&m->q.lock);
65 }
66
67 static void put(struct slot_map *m, int slot)
68 {
69         int v;
70         spin_lock(&m->q.lock);
71         __clear_bit(slot, m->map);
72         v = ++m->c;
73         if (unlikely(v == 1))   /* no free slots -> one free slot */
74                 wake_up_locked(&m->q);
75         else if (unlikely(v == -1))     /* finished dying */
76                 wake_up_all_locked(&m->q);
77         spin_unlock(&m->q.lock);
78 }
79
80 static int wait_for_free(struct slot_map *m)
81 {
82         long left = slot_timeout_secs * HZ;
83         DEFINE_WAIT(wait);
84
85         do {
86                 long n = left, t;
87                 if (likely(list_empty(&wait.task_list)))
88                         __add_wait_queue_tail_exclusive(&m->q, &wait);
89                 set_current_state(TASK_INTERRUPTIBLE);
90
91                 if (m->c > 0)
92                         break;
93
94                 if (m->c < 0) {
95                         /* we are waiting for map to be installed */
96                         /* it would better be there soon, or we go away */
97                         if (n > ORANGEFS_BUFMAP_WAIT_TIMEOUT_SECS * HZ)
98                                 n = ORANGEFS_BUFMAP_WAIT_TIMEOUT_SECS * HZ;
99                 }
100                 spin_unlock(&m->q.lock);
101                 t = schedule_timeout(n);
102                 spin_lock(&m->q.lock);
103                 if (unlikely(!t) && n != left && m->c < 0)
104                         left = t;
105                 else
106                         left = t + (left - n);
107                 if (unlikely(signal_pending(current)))
108                         left = -EINTR;
109         } while (left > 0);
110
111         if (!list_empty(&wait.task_list))
112                 list_del(&wait.task_list);
113         else if (left <= 0 && waitqueue_active(&m->q))
114                 __wake_up_locked_key(&m->q, TASK_INTERRUPTIBLE, NULL);
115         __set_current_state(TASK_RUNNING);
116
117         if (likely(left > 0))
118                 return 0;
119
120         return left < 0 ? -EINTR : -ETIMEDOUT;
121 }
122
123 static int get(struct slot_map *m)
124 {
125         int res = 0;
126         spin_lock(&m->q.lock);
127         if (unlikely(m->c <= 0))
128                 res = wait_for_free(m);
129         if (likely(!res)) {
130                 m->c--;
131                 res = find_first_zero_bit(m->map, m->count);
132                 __set_bit(res, m->map);
133         }
134         spin_unlock(&m->q.lock);
135         return res;
136 }
137
138 /* used to describe mapped buffers */
139 struct orangefs_bufmap_desc {
140         void *uaddr;                    /* user space address pointer */
141         struct page **page_array;       /* array of mapped pages */
142         int array_count;                /* size of above arrays */
143         struct list_head list_link;
144 };
145
146 static struct orangefs_bufmap {
147         int desc_size;
148         int desc_shift;
149         int desc_count;
150         int total_size;
151         int page_count;
152
153         struct page **page_array;
154         struct orangefs_bufmap_desc *desc_array;
155
156         /* array to track usage of buffer descriptors */
157         unsigned long *buffer_index_array;
158
159         /* array to track usage of buffer descriptors for readdir */
160 #define N DIV_ROUND_UP(ORANGEFS_READDIR_DEFAULT_DESC_COUNT, BITS_PER_LONG)
161         unsigned long readdir_index_array[N];
162 #undef N
163 } *__orangefs_bufmap;
164
165 static DEFINE_SPINLOCK(orangefs_bufmap_lock);
166
167 static void
168 orangefs_bufmap_unmap(struct orangefs_bufmap *bufmap)
169 {
170         int i;
171
172         for (i = 0; i < bufmap->page_count; i++)
173                 put_page(bufmap->page_array[i]);
174 }
175
176 static void
177 orangefs_bufmap_free(struct orangefs_bufmap *bufmap)
178 {
179         kfree(bufmap->page_array);
180         kfree(bufmap->desc_array);
181         kfree(bufmap->buffer_index_array);
182         kfree(bufmap);
183 }
184
185 /*
186  * XXX: Can the size and shift change while the caller gives up the 
187  * XXX: lock between calling this and doing something useful?
188  */
189
190 int orangefs_bufmap_size_query(void)
191 {
192         struct orangefs_bufmap *bufmap;
193         int size = 0;
194         spin_lock(&orangefs_bufmap_lock);
195         bufmap = __orangefs_bufmap;
196         if (bufmap)
197                 size = bufmap->desc_size;
198         spin_unlock(&orangefs_bufmap_lock);
199         return size;
200 }
201
202 int orangefs_bufmap_shift_query(void)
203 {
204         struct orangefs_bufmap *bufmap;
205         int shift = 0;
206         spin_lock(&orangefs_bufmap_lock);
207         bufmap = __orangefs_bufmap;
208         if (bufmap)
209                 shift = bufmap->desc_shift;
210         spin_unlock(&orangefs_bufmap_lock);
211         return shift;
212 }
213
214 static DECLARE_WAIT_QUEUE_HEAD(bufmap_waitq);
215 static DECLARE_WAIT_QUEUE_HEAD(readdir_waitq);
216
217 /*
218  * orangefs_get_bufmap_init
219  *
220  * If bufmap_init is 1, then the shared memory system, including the
221  * buffer_index_array, is available.  Otherwise, it is not.
222  *
223  * returns the value of bufmap_init
224  */
225 int orangefs_get_bufmap_init(void)
226 {
227         return __orangefs_bufmap ? 1 : 0;
228 }
229
230
231 static struct orangefs_bufmap *
232 orangefs_bufmap_alloc(struct ORANGEFS_dev_map_desc *user_desc)
233 {
234         struct orangefs_bufmap *bufmap;
235
236         bufmap = kzalloc(sizeof(*bufmap), GFP_KERNEL);
237         if (!bufmap)
238                 goto out;
239
240         bufmap->total_size = user_desc->total_size;
241         bufmap->desc_count = user_desc->count;
242         bufmap->desc_size = user_desc->size;
243         bufmap->desc_shift = ilog2(bufmap->desc_size);
244
245         bufmap->buffer_index_array =
246                 kzalloc(DIV_ROUND_UP(bufmap->desc_count, BITS_PER_LONG), GFP_KERNEL);
247         if (!bufmap->buffer_index_array) {
248                 gossip_err("orangefs: could not allocate %d buffer indices\n",
249                                 bufmap->desc_count);
250                 goto out_free_bufmap;
251         }
252
253         bufmap->desc_array =
254                 kcalloc(bufmap->desc_count, sizeof(struct orangefs_bufmap_desc),
255                         GFP_KERNEL);
256         if (!bufmap->desc_array) {
257                 gossip_err("orangefs: could not allocate %d descriptors\n",
258                                 bufmap->desc_count);
259                 goto out_free_index_array;
260         }
261
262         bufmap->page_count = bufmap->total_size / PAGE_SIZE;
263
264         /* allocate storage to track our page mappings */
265         bufmap->page_array =
266                 kcalloc(bufmap->page_count, sizeof(struct page *), GFP_KERNEL);
267         if (!bufmap->page_array)
268                 goto out_free_desc_array;
269
270         return bufmap;
271
272 out_free_desc_array:
273         kfree(bufmap->desc_array);
274 out_free_index_array:
275         kfree(bufmap->buffer_index_array);
276 out_free_bufmap:
277         kfree(bufmap);
278 out:
279         return NULL;
280 }
281
282 static int
283 orangefs_bufmap_map(struct orangefs_bufmap *bufmap,
284                 struct ORANGEFS_dev_map_desc *user_desc)
285 {
286         int pages_per_desc = bufmap->desc_size / PAGE_SIZE;
287         int offset = 0, ret, i;
288
289         /* map the pages */
290         ret = get_user_pages_fast((unsigned long)user_desc->ptr,
291                              bufmap->page_count, 1, bufmap->page_array);
292
293         if (ret < 0)
294                 return ret;
295
296         if (ret != bufmap->page_count) {
297                 gossip_err("orangefs error: asked for %d pages, only got %d.\n",
298                                 bufmap->page_count, ret);
299
300                 for (i = 0; i < ret; i++) {
301                         SetPageError(bufmap->page_array[i]);
302                         put_page(bufmap->page_array[i]);
303                 }
304                 return -ENOMEM;
305         }
306
307         /*
308          * ideally we want to get kernel space pointers for each page, but
309          * we can't kmap that many pages at once if highmem is being used.
310          * so instead, we just kmap/kunmap the page address each time the
311          * kaddr is needed.
312          */
313         for (i = 0; i < bufmap->page_count; i++)
314                 flush_dcache_page(bufmap->page_array[i]);
315
316         /* build a list of available descriptors */
317         for (offset = 0, i = 0; i < bufmap->desc_count; i++) {
318                 bufmap->desc_array[i].page_array = &bufmap->page_array[offset];
319                 bufmap->desc_array[i].array_count = pages_per_desc;
320                 bufmap->desc_array[i].uaddr =
321                     (user_desc->ptr + (i * pages_per_desc * PAGE_SIZE));
322                 offset += pages_per_desc;
323         }
324
325         return 0;
326 }
327
328 /*
329  * orangefs_bufmap_initialize()
330  *
331  * initializes the mapped buffer interface
332  *
333  * returns 0 on success, -errno on failure
334  */
335 int orangefs_bufmap_initialize(struct ORANGEFS_dev_map_desc *user_desc)
336 {
337         struct orangefs_bufmap *bufmap;
338         int ret = -EINVAL;
339
340         gossip_debug(GOSSIP_BUFMAP_DEBUG,
341                      "orangefs_bufmap_initialize: called (ptr ("
342                      "%p) sz (%d) cnt(%d).\n",
343                      user_desc->ptr,
344                      user_desc->size,
345                      user_desc->count);
346
347         /*
348          * sanity check alignment and size of buffer that caller wants to
349          * work with
350          */
351         if (PAGE_ALIGN((unsigned long)user_desc->ptr) !=
352             (unsigned long)user_desc->ptr) {
353                 gossip_err("orangefs error: memory alignment (front). %p\n",
354                            user_desc->ptr);
355                 goto out;
356         }
357
358         if (PAGE_ALIGN(((unsigned long)user_desc->ptr + user_desc->total_size))
359             != (unsigned long)(user_desc->ptr + user_desc->total_size)) {
360                 gossip_err("orangefs error: memory alignment (back).(%p + %d)\n",
361                            user_desc->ptr,
362                            user_desc->total_size);
363                 goto out;
364         }
365
366         if (user_desc->total_size != (user_desc->size * user_desc->count)) {
367                 gossip_err("orangefs error: user provided an oddly sized buffer: (%d, %d, %d)\n",
368                            user_desc->total_size,
369                            user_desc->size,
370                            user_desc->count);
371                 goto out;
372         }
373
374         if ((user_desc->size % PAGE_SIZE) != 0) {
375                 gossip_err("orangefs error: bufmap size not page size divisible (%d).\n",
376                            user_desc->size);
377                 goto out;
378         }
379
380         ret = -ENOMEM;
381         bufmap = orangefs_bufmap_alloc(user_desc);
382         if (!bufmap)
383                 goto out;
384
385         ret = orangefs_bufmap_map(bufmap, user_desc);
386         if (ret)
387                 goto out_free_bufmap;
388
389
390         spin_lock(&orangefs_bufmap_lock);
391         if (__orangefs_bufmap) {
392                 spin_unlock(&orangefs_bufmap_lock);
393                 gossip_err("orangefs: error: bufmap already initialized.\n");
394                 ret = -EINVAL;
395                 goto out_unmap_bufmap;
396         }
397         __orangefs_bufmap = bufmap;
398         install(&rw_map,
399                 bufmap->desc_count,
400                 bufmap->buffer_index_array);
401         install(&readdir_map,
402                 ORANGEFS_READDIR_DEFAULT_DESC_COUNT,
403                 bufmap->readdir_index_array);
404         spin_unlock(&orangefs_bufmap_lock);
405
406         gossip_debug(GOSSIP_BUFMAP_DEBUG,
407                      "orangefs_bufmap_initialize: exiting normally\n");
408         return 0;
409
410 out_unmap_bufmap:
411         orangefs_bufmap_unmap(bufmap);
412 out_free_bufmap:
413         orangefs_bufmap_free(bufmap);
414 out:
415         return ret;
416 }
417
418 /*
419  * orangefs_bufmap_finalize()
420  *
421  * shuts down the mapped buffer interface and releases any resources
422  * associated with it
423  *
424  * no return value
425  */
426 void orangefs_bufmap_finalize(void)
427 {
428         struct orangefs_bufmap *bufmap = __orangefs_bufmap;
429         if (!bufmap)
430                 return;
431         gossip_debug(GOSSIP_BUFMAP_DEBUG, "orangefs_bufmap_finalize: called\n");
432         mark_killed(&rw_map);
433         mark_killed(&readdir_map);
434         gossip_debug(GOSSIP_BUFMAP_DEBUG,
435                      "orangefs_bufmap_finalize: exiting normally\n");
436 }
437
438 void orangefs_bufmap_run_down(void)
439 {
440         struct orangefs_bufmap *bufmap = __orangefs_bufmap;
441         if (!bufmap)
442                 return;
443         run_down(&rw_map);
444         run_down(&readdir_map);
445         spin_lock(&orangefs_bufmap_lock);
446         __orangefs_bufmap = NULL;
447         spin_unlock(&orangefs_bufmap_lock);
448         orangefs_bufmap_unmap(bufmap);
449         orangefs_bufmap_free(bufmap);
450 }
451
452 /*
453  * orangefs_bufmap_get()
454  *
455  * gets a free mapped buffer descriptor, will sleep until one becomes
456  * available if necessary
457  *
458  * returns slot on success, -errno on failure
459  */
460 int orangefs_bufmap_get(void)
461 {
462         return get(&rw_map);
463 }
464
465 /*
466  * orangefs_bufmap_put()
467  *
468  * returns a mapped buffer descriptor to the collection
469  *
470  * no return value
471  */
472 void orangefs_bufmap_put(int buffer_index)
473 {
474         put(&rw_map, buffer_index);
475 }
476
477 /*
478  * orangefs_readdir_index_get()
479  *
480  * gets a free descriptor, will sleep until one becomes
481  * available if necessary.
482  * Although the readdir buffers are not mapped into kernel space
483  * we could do that at a later point of time. Regardless, these
484  * indices are used by the client-core.
485  *
486  * returns slot on success, -errno on failure
487  */
488 int orangefs_readdir_index_get(void)
489 {
490         return get(&readdir_map);
491 }
492
493 void orangefs_readdir_index_put(int buffer_index)
494 {
495         put(&readdir_map, buffer_index);
496 }
497
498 /*
499  * we've been handed an iovec, we need to copy it to 
500  * the shared memory descriptor at "buffer_index".
501  */
502 int orangefs_bufmap_copy_from_iovec(struct iov_iter *iter,
503                                 int buffer_index,
504                                 size_t size)
505 {
506         struct orangefs_bufmap_desc *to;
507         int i;
508
509         gossip_debug(GOSSIP_BUFMAP_DEBUG,
510                      "%s: buffer_index:%d: size:%zu:\n",
511                      __func__, buffer_index, size);
512
513         to = &__orangefs_bufmap->desc_array[buffer_index];
514         for (i = 0; size; i++) {
515                 struct page *page = to->page_array[i];
516                 size_t n = size;
517                 if (n > PAGE_SIZE)
518                         n = PAGE_SIZE;
519                 n = copy_page_from_iter(page, 0, n, iter);
520                 if (!n)
521                         return -EFAULT;
522                 size -= n;
523         }
524         return 0;
525
526 }
527
528 /*
529  * we've been handed an iovec, we need to fill it from
530  * the shared memory descriptor at "buffer_index".
531  */
532 int orangefs_bufmap_copy_to_iovec(struct iov_iter *iter,
533                                     int buffer_index,
534                                     size_t size)
535 {
536         struct orangefs_bufmap_desc *from;
537         int i;
538
539         from = &__orangefs_bufmap->desc_array[buffer_index];
540         gossip_debug(GOSSIP_BUFMAP_DEBUG,
541                      "%s: buffer_index:%d: size:%zu:\n",
542                      __func__, buffer_index, size);
543
544
545         for (i = 0; size; i++) {
546                 struct page *page = from->page_array[i];
547                 size_t n = size;
548                 if (n > PAGE_SIZE)
549                         n = PAGE_SIZE;
550                 n = copy_page_to_iter(page, 0, n, iter);
551                 if (!n)
552                         return -EFAULT;
553                 size -= n;
554         }
555         return 0;
556 }