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Linux/fs/orangefs/orangefs-bufmap.c

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  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 (unlikely(v == 1))   /* no free slots -> one free slot */
 75                 wake_up_locked(&m->q);
 76         else 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 *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 /*
219  * orangefs_get_bufmap_init
220  *
221  * If bufmap_init is 1, then the shared memory system, including the
222  * buffer_index_array, is available.  Otherwise, it is not.
223  *
224  * returns the value of bufmap_init
225  */
226 int orangefs_get_bufmap_init(void)
227 {
228         return __orangefs_bufmap ? 1 : 0;
229 }
230 
231 
232 static struct orangefs_bufmap *
233 orangefs_bufmap_alloc(struct ORANGEFS_dev_map_desc *user_desc)
234 {
235         struct orangefs_bufmap *bufmap;
236 
237         bufmap = kzalloc(sizeof(*bufmap), GFP_KERNEL);
238         if (!bufmap)
239                 goto out;
240 
241         bufmap->total_size = user_desc->total_size;
242         bufmap->desc_count = user_desc->count;
243         bufmap->desc_size = user_desc->size;
244         bufmap->desc_shift = ilog2(bufmap->desc_size);
245 
246         bufmap->buffer_index_array =
247                 kzalloc(DIV_ROUND_UP(bufmap->desc_count, BITS_PER_LONG), GFP_KERNEL);
248         if (!bufmap->buffer_index_array)
249                 goto out_free_bufmap;
250 
251         bufmap->desc_array =
252                 kcalloc(bufmap->desc_count, sizeof(struct orangefs_bufmap_desc),
253                         GFP_KERNEL);
254         if (!bufmap->desc_array)
255                 goto out_free_index_array;
256 
257         bufmap->page_count = bufmap->total_size / PAGE_SIZE;
258 
259         /* allocate storage to track our page mappings */
260         bufmap->page_array =
261                 kcalloc(bufmap->page_count, sizeof(struct page *), GFP_KERNEL);
262         if (!bufmap->page_array)
263                 goto out_free_desc_array;
264 
265         return bufmap;
266 
267 out_free_desc_array:
268         kfree(bufmap->desc_array);
269 out_free_index_array:
270         kfree(bufmap->buffer_index_array);
271 out_free_bufmap:
272         kfree(bufmap);
273 out:
274         return NULL;
275 }
276 
277 static int
278 orangefs_bufmap_map(struct orangefs_bufmap *bufmap,
279                 struct ORANGEFS_dev_map_desc *user_desc)
280 {
281         int pages_per_desc = bufmap->desc_size / PAGE_SIZE;
282         int offset = 0, ret, i;
283 
284         /* map the pages */
285         ret = get_user_pages_fast((unsigned long)user_desc->ptr,
286                              bufmap->page_count, 1, bufmap->page_array);
287 
288         if (ret < 0)
289                 return ret;
290 
291         if (ret != bufmap->page_count) {
292                 gossip_err("orangefs error: asked for %d pages, only got %d.\n",
293                                 bufmap->page_count, ret);
294 
295                 for (i = 0; i < ret; i++) {
296                         SetPageError(bufmap->page_array[i]);
297                         put_page(bufmap->page_array[i]);
298                 }
299                 return -ENOMEM;
300         }
301 
302         /*
303          * ideally we want to get kernel space pointers for each page, but
304          * we can't kmap that many pages at once if highmem is being used.
305          * so instead, we just kmap/kunmap the page address each time the
306          * kaddr is needed.
307          */
308         for (i = 0; i < bufmap->page_count; i++)
309                 flush_dcache_page(bufmap->page_array[i]);
310 
311         /* build a list of available descriptors */
312         for (offset = 0, i = 0; i < bufmap->desc_count; i++) {
313                 bufmap->desc_array[i].page_array = &bufmap->page_array[offset];
314                 bufmap->desc_array[i].array_count = pages_per_desc;
315                 bufmap->desc_array[i].uaddr =
316                     (user_desc->ptr + (i * pages_per_desc * PAGE_SIZE));
317                 offset += pages_per_desc;
318         }
319 
320         return 0;
321 }
322 
323 /*
324  * orangefs_bufmap_initialize()
325  *
326  * initializes the mapped buffer interface
327  *
328  * returns 0 on success, -errno on failure
329  */
330 int orangefs_bufmap_initialize(struct ORANGEFS_dev_map_desc *user_desc)
331 {
332         struct orangefs_bufmap *bufmap;
333         int ret = -EINVAL;
334 
335         gossip_debug(GOSSIP_BUFMAP_DEBUG,
336                      "orangefs_bufmap_initialize: called (ptr ("
337                      "%p) sz (%d) cnt(%d).\n",
338                      user_desc->ptr,
339                      user_desc->size,
340                      user_desc->count);
341 
342         if (user_desc->total_size < 0 ||
343             user_desc->size < 0 ||
344             user_desc->count < 0)
345                 goto out;
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                 if (copy_page_from_iter(page, 0, n, iter) != n)
520                         return -EFAULT;
521                 size -= n;
522         }
523         return 0;
524 }
525 
526 /*
527  * we've been handed an iovec, we need to fill it from
528  * the shared memory descriptor at "buffer_index".
529  */
530 int orangefs_bufmap_copy_to_iovec(struct iov_iter *iter,
531                                     int buffer_index,
532                                     size_t size)
533 {
534         struct orangefs_bufmap_desc *from;
535         int i;
536 
537         from = &__orangefs_bufmap->desc_array[buffer_index];
538         gossip_debug(GOSSIP_BUFMAP_DEBUG,
539                      "%s: buffer_index:%d: size:%zu:\n",
540                      __func__, buffer_index, size);
541 
542 
543         for (i = 0; size; i++) {
544                 struct page *page = from->page_array[i];
545                 size_t n = size;
546                 if (n > PAGE_SIZE)
547                         n = PAGE_SIZE;
548                 n = copy_page_to_iter(page, 0, n, iter);
549                 if (!n)
550                         return -EFAULT;
551                 size -= n;
552         }
553         return 0;
554 }
555 

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