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
 11struct slot_map {
 12	int c;
 13	wait_queue_head_t q;
 14	int count;
 15	unsigned long *map;
 16};
 17
 18static struct slot_map rw_map = {
 19	.c = -1,
 20	.q = __WAIT_QUEUE_HEAD_INITIALIZER(rw_map.q)
 21};
 22static struct slot_map readdir_map = {
 23	.c = -1,
 24	.q = __WAIT_QUEUE_HEAD_INITIALIZER(readdir_map.q)
 25};
 26
 27
 28static 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
 37static 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
 44static 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
 68static 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
 81static 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
124static 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 */
140struct 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
147static 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
166static DEFINE_SPINLOCK(orangefs_bufmap_lock);
167
168static void
169orangefs_bufmap_unmap(struct orangefs_bufmap *bufmap)
170{
171	unpin_user_pages(bufmap->page_array, bufmap->page_count);
172}
173
174static void
175orangefs_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
188int 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
200int 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
212static DECLARE_WAIT_QUEUE_HEAD(bufmap_waitq);
213static DECLARE_WAIT_QUEUE_HEAD(readdir_waitq);
214
215static struct orangefs_bufmap *
216orangefs_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
249out_free_desc_array:
250	kfree(bufmap->desc_array);
251out_free_index_array:
252	bitmap_free(bufmap->buffer_index_array);
253out_free_bufmap:
254	kfree(bufmap);
255out:
256	return NULL;
257}
258
259static int
260orangefs_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			unpin_user_page(bufmap->page_array[i]);
279		return -ENOMEM;
280	}
281
282	/*
283	 * ideally we want to get kernel space pointers for each page, but
284	 * we can't kmap that many pages at once if highmem is being used.
285	 * so instead, we just kmap/kunmap the page address each time the
286	 * kaddr is needed.
287	 */
288	for (i = 0; i < bufmap->page_count; i++)
289		flush_dcache_page(bufmap->page_array[i]);
290
291	/* build a list of available descriptors */
292	for (offset = 0, i = 0; i < bufmap->desc_count; i++) {
293		bufmap->desc_array[i].page_array = &bufmap->page_array[offset];
294		bufmap->desc_array[i].array_count = pages_per_desc;
295		bufmap->desc_array[i].uaddr =
296		    (user_desc->ptr + (i * pages_per_desc * PAGE_SIZE));
297		offset += pages_per_desc;
298	}
299
300	return 0;
301}
302
303/*
304 * orangefs_bufmap_initialize()
305 *
306 * initializes the mapped buffer interface
307 *
308 * returns 0 on success, -errno on failure
309 */
310int orangefs_bufmap_initialize(struct ORANGEFS_dev_map_desc *user_desc)
311{
312	struct orangefs_bufmap *bufmap;
313	int ret = -EINVAL;
314
315	gossip_debug(GOSSIP_BUFMAP_DEBUG,
316		     "orangefs_bufmap_initialize: called (ptr ("
317		     "%p) sz (%d) cnt(%d).\n",
318		     user_desc->ptr,
319		     user_desc->size,
320		     user_desc->count);
321
322	if (user_desc->total_size < 0 ||
323	    user_desc->size < 0 ||
324	    user_desc->count < 0)
325		goto out;
326
327	/*
328	 * sanity check alignment and size of buffer that caller wants to
329	 * work with
330	 */
331	if (PAGE_ALIGN((unsigned long)user_desc->ptr) !=
332	    (unsigned long)user_desc->ptr) {
333		gossip_err("orangefs error: memory alignment (front). %p\n",
334			   user_desc->ptr);
335		goto out;
336	}
337
338	if (PAGE_ALIGN(((unsigned long)user_desc->ptr + user_desc->total_size))
339	    != (unsigned long)(user_desc->ptr + user_desc->total_size)) {
340		gossip_err("orangefs error: memory alignment (back).(%p + %d)\n",
341			   user_desc->ptr,
342			   user_desc->total_size);
343		goto out;
344	}
345
346	if (user_desc->total_size != (user_desc->size * user_desc->count)) {
347		gossip_err("orangefs error: user provided an oddly sized buffer: (%d, %d, %d)\n",
348			   user_desc->total_size,
349			   user_desc->size,
350			   user_desc->count);
351		goto out;
352	}
353
354	if ((user_desc->size % PAGE_SIZE) != 0) {
355		gossip_err("orangefs error: bufmap size not page size divisible (%d).\n",
356			   user_desc->size);
357		goto out;
358	}
359
360	ret = -ENOMEM;
361	bufmap = orangefs_bufmap_alloc(user_desc);
362	if (!bufmap)
363		goto out;
364
365	ret = orangefs_bufmap_map(bufmap, user_desc);
366	if (ret)
367		goto out_free_bufmap;
368
369
370	spin_lock(&orangefs_bufmap_lock);
371	if (__orangefs_bufmap) {
372		spin_unlock(&orangefs_bufmap_lock);
373		gossip_err("orangefs: error: bufmap already initialized.\n");
374		ret = -EINVAL;
375		goto out_unmap_bufmap;
376	}
377	__orangefs_bufmap = bufmap;
378	install(&rw_map,
379		bufmap->desc_count,
380		bufmap->buffer_index_array);
381	install(&readdir_map,
382		ORANGEFS_READDIR_DEFAULT_DESC_COUNT,
383		bufmap->readdir_index_array);
384	spin_unlock(&orangefs_bufmap_lock);
385
386	gossip_debug(GOSSIP_BUFMAP_DEBUG,
387		     "orangefs_bufmap_initialize: exiting normally\n");
388	return 0;
389
390out_unmap_bufmap:
391	orangefs_bufmap_unmap(bufmap);
392out_free_bufmap:
393	orangefs_bufmap_free(bufmap);
394out:
395	return ret;
396}
397
398/*
399 * orangefs_bufmap_finalize()
400 *
401 * shuts down the mapped buffer interface and releases any resources
402 * associated with it
403 *
404 * no return value
405 */
406void orangefs_bufmap_finalize(void)
407{
408	struct orangefs_bufmap *bufmap = __orangefs_bufmap;
409	if (!bufmap)
410		return;
411	gossip_debug(GOSSIP_BUFMAP_DEBUG, "orangefs_bufmap_finalize: called\n");
412	mark_killed(&rw_map);
413	mark_killed(&readdir_map);
414	gossip_debug(GOSSIP_BUFMAP_DEBUG,
415		     "orangefs_bufmap_finalize: exiting normally\n");
416}
417
418void orangefs_bufmap_run_down(void)
419{
420	struct orangefs_bufmap *bufmap = __orangefs_bufmap;
421	if (!bufmap)
422		return;
423	run_down(&rw_map);
424	run_down(&readdir_map);
425	spin_lock(&orangefs_bufmap_lock);
426	__orangefs_bufmap = NULL;
427	spin_unlock(&orangefs_bufmap_lock);
428	orangefs_bufmap_unmap(bufmap);
429	orangefs_bufmap_free(bufmap);
430}
431
432/*
433 * orangefs_bufmap_get()
434 *
435 * gets a free mapped buffer descriptor, will sleep until one becomes
436 * available if necessary
437 *
438 * returns slot on success, -errno on failure
439 */
440int orangefs_bufmap_get(void)
441{
442	return get(&rw_map);
443}
444
445/*
446 * orangefs_bufmap_put()
447 *
448 * returns a mapped buffer descriptor to the collection
449 *
450 * no return value
451 */
452void orangefs_bufmap_put(int buffer_index)
453{
454	put(&rw_map, buffer_index);
455}
456
457/*
458 * orangefs_readdir_index_get()
459 *
460 * gets a free descriptor, will sleep until one becomes
461 * available if necessary.
462 * Although the readdir buffers are not mapped into kernel space
463 * we could do that at a later point of time. Regardless, these
464 * indices are used by the client-core.
465 *
466 * returns slot on success, -errno on failure
467 */
468int orangefs_readdir_index_get(void)
469{
470	return get(&readdir_map);
471}
472
473void orangefs_readdir_index_put(int buffer_index)
474{
475	put(&readdir_map, buffer_index);
476}
477
478/*
479 * we've been handed an iovec, we need to copy it to
480 * the shared memory descriptor at "buffer_index".
481 */
482int orangefs_bufmap_copy_from_iovec(struct iov_iter *iter,
483				int buffer_index,
484				size_t size)
485{
486	struct orangefs_bufmap_desc *to;
487	int i;
488
489	gossip_debug(GOSSIP_BUFMAP_DEBUG,
490		     "%s: buffer_index:%d: size:%zu:\n",
491		     __func__, buffer_index, size);
492
493	to = &__orangefs_bufmap->desc_array[buffer_index];
494	for (i = 0; size; i++) {
495		struct page *page = to->page_array[i];
496		size_t n = size;
497		if (n > PAGE_SIZE)
498			n = PAGE_SIZE;
499		if (copy_page_from_iter(page, 0, n, iter) != n)
500			return -EFAULT;
501		size -= n;
502	}
503	return 0;
504}
505
506/*
507 * we've been handed an iovec, we need to fill it from
508 * the shared memory descriptor at "buffer_index".
509 */
510int orangefs_bufmap_copy_to_iovec(struct iov_iter *iter,
511				    int buffer_index,
512				    size_t size)
513{
514	struct orangefs_bufmap_desc *from;
515	int i;
516
517	from = &__orangefs_bufmap->desc_array[buffer_index];
518	gossip_debug(GOSSIP_BUFMAP_DEBUG,
519		     "%s: buffer_index:%d: size:%zu:\n",
520		     __func__, buffer_index, size);
521
522
523	for (i = 0; size; i++) {
524		struct page *page = from->page_array[i];
525		size_t n = size;
526		if (n > PAGE_SIZE)
527			n = PAGE_SIZE;
528		n = copy_page_to_iter(page, 0, n, iter);
529		if (!n)
530			return -EFAULT;
531		size -= n;
532	}
533	return 0;
534}
535
536void orangefs_bufmap_page_fill(void *page_to,
537				int buffer_index,
538				int slot_index)
539{
540	struct orangefs_bufmap_desc *from;
541	void *page_from;
542
543	from = &__orangefs_bufmap->desc_array[buffer_index];
544	page_from = kmap_atomic(from->page_array[slot_index]);
545	memcpy(page_to, page_from, PAGE_SIZE);
546	kunmap_atomic(page_from);
547}