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			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 */
312int 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
392out_unmap_bufmap:
393	orangefs_bufmap_unmap(bufmap);
394out_free_bufmap:
395	orangefs_bufmap_free(bufmap);
396out:
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 */
408void 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
420void 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 */
442int 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 */
454void 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 */
470int orangefs_readdir_index_get(void)
471{
472	return get(&readdir_map);
473}
474
475void 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 */
484int 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 */
512int 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
538void 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}
550