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 
install(struct slot_map * m,int count,unsigned long * map)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 
mark_killed(struct slot_map * m)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 
run_down(struct slot_map * m)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 
put(struct slot_map * m,int slot)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 
wait_for_free(struct slot_map * m)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 
get(struct slot_map * m)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
orangefs_bufmap_unmap(struct orangefs_bufmap * bufmap)169 orangefs_bufmap_unmap(struct orangefs_bufmap *bufmap)
170 {
171 	unpin_user_pages(bufmap->page_array, bufmap->page_count);
172 }
173 
174 static void
orangefs_bufmap_free(struct orangefs_bufmap * bufmap)175 orangefs_bufmap_free(struct orangefs_bufmap *bufmap)
176 {
177 	kfree(bufmap->page_array);
178 	kfree(bufmap->desc_array);
179 	kfree(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 
orangefs_bufmap_size_query(void)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 
orangefs_bufmap_shift_query(void)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 *
orangefs_bufmap_alloc(struct ORANGEFS_dev_map_desc * user_desc)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 =
230 		kzalloc(DIV_ROUND_UP(bufmap->desc_count, BITS_PER_LONG), GFP_KERNEL);
231 	if (!bufmap->buffer_index_array)
232 		goto out_free_bufmap;
233 
234 	bufmap->desc_array =
235 		kcalloc(bufmap->desc_count, sizeof(struct orangefs_bufmap_desc),
236 			GFP_KERNEL);
237 	if (!bufmap->desc_array)
238 		goto out_free_index_array;
239 
240 	bufmap->page_count = bufmap->total_size / PAGE_SIZE;
241 
242 	/* allocate storage to track our page mappings */
243 	bufmap->page_array =
244 		kcalloc(bufmap->page_count, sizeof(struct page *), GFP_KERNEL);
245 	if (!bufmap->page_array)
246 		goto out_free_desc_array;
247 
248 	return bufmap;
249 
250 out_free_desc_array:
251 	kfree(bufmap->desc_array);
252 out_free_index_array:
253 	kfree(bufmap->buffer_index_array);
254 out_free_bufmap:
255 	kfree(bufmap);
256 out:
257 	return NULL;
258 }
259 
260 static int
orangefs_bufmap_map(struct orangefs_bufmap * bufmap,struct ORANGEFS_dev_map_desc * user_desc)261 orangefs_bufmap_map(struct orangefs_bufmap *bufmap,
262 		struct ORANGEFS_dev_map_desc *user_desc)
263 {
264 	int pages_per_desc = bufmap->desc_size / PAGE_SIZE;
265 	int offset = 0, ret, i;
266 
267 	/* map the pages */
268 	ret = pin_user_pages_fast((unsigned long)user_desc->ptr,
269 			     bufmap->page_count, FOLL_WRITE, bufmap->page_array);
270 
271 	if (ret < 0)
272 		return ret;
273 
274 	if (ret != bufmap->page_count) {
275 		gossip_err("orangefs error: asked for %d pages, only got %d.\n",
276 				bufmap->page_count, ret);
277 
278 		for (i = 0; i < ret; i++) {
279 			SetPageError(bufmap->page_array[i]);
280 			unpin_user_page(bufmap->page_array[i]);
281 		}
282 		return -ENOMEM;
283 	}
284 
285 	/*
286 	 * ideally we want to get kernel space pointers for each page, but
287 	 * we can't kmap that many pages at once if highmem is being used.
288 	 * so instead, we just kmap/kunmap the page address each time the
289 	 * kaddr is needed.
290 	 */
291 	for (i = 0; i < bufmap->page_count; i++)
292 		flush_dcache_page(bufmap->page_array[i]);
293 
294 	/* build a list of available descriptors */
295 	for (offset = 0, i = 0; i < bufmap->desc_count; i++) {
296 		bufmap->desc_array[i].page_array = &bufmap->page_array[offset];
297 		bufmap->desc_array[i].array_count = pages_per_desc;
298 		bufmap->desc_array[i].uaddr =
299 		    (user_desc->ptr + (i * pages_per_desc * PAGE_SIZE));
300 		offset += pages_per_desc;
301 	}
302 
303 	return 0;
304 }
305 
306 /*
307  * orangefs_bufmap_initialize()
308  *
309  * initializes the mapped buffer interface
310  *
311  * returns 0 on success, -errno on failure
312  */
orangefs_bufmap_initialize(struct ORANGEFS_dev_map_desc * user_desc)313 int orangefs_bufmap_initialize(struct ORANGEFS_dev_map_desc *user_desc)
314 {
315 	struct orangefs_bufmap *bufmap;
316 	int ret = -EINVAL;
317 
318 	gossip_debug(GOSSIP_BUFMAP_DEBUG,
319 		     "orangefs_bufmap_initialize: called (ptr ("
320 		     "%p) sz (%d) cnt(%d).\n",
321 		     user_desc->ptr,
322 		     user_desc->size,
323 		     user_desc->count);
324 
325 	if (user_desc->total_size < 0 ||
326 	    user_desc->size < 0 ||
327 	    user_desc->count < 0)
328 		goto out;
329 
330 	/*
331 	 * sanity check alignment and size of buffer that caller wants to
332 	 * work with
333 	 */
334 	if (PAGE_ALIGN((unsigned long)user_desc->ptr) !=
335 	    (unsigned long)user_desc->ptr) {
336 		gossip_err("orangefs error: memory alignment (front). %p\n",
337 			   user_desc->ptr);
338 		goto out;
339 	}
340 
341 	if (PAGE_ALIGN(((unsigned long)user_desc->ptr + user_desc->total_size))
342 	    != (unsigned long)(user_desc->ptr + user_desc->total_size)) {
343 		gossip_err("orangefs error: memory alignment (back).(%p + %d)\n",
344 			   user_desc->ptr,
345 			   user_desc->total_size);
346 		goto out;
347 	}
348 
349 	if (user_desc->total_size != (user_desc->size * user_desc->count)) {
350 		gossip_err("orangefs error: user provided an oddly sized buffer: (%d, %d, %d)\n",
351 			   user_desc->total_size,
352 			   user_desc->size,
353 			   user_desc->count);
354 		goto out;
355 	}
356 
357 	if ((user_desc->size % PAGE_SIZE) != 0) {
358 		gossip_err("orangefs error: bufmap size not page size divisible (%d).\n",
359 			   user_desc->size);
360 		goto out;
361 	}
362 
363 	ret = -ENOMEM;
364 	bufmap = orangefs_bufmap_alloc(user_desc);
365 	if (!bufmap)
366 		goto out;
367 
368 	ret = orangefs_bufmap_map(bufmap, user_desc);
369 	if (ret)
370 		goto out_free_bufmap;
371 
372 
373 	spin_lock(&orangefs_bufmap_lock);
374 	if (__orangefs_bufmap) {
375 		spin_unlock(&orangefs_bufmap_lock);
376 		gossip_err("orangefs: error: bufmap already initialized.\n");
377 		ret = -EINVAL;
378 		goto out_unmap_bufmap;
379 	}
380 	__orangefs_bufmap = bufmap;
381 	install(&rw_map,
382 		bufmap->desc_count,
383 		bufmap->buffer_index_array);
384 	install(&readdir_map,
385 		ORANGEFS_READDIR_DEFAULT_DESC_COUNT,
386 		bufmap->readdir_index_array);
387 	spin_unlock(&orangefs_bufmap_lock);
388 
389 	gossip_debug(GOSSIP_BUFMAP_DEBUG,
390 		     "orangefs_bufmap_initialize: exiting normally\n");
391 	return 0;
392 
393 out_unmap_bufmap:
394 	orangefs_bufmap_unmap(bufmap);
395 out_free_bufmap:
396 	orangefs_bufmap_free(bufmap);
397 out:
398 	return ret;
399 }
400 
401 /*
402  * orangefs_bufmap_finalize()
403  *
404  * shuts down the mapped buffer interface and releases any resources
405  * associated with it
406  *
407  * no return value
408  */
orangefs_bufmap_finalize(void)409 void orangefs_bufmap_finalize(void)
410 {
411 	struct orangefs_bufmap *bufmap = __orangefs_bufmap;
412 	if (!bufmap)
413 		return;
414 	gossip_debug(GOSSIP_BUFMAP_DEBUG, "orangefs_bufmap_finalize: called\n");
415 	mark_killed(&rw_map);
416 	mark_killed(&readdir_map);
417 	gossip_debug(GOSSIP_BUFMAP_DEBUG,
418 		     "orangefs_bufmap_finalize: exiting normally\n");
419 }
420 
orangefs_bufmap_run_down(void)421 void orangefs_bufmap_run_down(void)
422 {
423 	struct orangefs_bufmap *bufmap = __orangefs_bufmap;
424 	if (!bufmap)
425 		return;
426 	run_down(&rw_map);
427 	run_down(&readdir_map);
428 	spin_lock(&orangefs_bufmap_lock);
429 	__orangefs_bufmap = NULL;
430 	spin_unlock(&orangefs_bufmap_lock);
431 	orangefs_bufmap_unmap(bufmap);
432 	orangefs_bufmap_free(bufmap);
433 }
434 
435 /*
436  * orangefs_bufmap_get()
437  *
438  * gets a free mapped buffer descriptor, will sleep until one becomes
439  * available if necessary
440  *
441  * returns slot on success, -errno on failure
442  */
orangefs_bufmap_get(void)443 int orangefs_bufmap_get(void)
444 {
445 	return get(&rw_map);
446 }
447 
448 /*
449  * orangefs_bufmap_put()
450  *
451  * returns a mapped buffer descriptor to the collection
452  *
453  * no return value
454  */
orangefs_bufmap_put(int buffer_index)455 void orangefs_bufmap_put(int buffer_index)
456 {
457 	put(&rw_map, buffer_index);
458 }
459 
460 /*
461  * orangefs_readdir_index_get()
462  *
463  * gets a free descriptor, will sleep until one becomes
464  * available if necessary.
465  * Although the readdir buffers are not mapped into kernel space
466  * we could do that at a later point of time. Regardless, these
467  * indices are used by the client-core.
468  *
469  * returns slot on success, -errno on failure
470  */
orangefs_readdir_index_get(void)471 int orangefs_readdir_index_get(void)
472 {
473 	return get(&readdir_map);
474 }
475 
orangefs_readdir_index_put(int buffer_index)476 void orangefs_readdir_index_put(int buffer_index)
477 {
478 	put(&readdir_map, buffer_index);
479 }
480 
481 /*
482  * we've been handed an iovec, we need to copy it to
483  * the shared memory descriptor at "buffer_index".
484  */
orangefs_bufmap_copy_from_iovec(struct iov_iter * iter,int buffer_index,size_t size)485 int orangefs_bufmap_copy_from_iovec(struct iov_iter *iter,
486 				int buffer_index,
487 				size_t size)
488 {
489 	struct orangefs_bufmap_desc *to;
490 	int i;
491 
492 	gossip_debug(GOSSIP_BUFMAP_DEBUG,
493 		     "%s: buffer_index:%d: size:%zu:\n",
494 		     __func__, buffer_index, size);
495 
496 	to = &__orangefs_bufmap->desc_array[buffer_index];
497 	for (i = 0; size; i++) {
498 		struct page *page = to->page_array[i];
499 		size_t n = size;
500 		if (n > PAGE_SIZE)
501 			n = PAGE_SIZE;
502 		if (copy_page_from_iter(page, 0, n, iter) != n)
503 			return -EFAULT;
504 		size -= n;
505 	}
506 	return 0;
507 }
508 
509 /*
510  * we've been handed an iovec, we need to fill it from
511  * the shared memory descriptor at "buffer_index".
512  */
orangefs_bufmap_copy_to_iovec(struct iov_iter * iter,int buffer_index,size_t size)513 int orangefs_bufmap_copy_to_iovec(struct iov_iter *iter,
514 				    int buffer_index,
515 				    size_t size)
516 {
517 	struct orangefs_bufmap_desc *from;
518 	int i;
519 
520 	from = &__orangefs_bufmap->desc_array[buffer_index];
521 	gossip_debug(GOSSIP_BUFMAP_DEBUG,
522 		     "%s: buffer_index:%d: size:%zu:\n",
523 		     __func__, buffer_index, size);
524 
525 
526 	for (i = 0; size; i++) {
527 		struct page *page = from->page_array[i];
528 		size_t n = size;
529 		if (n > PAGE_SIZE)
530 			n = PAGE_SIZE;
531 		n = copy_page_to_iter(page, 0, n, iter);
532 		if (!n)
533 			return -EFAULT;
534 		size -= n;
535 	}
536 	return 0;
537 }
538 
orangefs_bufmap_page_fill(void * page_to,int buffer_index,int slot_index)539 void orangefs_bufmap_page_fill(void *page_to,
540 				int buffer_index,
541 				int slot_index)
542 {
543 	struct orangefs_bufmap_desc *from;
544 	void *page_from;
545 
546 	from = &__orangefs_bufmap->desc_array[buffer_index];
547 	page_from = kmap_atomic(from->page_array[slot_index]);
548 	memcpy(page_to, page_from, PAGE_SIZE);
549 	kunmap_atomic(page_from);
550 }
551