1 /*
2  * Copyright (c) 2006, 2007 Cisco Systems, Inc.  All rights reserved.
3  * Copyright (c) 2007, 2008 Mellanox Technologies. All rights reserved.
4  *
5  * This software is available to you under a choice of one of two
6  * licenses.  You may choose to be licensed under the terms of the GNU
7  * General Public License (GPL) Version 2, available from the file
8  * COPYING in the main directory of this source tree, or the
9  * OpenIB.org BSD license below:
10  *
11  *     Redistribution and use in source and binary forms, with or
12  *     without modification, are permitted provided that the following
13  *     conditions are met:
14  *
15  *      - Redistributions of source code must retain the above
16  *        copyright notice, this list of conditions and the following
17  *        disclaimer.
18  *
19  *      - Redistributions in binary form must reproduce the above
20  *        copyright notice, this list of conditions and the following
21  *        disclaimer in the documentation and/or other materials
22  *        provided with the distribution.
23  *
24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
28  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
29  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
30  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
31  * SOFTWARE.
32  */
33 
34 #include <linux/errno.h>
35 #include <linux/slab.h>
36 #include <linux/mm.h>
37 #include <linux/export.h>
38 #include <linux/bitmap.h>
39 #include <linux/dma-mapping.h>
40 #include <linux/vmalloc.h>
41 
42 #include "mlx4.h"
43 
44 u32 mlx4_bitmap_alloc(struct mlx4_bitmap *bitmap)
45 {
46 	u32 obj;
47 
48 	spin_lock(&bitmap->lock);
49 
50 	obj = find_next_zero_bit(bitmap->table, bitmap->max, bitmap->last);
51 	if (obj >= bitmap->max) {
52 		bitmap->top = (bitmap->top + bitmap->max + bitmap->reserved_top)
53 				& bitmap->mask;
54 		obj = find_first_zero_bit(bitmap->table, bitmap->max);
55 	}
56 
57 	if (obj < bitmap->max) {
58 		set_bit(obj, bitmap->table);
59 		bitmap->last = (obj + 1);
60 		if (bitmap->last == bitmap->max)
61 			bitmap->last = 0;
62 		obj |= bitmap->top;
63 	} else
64 		obj = -1;
65 
66 	if (obj != -1)
67 		--bitmap->avail;
68 
69 	spin_unlock(&bitmap->lock);
70 
71 	return obj;
72 }
73 
74 void mlx4_bitmap_free(struct mlx4_bitmap *bitmap, u32 obj, int use_rr)
75 {
76 	mlx4_bitmap_free_range(bitmap, obj, 1, use_rr);
77 }
78 
79 static unsigned long find_aligned_range(unsigned long *bitmap,
80 					u32 start, u32 nbits,
81 					int len, int align, u32 skip_mask)
82 {
83 	unsigned long end, i;
84 
85 again:
86 	start = ALIGN(start, align);
87 
88 	while ((start < nbits) && (test_bit(start, bitmap) ||
89 				   (start & skip_mask)))
90 		start += align;
91 
92 	if (start >= nbits)
93 		return -1;
94 
95 	end = start+len;
96 	if (end > nbits)
97 		return -1;
98 
99 	for (i = start + 1; i < end; i++) {
100 		if (test_bit(i, bitmap) || ((u32)i & skip_mask)) {
101 			start = i + 1;
102 			goto again;
103 		}
104 	}
105 
106 	return start;
107 }
108 
109 u32 mlx4_bitmap_alloc_range(struct mlx4_bitmap *bitmap, int cnt,
110 			    int align, u32 skip_mask)
111 {
112 	u32 obj;
113 
114 	if (likely(cnt == 1 && align == 1 && !skip_mask))
115 		return mlx4_bitmap_alloc(bitmap);
116 
117 	spin_lock(&bitmap->lock);
118 
119 	obj = find_aligned_range(bitmap->table, bitmap->last,
120 				 bitmap->max, cnt, align, skip_mask);
121 	if (obj >= bitmap->max) {
122 		bitmap->top = (bitmap->top + bitmap->max + bitmap->reserved_top)
123 				& bitmap->mask;
124 		obj = find_aligned_range(bitmap->table, 0, bitmap->max,
125 					 cnt, align, skip_mask);
126 	}
127 
128 	if (obj < bitmap->max) {
129 		bitmap_set(bitmap->table, obj, cnt);
130 		if (obj == bitmap->last) {
131 			bitmap->last = (obj + cnt);
132 			if (bitmap->last >= bitmap->max)
133 				bitmap->last = 0;
134 		}
135 		obj |= bitmap->top;
136 	} else
137 		obj = -1;
138 
139 	if (obj != -1)
140 		bitmap->avail -= cnt;
141 
142 	spin_unlock(&bitmap->lock);
143 
144 	return obj;
145 }
146 
147 u32 mlx4_bitmap_avail(struct mlx4_bitmap *bitmap)
148 {
149 	return bitmap->avail;
150 }
151 
152 static u32 mlx4_bitmap_masked_value(struct mlx4_bitmap *bitmap, u32 obj)
153 {
154 	return obj & (bitmap->max + bitmap->reserved_top - 1);
155 }
156 
157 void mlx4_bitmap_free_range(struct mlx4_bitmap *bitmap, u32 obj, int cnt,
158 			    int use_rr)
159 {
160 	obj &= bitmap->max + bitmap->reserved_top - 1;
161 
162 	spin_lock(&bitmap->lock);
163 	if (!use_rr) {
164 		bitmap->last = min(bitmap->last, obj);
165 		bitmap->top = (bitmap->top + bitmap->max + bitmap->reserved_top)
166 				& bitmap->mask;
167 	}
168 	bitmap_clear(bitmap->table, obj, cnt);
169 	bitmap->avail += cnt;
170 	spin_unlock(&bitmap->lock);
171 }
172 
173 int mlx4_bitmap_init(struct mlx4_bitmap *bitmap, u32 num, u32 mask,
174 		     u32 reserved_bot, u32 reserved_top)
175 {
176 	/* num must be a power of 2 */
177 	if (num != roundup_pow_of_two(num))
178 		return -EINVAL;
179 
180 	bitmap->last = 0;
181 	bitmap->top  = 0;
182 	bitmap->max  = num - reserved_top;
183 	bitmap->mask = mask;
184 	bitmap->reserved_top = reserved_top;
185 	bitmap->avail = num - reserved_top - reserved_bot;
186 	bitmap->effective_len = bitmap->avail;
187 	spin_lock_init(&bitmap->lock);
188 	bitmap->table = kzalloc(BITS_TO_LONGS(bitmap->max) *
189 				sizeof (long), GFP_KERNEL);
190 	if (!bitmap->table)
191 		return -ENOMEM;
192 
193 	bitmap_set(bitmap->table, 0, reserved_bot);
194 
195 	return 0;
196 }
197 
198 void mlx4_bitmap_cleanup(struct mlx4_bitmap *bitmap)
199 {
200 	kfree(bitmap->table);
201 }
202 
203 struct mlx4_zone_allocator {
204 	struct list_head		entries;
205 	struct list_head		prios;
206 	u32				last_uid;
207 	u32				mask;
208 	/* protect the zone_allocator from concurrent accesses */
209 	spinlock_t			lock;
210 	enum mlx4_zone_alloc_flags	flags;
211 };
212 
213 struct mlx4_zone_entry {
214 	struct list_head		list;
215 	struct list_head		prio_list;
216 	u32				uid;
217 	struct mlx4_zone_allocator	*allocator;
218 	struct mlx4_bitmap		*bitmap;
219 	int				use_rr;
220 	int				priority;
221 	int				offset;
222 	enum mlx4_zone_flags		flags;
223 };
224 
225 struct mlx4_zone_allocator *mlx4_zone_allocator_create(enum mlx4_zone_alloc_flags flags)
226 {
227 	struct mlx4_zone_allocator *zones = kmalloc(sizeof(*zones), GFP_KERNEL);
228 
229 	if (NULL == zones)
230 		return NULL;
231 
232 	INIT_LIST_HEAD(&zones->entries);
233 	INIT_LIST_HEAD(&zones->prios);
234 	spin_lock_init(&zones->lock);
235 	zones->last_uid = 0;
236 	zones->mask = 0;
237 	zones->flags = flags;
238 
239 	return zones;
240 }
241 
242 int mlx4_zone_add_one(struct mlx4_zone_allocator *zone_alloc,
243 		      struct mlx4_bitmap *bitmap,
244 		      u32 flags,
245 		      int priority,
246 		      int offset,
247 		      u32 *puid)
248 {
249 	u32 mask = mlx4_bitmap_masked_value(bitmap, (u32)-1);
250 	struct mlx4_zone_entry *it;
251 	struct mlx4_zone_entry *zone = kmalloc(sizeof(*zone), GFP_KERNEL);
252 
253 	if (NULL == zone)
254 		return -ENOMEM;
255 
256 	zone->flags = flags;
257 	zone->bitmap = bitmap;
258 	zone->use_rr = (flags & MLX4_ZONE_USE_RR) ? MLX4_USE_RR : 0;
259 	zone->priority = priority;
260 	zone->offset = offset;
261 
262 	spin_lock(&zone_alloc->lock);
263 
264 	zone->uid = zone_alloc->last_uid++;
265 	zone->allocator = zone_alloc;
266 
267 	if (zone_alloc->mask < mask)
268 		zone_alloc->mask = mask;
269 
270 	list_for_each_entry(it, &zone_alloc->prios, prio_list)
271 		if (it->priority >= priority)
272 			break;
273 
274 	if (&it->prio_list == &zone_alloc->prios || it->priority > priority)
275 		list_add_tail(&zone->prio_list, &it->prio_list);
276 	list_add_tail(&zone->list, &it->list);
277 
278 	spin_unlock(&zone_alloc->lock);
279 
280 	*puid = zone->uid;
281 
282 	return 0;
283 }
284 
285 /* Should be called under a lock */
286 static int __mlx4_zone_remove_one_entry(struct mlx4_zone_entry *entry)
287 {
288 	struct mlx4_zone_allocator *zone_alloc = entry->allocator;
289 
290 	if (!list_empty(&entry->prio_list)) {
291 		/* Check if we need to add an alternative node to the prio list */
292 		if (!list_is_last(&entry->list, &zone_alloc->entries)) {
293 			struct mlx4_zone_entry *next = list_first_entry(&entry->list,
294 									typeof(*next),
295 									list);
296 
297 			if (next->priority == entry->priority)
298 				list_add_tail(&next->prio_list, &entry->prio_list);
299 		}
300 
301 		list_del(&entry->prio_list);
302 	}
303 
304 	list_del(&entry->list);
305 
306 	if (zone_alloc->flags & MLX4_ZONE_ALLOC_FLAGS_NO_OVERLAP) {
307 		u32 mask = 0;
308 		struct mlx4_zone_entry *it;
309 
310 		list_for_each_entry(it, &zone_alloc->prios, prio_list) {
311 			u32 cur_mask = mlx4_bitmap_masked_value(it->bitmap, (u32)-1);
312 
313 			if (mask < cur_mask)
314 				mask = cur_mask;
315 		}
316 		zone_alloc->mask = mask;
317 	}
318 
319 	return 0;
320 }
321 
322 void mlx4_zone_allocator_destroy(struct mlx4_zone_allocator *zone_alloc)
323 {
324 	struct mlx4_zone_entry *zone, *tmp;
325 
326 	spin_lock(&zone_alloc->lock);
327 
328 	list_for_each_entry_safe(zone, tmp, &zone_alloc->entries, list) {
329 		list_del(&zone->list);
330 		list_del(&zone->prio_list);
331 		kfree(zone);
332 	}
333 
334 	spin_unlock(&zone_alloc->lock);
335 	kfree(zone_alloc);
336 }
337 
338 /* Should be called under a lock */
339 static u32 __mlx4_alloc_from_zone(struct mlx4_zone_entry *zone, int count,
340 				  int align, u32 skip_mask, u32 *puid)
341 {
342 	u32 uid;
343 	u32 res;
344 	struct mlx4_zone_allocator *zone_alloc = zone->allocator;
345 	struct mlx4_zone_entry *curr_node;
346 
347 	res = mlx4_bitmap_alloc_range(zone->bitmap, count,
348 				      align, skip_mask);
349 
350 	if (res != (u32)-1) {
351 		res += zone->offset;
352 		uid = zone->uid;
353 		goto out;
354 	}
355 
356 	list_for_each_entry(curr_node, &zone_alloc->prios, prio_list) {
357 		if (unlikely(curr_node->priority == zone->priority))
358 			break;
359 	}
360 
361 	if (zone->flags & MLX4_ZONE_ALLOW_ALLOC_FROM_LOWER_PRIO) {
362 		struct mlx4_zone_entry *it = curr_node;
363 
364 		list_for_each_entry_continue_reverse(it, &zone_alloc->entries, list) {
365 			res = mlx4_bitmap_alloc_range(it->bitmap, count,
366 						      align, skip_mask);
367 			if (res != (u32)-1) {
368 				res += it->offset;
369 				uid = it->uid;
370 				goto out;
371 			}
372 		}
373 	}
374 
375 	if (zone->flags & MLX4_ZONE_ALLOW_ALLOC_FROM_EQ_PRIO) {
376 		struct mlx4_zone_entry *it = curr_node;
377 
378 		list_for_each_entry_from(it, &zone_alloc->entries, list) {
379 			if (unlikely(it == zone))
380 				continue;
381 
382 			if (unlikely(it->priority != curr_node->priority))
383 				break;
384 
385 			res = mlx4_bitmap_alloc_range(it->bitmap, count,
386 						      align, skip_mask);
387 			if (res != (u32)-1) {
388 				res += it->offset;
389 				uid = it->uid;
390 				goto out;
391 			}
392 		}
393 	}
394 
395 	if (zone->flags & MLX4_ZONE_FALLBACK_TO_HIGHER_PRIO) {
396 		if (list_is_last(&curr_node->prio_list, &zone_alloc->prios))
397 			goto out;
398 
399 		curr_node = list_first_entry(&curr_node->prio_list,
400 					     typeof(*curr_node),
401 					     prio_list);
402 
403 		list_for_each_entry_from(curr_node, &zone_alloc->entries, list) {
404 			res = mlx4_bitmap_alloc_range(curr_node->bitmap, count,
405 						      align, skip_mask);
406 			if (res != (u32)-1) {
407 				res += curr_node->offset;
408 				uid = curr_node->uid;
409 				goto out;
410 			}
411 		}
412 	}
413 
414 out:
415 	if (NULL != puid && res != (u32)-1)
416 		*puid = uid;
417 	return res;
418 }
419 
420 /* Should be called under a lock */
421 static void __mlx4_free_from_zone(struct mlx4_zone_entry *zone, u32 obj,
422 				  u32 count)
423 {
424 	mlx4_bitmap_free_range(zone->bitmap, obj - zone->offset, count, zone->use_rr);
425 }
426 
427 /* Should be called under a lock */
428 static struct mlx4_zone_entry *__mlx4_find_zone_by_uid(
429 		struct mlx4_zone_allocator *zones, u32 uid)
430 {
431 	struct mlx4_zone_entry *zone;
432 
433 	list_for_each_entry(zone, &zones->entries, list) {
434 		if (zone->uid == uid)
435 			return zone;
436 	}
437 
438 	return NULL;
439 }
440 
441 struct mlx4_bitmap *mlx4_zone_get_bitmap(struct mlx4_zone_allocator *zones, u32 uid)
442 {
443 	struct mlx4_zone_entry *zone;
444 	struct mlx4_bitmap *bitmap;
445 
446 	spin_lock(&zones->lock);
447 
448 	zone = __mlx4_find_zone_by_uid(zones, uid);
449 
450 	bitmap = zone == NULL ? NULL : zone->bitmap;
451 
452 	spin_unlock(&zones->lock);
453 
454 	return bitmap;
455 }
456 
457 int mlx4_zone_remove_one(struct mlx4_zone_allocator *zones, u32 uid)
458 {
459 	struct mlx4_zone_entry *zone;
460 	int res;
461 
462 	spin_lock(&zones->lock);
463 
464 	zone = __mlx4_find_zone_by_uid(zones, uid);
465 
466 	if (NULL == zone) {
467 		res = -1;
468 		goto out;
469 	}
470 
471 	res = __mlx4_zone_remove_one_entry(zone);
472 
473 out:
474 	spin_unlock(&zones->lock);
475 	kfree(zone);
476 
477 	return res;
478 }
479 
480 /* Should be called under a lock */
481 static struct mlx4_zone_entry *__mlx4_find_zone_by_uid_unique(
482 		struct mlx4_zone_allocator *zones, u32 obj)
483 {
484 	struct mlx4_zone_entry *zone, *zone_candidate = NULL;
485 	u32 dist = (u32)-1;
486 
487 	/* Search for the smallest zone that this obj could be
488 	 * allocated from. This is done in order to handle
489 	 * situations when small bitmaps are allocated from bigger
490 	 * bitmaps (and the allocated space is marked as reserved in
491 	 * the bigger bitmap.
492 	 */
493 	list_for_each_entry(zone, &zones->entries, list) {
494 		if (obj >= zone->offset) {
495 			u32 mobj = (obj - zone->offset) & zones->mask;
496 
497 			if (mobj < zone->bitmap->max) {
498 				u32 curr_dist = zone->bitmap->effective_len;
499 
500 				if (curr_dist < dist) {
501 					dist = curr_dist;
502 					zone_candidate = zone;
503 				}
504 			}
505 		}
506 	}
507 
508 	return zone_candidate;
509 }
510 
511 u32 mlx4_zone_alloc_entries(struct mlx4_zone_allocator *zones, u32 uid, int count,
512 			    int align, u32 skip_mask, u32 *puid)
513 {
514 	struct mlx4_zone_entry *zone;
515 	int res = -1;
516 
517 	spin_lock(&zones->lock);
518 
519 	zone = __mlx4_find_zone_by_uid(zones, uid);
520 
521 	if (NULL == zone)
522 		goto out;
523 
524 	res = __mlx4_alloc_from_zone(zone, count, align, skip_mask, puid);
525 
526 out:
527 	spin_unlock(&zones->lock);
528 
529 	return res;
530 }
531 
532 u32 mlx4_zone_free_entries(struct mlx4_zone_allocator *zones, u32 uid, u32 obj, u32 count)
533 {
534 	struct mlx4_zone_entry *zone;
535 	int res = 0;
536 
537 	spin_lock(&zones->lock);
538 
539 	zone = __mlx4_find_zone_by_uid(zones, uid);
540 
541 	if (NULL == zone) {
542 		res = -1;
543 		goto out;
544 	}
545 
546 	__mlx4_free_from_zone(zone, obj, count);
547 
548 out:
549 	spin_unlock(&zones->lock);
550 
551 	return res;
552 }
553 
554 u32 mlx4_zone_free_entries_unique(struct mlx4_zone_allocator *zones, u32 obj, u32 count)
555 {
556 	struct mlx4_zone_entry *zone;
557 	int res;
558 
559 	if (!(zones->flags & MLX4_ZONE_ALLOC_FLAGS_NO_OVERLAP))
560 		return -EFAULT;
561 
562 	spin_lock(&zones->lock);
563 
564 	zone = __mlx4_find_zone_by_uid_unique(zones, obj);
565 
566 	if (NULL == zone) {
567 		res = -1;
568 		goto out;
569 	}
570 
571 	__mlx4_free_from_zone(zone, obj, count);
572 	res = 0;
573 
574 out:
575 	spin_unlock(&zones->lock);
576 
577 	return res;
578 }
579 /*
580  * Handling for queue buffers -- we allocate a bunch of memory and
581  * register it in a memory region at HCA virtual address 0.  If the
582  * requested size is > max_direct, we split the allocation into
583  * multiple pages, so we don't require too much contiguous memory.
584  */
585 
586 int mlx4_buf_alloc(struct mlx4_dev *dev, int size, int max_direct,
587 		   struct mlx4_buf *buf, gfp_t gfp)
588 {
589 	dma_addr_t t;
590 
591 	if (size <= max_direct) {
592 		buf->nbufs        = 1;
593 		buf->npages       = 1;
594 		buf->page_shift   = get_order(size) + PAGE_SHIFT;
595 		buf->direct.buf   = dma_alloc_coherent(&dev->pdev->dev,
596 						       size, &t, gfp);
597 		if (!buf->direct.buf)
598 			return -ENOMEM;
599 
600 		buf->direct.map = t;
601 
602 		while (t & ((1 << buf->page_shift) - 1)) {
603 			--buf->page_shift;
604 			buf->npages *= 2;
605 		}
606 
607 		memset(buf->direct.buf, 0, size);
608 	} else {
609 		int i;
610 
611 		buf->direct.buf  = NULL;
612 		buf->nbufs       = (size + PAGE_SIZE - 1) / PAGE_SIZE;
613 		buf->npages      = buf->nbufs;
614 		buf->page_shift  = PAGE_SHIFT;
615 		buf->page_list   = kcalloc(buf->nbufs, sizeof(*buf->page_list),
616 					   gfp);
617 		if (!buf->page_list)
618 			return -ENOMEM;
619 
620 		for (i = 0; i < buf->nbufs; ++i) {
621 			buf->page_list[i].buf =
622 				dma_alloc_coherent(&dev->pdev->dev, PAGE_SIZE,
623 						   &t, gfp);
624 			if (!buf->page_list[i].buf)
625 				goto err_free;
626 
627 			buf->page_list[i].map = t;
628 
629 			memset(buf->page_list[i].buf, 0, PAGE_SIZE);
630 		}
631 
632 		if (BITS_PER_LONG == 64) {
633 			struct page **pages;
634 			pages = kmalloc(sizeof *pages * buf->nbufs, gfp);
635 			if (!pages)
636 				goto err_free;
637 			for (i = 0; i < buf->nbufs; ++i)
638 				pages[i] = virt_to_page(buf->page_list[i].buf);
639 			buf->direct.buf = vmap(pages, buf->nbufs, VM_MAP, PAGE_KERNEL);
640 			kfree(pages);
641 			if (!buf->direct.buf)
642 				goto err_free;
643 		}
644 	}
645 
646 	return 0;
647 
648 err_free:
649 	mlx4_buf_free(dev, size, buf);
650 
651 	return -ENOMEM;
652 }
653 EXPORT_SYMBOL_GPL(mlx4_buf_alloc);
654 
655 void mlx4_buf_free(struct mlx4_dev *dev, int size, struct mlx4_buf *buf)
656 {
657 	int i;
658 
659 	if (buf->nbufs == 1)
660 		dma_free_coherent(&dev->pdev->dev, size, buf->direct.buf,
661 				  buf->direct.map);
662 	else {
663 		if (BITS_PER_LONG == 64 && buf->direct.buf)
664 			vunmap(buf->direct.buf);
665 
666 		for (i = 0; i < buf->nbufs; ++i)
667 			if (buf->page_list[i].buf)
668 				dma_free_coherent(&dev->pdev->dev, PAGE_SIZE,
669 						  buf->page_list[i].buf,
670 						  buf->page_list[i].map);
671 		kfree(buf->page_list);
672 	}
673 }
674 EXPORT_SYMBOL_GPL(mlx4_buf_free);
675 
676 static struct mlx4_db_pgdir *mlx4_alloc_db_pgdir(struct device *dma_device,
677 						 gfp_t gfp)
678 {
679 	struct mlx4_db_pgdir *pgdir;
680 
681 	pgdir = kzalloc(sizeof *pgdir, gfp);
682 	if (!pgdir)
683 		return NULL;
684 
685 	bitmap_fill(pgdir->order1, MLX4_DB_PER_PAGE / 2);
686 	pgdir->bits[0] = pgdir->order0;
687 	pgdir->bits[1] = pgdir->order1;
688 	pgdir->db_page = dma_alloc_coherent(dma_device, PAGE_SIZE,
689 					    &pgdir->db_dma, gfp);
690 	if (!pgdir->db_page) {
691 		kfree(pgdir);
692 		return NULL;
693 	}
694 
695 	return pgdir;
696 }
697 
698 static int mlx4_alloc_db_from_pgdir(struct mlx4_db_pgdir *pgdir,
699 				    struct mlx4_db *db, int order)
700 {
701 	int o;
702 	int i;
703 
704 	for (o = order; o <= 1; ++o) {
705 		i = find_first_bit(pgdir->bits[o], MLX4_DB_PER_PAGE >> o);
706 		if (i < MLX4_DB_PER_PAGE >> o)
707 			goto found;
708 	}
709 
710 	return -ENOMEM;
711 
712 found:
713 	clear_bit(i, pgdir->bits[o]);
714 
715 	i <<= o;
716 
717 	if (o > order)
718 		set_bit(i ^ 1, pgdir->bits[order]);
719 
720 	db->u.pgdir = pgdir;
721 	db->index   = i;
722 	db->db      = pgdir->db_page + db->index;
723 	db->dma     = pgdir->db_dma  + db->index * 4;
724 	db->order   = order;
725 
726 	return 0;
727 }
728 
729 int mlx4_db_alloc(struct mlx4_dev *dev, struct mlx4_db *db, int order, gfp_t gfp)
730 {
731 	struct mlx4_priv *priv = mlx4_priv(dev);
732 	struct mlx4_db_pgdir *pgdir;
733 	int ret = 0;
734 
735 	mutex_lock(&priv->pgdir_mutex);
736 
737 	list_for_each_entry(pgdir, &priv->pgdir_list, list)
738 		if (!mlx4_alloc_db_from_pgdir(pgdir, db, order))
739 			goto out;
740 
741 	pgdir = mlx4_alloc_db_pgdir(&(dev->pdev->dev), gfp);
742 	if (!pgdir) {
743 		ret = -ENOMEM;
744 		goto out;
745 	}
746 
747 	list_add(&pgdir->list, &priv->pgdir_list);
748 
749 	/* This should never fail -- we just allocated an empty page: */
750 	WARN_ON(mlx4_alloc_db_from_pgdir(pgdir, db, order));
751 
752 out:
753 	mutex_unlock(&priv->pgdir_mutex);
754 
755 	return ret;
756 }
757 EXPORT_SYMBOL_GPL(mlx4_db_alloc);
758 
759 void mlx4_db_free(struct mlx4_dev *dev, struct mlx4_db *db)
760 {
761 	struct mlx4_priv *priv = mlx4_priv(dev);
762 	int o;
763 	int i;
764 
765 	mutex_lock(&priv->pgdir_mutex);
766 
767 	o = db->order;
768 	i = db->index;
769 
770 	if (db->order == 0 && test_bit(i ^ 1, db->u.pgdir->order0)) {
771 		clear_bit(i ^ 1, db->u.pgdir->order0);
772 		++o;
773 	}
774 	i >>= o;
775 	set_bit(i, db->u.pgdir->bits[o]);
776 
777 	if (bitmap_full(db->u.pgdir->order1, MLX4_DB_PER_PAGE / 2)) {
778 		dma_free_coherent(&(dev->pdev->dev), PAGE_SIZE,
779 				  db->u.pgdir->db_page, db->u.pgdir->db_dma);
780 		list_del(&db->u.pgdir->list);
781 		kfree(db->u.pgdir);
782 	}
783 
784 	mutex_unlock(&priv->pgdir_mutex);
785 }
786 EXPORT_SYMBOL_GPL(mlx4_db_free);
787 
788 int mlx4_alloc_hwq_res(struct mlx4_dev *dev, struct mlx4_hwq_resources *wqres,
789 		       int size, int max_direct)
790 {
791 	int err;
792 
793 	err = mlx4_db_alloc(dev, &wqres->db, 1, GFP_KERNEL);
794 	if (err)
795 		return err;
796 
797 	*wqres->db.db = 0;
798 
799 	err = mlx4_buf_alloc(dev, size, max_direct, &wqres->buf, GFP_KERNEL);
800 	if (err)
801 		goto err_db;
802 
803 	err = mlx4_mtt_init(dev, wqres->buf.npages, wqres->buf.page_shift,
804 			    &wqres->mtt);
805 	if (err)
806 		goto err_buf;
807 
808 	err = mlx4_buf_write_mtt(dev, &wqres->mtt, &wqres->buf, GFP_KERNEL);
809 	if (err)
810 		goto err_mtt;
811 
812 	return 0;
813 
814 err_mtt:
815 	mlx4_mtt_cleanup(dev, &wqres->mtt);
816 err_buf:
817 	mlx4_buf_free(dev, size, &wqres->buf);
818 err_db:
819 	mlx4_db_free(dev, &wqres->db);
820 
821 	return err;
822 }
823 EXPORT_SYMBOL_GPL(mlx4_alloc_hwq_res);
824 
825 void mlx4_free_hwq_res(struct mlx4_dev *dev, struct mlx4_hwq_resources *wqres,
826 		       int size)
827 {
828 	mlx4_mtt_cleanup(dev, &wqres->mtt);
829 	mlx4_buf_free(dev, size, &wqres->buf);
830 	mlx4_db_free(dev, &wqres->db);
831 }
832 EXPORT_SYMBOL_GPL(mlx4_free_hwq_res);
833