/*
   * Copyright (c) 2006, 2007 Cisco Systems, Inc.  All rights reserved.
   * Copyright (c) 2007, 2008 Mellanox Technologies. All rights reserved.
   *
   * This software is available to you under a choice of one of two
   * licenses.  You may choose to be licensed under the terms of the GNU
   * General Public License (GPL) Version 2, available from the file
   * COPYING in the main directory of this source tree, or the
   * OpenIB.org BSD license below:
   *
   *     Redistribution and use in source and binary forms, with or
   *     without modification, are permitted provided that the following
   *     conditions are met:
   *
   *      - Redistributions of source code must retain the above
   *        copyright notice, this list of conditions and the following
   *        disclaimer.
   *
   *      - Redistributions in binary form must reproduce the above
   *        copyright notice, this list of conditions and the following
   *        disclaimer in the documentation and/or other materials
   *        provided with the distribution.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
   * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
   * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   */
  
  #include <linux/errno.h>
  #include <linux/slab.h>
  #include <linux/mm.h>
  #include <linux/export.h>
  #include <linux/bitmap.h>
  #include <linux/dma-mapping.h>
  #include <linux/vmalloc.h>
  
  #include "mlx4.h"
  
  u32 mlx4_bitmap_alloc(struct mlx4_bitmap *bitmap)
  {
  	u32 obj;
  
  	spin_lock(&bitmap->lock);
  
  	obj = find_next_zero_bit(bitmap->table, bitmap->max, bitmap->last);
  	if (obj >= bitmap->max) {
  		bitmap->top = (bitmap->top + bitmap->max + bitmap->reserved_top)
  				& bitmap->mask;
  		obj = find_first_zero_bit(bitmap->table, bitmap->max);
  	}
  
  	if (obj < bitmap->max) {
  		set_bit(obj, bitmap->table);
  		bitmap->last = (obj + 1);
  		if (bitmap->last == bitmap->max)
  			bitmap->last = 0;
  		obj |= bitmap->top;
  	} else
  		obj = -1;
  
  	if (obj != -1)
  		--bitmap->avail;
  
  	spin_unlock(&bitmap->lock);
  
  	return obj;
  }
  
  void mlx4_bitmap_free(struct mlx4_bitmap *bitmap, u32 obj, int use_rr)
  {
  	mlx4_bitmap_free_range(bitmap, obj, 1, use_rr);
  }
  
  static unsigned long find_aligned_range(unsigned long *bitmap,
  					u32 start, u32 nbits,
  					int len, int align, u32 skip_mask)
  {
  	unsigned long end, i;
  
  again:
  	start = ALIGN(start, align);
  
  	while ((start < nbits) && (test_bit(start, bitmap) ||
  				   (start & skip_mask)))
  		start += align;
  
  	if (start >= nbits)
  		return -1;
  
  	end = start+len;
  	if (end > nbits)
  		return -1;
  
  	for (i = start + 1; i < end; i++) {
  		if (test_bit(i, bitmap) || ((u32)i & skip_mask)) {
  			start = i + 1;
  			goto again;
  		}
  	}
  
  	return start;
  }
  
  u32 mlx4_bitmap_alloc_range(struct mlx4_bitmap *bitmap, int cnt,
  			    int align, u32 skip_mask)
  {
  	u32 obj;
  
  	if (likely(cnt == 1 && align == 1 && !skip_mask))
  		return mlx4_bitmap_alloc(bitmap);
  
  	spin_lock(&bitmap->lock);
  
  	obj = find_aligned_range(bitmap->table, bitmap->last,
  				 bitmap->max, cnt, align, skip_mask);
  	if (obj >= bitmap->max) {
  		bitmap->top = (bitmap->top + bitmap->max + bitmap->reserved_top)
  				& bitmap->mask;
  		obj = find_aligned_range(bitmap->table, 0, bitmap->max,
  					 cnt, align, skip_mask);
  	}
  
  	if (obj < bitmap->max) {
  		bitmap_set(bitmap->table, obj, cnt);
  		if (obj == bitmap->last) {
  			bitmap->last = (obj + cnt);
  			if (bitmap->last >= bitmap->max)
  				bitmap->last = 0;
  		}
  		obj |= bitmap->top;
  	} else
  		obj = -1;
  
  	if (obj != -1)
  		bitmap->avail -= cnt;
  
  	spin_unlock(&bitmap->lock);
  
  	return obj;
  }
  
  u32 mlx4_bitmap_avail(struct mlx4_bitmap *bitmap)
  {
  	return bitmap->avail;
  }
  
  static u32 mlx4_bitmap_masked_value(struct mlx4_bitmap *bitmap, u32 obj)
  {
  	return obj & (bitmap->max + bitmap->reserved_top - 1);
  }
  
  void mlx4_bitmap_free_range(struct mlx4_bitmap *bitmap, u32 obj, int cnt,
  			    int use_rr)
  {
  	obj &= bitmap->max + bitmap->reserved_top - 1;
  
  	spin_lock(&bitmap->lock);
  	if (!use_rr) {
  		bitmap->last = min(bitmap->last, obj);
  		bitmap->top = (bitmap->top + bitmap->max + bitmap->reserved_top)
  				& bitmap->mask;
  	}
  	bitmap_clear(bitmap->table, obj, cnt);
  	bitmap->avail += cnt;
  	spin_unlock(&bitmap->lock);
  }
  
  int mlx4_bitmap_init(struct mlx4_bitmap *bitmap, u32 num, u32 mask,
  		     u32 reserved_bot, u32 reserved_top)
  {
  	/* num must be a power of 2 */
  	if (num != roundup_pow_of_two(num))
  		return -EINVAL;
  
  	bitmap->last = 0;
  	bitmap->top  = 0;
  	bitmap->max  = num - reserved_top;
  	bitmap->mask = mask;
  	bitmap->reserved_top = reserved_top;
  	bitmap->avail = num - reserved_top - reserved_bot;
  	bitmap->effective_len = bitmap->avail;
  	spin_lock_init(&bitmap->lock);
  	bitmap->table = kzalloc(BITS_TO_LONGS(bitmap->max) *
  				sizeof (long), GFP_KERNEL);
  	if (!bitmap->table)
  		return -ENOMEM;
  
  	bitmap_set(bitmap->table, 0, reserved_bot);
  
  	return 0;
  }
  
  void mlx4_bitmap_cleanup(struct mlx4_bitmap *bitmap)
  {
  	kfree(bitmap->table);
  }
  
  struct mlx4_zone_allocator {
  	struct list_head		entries;
  	struct list_head		prios;
  	u32				last_uid;
  	u32				mask;
  	/* protect the zone_allocator from concurrent accesses */
  	spinlock_t			lock;
  	enum mlx4_zone_alloc_flags	flags;
  };
  
  struct mlx4_zone_entry {
  	struct list_head		list;
  	struct list_head		prio_list;
  	u32				uid;
  	struct mlx4_zone_allocator	*allocator;
  	struct mlx4_bitmap		*bitmap;
  	int				use_rr;
  	int				priority;
  	int				offset;
  	enum mlx4_zone_flags		flags;
  };
  
  struct mlx4_zone_allocator *mlx4_zone_allocator_create(enum mlx4_zone_alloc_flags flags)
  {
  	struct mlx4_zone_allocator *zones = kmalloc(sizeof(*zones), GFP_KERNEL);
  
  	if (NULL == zones)
  		return NULL;
  
  	INIT_LIST_HEAD(&zones->entries);
  	INIT_LIST_HEAD(&zones->prios);
  	spin_lock_init(&zones->lock);
  	zones->last_uid = 0;
  	zones->mask = 0;
  	zones->flags = flags;
  
  	return zones;
  }
  
  int mlx4_zone_add_one(struct mlx4_zone_allocator *zone_alloc,
  		      struct mlx4_bitmap *bitmap,
  		      u32 flags,
  		      int priority,
  		      int offset,
  		      u32 *puid)
  {
  	u32 mask = mlx4_bitmap_masked_value(bitmap, (u32)-1);
  	struct mlx4_zone_entry *it;
  	struct mlx4_zone_entry *zone = kmalloc(sizeof(*zone), GFP_KERNEL);
  
  	if (NULL == zone)
  		return -ENOMEM;
  
  	zone->flags = flags;
  	zone->bitmap = bitmap;
  	zone->use_rr = (flags & MLX4_ZONE_USE_RR) ? MLX4_USE_RR : 0;
  	zone->priority = priority;
  	zone->offset = offset;
  
  	spin_lock(&zone_alloc->lock);
  
  	zone->uid = zone_alloc->last_uid++;
  	zone->allocator = zone_alloc;
  
  	if (zone_alloc->mask < mask)
  		zone_alloc->mask = mask;
  
  	list_for_each_entry(it, &zone_alloc->prios, prio_list)
  		if (it->priority >= priority)
  			break;
  
  	if (&it->prio_list == &zone_alloc->prios || it->priority > priority)
  		list_add_tail(&zone->prio_list, &it->prio_list);
  	list_add_tail(&zone->list, &it->list);
  
  	spin_unlock(&zone_alloc->lock);
  
  	*puid = zone->uid;
  
  	return 0;
  }
  
  /* Should be called under a lock */
  static int __mlx4_zone_remove_one_entry(struct mlx4_zone_entry *entry)
  {
  	struct mlx4_zone_allocator *zone_alloc = entry->allocator;
  
  	if (!list_empty(&entry->prio_list)) {
  		/* Check if we need to add an alternative node to the prio list */
  		if (!list_is_last(&entry->list, &zone_alloc->entries)) {
  			struct mlx4_zone_entry *next = list_first_entry(&entry->list,
  									typeof(*next),
  									list);
  
  			if (next->priority == entry->priority)
  				list_add_tail(&next->prio_list, &entry->prio_list);
  		}
  
  		list_del(&entry->prio_list);
  	}
  
  	list_del(&entry->list);
  
  	if (zone_alloc->flags & MLX4_ZONE_ALLOC_FLAGS_NO_OVERLAP) {
  		u32 mask = 0;
  		struct mlx4_zone_entry *it;
  
  		list_for_each_entry(it, &zone_alloc->prios, prio_list) {
  			u32 cur_mask = mlx4_bitmap_masked_value(it->bitmap, (u32)-1);
  
  			if (mask < cur_mask)
  				mask = cur_mask;
  		}
  		zone_alloc->mask = mask;
  	}
  
  	return 0;
  }
  
  void mlx4_zone_allocator_destroy(struct mlx4_zone_allocator *zone_alloc)
  {
  	struct mlx4_zone_entry *zone, *tmp;
  
  	spin_lock(&zone_alloc->lock);
  
  	list_for_each_entry_safe(zone, tmp, &zone_alloc->entries, list) {
  		list_del(&zone->list);
  		list_del(&zone->prio_list);
  		kfree(zone);
  	}
  
  	spin_unlock(&zone_alloc->lock);
  	kfree(zone_alloc);
  }
  
  /* Should be called under a lock */
  static u32 __mlx4_alloc_from_zone(struct mlx4_zone_entry *zone, int count,
  				  int align, u32 skip_mask, u32 *puid)
  {
  	u32 uid;
  	u32 res;
  	struct mlx4_zone_allocator *zone_alloc = zone->allocator;
  	struct mlx4_zone_entry *curr_node;
  
  	res = mlx4_bitmap_alloc_range(zone->bitmap, count,
  				      align, skip_mask);
  
  	if (res != (u32)-1) {
  		res += zone->offset;
  		uid = zone->uid;
  		goto out;
  	}
  
  	list_for_each_entry(curr_node, &zone_alloc->prios, prio_list) {
  		if (unlikely(curr_node->priority == zone->priority))
  			break;
  	}
  
  	if (zone->flags & MLX4_ZONE_ALLOW_ALLOC_FROM_LOWER_PRIO) {
  		struct mlx4_zone_entry *it = curr_node;
  
  		list_for_each_entry_continue_reverse(it, &zone_alloc->entries, list) {
  			res = mlx4_bitmap_alloc_range(it->bitmap, count,
  						      align, skip_mask);
  			if (res != (u32)-1) {
  				res += it->offset;
  				uid = it->uid;
  				goto out;
  			}
  		}
  	}
  
  	if (zone->flags & MLX4_ZONE_ALLOW_ALLOC_FROM_EQ_PRIO) {
  		struct mlx4_zone_entry *it = curr_node;
  
  		list_for_each_entry_from(it, &zone_alloc->entries, list) {
  			if (unlikely(it == zone))
  				continue;
  
  			if (unlikely(it->priority != curr_node->priority))
  				break;
  
  			res = mlx4_bitmap_alloc_range(it->bitmap, count,
  						      align, skip_mask);
  			if (res != (u32)-1) {
  				res += it->offset;
  				uid = it->uid;
  				goto out;
  			}
  		}
  	}
  
  	if (zone->flags & MLX4_ZONE_FALLBACK_TO_HIGHER_PRIO) {
  		if (list_is_last(&curr_node->prio_list, &zone_alloc->prios))
  			goto out;
  
  		curr_node = list_first_entry(&curr_node->prio_list,
  					     typeof(*curr_node),
  					     prio_list);
  
  		list_for_each_entry_from(curr_node, &zone_alloc->entries, list) {
  			res = mlx4_bitmap_alloc_range(curr_node->bitmap, count,
  						      align, skip_mask);
  			if (res != (u32)-1) {
  				res += curr_node->offset;
  				uid = curr_node->uid;
  				goto out;
  			}
  		}
  	}
  
  out:
  	if (NULL != puid && res != (u32)-1)
  		*puid = uid;
  	return res;
  }
  
  /* Should be called under a lock */
  static void __mlx4_free_from_zone(struct mlx4_zone_entry *zone, u32 obj,
  				  u32 count)
  {
  	mlx4_bitmap_free_range(zone->bitmap, obj - zone->offset, count, zone->use_rr);
  }
  
  /* Should be called under a lock */
  static struct mlx4_zone_entry *__mlx4_find_zone_by_uid(
  		struct mlx4_zone_allocator *zones, u32 uid)
  {
  	struct mlx4_zone_entry *zone;
  
  	list_for_each_entry(zone, &zones->entries, list) {
  		if (zone->uid == uid)
  			return zone;
  	}
  
  	return NULL;
  }
  
  struct mlx4_bitmap *mlx4_zone_get_bitmap(struct mlx4_zone_allocator *zones, u32 uid)
  {
  	struct mlx4_zone_entry *zone;
  	struct mlx4_bitmap *bitmap;
  
  	spin_lock(&zones->lock);
  
  	zone = __mlx4_find_zone_by_uid(zones, uid);
  
  	bitmap = zone == NULL ? NULL : zone->bitmap;
  
  	spin_unlock(&zones->lock);
  
  	return bitmap;
  }
  
  int mlx4_zone_remove_one(struct mlx4_zone_allocator *zones, u32 uid)
  {
  	struct mlx4_zone_entry *zone;
  	int res;
  
  	spin_lock(&zones->lock);
  
  	zone = __mlx4_find_zone_by_uid(zones, uid);
  
  	if (NULL == zone) {
  		res = -1;
  		goto out;
  	}
  
  	res = __mlx4_zone_remove_one_entry(zone);
  
  out:
  	spin_unlock(&zones->lock);
  	kfree(zone);
  
  	return res;
  }
  
  /* Should be called under a lock */
  static struct mlx4_zone_entry *__mlx4_find_zone_by_uid_unique(
  		struct mlx4_zone_allocator *zones, u32 obj)
  {
  	struct mlx4_zone_entry *zone, *zone_candidate = NULL;
  	u32 dist = (u32)-1;
  
  	/* Search for the smallest zone that this obj could be
  	 * allocated from. This is done in order to handle
  	 * situations when small bitmaps are allocated from bigger
  	 * bitmaps (and the allocated space is marked as reserved in
  	 * the bigger bitmap.
  	 */
  	list_for_each_entry(zone, &zones->entries, list) {
  		if (obj >= zone->offset) {
  			u32 mobj = (obj - zone->offset) & zones->mask;
  
  			if (mobj < zone->bitmap->max) {
  				u32 curr_dist = zone->bitmap->effective_len;
  
  				if (curr_dist < dist) {
  					dist = curr_dist;
  					zone_candidate = zone;
  				}
  			}
  		}
  	}
  
  	return zone_candidate;
  }
  
  u32 mlx4_zone_alloc_entries(struct mlx4_zone_allocator *zones, u32 uid, int count,
  			    int align, u32 skip_mask, u32 *puid)
  {
  	struct mlx4_zone_entry *zone;
  	int res = -1;
  
  	spin_lock(&zones->lock);
  
  	zone = __mlx4_find_zone_by_uid(zones, uid);
  
  	if (NULL == zone)
  		goto out;
  
  	res = __mlx4_alloc_from_zone(zone, count, align, skip_mask, puid);
  
  out:
  	spin_unlock(&zones->lock);
  
  	return res;
  }
  
  u32 mlx4_zone_free_entries(struct mlx4_zone_allocator *zones, u32 uid, u32 obj, u32 count)
  {
  	struct mlx4_zone_entry *zone;
  	int res = 0;
  
  	spin_lock(&zones->lock);
  
  	zone = __mlx4_find_zone_by_uid(zones, uid);
  
  	if (NULL == zone) {
  		res = -1;
  		goto out;
  	}
  
  	__mlx4_free_from_zone(zone, obj, count);
  
  out:
  	spin_unlock(&zones->lock);
  
  	return res;
  }
  
  u32 mlx4_zone_free_entries_unique(struct mlx4_zone_allocator *zones, u32 obj, u32 count)
  {
  	struct mlx4_zone_entry *zone;
  	int res;
  
  	if (!(zones->flags & MLX4_ZONE_ALLOC_FLAGS_NO_OVERLAP))
  		return -EFAULT;
  
  	spin_lock(&zones->lock);
  
  	zone = __mlx4_find_zone_by_uid_unique(zones, obj);
  
  	if (NULL == zone) {
  		res = -1;
  		goto out;
  	}
  
  	__mlx4_free_from_zone(zone, obj, count);
  	res = 0;
  
  out:
  	spin_unlock(&zones->lock);
  
  	return res;
  }
  /*
   * Handling for queue buffers -- we allocate a bunch of memory and
   * register it in a memory region at HCA virtual address 0.  If the
   * requested size is > max_direct, we split the allocation into
   * multiple pages, so we don't require too much contiguous memory.
   */
  
  int mlx4_buf_alloc(struct mlx4_dev *dev, int size, int max_direct,
  		   struct mlx4_buf *buf, gfp_t gfp)
  {
  	dma_addr_t t;
  
  	if (size <= max_direct) {
  		buf->nbufs        = 1;
  		buf->npages       = 1;
  		buf->page_shift   = get_order(size) + PAGE_SHIFT;
  		buf->direct.buf   = dma_alloc_coherent(&dev->persist->pdev->dev,
  						       size, &t, gfp);
  		if (!buf->direct.buf)
  			return -ENOMEM;
  
  		buf->direct.map = t;
  
  		while (t & ((1 << buf->page_shift) - 1)) {
  			--buf->page_shift;
  			buf->npages *= 2;
  		}
  
  		memset(buf->direct.buf, 0, size);
  	} else {
  		int i;
  
  		buf->direct.buf  = NULL;
  		buf->nbufs       = (size + PAGE_SIZE - 1) / PAGE_SIZE;
  		buf->npages      = buf->nbufs;
  		buf->page_shift  = PAGE_SHIFT;
  		buf->page_list   = kcalloc(buf->nbufs, sizeof(*buf->page_list),
  					   gfp);
  		if (!buf->page_list)
  			return -ENOMEM;
  
  		for (i = 0; i < buf->nbufs; ++i) {
  			buf->page_list[i].buf =
  				dma_alloc_coherent(&dev->persist->pdev->dev,
  						   PAGE_SIZE,
  						   &t, gfp);
  			if (!buf->page_list[i].buf)
  				goto err_free;
  
  			buf->page_list[i].map = t;
  
  			memset(buf->page_list[i].buf, 0, PAGE_SIZE);
  		}
  
  		if (BITS_PER_LONG == 64) {
  			struct page **pages;
  			pages = kmalloc(sizeof *pages * buf->nbufs, gfp);
  			if (!pages)
  				goto err_free;
  			for (i = 0; i < buf->nbufs; ++i)
  				pages[i] = virt_to_page(buf->page_list[i].buf);
  			buf->direct.buf = vmap(pages, buf->nbufs, VM_MAP, PAGE_KERNEL);
  			kfree(pages);
  			if (!buf->direct.buf)
  				goto err_free;
  		}
  	}
  
  	return 0;
  
  err_free:
  	mlx4_buf_free(dev, size, buf);
  
  	return -ENOMEM;
  }
  EXPORT_SYMBOL_GPL(mlx4_buf_alloc);
  
  void mlx4_buf_free(struct mlx4_dev *dev, int size, struct mlx4_buf *buf)
  {
  	int i;
  
  	if (buf->nbufs == 1)
  		dma_free_coherent(&dev->persist->pdev->dev, size,
  				  buf->direct.buf,
  				  buf->direct.map);
  	else {
  		if (BITS_PER_LONG == 64)
  			vunmap(buf->direct.buf);
  
  		for (i = 0; i < buf->nbufs; ++i)
  			if (buf->page_list[i].buf)
  				dma_free_coherent(&dev->persist->pdev->dev,
  						  PAGE_SIZE,
  						  buf->page_list[i].buf,
  						  buf->page_list[i].map);
  		kfree(buf->page_list);
  	}
  }
  EXPORT_SYMBOL_GPL(mlx4_buf_free);
  
  static struct mlx4_db_pgdir *mlx4_alloc_db_pgdir(struct device *dma_device,
  						 gfp_t gfp)
  {
  	struct mlx4_db_pgdir *pgdir;
  
  	pgdir = kzalloc(sizeof *pgdir, gfp);
  	if (!pgdir)
  		return NULL;
  
  	bitmap_fill(pgdir->order1, MLX4_DB_PER_PAGE / 2);
  	pgdir->bits[0] = pgdir->order0;
  	pgdir->bits[1] = pgdir->order1;
  	pgdir->db_page = dma_alloc_coherent(dma_device, PAGE_SIZE,
  					    &pgdir->db_dma, gfp);
  	if (!pgdir->db_page) {
  		kfree(pgdir);
  		return NULL;
  	}
  
  	return pgdir;
  }
  
  static int mlx4_alloc_db_from_pgdir(struct mlx4_db_pgdir *pgdir,
  				    struct mlx4_db *db, int order)
  {
  	int o;
  	int i;
  
  	for (o = order; o <= 1; ++o) {
  		i = find_first_bit(pgdir->bits[o], MLX4_DB_PER_PAGE >> o);
  		if (i < MLX4_DB_PER_PAGE >> o)
  			goto found;
  	}
  
  	return -ENOMEM;
  
  found:
  	clear_bit(i, pgdir->bits[o]);
  
  	i <<= o;
  
  	if (o > order)
  		set_bit(i ^ 1, pgdir->bits[order]);
  
  	db->u.pgdir = pgdir;
  	db->index   = i;
  	db->db      = pgdir->db_page + db->index;
  	db->dma     = pgdir->db_dma  + db->index * 4;
  	db->order   = order;
  
  	return 0;
  }
  
  int mlx4_db_alloc(struct mlx4_dev *dev, struct mlx4_db *db, int order, gfp_t gfp)
  {
  	struct mlx4_priv *priv = mlx4_priv(dev);
  	struct mlx4_db_pgdir *pgdir;
  	int ret = 0;
  
  	mutex_lock(&priv->pgdir_mutex);
  
  	list_for_each_entry(pgdir, &priv->pgdir_list, list)
  		if (!mlx4_alloc_db_from_pgdir(pgdir, db, order))
  			goto out;
  
  	pgdir = mlx4_alloc_db_pgdir(&dev->persist->pdev->dev, gfp);
  	if (!pgdir) {
  		ret = -ENOMEM;
  		goto out;
  	}
  
  	list_add(&pgdir->list, &priv->pgdir_list);
  
  	/* This should never fail -- we just allocated an empty page: */
  	WARN_ON(mlx4_alloc_db_from_pgdir(pgdir, db, order));
  
  out:
  	mutex_unlock(&priv->pgdir_mutex);
  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(mlx4_db_alloc);
  
  void mlx4_db_free(struct mlx4_dev *dev, struct mlx4_db *db)
  {
  	struct mlx4_priv *priv = mlx4_priv(dev);
  	int o;
  	int i;
  
  	mutex_lock(&priv->pgdir_mutex);
  
  	o = db->order;
  	i = db->index;
  
  	if (db->order == 0 && test_bit(i ^ 1, db->u.pgdir->order0)) {
  		clear_bit(i ^ 1, db->u.pgdir->order0);
  		++o;
  	}
  	i >>= o;
  	set_bit(i, db->u.pgdir->bits[o]);
  
  	if (bitmap_full(db->u.pgdir->order1, MLX4_DB_PER_PAGE / 2)) {
  		dma_free_coherent(&dev->persist->pdev->dev, PAGE_SIZE,
  				  db->u.pgdir->db_page, db->u.pgdir->db_dma);
  		list_del(&db->u.pgdir->list);
  		kfree(db->u.pgdir);
  	}
  
  	mutex_unlock(&priv->pgdir_mutex);
  }
  EXPORT_SYMBOL_GPL(mlx4_db_free);
  
  int mlx4_alloc_hwq_res(struct mlx4_dev *dev, struct mlx4_hwq_resources *wqres,
  		       int size, int max_direct)
  {
  	int err;
  
  	err = mlx4_db_alloc(dev, &wqres->db, 1, GFP_KERNEL);
  	if (err)
  		return err;
  
  	*wqres->db.db = 0;
  
  	err = mlx4_buf_alloc(dev, size, max_direct, &wqres->buf, GFP_KERNEL);
  	if (err)
  		goto err_db;
  
  	err = mlx4_mtt_init(dev, wqres->buf.npages, wqres->buf.page_shift,
  			    &wqres->mtt);
  	if (err)
  		goto err_buf;
  
  	err = mlx4_buf_write_mtt(dev, &wqres->mtt, &wqres->buf, GFP_KERNEL);
  	if (err)
  		goto err_mtt;
  
  	return 0;
  
  err_mtt:
  	mlx4_mtt_cleanup(dev, &wqres->mtt);
  err_buf:
  	mlx4_buf_free(dev, size, &wqres->buf);
  err_db:
  	mlx4_db_free(dev, &wqres->db);
  
  	return err;
  }
  EXPORT_SYMBOL_GPL(mlx4_alloc_hwq_res);
  
  void mlx4_free_hwq_res(struct mlx4_dev *dev, struct mlx4_hwq_resources *wqres,
  		       int size)
  {
  	mlx4_mtt_cleanup(dev, &wqres->mtt);
  	mlx4_buf_free(dev, size, &wqres->buf);
  	mlx4_db_free(dev, &wqres->db);
  }
  EXPORT_SYMBOL_GPL(mlx4_free_hwq_res);