drivers/net/mlx4/alloc.c - kernel/msm-4.9 - Gitiles

 /*
  * 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/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;

 	spin_unlock(&bitmap->lock);

 	return obj;
 }

 void mlx4_bitmap_free(struct mlx4_bitmap *bitmap, u32 obj)
 {
 	mlx4_bitmap_free_range(bitmap, obj, 1);
 }

 static unsigned long find_aligned_range(unsigned long *bitmap,
 					u32 start, u32 nbits,
 					int len, int align)
 {
 	unsigned long end, i;

 again:
 	start = ALIGN(start, align);

 	while ((start < nbits) && test_bit(start, bitmap))
 		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)) {
 			start = i + 1;
 			goto again;
 		}
 	}

 	return start;
 }

 u32 mlx4_bitmap_alloc_range(struct mlx4_bitmap *bitmap, int cnt, int align)
 {
 	u32 obj, i;

 	if (likely(cnt == 1 && align == 1))
 		return mlx4_bitmap_alloc(bitmap);

 	spin_lock(&bitmap->lock);

 	obj = find_aligned_range(bitmap->table, bitmap->last,
 				 bitmap->max, cnt, align);
 	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);
 	}

 	if (obj < bitmap->max) {
 		for (i = 0; i < cnt; i++)
 			set_bit(obj + i, bitmap->table);
 		if (obj == bitmap->last) {
 			bitmap->last = (obj + cnt);
 			if (bitmap->last >= bitmap->max)
 				bitmap->last = 0;
 		}
 		obj |= bitmap->top;
 	} else
 		obj = -1;

 	spin_unlock(&bitmap->lock);

 	return obj;
 }

 void mlx4_bitmap_free_range(struct mlx4_bitmap *bitmap, u32 obj, int cnt)
 {
 	u32 i;

 	obj &= bitmap->max + bitmap->reserved_top - 1;

 	spin_lock(&bitmap->lock);
 	for (i = 0; i < cnt; i++)
 		clear_bit(obj + i, bitmap->table);
 	bitmap->last = min(bitmap->last, obj);
 	bitmap->top = (bitmap->top + bitmap->max + bitmap->reserved_top)
 			& bitmap->mask;
 	spin_unlock(&bitmap->lock);
 }

 int mlx4_bitmap_init(struct mlx4_bitmap *bitmap, u32 num, u32 mask,
 		     u32 reserved_bot, u32 reserved_top)
 {
 	int i;

 	/* 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;
 	spin_lock_init(&bitmap->lock);
 	bitmap->table = kzalloc(BITS_TO_LONGS(bitmap->max) *
 				sizeof (long), GFP_KERNEL);
 	if (!bitmap->table)
 		return -ENOMEM;

 	for (i = 0; i < reserved_bot; ++i)
 		set_bit(i, bitmap->table);

 	return 0;
 }

 void mlx4_bitmap_cleanup(struct mlx4_bitmap *bitmap)
 {
 	kfree(bitmap->table);
 }

 /*
  * 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)
 {
 	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->pdev->dev,
 						       size, &t, GFP_KERNEL);
 		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->nbufs       = (size + PAGE_SIZE - 1) / PAGE_SIZE;
 		buf->npages      = buf->nbufs;
 		buf->page_shift  = PAGE_SHIFT;
 		buf->page_list   = kzalloc(buf->nbufs * sizeof *buf->page_list,
 					   GFP_KERNEL);
 		if (!buf->page_list)
 			return -ENOMEM;

 		for (i = 0; i < buf->nbufs; ++i) {
 			buf->page_list[i].buf =
 				dma_alloc_coherent(&dev->pdev->dev, PAGE_SIZE,
 						   &t, GFP_KERNEL);
 			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_KERNEL);
 			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->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->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)
 {
 	struct mlx4_db_pgdir *pgdir;

 	pgdir = kzalloc(sizeof *pgdir, GFP_KERNEL);
 	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_KERNEL);
 	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)
 {
 	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->pdev->dev));
 	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->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);
 	if (err)
 		return err;

 	*wqres->db.db = 0;

 	err = mlx4_buf_alloc(dev, size, max_direct, &wqres->buf);
 	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);
 	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);
	/*
	* 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/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;

	spin_unlock(&bitmap->lock);

	return obj;
	}

	void mlx4_bitmap_free(struct mlx4_bitmap *bitmap, u32 obj)
	{
	mlx4_bitmap_free_range(bitmap, obj, 1);
	}

	static unsigned long find_aligned_range(unsigned long *bitmap,
	u32 start, u32 nbits,
	int len, int align)
	{
	unsigned long end, i;

	again:
	start = ALIGN(start, align);

	while ((start < nbits) && test_bit(start, bitmap))
	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)) {
	start = i + 1;
	goto again;
	}
	}

	return start;
	}

	u32 mlx4_bitmap_alloc_range(struct mlx4_bitmap *bitmap, int cnt, int align)
	{
	u32 obj, i;

	if (likely(cnt == 1 && align == 1))
	return mlx4_bitmap_alloc(bitmap);

	spin_lock(&bitmap->lock);

	obj = find_aligned_range(bitmap->table, bitmap->last,
	bitmap->max, cnt, align);
	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);
	}

	if (obj < bitmap->max) {
	for (i = 0; i < cnt; i++)
	set_bit(obj + i, bitmap->table);
	if (obj == bitmap->last) {
	bitmap->last = (obj + cnt);
	if (bitmap->last >= bitmap->max)
	bitmap->last = 0;
	}
	obj \|= bitmap->top;
	} else
	obj = -1;

	spin_unlock(&bitmap->lock);

	return obj;
	}

	void mlx4_bitmap_free_range(struct mlx4_bitmap *bitmap, u32 obj, int cnt)
	{
	u32 i;

	obj &= bitmap->max + bitmap->reserved_top - 1;

	spin_lock(&bitmap->lock);
	for (i = 0; i < cnt; i++)
	clear_bit(obj + i, bitmap->table);
	bitmap->last = min(bitmap->last, obj);
	bitmap->top = (bitmap->top + bitmap->max + bitmap->reserved_top)
	& bitmap->mask;
	spin_unlock(&bitmap->lock);
	}

	int mlx4_bitmap_init(struct mlx4_bitmap *bitmap, u32 num, u32 mask,
	u32 reserved_bot, u32 reserved_top)
	{
	int i;

	/* 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;
	spin_lock_init(&bitmap->lock);
	bitmap->table = kzalloc(BITS_TO_LONGS(bitmap->max) *
	sizeof (long), GFP_KERNEL);
	if (!bitmap->table)
	return -ENOMEM;

	for (i = 0; i < reserved_bot; ++i)
	set_bit(i, bitmap->table);

	return 0;
	}

	void mlx4_bitmap_cleanup(struct mlx4_bitmap *bitmap)
	{
	kfree(bitmap->table);
	}

	/*
	* 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)
	{
	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->pdev->dev,
	size, &t, GFP_KERNEL);
	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->nbufs = (size + PAGE_SIZE - 1) / PAGE_SIZE;
	buf->npages = buf->nbufs;
	buf->page_shift = PAGE_SHIFT;
	buf->page_list = kzalloc(buf->nbufs * sizeof *buf->page_list,
	GFP_KERNEL);
	if (!buf->page_list)
	return -ENOMEM;

	for (i = 0; i < buf->nbufs; ++i) {
	buf->page_list[i].buf =
	dma_alloc_coherent(&dev->pdev->dev, PAGE_SIZE,
	&t, GFP_KERNEL);
	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_KERNEL);
	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->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->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)
	{
	struct mlx4_db_pgdir *pgdir;

	pgdir = kzalloc(sizeof *pgdir, GFP_KERNEL);
	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_KERNEL);
	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)
	{
	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->pdev->dev));
	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->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);
	if (err)
	return err;

	*wqres->db.db = 0;

	err = mlx4_buf_alloc(dev, size, max_direct, &wqres->buf);
	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);
	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);