drivers/net/ethernet/mellanox/mlx5/core/uar.c - linux - Git at Google

 /*
  * Copyright (c) 2013-2015, 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/kernel.h>
 #include <linux/io-mapping.h>
 #include <linux/mlx5/driver.h>
 #include "mlx5_core.h"

 static int mlx5_cmd_alloc_uar(struct mlx5_core_dev *dev, u32 *uarn)
 {
 	u32 out[MLX5_ST_SZ_DW(alloc_uar_out)] = {};
 	u32 in[MLX5_ST_SZ_DW(alloc_uar_in)] = {};
 	int err;

 	MLX5_SET(alloc_uar_in, in, opcode, MLX5_CMD_OP_ALLOC_UAR);
 	err = mlx5_cmd_exec_inout(dev, alloc_uar, in, out);
 	if (err)
 		return err;

 	*uarn = MLX5_GET(alloc_uar_out, out, uar);
 	return 0;
 }

 static int mlx5_cmd_free_uar(struct mlx5_core_dev *dev, u32 uarn)
 {
 	u32 in[MLX5_ST_SZ_DW(dealloc_uar_in)] = {};

 	MLX5_SET(dealloc_uar_in, in, opcode, MLX5_CMD_OP_DEALLOC_UAR);
 	MLX5_SET(dealloc_uar_in, in, uar, uarn);
 	return mlx5_cmd_exec_in(dev, dealloc_uar, in);
 }

 static int uars_per_sys_page(struct mlx5_core_dev *mdev)
 {
 	if (MLX5_CAP_GEN(mdev, uar_4k))
 		return MLX5_CAP_GEN(mdev, num_of_uars_per_page);

 	return 1;
 }

 static u64 uar2pfn(struct mlx5_core_dev *mdev, u32 index)
 {
 	u32 system_page_index;

 	if (MLX5_CAP_GEN(mdev, uar_4k))
 		system_page_index = index >> (PAGE_SHIFT - MLX5_ADAPTER_PAGE_SHIFT);
 	else
 		system_page_index = index;

 	return (mdev->bar_addr >> PAGE_SHIFT) + system_page_index;
 }

 static void up_rel_func(struct kref *kref)
 {
 	struct mlx5_uars_page *up = container_of(kref, struct mlx5_uars_page, ref_count);

 	list_del(&up->list);
 	iounmap(up->map);
 	if (mlx5_cmd_free_uar(up->mdev, up->index))
 		mlx5_core_warn(up->mdev, "failed to free uar index %d\n", up->index);
 	bitmap_free(up->reg_bitmap);
 	bitmap_free(up->fp_bitmap);
 	kfree(up);
 }

 static struct mlx5_uars_page *alloc_uars_page(struct mlx5_core_dev *mdev,
 					      bool map_wc)
 {
 	struct mlx5_uars_page *up;
 	int err = -ENOMEM;
 	phys_addr_t pfn;
 	int bfregs;
 	int node;
 	int i;

 	bfregs = uars_per_sys_page(mdev) * MLX5_BFREGS_PER_UAR;
 	node = mdev->priv.numa_node;
 	up = kzalloc_node(sizeof(*up), GFP_KERNEL, node);
 	if (!up)
 		return ERR_PTR(err);

 	up->mdev = mdev;
 	up->reg_bitmap = bitmap_zalloc_node(bfregs, GFP_KERNEL, node);
 	if (!up->reg_bitmap)
 		goto error1;

 	up->fp_bitmap = bitmap_zalloc_node(bfregs, GFP_KERNEL, node);
 	if (!up->fp_bitmap)
 		goto error1;

 	for (i = 0; i < bfregs; i++)
 		if ((i % MLX5_BFREGS_PER_UAR) < MLX5_NON_FP_BFREGS_PER_UAR)
 			set_bit(i, up->reg_bitmap);
 		else
 			set_bit(i, up->fp_bitmap);

 	up->bfregs = bfregs;
 	up->fp_avail = bfregs * MLX5_FP_BFREGS_PER_UAR / MLX5_BFREGS_PER_UAR;
 	up->reg_avail = bfregs * MLX5_NON_FP_BFREGS_PER_UAR / MLX5_BFREGS_PER_UAR;

 	err = mlx5_cmd_alloc_uar(mdev, &up->index);
 	if (err) {
 		mlx5_core_warn(mdev, "mlx5_cmd_alloc_uar() failed, %d\n", err);
 		goto error1;
 	}

 	pfn = uar2pfn(mdev, up->index);
 	if (map_wc) {
 		up->map = ioremap_wc(pfn << PAGE_SHIFT, PAGE_SIZE);
 		if (!up->map) {
 			err = -EAGAIN;
 			goto error2;
 		}
 	} else {
 		up->map = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE);
 		if (!up->map) {
 			err = -ENOMEM;
 			goto error2;
 		}
 	}
 	kref_init(&up->ref_count);
 	mlx5_core_dbg(mdev, "allocated UAR page: index %d, total bfregs %d\n",
 		      up->index, up->bfregs);
 	return up;

 error2:
 	if (mlx5_cmd_free_uar(mdev, up->index))
 		mlx5_core_warn(mdev, "failed to free uar index %d\n", up->index);
 error1:
 	bitmap_free(up->fp_bitmap);
 	bitmap_free(up->reg_bitmap);
 	kfree(up);
 	return ERR_PTR(err);
 }

 struct mlx5_uars_page *mlx5_get_uars_page(struct mlx5_core_dev *mdev)
 {
 	struct mlx5_uars_page *ret;

 	mutex_lock(&mdev->priv.bfregs.reg_head.lock);
 	if (!list_empty(&mdev->priv.bfregs.reg_head.list)) {
 		ret = list_first_entry(&mdev->priv.bfregs.reg_head.list,
 				       struct mlx5_uars_page, list);
 		kref_get(&ret->ref_count);
 		goto out;
 	}
 	ret = alloc_uars_page(mdev, false);
 	if (IS_ERR(ret))
 		goto out;
 	list_add(&ret->list, &mdev->priv.bfregs.reg_head.list);
 out:
 	mutex_unlock(&mdev->priv.bfregs.reg_head.lock);

 	return ret;
 }
 EXPORT_SYMBOL(mlx5_get_uars_page);

 void mlx5_put_uars_page(struct mlx5_core_dev *mdev, struct mlx5_uars_page *up)
 {
 	mutex_lock(&mdev->priv.bfregs.reg_head.lock);
 	kref_put(&up->ref_count, up_rel_func);
 	mutex_unlock(&mdev->priv.bfregs.reg_head.lock);
 }
 EXPORT_SYMBOL(mlx5_put_uars_page);

 static unsigned long map_offset(struct mlx5_core_dev *mdev, int dbi)
 {
 	/* return the offset in bytes from the start of the page to the
 	 * blue flame area of the UAR
 	 */
 	return dbi / MLX5_BFREGS_PER_UAR * MLX5_ADAPTER_PAGE_SIZE +
 	       (dbi % MLX5_BFREGS_PER_UAR) *
 	       (1 << MLX5_CAP_GEN(mdev, log_bf_reg_size)) + MLX5_BF_OFFSET;
 }

 static int alloc_bfreg(struct mlx5_core_dev *mdev, struct mlx5_sq_bfreg *bfreg,
 		       bool map_wc, bool fast_path)
 {
 	struct mlx5_bfreg_data *bfregs;
 	struct mlx5_uars_page *up;
 	struct list_head *head;
 	unsigned long *bitmap;
 	unsigned int *avail;
 	struct mutex *lock;  /* pointer to right mutex */
 	int dbi;

 	bfregs = &mdev->priv.bfregs;
 	if (map_wc) {
 		head = &bfregs->wc_head.list;
 		lock = &bfregs->wc_head.lock;
 	} else {
 		head = &bfregs->reg_head.list;
 		lock = &bfregs->reg_head.lock;
 	}
 	mutex_lock(lock);
 	if (list_empty(head)) {
 		up = alloc_uars_page(mdev, map_wc);
 		if (IS_ERR(up)) {
 			mutex_unlock(lock);
 			return PTR_ERR(up);
 		}
 		list_add(&up->list, head);
 	} else {
 		up = list_entry(head->next, struct mlx5_uars_page, list);
 		kref_get(&up->ref_count);
 	}
 	if (fast_path) {
 		bitmap = up->fp_bitmap;
 		avail = &up->fp_avail;
 	} else {
 		bitmap = up->reg_bitmap;
 		avail = &up->reg_avail;
 	}
 	dbi = find_first_bit(bitmap, up->bfregs);
 	clear_bit(dbi, bitmap);
 	(*avail)--;
 	if (!(*avail))
 		list_del(&up->list);

 	bfreg->map = up->map + map_offset(mdev, dbi);
 	bfreg->up = up;
 	bfreg->wc = map_wc;
 	bfreg->index = up->index + dbi / MLX5_BFREGS_PER_UAR;
 	mutex_unlock(lock);

 	return 0;
 }

 int mlx5_alloc_bfreg(struct mlx5_core_dev *mdev, struct mlx5_sq_bfreg *bfreg,
 		     bool map_wc, bool fast_path)
 {
 	int err;

 	err = alloc_bfreg(mdev, bfreg, map_wc, fast_path);
 	if (!err)
 		return 0;

 	if (err == -EAGAIN && map_wc)
 		return alloc_bfreg(mdev, bfreg, false, fast_path);

 	return err;
 }
 EXPORT_SYMBOL(mlx5_alloc_bfreg);

 static unsigned int addr_to_dbi_in_syspage(struct mlx5_core_dev *dev,
 					   struct mlx5_uars_page *up,
 					   struct mlx5_sq_bfreg *bfreg)
 {
 	unsigned int uar_idx;
 	unsigned int bfreg_idx;
 	unsigned int bf_reg_size;

 	bf_reg_size = 1 << MLX5_CAP_GEN(dev, log_bf_reg_size);

 	uar_idx = (bfreg->map - up->map) >> MLX5_ADAPTER_PAGE_SHIFT;
 	bfreg_idx = (((uintptr_t)bfreg->map % MLX5_ADAPTER_PAGE_SIZE) - MLX5_BF_OFFSET) / bf_reg_size;

 	return uar_idx * MLX5_BFREGS_PER_UAR + bfreg_idx;
 }

 void mlx5_free_bfreg(struct mlx5_core_dev *mdev, struct mlx5_sq_bfreg *bfreg)
 {
 	struct mlx5_bfreg_data *bfregs;
 	struct mlx5_uars_page *up;
 	struct mutex *lock; /* pointer to right mutex */
 	unsigned int dbi;
 	bool fp;
 	unsigned int *avail;
 	unsigned long *bitmap;
 	struct list_head *head;

 	bfregs = &mdev->priv.bfregs;
 	if (bfreg->wc) {
 		head = &bfregs->wc_head.list;
 		lock = &bfregs->wc_head.lock;
 	} else {
 		head = &bfregs->reg_head.list;
 		lock = &bfregs->reg_head.lock;
 	}
 	up = bfreg->up;
 	dbi = addr_to_dbi_in_syspage(mdev, up, bfreg);
 	fp = (dbi % MLX5_BFREGS_PER_UAR) >= MLX5_NON_FP_BFREGS_PER_UAR;
 	if (fp) {
 		avail = &up->fp_avail;
 		bitmap = up->fp_bitmap;
 	} else {
 		avail = &up->reg_avail;
 		bitmap = up->reg_bitmap;
 	}
 	mutex_lock(lock);
 	(*avail)++;
 	set_bit(dbi, bitmap);
 	if (*avail == 1)
 		list_add_tail(&up->list, head);

 	kref_put(&up->ref_count, up_rel_func);
 	mutex_unlock(lock);
 }
 EXPORT_SYMBOL(mlx5_free_bfreg);
	/*
	* Copyright (c) 2013-2015, 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/kernel.h>
	#include <linux/io-mapping.h>
	#include <linux/mlx5/driver.h>
	#include "mlx5_core.h"

	static int mlx5_cmd_alloc_uar(struct mlx5_core_dev dev, u32 uarn)
	{
	u32 out[MLX5_ST_SZ_DW(alloc_uar_out)] = {};
	u32 in[MLX5_ST_SZ_DW(alloc_uar_in)] = {};
	int err;

	MLX5_SET(alloc_uar_in, in, opcode, MLX5_CMD_OP_ALLOC_UAR);
	err = mlx5_cmd_exec_inout(dev, alloc_uar, in, out);
	if (err)
	return err;

	*uarn = MLX5_GET(alloc_uar_out, out, uar);
	return 0;
	}

	static int mlx5_cmd_free_uar(struct mlx5_core_dev *dev, u32 uarn)
	{
	u32 in[MLX5_ST_SZ_DW(dealloc_uar_in)] = {};

	MLX5_SET(dealloc_uar_in, in, opcode, MLX5_CMD_OP_DEALLOC_UAR);
	MLX5_SET(dealloc_uar_in, in, uar, uarn);
	return mlx5_cmd_exec_in(dev, dealloc_uar, in);
	}

	static int uars_per_sys_page(struct mlx5_core_dev *mdev)
	{
	if (MLX5_CAP_GEN(mdev, uar_4k))
	return MLX5_CAP_GEN(mdev, num_of_uars_per_page);

	return 1;
	}

	static u64 uar2pfn(struct mlx5_core_dev *mdev, u32 index)
	{
	u32 system_page_index;

	if (MLX5_CAP_GEN(mdev, uar_4k))
	system_page_index = index >> (PAGE_SHIFT - MLX5_ADAPTER_PAGE_SHIFT);
	else
	system_page_index = index;

	return (mdev->bar_addr >> PAGE_SHIFT) + system_page_index;
	}

	static void up_rel_func(struct kref *kref)
	{
	struct mlx5_uars_page *up = container_of(kref, struct mlx5_uars_page, ref_count);

	list_del(&up->list);
	iounmap(up->map);
	if (mlx5_cmd_free_uar(up->mdev, up->index))
	mlx5_core_warn(up->mdev, "failed to free uar index %d\n", up->index);
	bitmap_free(up->reg_bitmap);
	bitmap_free(up->fp_bitmap);
	kfree(up);
	}

	static struct mlx5_uars_page alloc_uars_page(struct mlx5_core_dev mdev,
	bool map_wc)
	{
	struct mlx5_uars_page *up;
	int err = -ENOMEM;
	phys_addr_t pfn;
	int bfregs;
	int node;
	int i;

	bfregs = uars_per_sys_page(mdev) * MLX5_BFREGS_PER_UAR;
	node = mdev->priv.numa_node;
	up = kzalloc_node(sizeof(*up), GFP_KERNEL, node);
	if (!up)
	return ERR_PTR(err);

	up->mdev = mdev;
	up->reg_bitmap = bitmap_zalloc_node(bfregs, GFP_KERNEL, node);
	if (!up->reg_bitmap)
	goto error1;

	up->fp_bitmap = bitmap_zalloc_node(bfregs, GFP_KERNEL, node);
	if (!up->fp_bitmap)
	goto error1;

	for (i = 0; i < bfregs; i++)
	if ((i % MLX5_BFREGS_PER_UAR) < MLX5_NON_FP_BFREGS_PER_UAR)
	set_bit(i, up->reg_bitmap);
	else
	set_bit(i, up->fp_bitmap);

	up->bfregs = bfregs;
	up->fp_avail = bfregs * MLX5_FP_BFREGS_PER_UAR / MLX5_BFREGS_PER_UAR;
	up->reg_avail = bfregs * MLX5_NON_FP_BFREGS_PER_UAR / MLX5_BFREGS_PER_UAR;

	err = mlx5_cmd_alloc_uar(mdev, &up->index);
	if (err) {
	mlx5_core_warn(mdev, "mlx5_cmd_alloc_uar() failed, %d\n", err);
	goto error1;
	}

	pfn = uar2pfn(mdev, up->index);
	if (map_wc) {
	up->map = ioremap_wc(pfn << PAGE_SHIFT, PAGE_SIZE);
	if (!up->map) {
	err = -EAGAIN;
	goto error2;
	}
	} else {
	up->map = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE);
	if (!up->map) {
	err = -ENOMEM;
	goto error2;
	}
	}
	kref_init(&up->ref_count);
	mlx5_core_dbg(mdev, "allocated UAR page: index %d, total bfregs %d\n",
	up->index, up->bfregs);
	return up;

	error2:
	if (mlx5_cmd_free_uar(mdev, up->index))
	mlx5_core_warn(mdev, "failed to free uar index %d\n", up->index);
	error1:
	bitmap_free(up->fp_bitmap);
	bitmap_free(up->reg_bitmap);
	kfree(up);
	return ERR_PTR(err);
	}

	struct mlx5_uars_page mlx5_get_uars_page(struct mlx5_core_dev mdev)
	{
	struct mlx5_uars_page *ret;

	mutex_lock(&mdev->priv.bfregs.reg_head.lock);
	if (!list_empty(&mdev->priv.bfregs.reg_head.list)) {
	ret = list_first_entry(&mdev->priv.bfregs.reg_head.list,
	struct mlx5_uars_page, list);
	kref_get(&ret->ref_count);
	goto out;
	}
	ret = alloc_uars_page(mdev, false);
	if (IS_ERR(ret))
	goto out;
	list_add(&ret->list, &mdev->priv.bfregs.reg_head.list);
	out:
	mutex_unlock(&mdev->priv.bfregs.reg_head.lock);

	return ret;
	}
	EXPORT_SYMBOL(mlx5_get_uars_page);

	void mlx5_put_uars_page(struct mlx5_core_dev mdev, struct mlx5_uars_page up)
	{
	mutex_lock(&mdev->priv.bfregs.reg_head.lock);
	kref_put(&up->ref_count, up_rel_func);
	mutex_unlock(&mdev->priv.bfregs.reg_head.lock);
	}
	EXPORT_SYMBOL(mlx5_put_uars_page);

	static unsigned long map_offset(struct mlx5_core_dev *mdev, int dbi)
	{
	/* return the offset in bytes from the start of the page to the
	* blue flame area of the UAR
	*/
	return dbi / MLX5_BFREGS_PER_UAR * MLX5_ADAPTER_PAGE_SIZE +
	(dbi % MLX5_BFREGS_PER_UAR) *
	(1 << MLX5_CAP_GEN(mdev, log_bf_reg_size)) + MLX5_BF_OFFSET;
	}

	static int alloc_bfreg(struct mlx5_core_dev mdev, struct mlx5_sq_bfreg bfreg,
	bool map_wc, bool fast_path)
	{
	struct mlx5_bfreg_data *bfregs;
	struct mlx5_uars_page *up;
	struct list_head *head;
	unsigned long *bitmap;
	unsigned int *avail;
	struct mutex lock; / pointer to right mutex */
	int dbi;

	bfregs = &mdev->priv.bfregs;
	if (map_wc) {
	head = &bfregs->wc_head.list;
	lock = &bfregs->wc_head.lock;
	} else {
	head = &bfregs->reg_head.list;
	lock = &bfregs->reg_head.lock;
	}
	mutex_lock(lock);
	if (list_empty(head)) {
	up = alloc_uars_page(mdev, map_wc);
	if (IS_ERR(up)) {
	mutex_unlock(lock);
	return PTR_ERR(up);
	}
	list_add(&up->list, head);
	} else {
	up = list_entry(head->next, struct mlx5_uars_page, list);
	kref_get(&up->ref_count);
	}
	if (fast_path) {
	bitmap = up->fp_bitmap;
	avail = &up->fp_avail;
	} else {
	bitmap = up->reg_bitmap;
	avail = &up->reg_avail;
	}
	dbi = find_first_bit(bitmap, up->bfregs);
	clear_bit(dbi, bitmap);
	(*avail)--;
	if (!(*avail))
	list_del(&up->list);

	bfreg->map = up->map + map_offset(mdev, dbi);
	bfreg->up = up;
	bfreg->wc = map_wc;
	bfreg->index = up->index + dbi / MLX5_BFREGS_PER_UAR;
	mutex_unlock(lock);

	return 0;
	}

	int mlx5_alloc_bfreg(struct mlx5_core_dev mdev, struct mlx5_sq_bfreg bfreg,
	bool map_wc, bool fast_path)
	{
	int err;

	err = alloc_bfreg(mdev, bfreg, map_wc, fast_path);
	if (!err)
	return 0;

	if (err == -EAGAIN && map_wc)
	return alloc_bfreg(mdev, bfreg, false, fast_path);

	return err;
	}
	EXPORT_SYMBOL(mlx5_alloc_bfreg);

	static unsigned int addr_to_dbi_in_syspage(struct mlx5_core_dev *dev,
	struct mlx5_uars_page *up,
	struct mlx5_sq_bfreg *bfreg)
	{
	unsigned int uar_idx;
	unsigned int bfreg_idx;
	unsigned int bf_reg_size;

	bf_reg_size = 1 << MLX5_CAP_GEN(dev, log_bf_reg_size);

	uar_idx = (bfreg->map - up->map) >> MLX5_ADAPTER_PAGE_SHIFT;
	bfreg_idx = (((uintptr_t)bfreg->map % MLX5_ADAPTER_PAGE_SIZE) - MLX5_BF_OFFSET) / bf_reg_size;

	return uar_idx * MLX5_BFREGS_PER_UAR + bfreg_idx;
	}

	void mlx5_free_bfreg(struct mlx5_core_dev mdev, struct mlx5_sq_bfreg bfreg)
	{
	struct mlx5_bfreg_data *bfregs;
	struct mlx5_uars_page *up;
	struct mutex lock; / pointer to right mutex */
	unsigned int dbi;
	bool fp;
	unsigned int *avail;
	unsigned long *bitmap;
	struct list_head *head;

	bfregs = &mdev->priv.bfregs;
	if (bfreg->wc) {
	head = &bfregs->wc_head.list;
	lock = &bfregs->wc_head.lock;
	} else {
	head = &bfregs->reg_head.list;
	lock = &bfregs->reg_head.lock;
	}
	up = bfreg->up;
	dbi = addr_to_dbi_in_syspage(mdev, up, bfreg);
	fp = (dbi % MLX5_BFREGS_PER_UAR) >= MLX5_NON_FP_BFREGS_PER_UAR;
	if (fp) {
	avail = &up->fp_avail;
	bitmap = up->fp_bitmap;
	} else {
	avail = &up->reg_avail;
	bitmap = up->reg_bitmap;
	}
	mutex_lock(lock);
	(*avail)++;
	set_bit(dbi, bitmap);
	if (*avail == 1)
	list_add_tail(&up->list, head);

	kref_put(&up->ref_count, up_rel_func);
	mutex_unlock(lock);
	}
	EXPORT_SYMBOL(mlx5_free_bfreg);