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kernel/linux-rt-4.4.41/drivers/infiniband/hw/mlx4/doorbell.c 2.73 KB
5113f6f70   김현기   kernel add
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  /*
   * Copyright (c) 2007 Cisco Systems, Inc. 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/slab.h>
  
  #include "mlx4_ib.h"
  
  struct mlx4_ib_user_db_page {
  	struct list_head	list;
  	struct ib_umem	       *umem;
  	unsigned long		user_virt;
  	int			refcnt;
  };
  
  int mlx4_ib_db_map_user(struct mlx4_ib_ucontext *context, unsigned long virt,
  			struct mlx4_db *db)
  {
  	struct mlx4_ib_user_db_page *page;
  	int err = 0;
  
  	mutex_lock(&context->db_page_mutex);
  
  	list_for_each_entry(page, &context->db_page_list, list)
  		if (page->user_virt == (virt & PAGE_MASK))
  			goto found;
  
  	page = kmalloc(sizeof *page, GFP_KERNEL);
  	if (!page) {
  		err = -ENOMEM;
  		goto out;
  	}
  
  	page->user_virt = (virt & PAGE_MASK);
  	page->refcnt    = 0;
  	page->umem      = ib_umem_get(&context->ibucontext, virt & PAGE_MASK,
  				      PAGE_SIZE, 0, 0);
  	if (IS_ERR(page->umem)) {
  		err = PTR_ERR(page->umem);
  		kfree(page);
  		goto out;
  	}
  
  	list_add(&page->list, &context->db_page_list);
  
  found:
  	db->dma = sg_dma_address(page->umem->sg_head.sgl) + (virt & ~PAGE_MASK);
  	db->u.user_page = page;
  	++page->refcnt;
  
  out:
  	mutex_unlock(&context->db_page_mutex);
  
  	return err;
  }
  
  void mlx4_ib_db_unmap_user(struct mlx4_ib_ucontext *context, struct mlx4_db *db)
  {
  	mutex_lock(&context->db_page_mutex);
  
  	if (!--db->u.user_page->refcnt) {
  		list_del(&db->u.user_page->list);
  		ib_umem_release(db->u.user_page->umem);
  		kfree(db->u.user_page);
  	}
  
  	mutex_unlock(&context->db_page_mutex);
  }