drivers/infiniband/hw/mlx5/doorbell.c

   1 /*
   2  * Copyright (c) 2013-2015, Mellanox Technologies. All rights reserved.
   3  *
   4  * This software is available to you under a choice of one of two
   5  * licenses.  You may choose to be licensed under the terms of the GNU
   6  * General Public License (GPL) Version 2, available from the file
   7  * COPYING in the main directory of this source tree, or the
   8  * OpenIB.org BSD license below:
   9  *
  10  *     Redistribution and use in source and binary forms, with or
  11  *     without modification, are permitted provided that the following
  12  *     conditions are met:
  13  *
  14  *      - Redistributions of source code must retain the above
  15  *        copyright notice, this list of conditions and the following
  16  *        disclaimer.
  17  *
  18  *      - Redistributions in binary form must reproduce the above
  19  *        copyright notice, this list of conditions and the following
  20  *        disclaimer in the documentation and/or other materials
  21  *        provided with the distribution.
  22  *
  23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  30  * SOFTWARE.
  31  */
  32
  33 #include <linux/kref.h>
  34 #include <linux/slab.h>
  35 #include <rdma/ib_umem.h>
  36
  37 #include "mlx5_ib.h"
  38
  39 struct mlx5_ib_user_db_page {
  40         struct list_head        list;
  41         struct ib_umem         *umem;
  42         unsigned long           user_virt;
  43         int                     refcnt;
  44 };
  45
  46 int mlx5_ib_db_map_user(struct mlx5_ib_ucontext *context, unsigned long virt,
  47                         struct mlx5_db *db)
  48 {
  49         struct mlx5_ib_user_db_page *page;
  50         int err = 0;
  51
  52         mutex_lock(&context->db_page_mutex);
  53
  54         list_for_each_entry(page, &context->db_page_list, list)
  55                 if (page->user_virt == (virt & PAGE_MASK))
  56                         goto found;
  57
  58         page = kmalloc(sizeof(*page), GFP_KERNEL);
  59         if (!page) {
  60                 err = -ENOMEM;
  61                 goto out;
  62         }
  63
  64         page->user_virt = (virt & PAGE_MASK);
  65         page->refcnt    = 0;
  66         page->umem      = ib_umem_get(&context->ibucontext, virt & PAGE_MASK,
  67                                       PAGE_SIZE, 0, 0);
  68         if (IS_ERR(page->umem)) {
  69                 err = PTR_ERR(page->umem);
  70                 kfree(page);
  71                 goto out;
  72         }
  73
  74         list_add(&page->list, &context->db_page_list);
  75
  76 found:
  77         db->dma = sg_dma_address(page->umem->sg_head.sgl) + (virt & ~PAGE_MASK);
  78         db->u.user_page = page;
  79         ++page->refcnt;
  80
  81 out:
  82         mutex_unlock(&context->db_page_mutex);
  83
  84         return err;
  85 }
  86
  87 void mlx5_ib_db_unmap_user(struct mlx5_ib_ucontext *context, struct mlx5_db *db)
  88 {
  89         mutex_lock(&context->db_page_mutex);
  90
  91         if (!--db->u.user_page->refcnt) {
  92                 list_del(&db->u.user_page->list);
  93                 ib_umem_release(db->u.user_page->umem);
  94                 kfree(db->u.user_page);
  95         }
  96
  97         mutex_unlock(&context->db_page_mutex);
  98 }