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 <linux/sched/mm.h>
  36 #include <rdma/ib_umem.h>
  37
  38 #include "mlx5_ib.h"
  39
  40 struct mlx5_ib_user_db_page {
  41         struct list_head        list;
  42         struct ib_umem         *umem;
  43         unsigned long           user_virt;
  44         int                     refcnt;
  45         struct mm_struct        *mm;
  46 };
  47
  48 int mlx5_ib_db_map_user(struct mlx5_ib_ucontext *context, unsigned long virt,
  49                         struct mlx5_db *db)
  50 {
  51         struct mlx5_ib_user_db_page *page;
  52         int err = 0;
  53
  54         mutex_lock(&context->db_page_mutex);
  55
  56         list_for_each_entry(page, &context->db_page_list, list)
  57                 if ((current->mm == page->mm) &&
  58                     (page->user_virt == (virt & PAGE_MASK)))
  59                         goto found;
  60
  61         page = kmalloc(sizeof(*page), GFP_KERNEL);
  62         if (!page) {
  63                 err = -ENOMEM;
  64                 goto out;
  65         }
  66
  67         page->user_virt = (virt & PAGE_MASK);
  68         page->refcnt    = 0;
  69         page->umem = ib_umem_get(context->ibucontext.device, virt & PAGE_MASK,
  70                                  PAGE_SIZE, 0);
  71         if (IS_ERR(page->umem)) {
  72                 err = PTR_ERR(page->umem);
  73                 kfree(page);
  74                 goto out;
  75         }
  76         mmgrab(current->mm);
  77         page->mm = current->mm;
  78
  79         list_add(&page->list, &context->db_page_list);
  80
  81 found:
  82         db->dma = sg_dma_address(page->umem->sgt_append.sgt.sgl) +
  83                   (virt & ~PAGE_MASK);
  84         db->u.user_page = page;
  85         ++page->refcnt;
  86
  87 out:
  88         mutex_unlock(&context->db_page_mutex);
  89
  90         return err;
  91 }
  92
  93 void mlx5_ib_db_unmap_user(struct mlx5_ib_ucontext *context, struct mlx5_db *db)
  94 {
  95         mutex_lock(&context->db_page_mutex);
  96
  97         if (!--db->u.user_page->refcnt) {
  98                 list_del(&db->u.user_page->list);
  99                 mmdrop(db->u.user_page->mm);
 100                 ib_umem_release(db->u.user_page->umem);
 101                 kfree(db->u.user_page);
 102         }
 103
 104         mutex_unlock(&context->db_page_mutex);
 105 }