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