drivers/infiniband/hw/mlx4/doorbell.c

   1 /*
   2  * Copyright (c) 2007 Cisco Systems, Inc. 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/slab.h>
  34 #include <rdma/uverbs_ioctl.h>
  35
  36 #include "mlx4_ib.h"
  37
  38 struct mlx4_ib_user_db_page {
  39         struct list_head        list;
  40         struct ib_umem         *umem;
  41         unsigned long           user_virt;
  42         int                     refcnt;
  43 };
  44
  45 int mlx4_ib_db_map_user(struct ib_udata *udata, unsigned long virt,
  46                         struct mlx4_db *db)
  47 {
  48         struct mlx4_ib_user_db_page *page;
  49         int err = 0;
  50         struct mlx4_ib_ucontext *context = rdma_udata_to_drv_context(
  51                 udata, struct mlx4_ib_ucontext, ibucontext);
  52
  53         mutex_lock(&context->db_page_mutex);
  54
  55         list_for_each_entry(page, &context->db_page_list, list)
  56                 if (page->user_virt == (virt & PAGE_MASK))
  57                         goto found;
  58
  59         page = kmalloc(sizeof *page, GFP_KERNEL);
  60         if (!page) {
  61                 err = -ENOMEM;
  62                 goto out;
  63         }
  64
  65         page->user_virt = (virt & PAGE_MASK);
  66         page->refcnt    = 0;
  67         page->umem = ib_umem_get(context->ibucontext.device, virt & PAGE_MASK,
  68                                  PAGE_SIZE, 0);
  69         if (IS_ERR(page->umem)) {
  70                 err = PTR_ERR(page->umem);
  71                 kfree(page);
  72                 goto out;
  73         }
  74
  75         list_add(&page->list, &context->db_page_list);
  76
  77 found:
  78         db->dma = sg_dma_address(page->umem->sg_head.sgl) + (virt & ~PAGE_MASK);
  79         db->u.user_page = page;
  80         ++page->refcnt;
  81
  82 out:
  83         mutex_unlock(&context->db_page_mutex);
  84
  85         return err;
  86 }
  87
  88 void mlx4_ib_db_unmap_user(struct mlx4_ib_ucontext *context, struct mlx4_db *db)
  89 {
  90         mutex_lock(&context->db_page_mutex);
  91
  92         if (!--db->u.user_page->refcnt) {
  93                 list_del(&db->u.user_page->list);
  94                 ib_umem_release(db->u.user_page->umem);
  95                 kfree(db->u.user_page);
  96         }
  97
  98         mutex_unlock(&context->db_page_mutex);
  99 }