LXR linux/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
  35#include "mlx4_ib.h"
  36
  37struct mlx4_ib_user_db_page {
  38        struct list_head        list;
  39        struct ib_umem         *umem;
  40        unsigned long           user_virt;
  41        int                     refcnt;
  42};
  43
  44int mlx4_ib_db_map_user(struct mlx4_ib_ucontext *context, unsigned long virt,
  45                        struct mlx4_db *db)
  46{
  47        struct mlx4_ib_user_db_page *page;
  48        struct ib_umem_chunk *chunk;
  49        int err = 0;
  50
  51        mutex_lock(&context->db_page_mutex);
  52
  53        list_for_each_entry(page, &context->db_page_list, list)
  54                if (page->user_virt == (virt & PAGE_MASK))
  55                        goto found;
  56
  57        page = kmalloc(sizeof *page, GFP_KERNEL);
  58        if (!page) {
  59                err = -ENOMEM;
  60                goto out;
  61        }
  62
  63        page->user_virt = (virt & PAGE_MASK);
  64        page->refcnt    = 0;
  65        page->umem      = ib_umem_get(&context->ibucontext, virt & PAGE_MASK,
  66                                      PAGE_SIZE, 0, 0);
  67        if (IS_ERR(page->umem)) {
  68                err = PTR_ERR(page->umem);
  69                kfree(page);
  70                goto out;
  71        }
  72
  73        list_add(&page->list, &context->db_page_list);
  74
  75found:
  76        chunk = list_entry(page->umem->chunk_list.next, struct ib_umem_chunk, list);
  77        db->dma         = sg_dma_address(chunk->page_list) + (virt & ~PAGE_MASK);
  78        db->u.user_page = page;
  79        ++page->refcnt;
  80
  81out:
  82        mutex_unlock(&context->db_page_mutex);
  83
  84        return err;
  85}
  86
  87void mlx4_ib_db_unmap_user(struct mlx4_ib_ucontext *context, struct mlx4_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}
  99