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 } 99