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, 47 struct ib_udata *udata, 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 (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 mlx5_ib_db_unmap_user(struct mlx5_ib_ucontext *context, struct mlx5_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 } 100