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 struct mm_struct *mm; 45 }; 46 47 int 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 80 found: 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 86 out: 87 mutex_unlock(&context->db_page_mutex); 88 89 return err; 90 } 91 92 void 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