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 <linux/sched/mm.h> 36 #include <rdma/ib_umem.h> 37 38 #include "mlx5_ib.h" 39 40 struct mlx5_ib_user_db_page { 41 struct list_head list; 42 struct ib_umem *umem; 43 unsigned long user_virt; 44 int refcnt; 45 struct mm_struct *mm; 46 }; 47 48 int mlx5_ib_db_map_user(struct mlx5_ib_ucontext *context, unsigned long virt, 49 struct mlx5_db *db) 50 { 51 struct mlx5_ib_user_db_page *page; 52 int err = 0; 53 54 mutex_lock(&context->db_page_mutex); 55 56 list_for_each_entry(page, &context->db_page_list, list) 57 if ((current->mm == page->mm) && 58 (page->user_virt == (virt & PAGE_MASK))) 59 goto found; 60 61 page = kmalloc(sizeof(*page), GFP_KERNEL); 62 if (!page) { 63 err = -ENOMEM; 64 goto out; 65 } 66 67 page->user_virt = (virt & PAGE_MASK); 68 page->refcnt = 0; 69 page->umem = ib_umem_get(context->ibucontext.device, virt & PAGE_MASK, 70 PAGE_SIZE, 0); 71 if (IS_ERR(page->umem)) { 72 err = PTR_ERR(page->umem); 73 kfree(page); 74 goto out; 75 } 76 mmgrab(current->mm); 77 page->mm = current->mm; 78 79 list_add(&page->list, &context->db_page_list); 80 81 found: 82 db->dma = sg_dma_address(page->umem->sgt_append.sgt.sgl) + 83 (virt & ~PAGE_MASK); 84 db->u.user_page = page; 85 ++page->refcnt; 86 87 out: 88 mutex_unlock(&context->db_page_mutex); 89 90 return err; 91 } 92 93 void mlx5_ib_db_unmap_user(struct mlx5_ib_ucontext *context, struct mlx5_db *db) 94 { 95 mutex_lock(&context->db_page_mutex); 96 97 if (!--db->u.user_page->refcnt) { 98 list_del(&db->u.user_page->list); 99 mmdrop(db->u.user_page->mm); 100 ib_umem_release(db->u.user_page->umem); 101 kfree(db->u.user_page); 102 } 103 104 mutex_unlock(&context->db_page_mutex); 105 } 106