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 37 struct 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 44 int 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 int err = 0; 49 50 mutex_lock(&context->db_page_mutex); 51 52 list_for_each_entry(page, &context->db_page_list, list) 53 if (page->user_virt == (virt & PAGE_MASK)) 54 goto found; 55 56 page = kmalloc(sizeof *page, GFP_KERNEL); 57 if (!page) { 58 err = -ENOMEM; 59 goto out; 60 } 61 62 page->user_virt = (virt & PAGE_MASK); 63 page->refcnt = 0; 64 page->umem = ib_umem_get(&context->ibucontext, virt & PAGE_MASK, 65 PAGE_SIZE, 0, 0); 66 if (IS_ERR(page->umem)) { 67 err = PTR_ERR(page->umem); 68 kfree(page); 69 goto out; 70 } 71 72 list_add(&page->list, &context->db_page_list); 73 74 found: 75 db->dma = sg_dma_address(page->umem->sg_head.sgl) + (virt & ~PAGE_MASK); 76 db->u.user_page = page; 77 ++page->refcnt; 78 79 out: 80 mutex_unlock(&context->db_page_mutex); 81 82 return err; 83 } 84 85 void mlx4_ib_db_unmap_user(struct mlx4_ib_ucontext *context, struct mlx4_db *db) 86 { 87 mutex_lock(&context->db_page_mutex); 88 89 if (!--db->u.user_page->refcnt) { 90 list_del(&db->u.user_page->list); 91 ib_umem_release(db->u.user_page->umem); 92 kfree(db->u.user_page); 93 } 94 95 mutex_unlock(&context->db_page_mutex); 96 } 97