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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 two5 * licenses. You may choose to be licensed under the terms of the GNU6 * General Public License (GPL) Version 2, available from the file7 * COPYING in the main directory of this source tree, or the8 * OpenIB.org BSD license below:9 *10 * Redistribution and use in source and binary forms, with or11 * without modification, are permitted provided that the following12 * conditions are met:13 *14 * - Redistributions of source code must retain the above15 * copyright notice, this list of conditions and the following16 * disclaimer.17 *18 * - Redistributions in binary form must reproduce the above19 * copyright notice, this list of conditions and the following20 * disclaimer in the documentation and/or other materials21 * 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 OF25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE30 * 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 40struct 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 48int 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 81found: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 87out:88 mutex_unlock(&context->db_page_mutex);89 90 return err;91}92 93void 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