hw/mlx4/doorbell.c

0001 /*
0002  * Copyright (c) 2007 Cisco Systems, Inc. All rights reserved.
0003  *
0004  * This software is available to you under a choice of one of two
0005  * licenses.  You may choose to be licensed under the terms of the GNU
0006  * General Public License (GPL) Version 2, available from the file
0007  * COPYING in the main directory of this source tree, or the
0008  * OpenIB.org BSD license below:
0009  *
0010  *     Redistribution and use in source and binary forms, with or
0011  *     without modification, are permitted provided that the following
0012  *     conditions are met:
0013  *
0014  *      - Redistributions of source code must retain the above
0015  *        copyright notice, this list of conditions and the following
0016  *        disclaimer.
0017  *
0018  *      - Redistributions in binary form must reproduce the above
0019  *        copyright notice, this list of conditions and the following
0020  *        disclaimer in the documentation and/or other materials
0021  *        provided with the distribution.
0022  *
0023  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
0024  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
0025  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
0026  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
0027  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
0028  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
0029  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
0030  * SOFTWARE.
0031  */
0032
0033 #include <linux/slab.h>
0034 #include <rdma/uverbs_ioctl.h>
0035
0036 #include "mlx4_ib.h"
0037
0038 struct mlx4_ib_user_db_page {
0039     struct list_head    list;
0040     struct ib_umem         *umem;
0041     unsigned long       user_virt;
0042     int         refcnt;
0043 };
0044
0045 int mlx4_ib_db_map_user(struct ib_udata *udata, unsigned long virt,
0046             struct mlx4_db *db)
0047 {
0048     struct mlx4_ib_user_db_page *page;
0049     int err = 0;
0050     struct mlx4_ib_ucontext *context = rdma_udata_to_drv_context(
0051         udata, struct mlx4_ib_ucontext, ibucontext);
0052
0053     mutex_lock(&context->db_page_mutex);
0054
0055     list_for_each_entry(page, &context->db_page_list, list)
0056         if (page->user_virt == (virt & PAGE_MASK))
0057             goto found;
0058
0059     page = kmalloc(sizeof *page, GFP_KERNEL);
0060     if (!page) {
0061         err = -ENOMEM;
0062         goto out;
0063     }
0064
0065     page->user_virt = (virt & PAGE_MASK);
0066     page->refcnt    = 0;
0067     page->umem = ib_umem_get(context->ibucontext.device, virt & PAGE_MASK,
0068                  PAGE_SIZE, 0);
0069     if (IS_ERR(page->umem)) {
0070         err = PTR_ERR(page->umem);
0071         kfree(page);
0072         goto out;
0073     }
0074
0075     list_add(&page->list, &context->db_page_list);
0076
0077 found:
0078     db->dma = sg_dma_address(page->umem->sgt_append.sgt.sgl) +
0079           (virt & ~PAGE_MASK);
0080     db->u.user_page = page;
0081     ++page->refcnt;
0082
0083 out:
0084     mutex_unlock(&context->db_page_mutex);
0085
0086     return err;
0087 }
0088
0089 void mlx4_ib_db_unmap_user(struct mlx4_ib_ucontext *context, struct mlx4_db *db)
0090 {
0091     mutex_lock(&context->db_page_mutex);
0092
0093     if (!--db->u.user_page->refcnt) {
0094         list_del(&db->u.user_page->list);
0095         ib_umem_release(db->u.user_page->umem);
0096         kfree(db->u.user_page);
0097     }
0098
0099     mutex_unlock(&context->db_page_mutex);
0100 }