1 /*
2  * Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
3  * Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
4  *
5  * This software is available to you under a choice of one of two
6  * licenses.  You may choose to be licensed under the terms of the GNU
7  * General Public License (GPL) Version 2, available from the file
8  * COPYING in the main directory of this source tree, or the
9  * OpenIB.org BSD license below:
10  *
11  *     Redistribution and use in source and binary forms, with or
12  *     without modification, are permitted provided that the following
13  *     conditions are met:
14  *
15  *	- Redistributions of source code must retain the above
16  *	  copyright notice, this list of conditions and the following
17  *	  disclaimer.
18  *
19  *	- Redistributions in binary form must reproduce the above
20  *	  copyright notice, this list of conditions and the following
21  *	  disclaimer in the documentation and/or other materials
22  *	  provided with the distribution.
23  *
24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
28  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
29  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
30  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
31  * SOFTWARE.
32  */
33 
34 #include <linux/module.h>
35 #include <linux/vmalloc.h>
36 #include <linux/mm.h>
37 #include <linux/errno.h>
38 #include <asm/pgtable.h>
39 
40 #include "rxe.h"
41 #include "rxe_loc.h"
42 #include "rxe_queue.h"
43 
44 void rxe_mmap_release(struct kref *ref)
45 {
46 	struct rxe_mmap_info *ip = container_of(ref,
47 					struct rxe_mmap_info, ref);
48 	struct rxe_dev *rxe = to_rdev(ip->context->device);
49 
50 	spin_lock_bh(&rxe->pending_lock);
51 
52 	if (!list_empty(&ip->pending_mmaps))
53 		list_del(&ip->pending_mmaps);
54 
55 	spin_unlock_bh(&rxe->pending_lock);
56 
57 	vfree(ip->obj);		/* buf */
58 	kfree(ip);
59 }
60 
61 /*
62  * open and close keep track of how many times the memory region is mapped,
63  * to avoid releasing it.
64  */
65 static void rxe_vma_open(struct vm_area_struct *vma)
66 {
67 	struct rxe_mmap_info *ip = vma->vm_private_data;
68 
69 	kref_get(&ip->ref);
70 }
71 
72 static void rxe_vma_close(struct vm_area_struct *vma)
73 {
74 	struct rxe_mmap_info *ip = vma->vm_private_data;
75 
76 	kref_put(&ip->ref, rxe_mmap_release);
77 }
78 
79 static const struct vm_operations_struct rxe_vm_ops = {
80 	.open = rxe_vma_open,
81 	.close = rxe_vma_close,
82 };
83 
84 /**
85  * rxe_mmap - create a new mmap region
86  * @context: the IB user context of the process making the mmap() call
87  * @vma: the VMA to be initialized
88  * Return zero if the mmap is OK. Otherwise, return an errno.
89  */
90 int rxe_mmap(struct ib_ucontext *context, struct vm_area_struct *vma)
91 {
92 	struct rxe_dev *rxe = to_rdev(context->device);
93 	unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
94 	unsigned long size = vma->vm_end - vma->vm_start;
95 	struct rxe_mmap_info *ip, *pp;
96 	int ret;
97 
98 	/*
99 	 * Search the device's list of objects waiting for a mmap call.
100 	 * Normally, this list is very short since a call to create a
101 	 * CQ, QP, or SRQ is soon followed by a call to mmap().
102 	 */
103 	spin_lock_bh(&rxe->pending_lock);
104 	list_for_each_entry_safe(ip, pp, &rxe->pending_mmaps, pending_mmaps) {
105 		if (context != ip->context || (__u64)offset != ip->info.offset)
106 			continue;
107 
108 		/* Don't allow a mmap larger than the object. */
109 		if (size > ip->info.size) {
110 			pr_err("mmap region is larger than the object!\n");
111 			spin_unlock_bh(&rxe->pending_lock);
112 			ret = -EINVAL;
113 			goto done;
114 		}
115 
116 		goto found_it;
117 	}
118 	pr_warn("unable to find pending mmap info\n");
119 	spin_unlock_bh(&rxe->pending_lock);
120 	ret = -EINVAL;
121 	goto done;
122 
123 found_it:
124 	list_del_init(&ip->pending_mmaps);
125 	spin_unlock_bh(&rxe->pending_lock);
126 
127 	ret = remap_vmalloc_range(vma, ip->obj, 0);
128 	if (ret) {
129 		pr_err("err %d from remap_vmalloc_range\n", ret);
130 		goto done;
131 	}
132 
133 	vma->vm_ops = &rxe_vm_ops;
134 	vma->vm_private_data = ip;
135 	rxe_vma_open(vma);
136 done:
137 	return ret;
138 }
139 
140 /*
141  * Allocate information for rxe_mmap
142  */
143 struct rxe_mmap_info *rxe_create_mmap_info(struct rxe_dev *rxe,
144 					   u32 size,
145 					   struct ib_ucontext *context,
146 					   void *obj)
147 {
148 	struct rxe_mmap_info *ip;
149 
150 	ip = kmalloc(sizeof(*ip), GFP_KERNEL);
151 	if (!ip)
152 		return NULL;
153 
154 	size = PAGE_ALIGN(size);
155 
156 	spin_lock_bh(&rxe->mmap_offset_lock);
157 
158 	if (rxe->mmap_offset == 0)
159 		rxe->mmap_offset = ALIGN(PAGE_SIZE, SHMLBA);
160 
161 	ip->info.offset = rxe->mmap_offset;
162 	rxe->mmap_offset += ALIGN(size, SHMLBA);
163 
164 	spin_unlock_bh(&rxe->mmap_offset_lock);
165 
166 	INIT_LIST_HEAD(&ip->pending_mmaps);
167 	ip->info.size = size;
168 	ip->context = context;
169 	ip->obj = obj;
170 	kref_init(&ip->ref);
171 
172 	return ip;
173 }
174