1 // SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
2 /*
3  * Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
4  * Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
5  */
6 
7 #include <linux/module.h>
8 #include <linux/vmalloc.h>
9 #include <linux/mm.h>
10 #include <linux/errno.h>
11 #include <rdma/uverbs_ioctl.h>
12 
13 #include "rxe.h"
14 #include "rxe_loc.h"
15 #include "rxe_queue.h"
16 
17 void rxe_mmap_release(struct kref *ref)
18 {
19 	struct rxe_mmap_info *ip = container_of(ref,
20 					struct rxe_mmap_info, ref);
21 	struct rxe_dev *rxe = to_rdev(ip->context->device);
22 
23 	spin_lock_bh(&rxe->pending_lock);
24 
25 	if (!list_empty(&ip->pending_mmaps))
26 		list_del(&ip->pending_mmaps);
27 
28 	spin_unlock_bh(&rxe->pending_lock);
29 
30 	vfree(ip->obj);		/* buf */
31 	kfree(ip);
32 }
33 
34 /*
35  * open and close keep track of how many times the memory region is mapped,
36  * to avoid releasing it.
37  */
38 static void rxe_vma_open(struct vm_area_struct *vma)
39 {
40 	struct rxe_mmap_info *ip = vma->vm_private_data;
41 
42 	kref_get(&ip->ref);
43 }
44 
45 static void rxe_vma_close(struct vm_area_struct *vma)
46 {
47 	struct rxe_mmap_info *ip = vma->vm_private_data;
48 
49 	kref_put(&ip->ref, rxe_mmap_release);
50 }
51 
52 static const struct vm_operations_struct rxe_vm_ops = {
53 	.open = rxe_vma_open,
54 	.close = rxe_vma_close,
55 };
56 
57 /**
58  * rxe_mmap - create a new mmap region
59  * @context: the IB user context of the process making the mmap() call
60  * @vma: the VMA to be initialized
61  * Return zero if the mmap is OK. Otherwise, return an errno.
62  */
63 int rxe_mmap(struct ib_ucontext *context, struct vm_area_struct *vma)
64 {
65 	struct rxe_dev *rxe = to_rdev(context->device);
66 	unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
67 	unsigned long size = vma->vm_end - vma->vm_start;
68 	struct rxe_mmap_info *ip, *pp;
69 	int ret;
70 
71 	/*
72 	 * Search the device's list of objects waiting for a mmap call.
73 	 * Normally, this list is very short since a call to create a
74 	 * CQ, QP, or SRQ is soon followed by a call to mmap().
75 	 */
76 	spin_lock_bh(&rxe->pending_lock);
77 	list_for_each_entry_safe(ip, pp, &rxe->pending_mmaps, pending_mmaps) {
78 		if (context != ip->context || (__u64)offset != ip->info.offset)
79 			continue;
80 
81 		/* Don't allow a mmap larger than the object. */
82 		if (size > ip->info.size) {
83 			pr_err("mmap region is larger than the object!\n");
84 			spin_unlock_bh(&rxe->pending_lock);
85 			ret = -EINVAL;
86 			goto done;
87 		}
88 
89 		goto found_it;
90 	}
91 	pr_warn("unable to find pending mmap info\n");
92 	spin_unlock_bh(&rxe->pending_lock);
93 	ret = -EINVAL;
94 	goto done;
95 
96 found_it:
97 	list_del_init(&ip->pending_mmaps);
98 	spin_unlock_bh(&rxe->pending_lock);
99 
100 	ret = remap_vmalloc_range(vma, ip->obj, 0);
101 	if (ret) {
102 		pr_err("err %d from remap_vmalloc_range\n", ret);
103 		goto done;
104 	}
105 
106 	vma->vm_ops = &rxe_vm_ops;
107 	vma->vm_private_data = ip;
108 	rxe_vma_open(vma);
109 done:
110 	return ret;
111 }
112 
113 /*
114  * Allocate information for rxe_mmap
115  */
116 struct rxe_mmap_info *rxe_create_mmap_info(struct rxe_dev *rxe, u32 size,
117 					   struct ib_udata *udata, void *obj)
118 {
119 	struct rxe_mmap_info *ip;
120 
121 	if (!udata)
122 		return ERR_PTR(-EINVAL);
123 
124 	ip = kmalloc(sizeof(*ip), GFP_KERNEL);
125 	if (!ip)
126 		return ERR_PTR(-ENOMEM);
127 
128 	size = PAGE_ALIGN(size);
129 
130 	spin_lock_bh(&rxe->mmap_offset_lock);
131 
132 	if (rxe->mmap_offset == 0)
133 		rxe->mmap_offset = ALIGN(PAGE_SIZE, SHMLBA);
134 
135 	ip->info.offset = rxe->mmap_offset;
136 	rxe->mmap_offset += ALIGN(size, SHMLBA);
137 
138 	spin_unlock_bh(&rxe->mmap_offset_lock);
139 
140 	INIT_LIST_HEAD(&ip->pending_mmaps);
141 	ip->info.size = size;
142 	ip->context =
143 		container_of(udata, struct uverbs_attr_bundle, driver_udata)
144 			->context;
145 	ip->obj = obj;
146 	kref_init(&ip->ref);
147 
148 	return ip;
149 }
150