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