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qib_mmap.c
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1 /*
2  * Copyright (c) 2006, 2007, 2008, 2009 QLogic Corporation. All rights reserved.
3  *
4  * This software is available to you under a choice of one of two
5  * licenses. You may choose to be licensed under the terms of the GNU
6  * General Public License (GPL) Version 2, available from the file
7  * COPYING in the main directory of this source tree, or the
8  * OpenIB.org BSD license below:
9  *
10  * Redistribution and use in source and binary forms, with or
11  * without modification, are permitted provided that the following
12  * conditions are met:
13  *
14  * - Redistributions of source code must retain the above
15  * copyright notice, this list of conditions and the following
16  * disclaimer.
17  *
18  * - Redistributions in binary form must reproduce the above
19  * copyright notice, this list of conditions and the following
20  * disclaimer in the documentation and/or other materials
21  * 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 OF
25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30  * SOFTWARE.
31  */
32 
33 #include <linux/module.h>
34 #include <linux/slab.h>
35 #include <linux/vmalloc.h>
36 #include <linux/mm.h>
37 #include <linux/errno.h>
38 #include <asm/pgtable.h>
39 
40 #include "qib_verbs.h"
41 
46 void qib_release_mmap_info(struct kref *ref)
47 {
48  struct qib_mmap_info *ip =
49  container_of(ref, struct qib_mmap_info, ref);
50  struct qib_ibdev *dev = to_idev(ip->context->device);
51 
52  spin_lock_irq(&dev->pending_lock);
53  list_del(&ip->pending_mmaps);
54  spin_unlock_irq(&dev->pending_lock);
55 
56  vfree(ip->obj);
57  kfree(ip);
58 }
59 
60 /*
61  * open and close keep track of how many times the CQ is mapped,
62  * to avoid releasing it.
63  */
64 static void qib_vma_open(struct vm_area_struct *vma)
65 {
66  struct qib_mmap_info *ip = vma->vm_private_data;
67 
68  kref_get(&ip->ref);
69 }
70 
71 static void qib_vma_close(struct vm_area_struct *vma)
72 {
73  struct qib_mmap_info *ip = vma->vm_private_data;
74 
75  kref_put(&ip->ref, qib_release_mmap_info);
76 }
77 
78 static struct vm_operations_struct qib_vm_ops = {
79  .open = qib_vma_open,
80  .close = qib_vma_close,
81 };
82 
89 int qib_mmap(struct ib_ucontext *context, struct vm_area_struct *vma)
90 {
91  struct qib_ibdev *dev = to_idev(context->device);
92  unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
93  unsigned long size = vma->vm_end - vma->vm_start;
94  struct qib_mmap_info *ip, *pp;
95  int ret = -EINVAL;
96 
97  /*
98  * Search the device's list of objects waiting for a mmap call.
99  * Normally, this list is very short since a call to create a
100  * CQ, QP, or SRQ is soon followed by a call to mmap().
101  */
102  spin_lock_irq(&dev->pending_lock);
104  pending_mmaps) {
105  /* Only the creator is allowed to mmap the object */
106  if (context != ip->context || (__u64) offset != ip->offset)
107  continue;
108  /* Don't allow a mmap larger than the object. */
109  if (size > ip->size)
110  break;
111 
112  list_del_init(&ip->pending_mmaps);
113  spin_unlock_irq(&dev->pending_lock);
114 
115  ret = remap_vmalloc_range(vma, ip->obj, 0);
116  if (ret)
117  goto done;
118  vma->vm_ops = &qib_vm_ops;
119  vma->vm_private_data = ip;
120  qib_vma_open(vma);
121  goto done;
122  }
123  spin_unlock_irq(&dev->pending_lock);
124 done:
125  return ret;
126 }
127 
128 /*
129  * Allocate information for qib_mmap
130  */
132  u32 size,
133  struct ib_ucontext *context,
134  void *obj) {
135  struct qib_mmap_info *ip;
136 
137  ip = kmalloc(sizeof *ip, GFP_KERNEL);
138  if (!ip)
139  goto bail;
140 
141  size = PAGE_ALIGN(size);
142 
143  spin_lock_irq(&dev->mmap_offset_lock);
144  if (dev->mmap_offset == 0)
145  dev->mmap_offset = PAGE_SIZE;
146  ip->offset = dev->mmap_offset;
147  dev->mmap_offset += size;
148  spin_unlock_irq(&dev->mmap_offset_lock);
149 
150  INIT_LIST_HEAD(&ip->pending_mmaps);
151  ip->size = size;
152  ip->context = context;
153  ip->obj = obj;
154  kref_init(&ip->ref);
155 
156 bail:
157  return ip;
158 }
159 
161  u32 size, void *obj)
162 {
163  size = PAGE_ALIGN(size);
164 
165  spin_lock_irq(&dev->mmap_offset_lock);
166  if (dev->mmap_offset == 0)
167  dev->mmap_offset = PAGE_SIZE;
168  ip->offset = dev->mmap_offset;
169  dev->mmap_offset += size;
170  spin_unlock_irq(&dev->mmap_offset_lock);
171 
172  ip->size = size;
173  ip->obj = obj;
174 }