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qib_user_pages.c
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1 /*
2  * Copyright (c) 2006, 2007, 2008, 2009 QLogic Corporation. All rights reserved.
3  * Copyright (c) 2003, 2004, 2005, 2006 PathScale, 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/mm.h>
35 #include <linux/device.h>
36 
37 #include "qib.h"
38 
39 static void __qib_release_user_pages(struct page **p, size_t num_pages,
40  int dirty)
41 {
42  size_t i;
43 
44  for (i = 0; i < num_pages; i++) {
45  if (dirty)
46  set_page_dirty_lock(p[i]);
47  put_page(p[i]);
48  }
49 }
50 
51 /*
52  * Call with current->mm->mmap_sem held.
53  */
54 static int __qib_get_user_pages(unsigned long start_page, size_t num_pages,
55  struct page **p, struct vm_area_struct **vma)
56 {
57  unsigned long lock_limit;
58  size_t got;
59  int ret;
60 
61  lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
62 
63  if (num_pages > lock_limit && !capable(CAP_IPC_LOCK)) {
64  ret = -ENOMEM;
65  goto bail;
66  }
67 
68  for (got = 0; got < num_pages; got += ret) {
69  ret = get_user_pages(current, current->mm,
70  start_page + got * PAGE_SIZE,
71  num_pages - got, 1, 1,
72  p + got, vma);
73  if (ret < 0)
74  goto bail_release;
75  }
76 
77  current->mm->pinned_vm += num_pages;
78 
79  ret = 0;
80  goto bail;
81 
82 bail_release:
83  __qib_release_user_pages(p, got, 0);
84 bail:
85  return ret;
86 }
87 
101 dma_addr_t qib_map_page(struct pci_dev *hwdev, struct page *page,
102  unsigned long offset, size_t size, int direction)
103 {
105 
106  phys = pci_map_page(hwdev, page, offset, size, direction);
107 
108  if (phys == 0) {
109  pci_unmap_page(hwdev, phys, size, direction);
110  phys = pci_map_page(hwdev, page, offset, size, direction);
111  /*
112  * FIXME: If we get 0 again, we should keep this page,
113  * map another, then free the 0 page.
114  */
115  }
116 
117  return phys;
118 }
119 
132 int qib_get_user_pages(unsigned long start_page, size_t num_pages,
133  struct page **p)
134 {
135  int ret;
136 
137  down_write(&current->mm->mmap_sem);
138 
139  ret = __qib_get_user_pages(start_page, num_pages, p, NULL);
140 
141  up_write(&current->mm->mmap_sem);
142 
143  return ret;
144 }
145 
146 void qib_release_user_pages(struct page **p, size_t num_pages)
147 {
148  if (current->mm) /* during close after signal, mm can be NULL */
149  down_write(&current->mm->mmap_sem);
150 
151  __qib_release_user_pages(p, num_pages, 1);
152 
153  if (current->mm) {
154  current->mm->pinned_vm -= num_pages;
155  up_write(&current->mm->mmap_sem);
156  }
157 }