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/sched/signal.h>
36 #include <linux/device.h>
37 
38 #include "qib.h"
39 
40 static void __qib_release_user_pages(struct page **p, size_t num_pages,
41 				     int dirty)
42 {
43 	if (dirty)
44 		put_user_pages_dirty_lock(p, num_pages);
45 	else
46 		put_user_pages(p, num_pages);
47 }
48 
49 /**
50  * qib_map_page - a safety wrapper around pci_map_page()
51  *
52  * A dma_addr of all 0's is interpreted by the chip as "disabled".
53  * Unfortunately, it can also be a valid dma_addr returned on some
54  * architectures.
55  *
56  * The powerpc iommu assigns dma_addrs in ascending order, so we don't
57  * have to bother with retries or mapping a dummy page to insure we
58  * don't just get the same mapping again.
59  *
60  * I'm sure we won't be so lucky with other iommu's, so FIXME.
61  */
62 int qib_map_page(struct pci_dev *hwdev, struct page *page, dma_addr_t *daddr)
63 {
64 	dma_addr_t phys;
65 
66 	phys = pci_map_page(hwdev, page, 0, PAGE_SIZE, PCI_DMA_FROMDEVICE);
67 	if (pci_dma_mapping_error(hwdev, phys))
68 		return -ENOMEM;
69 
70 	if (!phys) {
71 		pci_unmap_page(hwdev, phys, PAGE_SIZE, PCI_DMA_FROMDEVICE);
72 		phys = pci_map_page(hwdev, page, 0, PAGE_SIZE,
73 				    PCI_DMA_FROMDEVICE);
74 		if (pci_dma_mapping_error(hwdev, phys))
75 			return -ENOMEM;
76 		/*
77 		 * FIXME: If we get 0 again, we should keep this page,
78 		 * map another, then free the 0 page.
79 		 */
80 	}
81 	*daddr = phys;
82 	return 0;
83 }
84 
85 /**
86  * qib_get_user_pages - lock user pages into memory
87  * @start_page: the start page
88  * @num_pages: the number of pages
89  * @p: the output page structures
90  *
91  * This function takes a given start page (page aligned user virtual
92  * address) and pins it and the following specified number of pages.  For
93  * now, num_pages is always 1, but that will probably change at some point
94  * (because caller is doing expected sends on a single virtually contiguous
95  * buffer, so we can do all pages at once).
96  */
97 int qib_get_user_pages(unsigned long start_page, size_t num_pages,
98 		       struct page **p)
99 {
100 	unsigned long locked, lock_limit;
101 	size_t got;
102 	int ret;
103 
104 	lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
105 	locked = atomic64_add_return(num_pages, &current->mm->pinned_vm);
106 
107 	if (locked > lock_limit && !capable(CAP_IPC_LOCK)) {
108 		ret = -ENOMEM;
109 		goto bail;
110 	}
111 
112 	down_read(&current->mm->mmap_sem);
113 	for (got = 0; got < num_pages; got += ret) {
114 		ret = get_user_pages(start_page + got * PAGE_SIZE,
115 				     num_pages - got,
116 				     FOLL_LONGTERM | FOLL_WRITE | FOLL_FORCE,
117 				     p + got, NULL);
118 		if (ret < 0) {
119 			up_read(&current->mm->mmap_sem);
120 			goto bail_release;
121 		}
122 	}
123 	up_read(&current->mm->mmap_sem);
124 
125 	return 0;
126 bail_release:
127 	__qib_release_user_pages(p, got, 0);
128 bail:
129 	atomic64_sub(num_pages, &current->mm->pinned_vm);
130 	return ret;
131 }
132 
133 void qib_release_user_pages(struct page **p, size_t num_pages)
134 {
135 	__qib_release_user_pages(p, num_pages, 1);
136 
137 	/* during close after signal, mm can be NULL */
138 	if (current->mm)
139 		atomic64_sub(num_pages, &current->mm->pinned_vm);
140 }
141