1 /*
2  * Copyright(c) 2015-2017 Intel Corporation.
3  *
4  * This file is provided under a dual BSD/GPLv2 license.  When using or
5  * redistributing this file, you may do so under either license.
6  *
7  * GPL LICENSE SUMMARY
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of version 2 of the GNU General Public License as
11  * published by the Free Software Foundation.
12  *
13  * This program is distributed in the hope that it will be useful, but
14  * WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16  * General Public License for more details.
17  *
18  * BSD LICENSE
19  *
20  * Redistribution and use in source and binary forms, with or without
21  * modification, are permitted provided that the following conditions
22  * are met:
23  *
24  *  - Redistributions of source code must retain the above copyright
25  *    notice, this list of conditions and the following disclaimer.
26  *  - Redistributions in binary form must reproduce the above copyright
27  *    notice, this list of conditions and the following disclaimer in
28  *    the documentation and/or other materials provided with the
29  *    distribution.
30  *  - Neither the name of Intel Corporation nor the names of its
31  *    contributors may be used to endorse or promote products derived
32  *    from this software without specific prior written permission.
33  *
34  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
35  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
36  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
37  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
38  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
39  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
40  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
41  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
42  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
43  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
44  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
45  *
46  */
47 
48 #include <linux/mm.h>
49 #include <linux/sched/signal.h>
50 #include <linux/device.h>
51 #include <linux/module.h>
52 
53 #include "hfi.h"
54 
55 static unsigned long cache_size = 256;
56 module_param(cache_size, ulong, S_IRUGO | S_IWUSR);
57 MODULE_PARM_DESC(cache_size, "Send and receive side cache size limit (in MB)");
58 
59 /*
60  * Determine whether the caller can pin pages.
61  *
62  * This function should be used in the implementation of buffer caches.
63  * The cache implementation should call this function prior to attempting
64  * to pin buffer pages in order to determine whether they should do so.
65  * The function computes cache limits based on the configured ulimit and
66  * cache size. Use of this function is especially important for caches
67  * which are not limited in any other way (e.g. by HW resources) and, thus,
68  * could keeping caching buffers.
69  *
70  */
71 bool hfi1_can_pin_pages(struct hfi1_devdata *dd, struct mm_struct *mm,
72 			u32 nlocked, u32 npages)
73 {
74 	unsigned long ulimit = rlimit(RLIMIT_MEMLOCK), pinned, cache_limit,
75 		size = (cache_size * (1UL << 20)); /* convert to bytes */
76 	unsigned int usr_ctxts =
77 			dd->num_rcv_contexts - dd->first_dyn_alloc_ctxt;
78 	bool can_lock = capable(CAP_IPC_LOCK);
79 
80 	/*
81 	 * Calculate per-cache size. The calculation below uses only a quarter
82 	 * of the available per-context limit. This leaves space for other
83 	 * pinning. Should we worry about shared ctxts?
84 	 */
85 	cache_limit = (ulimit / usr_ctxts) / 4;
86 
87 	/* If ulimit isn't set to "unlimited" and is smaller than cache_size. */
88 	if (ulimit != (-1UL) && size > cache_limit)
89 		size = cache_limit;
90 
91 	/* Convert to number of pages */
92 	size = DIV_ROUND_UP(size, PAGE_SIZE);
93 
94 	pinned = atomic64_read(&mm->pinned_vm);
95 
96 	/* First, check the absolute limit against all pinned pages. */
97 	if (pinned + npages >= ulimit && !can_lock)
98 		return false;
99 
100 	return ((nlocked + npages) <= size) || can_lock;
101 }
102 
103 int hfi1_acquire_user_pages(struct mm_struct *mm, unsigned long vaddr, size_t npages,
104 			    bool writable, struct page **pages)
105 {
106 	int ret;
107 	unsigned int gup_flags = FOLL_LONGTERM | (writable ? FOLL_WRITE : 0);
108 
109 	ret = get_user_pages_fast(vaddr, npages, gup_flags, pages);
110 	if (ret < 0)
111 		return ret;
112 
113 	atomic64_add(ret, &mm->pinned_vm);
114 
115 	return ret;
116 }
117 
118 void hfi1_release_user_pages(struct mm_struct *mm, struct page **p,
119 			     size_t npages, bool dirty)
120 {
121 	size_t i;
122 
123 	for (i = 0; i < npages; i++) {
124 		if (dirty)
125 			set_page_dirty_lock(p[i]);
126 		put_page(p[i]);
127 	}
128 
129 	if (mm) { /* during close after signal, mm can be NULL */
130 		atomic64_sub(npages, &mm->pinned_vm);
131 	}
132 }
133