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
55static unsigned long cache_size = 256;
56module_param(cache_size, ulong, S_IRUGO | S_IWUSR);
57MODULE_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 */
71bool 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
103int 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 = pin_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
118void hfi1_release_user_pages(struct mm_struct *mm, struct page **p,
119			     size_t npages, bool dirty)
120{
121	unpin_user_pages_dirty_lock(p, npages, dirty);
122
123	if (mm) { /* during close after signal, mm can be NULL */
124		atomic64_sub(npages, &mm->pinned_vm);
125	}
126}
127