1 // SPDX-License-Identifier: GPL-2.0 or BSD-3-Clause
2 /*
3 * Copyright(c) 2015-2017 Intel Corporation.
4 */
5
6 #include <linux/mm.h>
7 #include <linux/sched/signal.h>
8 #include <linux/device.h>
9 #include <linux/module.h>
10
11 #include "hfi.h"
12
13 static unsigned long cache_size = 256;
14 module_param(cache_size, ulong, S_IRUGO | S_IWUSR);
15 MODULE_PARM_DESC(cache_size, "Send and receive side cache size limit (in MB)");
16
17 /*
18 * Determine whether the caller can pin pages.
19 *
20 * This function should be used in the implementation of buffer caches.
21 * The cache implementation should call this function prior to attempting
22 * to pin buffer pages in order to determine whether they should do so.
23 * The function computes cache limits based on the configured ulimit and
24 * cache size. Use of this function is especially important for caches
25 * which are not limited in any other way (e.g. by HW resources) and, thus,
26 * could keeping caching buffers.
27 *
28 */
hfi1_can_pin_pages(struct hfi1_devdata * dd,struct mm_struct * mm,u32 nlocked,u32 npages)29 bool hfi1_can_pin_pages(struct hfi1_devdata *dd, struct mm_struct *mm,
30 u32 nlocked, u32 npages)
31 {
32 unsigned long ulimit = rlimit(RLIMIT_MEMLOCK), pinned, cache_limit,
33 size = (cache_size * (1UL << 20)); /* convert to bytes */
34 unsigned int usr_ctxts =
35 dd->num_rcv_contexts - dd->first_dyn_alloc_ctxt;
36 bool can_lock = capable(CAP_IPC_LOCK);
37
38 /*
39 * Calculate per-cache size. The calculation below uses only a quarter
40 * of the available per-context limit. This leaves space for other
41 * pinning. Should we worry about shared ctxts?
42 */
43 cache_limit = (ulimit / usr_ctxts) / 4;
44
45 /* If ulimit isn't set to "unlimited" and is smaller than cache_size. */
46 if (ulimit != (-1UL) && size > cache_limit)
47 size = cache_limit;
48
49 /* Convert to number of pages */
50 size = DIV_ROUND_UP(size, PAGE_SIZE);
51
52 pinned = atomic64_read(&mm->pinned_vm);
53
54 /* First, check the absolute limit against all pinned pages. */
55 if (pinned + npages >= ulimit && !can_lock)
56 return false;
57
58 return ((nlocked + npages) <= size) || can_lock;
59 }
60
hfi1_acquire_user_pages(struct mm_struct * mm,unsigned long vaddr,size_t npages,bool writable,struct page ** pages)61 int hfi1_acquire_user_pages(struct mm_struct *mm, unsigned long vaddr, size_t npages,
62 bool writable, struct page **pages)
63 {
64 int ret;
65 unsigned int gup_flags = FOLL_LONGTERM | (writable ? FOLL_WRITE : 0);
66
67 ret = pin_user_pages_fast(vaddr, npages, gup_flags, pages);
68 if (ret < 0)
69 return ret;
70
71 atomic64_add(ret, &mm->pinned_vm);
72
73 return ret;
74 }
75
hfi1_release_user_pages(struct mm_struct * mm,struct page ** p,size_t npages,bool dirty)76 void hfi1_release_user_pages(struct mm_struct *mm, struct page **p,
77 size_t npages, bool dirty)
78 {
79 unpin_user_pages_dirty_lock(p, npages, dirty);
80
81 if (mm) { /* during close after signal, mm can be NULL */
82 atomic64_sub(npages, &mm->pinned_vm);
83 }
84 }
85