LXR linux/drivers/infiniband/hw/hfi1/user

   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        down_read(&mm->mmap_sem);
  95        pinned = mm->pinned_vm;
  96        up_read(&mm->mmap_sem);
  97
  98        /* First, check the absolute limit against all pinned pages. */
  99        if (pinned + npages >= ulimit && !can_lock)
 100                return false;
 101
 102        return ((nlocked + npages) <= size) || can_lock;
 103}
 104
 105int hfi1_acquire_user_pages(struct mm_struct *mm, unsigned long vaddr, size_t npages,
 106                            bool writable, struct page **pages)
 107{
 108        int ret;
 109
 110        ret = get_user_pages_fast(vaddr, npages, writable, pages);
 111        if (ret < 0)
 112                return ret;
 113
 114        down_write(&mm->mmap_sem);
 115        mm->pinned_vm += ret;
 116        up_write(&mm->mmap_sem);
 117
 118        return ret;
 119}
 120
 121void hfi1_release_user_pages(struct mm_struct *mm, struct page **p,
 122                             size_t npages, bool dirty)
 123{
 124        size_t i;
 125
 126        for (i = 0; i < npages; i++) {
 127                if (dirty)
 128                        set_page_dirty_lock(p[i]);
 129                put_page(p[i]);
 130        }
 131
 132        if (mm) { /* during close after signal, mm can be NULL */
 133                down_write(&mm->mmap_sem);
 134                mm->pinned_vm -= npages;
 135                up_write(&mm->mmap_sem);
 136        }
 137}
 138