drivers/infiniband/hw/hfi1/user_pages.c

   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
 108         ret = get_user_pages_fast(vaddr, npages, writable, pages);
 109         if (ret < 0)
 110                 return ret;
 111
 112         atomic64_add(ret, &mm->pinned_vm);
 113
 114         return ret;
 115 }
 116
 117 void hfi1_release_user_pages(struct mm_struct *mm, struct page **p,
 118                              size_t npages, bool dirty)
 119 {
 120         size_t i;
 121
 122         for (i = 0; i < npages; i++) {
 123                 if (dirty)
 124                         set_page_dirty_lock(p[i]);
 125                 put_page(p[i]);
 126         }
 127
 128         if (mm) { /* during close after signal, mm can be NULL */
 129                 atomic64_sub(npages, &mm->pinned_vm);
 130         }
 131 }