drivers/infiniband/hw/ipath/ipath_user_pages.c

   1 /*
   2  * Copyright (c) 2003, 2004, 2005, 2006 PathScale, Inc. All rights reserved.
   3  *
   4  * This software is available to you under a choice of one of two
   5  * licenses.  You may choose to be licensed under the terms of the GNU
   6  * General Public License (GPL) Version 2, available from the file
   7  * COPYING in the main directory of this source tree, or the
   8  * OpenIB.org BSD license below:
   9  *
  10  *     Redistribution and use in source and binary forms, with or
  11  *     without modification, are permitted provided that the following
  12  *     conditions are met:
  13  *
  14  *      - Redistributions of source code must retain the above
  15  *        copyright notice, this list of conditions and the following
  16  *        disclaimer.
  17  *
  18  *      - Redistributions in binary form must reproduce the above
  19  *        copyright notice, this list of conditions and the following
  20  *        disclaimer in the documentation and/or other materials
  21  *        provided with the distribution.
  22  *
  23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  30  * SOFTWARE.
  31  */
  32
  33 #include <linux/mm.h>
  34 #include <linux/device.h>
  35
  36 #include "ipath_kernel.h"
  37
  38 static void __ipath_release_user_pages(struct page **p, size_t num_pages,
  39                                    int dirty)
  40 {
  41         size_t i;
  42
  43         for (i = 0; i < num_pages; i++) {
  44                 ipath_cdbg(MM, "%lu/%lu put_page %p\n", (unsigned long) i,
  45                            (unsigned long) num_pages, p[i]);
  46                 if (dirty)
  47                         set_page_dirty_lock(p[i]);
  48                 put_page(p[i]);
  49         }
  50 }
  51
  52 /* call with current->mm->mmap_sem held */
  53 static int __get_user_pages(unsigned long start_page, size_t num_pages,
  54                         struct page **p, struct vm_area_struct **vma)
  55 {
  56         unsigned long lock_limit;
  57         size_t got;
  58         int ret;
  59
  60 #if 0
  61         /*
  62          * XXX - causes MPI programs to fail, haven't had time to check
  63          * yet
  64          */
  65         if (!capable(CAP_IPC_LOCK)) {
  66                 ret = -EPERM;
  67                 goto bail;
  68         }
  69 #endif
  70
  71         lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur >>
  72                 PAGE_SHIFT;
  73
  74         if (num_pages > lock_limit) {
  75                 ret = -ENOMEM;
  76                 goto bail;
  77         }
  78
  79         ipath_cdbg(VERBOSE, "pin %lx pages from vaddr %lx\n",
  80                    (unsigned long) num_pages, start_page);
  81
  82         for (got = 0; got < num_pages; got += ret) {
  83                 ret = get_user_pages(current, current->mm,
  84                                      start_page + got * PAGE_SIZE,
  85                                      num_pages - got, 1, 1,
  86                                      p + got, vma);
  87                 if (ret < 0)
  88                         goto bail_release;
  89         }
  90
  91         current->mm->locked_vm += num_pages;
  92
  93         ret = 0;
  94         goto bail;
  95
  96 bail_release:
  97         __ipath_release_user_pages(p, got, 0);
  98 bail:
  99         return ret;
 100 }
 101
 102 /**
 103  * ipath_get_user_pages - lock user pages into memory
 104  * @start_page: the start page
 105  * @num_pages: the number of pages
 106  * @p: the output page structures
 107  *
 108  * This function takes a given start page (page aligned user virtual
 109  * address) and pins it and the following specified number of pages.  For
 110  * now, num_pages is always 1, but that will probably change at some point
 111  * (because caller is doing expected sends on a single virtually contiguous
 112  * buffer, so we can do all pages at once).
 113  */
 114 int ipath_get_user_pages(unsigned long start_page, size_t num_pages,
 115                          struct page **p)
 116 {
 117         int ret;
 118
 119         down_write(&current->mm->mmap_sem);
 120
 121         ret = __get_user_pages(start_page, num_pages, p, NULL);
 122
 123         up_write(&current->mm->mmap_sem);
 124
 125         return ret;
 126 }
 127
 128 /**
 129  * ipath_get_user_pages_nocopy - lock a single page for I/O and mark shared
 130  * @start_page: the page to lock
 131  * @p: the output page structure
 132  *
 133  * This is similar to ipath_get_user_pages, but it's always one page, and we
 134  * mark the page as locked for I/O, and shared.  This is used for the user
 135  * process page that contains the destination address for the rcvhdrq tail
 136  * update, so we need to have the vma. If we don't do this, the page can be
 137  * taken away from us on fork, even if the child never touches it, and then
 138  * the user process never sees the tail register updates.
 139  */
 140 int ipath_get_user_pages_nocopy(unsigned long page, struct page **p)
 141 {
 142         struct vm_area_struct *vma;
 143         int ret;
 144
 145         down_write(&current->mm->mmap_sem);
 146
 147         ret = __get_user_pages(page, 1, p, &vma);
 148
 149         up_write(&current->mm->mmap_sem);
 150
 151         return ret;
 152 }
 153
 154 void ipath_release_user_pages(struct page **p, size_t num_pages)
 155 {
 156         down_write(&current->mm->mmap_sem);
 157
 158         __ipath_release_user_pages(p, num_pages, 1);
 159
 160         current->mm->locked_vm -= num_pages;
 161
 162         up_write(&current->mm->mmap_sem);
 163 }
 164
 165 struct ipath_user_pages_work {
 166         struct work_struct work;
 167         struct mm_struct *mm;
 168         unsigned long num_pages;
 169 };
 170
 171 static void user_pages_account(void *ptr)
 172 {
 173         struct ipath_user_pages_work *work = ptr;
 174
 175         down_write(&work->mm->mmap_sem);
 176         work->mm->locked_vm -= work->num_pages;
 177         up_write(&work->mm->mmap_sem);
 178         mmput(work->mm);
 179         kfree(work);
 180 }
 181
 182 void ipath_release_user_pages_on_close(struct page **p, size_t num_pages)
 183 {
 184         struct ipath_user_pages_work *work;
 185         struct mm_struct *mm;
 186
 187         __ipath_release_user_pages(p, num_pages, 1);
 188
 189         mm = get_task_mm(current);
 190         if (!mm)
 191                 goto bail;
 192
 193         work = kmalloc(sizeof(*work), GFP_KERNEL);
 194         if (!work)
 195                 goto bail_mm;
 196
 197         goto bail;
 198
 199         INIT_WORK(&work->work, user_pages_account, work);
 200         work->mm = mm;
 201         work->num_pages = num_pages;
 202
 203 bail_mm:
 204         mmput(mm);
 205 bail:
 206         return;
 207 }