drivers/infiniband/hw/qib/qib_user_pages.c

   1 /*
   2  * Copyright (c) 2006, 2007, 2008, 2009 QLogic Corporation. All rights reserved.
   3  * Copyright (c) 2003, 2004, 2005, 2006 PathScale, Inc. All rights reserved.
   4  *
   5  * This software is available to you under a choice of one of two
   6  * licenses.  You may choose to be licensed under the terms of the GNU
   7  * General Public License (GPL) Version 2, available from the file
   8  * COPYING in the main directory of this source tree, or the
   9  * OpenIB.org BSD license below:
  10  *
  11  *     Redistribution and use in source and binary forms, with or
  12  *     without modification, are permitted provided that the following
  13  *     conditions are met:
  14  *
  15  *      - Redistributions of source code must retain the above
  16  *        copyright notice, this list of conditions and the following
  17  *        disclaimer.
  18  *
  19  *      - Redistributions in binary form must reproduce the above
  20  *        copyright notice, this list of conditions and the following
  21  *        disclaimer in the documentation and/or other materials
  22  *        provided with the distribution.
  23  *
  24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  28  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  29  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  30  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  31  * SOFTWARE.
  32  */
  33
  34 #include <linux/mm.h>
  35 #include <linux/sched/signal.h>
  36 #include <linux/device.h>
  37
  38 #include "qib.h"
  39
  40 static void __qib_release_user_pages(struct page **p, size_t num_pages,
  41                                      int dirty)
  42 {
  43         size_t i;
  44
  45         for (i = 0; i < num_pages; i++) {
  46                 if (dirty)
  47                         set_page_dirty_lock(p[i]);
  48                 put_page(p[i]);
  49         }
  50 }
  51
  52 /*
  53  * Call with current->mm->mmap_sem held.
  54  */
  55 static int __qib_get_user_pages(unsigned long start_page, size_t num_pages,
  56                                 struct page **p)
  57 {
  58         unsigned long lock_limit;
  59         size_t got;
  60         int ret;
  61
  62         lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
  63
  64         if (num_pages > lock_limit && !capable(CAP_IPC_LOCK)) {
  65                 ret = -ENOMEM;
  66                 goto bail;
  67         }
  68
  69         for (got = 0; got < num_pages; got += ret) {
  70                 ret = get_user_pages(start_page + got * PAGE_SIZE,
  71                                      num_pages - got,
  72                                      FOLL_WRITE | FOLL_FORCE,
  73                                      p + got, NULL);
  74                 if (ret < 0)
  75                         goto bail_release;
  76         }
  77
  78         current->mm->pinned_vm += num_pages;
  79
  80         ret = 0;
  81         goto bail;
  82
  83 bail_release:
  84         __qib_release_user_pages(p, got, 0);
  85 bail:
  86         return ret;
  87 }
  88
  89 /**
  90  * qib_map_page - a safety wrapper around pci_map_page()
  91  *
  92  * A dma_addr of all 0's is interpreted by the chip as "disabled".
  93  * Unfortunately, it can also be a valid dma_addr returned on some
  94  * architectures.
  95  *
  96  * The powerpc iommu assigns dma_addrs in ascending order, so we don't
  97  * have to bother with retries or mapping a dummy page to insure we
  98  * don't just get the same mapping again.
  99  *
 100  * I'm sure we won't be so lucky with other iommu's, so FIXME.
 101  */
 102 dma_addr_t qib_map_page(struct pci_dev *hwdev, struct page *page,
 103                         unsigned long offset, size_t size, int direction)
 104 {
 105         dma_addr_t phys;
 106
 107         phys = pci_map_page(hwdev, page, offset, size, direction);
 108
 109         if (phys == 0) {
 110                 pci_unmap_page(hwdev, phys, size, direction);
 111                 phys = pci_map_page(hwdev, page, offset, size, direction);
 112                 /*
 113                  * FIXME: If we get 0 again, we should keep this page,
 114                  * map another, then free the 0 page.
 115                  */
 116         }
 117
 118         return phys;
 119 }
 120
 121 /**
 122  * qib_get_user_pages - lock user pages into memory
 123  * @start_page: the start page
 124  * @num_pages: the number of pages
 125  * @p: the output page structures
 126  *
 127  * This function takes a given start page (page aligned user virtual
 128  * address) and pins it and the following specified number of pages.  For
 129  * now, num_pages is always 1, but that will probably change at some point
 130  * (because caller is doing expected sends on a single virtually contiguous
 131  * buffer, so we can do all pages at once).
 132  */
 133 int qib_get_user_pages(unsigned long start_page, size_t num_pages,
 134                        struct page **p)
 135 {
 136         int ret;
 137
 138         down_write(&current->mm->mmap_sem);
 139
 140         ret = __qib_get_user_pages(start_page, num_pages, p);
 141
 142         up_write(&current->mm->mmap_sem);
 143
 144         return ret;
 145 }
 146
 147 void qib_release_user_pages(struct page **p, size_t num_pages)
 148 {
 149         if (current->mm) /* during close after signal, mm can be NULL */
 150                 down_write(&current->mm->mmap_sem);
 151
 152         __qib_release_user_pages(p, num_pages, 1);
 153
 154         if (current->mm) {
 155                 current->mm->pinned_vm -= num_pages;
 156                 up_write(&current->mm->mmap_sem);
 157         }
 158 }