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/device.h>
  36
  37 #include "qib.h"
  38
  39 static void __qib_release_user_pages(struct page **p, size_t num_pages,
  40                                      int dirty)
  41 {
  42         size_t i;
  43
  44         for (i = 0; i < num_pages; i++) {
  45                 if (dirty)
  46                         set_page_dirty_lock(p[i]);
  47                 put_page(p[i]);
  48         }
  49 }
  50
  51 /*
  52  * Call with current->mm->mmap_sem held.
  53  */
  54 static int __qib_get_user_pages(unsigned long start_page, size_t num_pages,
  55                                 struct page **p)
  56 {
  57         unsigned long lock_limit;
  58         size_t got;
  59         int ret;
  60
  61         lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
  62
  63         if (num_pages > lock_limit && !capable(CAP_IPC_LOCK)) {
  64                 ret = -ENOMEM;
  65                 goto bail;
  66         }
  67
  68         for (got = 0; got < num_pages; got += ret) {
  69                 ret = get_user_pages(start_page + got * PAGE_SIZE,
  70                                      num_pages - got, 1, 1,
  71                                      p + got, NULL);
  72                 if (ret < 0)
  73                         goto bail_release;
  74         }
  75
  76         current->mm->pinned_vm += num_pages;
  77
  78         ret = 0;
  79         goto bail;
  80
  81 bail_release:
  82         __qib_release_user_pages(p, got, 0);
  83 bail:
  84         return ret;
  85 }
  86
  87 /**
  88  * qib_map_page - a safety wrapper around pci_map_page()
  89  *
  90  * A dma_addr of all 0's is interpreted by the chip as "disabled".
  91  * Unfortunately, it can also be a valid dma_addr returned on some
  92  * architectures.
  93  *
  94  * The powerpc iommu assigns dma_addrs in ascending order, so we don't
  95  * have to bother with retries or mapping a dummy page to insure we
  96  * don't just get the same mapping again.
  97  *
  98  * I'm sure we won't be so lucky with other iommu's, so FIXME.
  99  */
 100 dma_addr_t qib_map_page(struct pci_dev *hwdev, struct page *page,
 101                         unsigned long offset, size_t size, int direction)
 102 {
 103         dma_addr_t phys;
 104
 105         phys = pci_map_page(hwdev, page, offset, size, direction);
 106
 107         if (phys == 0) {
 108                 pci_unmap_page(hwdev, phys, size, direction);
 109                 phys = pci_map_page(hwdev, page, offset, size, direction);
 110                 /*
 111                  * FIXME: If we get 0 again, we should keep this page,
 112                  * map another, then free the 0 page.
 113                  */
 114         }
 115
 116         return phys;
 117 }
 118
 119 /**
 120  * qib_get_user_pages - lock user pages into memory
 121  * @start_page: the start page
 122  * @num_pages: the number of pages
 123  * @p: the output page structures
 124  *
 125  * This function takes a given start page (page aligned user virtual
 126  * address) and pins it and the following specified number of pages.  For
 127  * now, num_pages is always 1, but that will probably change at some point
 128  * (because caller is doing expected sends on a single virtually contiguous
 129  * buffer, so we can do all pages at once).
 130  */
 131 int qib_get_user_pages(unsigned long start_page, size_t num_pages,
 132                        struct page **p)
 133 {
 134         int ret;
 135
 136         down_write(&current->mm->mmap_sem);
 137
 138         ret = __qib_get_user_pages(start_page, num_pages, p);
 139
 140         up_write(&current->mm->mmap_sem);
 141
 142         return ret;
 143 }
 144
 145 void qib_release_user_pages(struct page **p, size_t num_pages)
 146 {
 147         if (current->mm) /* during close after signal, mm can be NULL */
 148                 down_write(&current->mm->mmap_sem);
 149
 150         __qib_release_user_pages(p, num_pages, 1);
 151
 152         if (current->mm) {
 153                 current->mm->pinned_vm -= num_pages;
 154                 up_write(&current->mm->mmap_sem);
 155         }
 156 }