release/src-rt-6.x.4708/linux/linux-2.6.36/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 __get_user_pages(unsigned long start_page, size_t num_pages,
  55                             struct page **p, struct vm_area_struct **vma)
  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(current, current->mm,
  70                                      start_page + got * PAGE_SIZE,
  71                                      num_pages - got, 1, 1,
  72                                      p + got, vma);
  73                 if (ret < 0)
  74                         goto bail_release;
  75         }
  76
  77         current->mm->locked_vm += num_pages;
  78
  79         ret = 0;
  80         goto bail;
  81
  82 bail_release:
  83         __qib_release_user_pages(p, got, 0);
  84 bail:
  85         return ret;
  86 }
  87
  88 dma_addr_t qib_map_page(struct pci_dev *hwdev, struct page *page,
  89                         unsigned long offset, size_t size, int direction)
  90 {
  91         dma_addr_t phys;
  92
  93         phys = pci_map_page(hwdev, page, offset, size, direction);
  94
  95         if (phys == 0) {
  96                 pci_unmap_page(hwdev, phys, size, direction);
  97                 phys = pci_map_page(hwdev, page, offset, size, direction);
  98         }
  99
 100         return phys;
 101 }
 102
 103 /**
 104  * qib_get_user_pages - lock user pages into memory
 105  * @start_page: the start page
 106  * @num_pages: the number of pages
 107  * @p: the output page structures
 108  *
 109  * This function takes a given start page (page aligned user virtual
 110  * address) and pins it and the following specified number of pages.  For
 111  * now, num_pages is always 1, but that will probably change at some point
 112  * (because caller is doing expected sends on a single virtually contiguous
 113  * buffer, so we can do all pages at once).
 114  */
 115 int qib_get_user_pages(unsigned long start_page, size_t num_pages,
 116                        struct page **p)
 117 {
 118         int ret;
 119
 120         down_write(&current->mm->mmap_sem);
 121
 122         ret = __get_user_pages(start_page, num_pages, p, NULL);
 123
 124         up_write(&current->mm->mmap_sem);
 125
 126         return ret;
 127 }
 128
 129 void qib_release_user_pages(struct page **p, size_t num_pages)
 130 {
 131         if (current->mm) /* during close after signal, mm can be NULL */
 132                 down_write(&current->mm->mmap_sem);
 133
 134         __qib_release_user_pages(p, num_pages, 1);
 135
 136         if (current->mm) {
 137                 current->mm->locked_vm -= num_pages;
 138                 up_write(&current->mm->mmap_sem);
 139         }
 140 }