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         unpin_user_pages_dirty_lock(p, num_pages, dirty);
  44 }
  45
  46 /**
  47  * qib_map_page - a safety wrapper around pci_map_page()
  48  *
  49  * A dma_addr of all 0's is interpreted by the chip as "disabled".
  50  * Unfortunately, it can also be a valid dma_addr returned on some
  51  * architectures.
  52  *
  53  * The powerpc iommu assigns dma_addrs in ascending order, so we don't
  54  * have to bother with retries or mapping a dummy page to insure we
  55  * don't just get the same mapping again.
  56  *
  57  * I'm sure we won't be so lucky with other iommu's, so FIXME.
  58  */
  59 int qib_map_page(struct pci_dev *hwdev, struct page *page, dma_addr_t *daddr)
  60 {
  61         dma_addr_t phys;
  62
  63         phys = pci_map_page(hwdev, page, 0, PAGE_SIZE, PCI_DMA_FROMDEVICE);
  64         if (pci_dma_mapping_error(hwdev, phys))
  65                 return -ENOMEM;
  66
  67         if (!phys) {
  68                 pci_unmap_page(hwdev, phys, PAGE_SIZE, PCI_DMA_FROMDEVICE);
  69                 phys = pci_map_page(hwdev, page, 0, PAGE_SIZE,
  70                                     PCI_DMA_FROMDEVICE);
  71                 if (pci_dma_mapping_error(hwdev, phys))
  72                         return -ENOMEM;
  73                 /*
  74                  * FIXME: If we get 0 again, we should keep this page,
  75                  * map another, then free the 0 page.
  76                  */
  77         }
  78         *daddr = phys;
  79         return 0;
  80 }
  81
  82 /**
  83  * qib_get_user_pages - lock user pages into memory
  84  * @start_page: the start page
  85  * @num_pages: the number of pages
  86  * @p: the output page structures
  87  *
  88  * This function takes a given start page (page aligned user virtual
  89  * address) and pins it and the following specified number of pages.  For
  90  * now, num_pages is always 1, but that will probably change at some point
  91  * (because caller is doing expected sends on a single virtually contiguous
  92  * buffer, so we can do all pages at once).
  93  */
  94 int qib_get_user_pages(unsigned long start_page, size_t num_pages,
  95                        struct page **p)
  96 {
  97         unsigned long locked, lock_limit;
  98         size_t got;
  99         int ret;
 100
 101         lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
 102         locked = atomic64_add_return(num_pages, &current->mm->pinned_vm);
 103
 104         if (locked > lock_limit && !capable(CAP_IPC_LOCK)) {
 105                 ret = -ENOMEM;
 106                 goto bail;
 107         }
 108
 109         down_read(&current->mm->mmap_sem);
 110         for (got = 0; got < num_pages; got += ret) {
 111                 ret = pin_user_pages(start_page + got * PAGE_SIZE,
 112                                      num_pages - got,
 113                                      FOLL_LONGTERM | FOLL_WRITE | FOLL_FORCE,
 114                                      p + got, NULL);
 115                 if (ret < 0) {
 116                         up_read(&current->mm->mmap_sem);
 117                         goto bail_release;
 118                 }
 119         }
 120         up_read(&current->mm->mmap_sem);
 121
 122         return 0;
 123 bail_release:
 124         __qib_release_user_pages(p, got, 0);
 125 bail:
 126         atomic64_sub(num_pages, &current->mm->pinned_vm);
 127         return ret;
 128 }
 129
 130 void qib_release_user_pages(struct page **p, size_t num_pages)
 131 {
 132         __qib_release_user_pages(p, num_pages, 1);
 133
 134         /* during close after signal, mm can be NULL */
 135         if (current->mm)
 136                 atomic64_sub(num_pages, &current->mm->pinned_vm);
 137 }