LXR linux/drivers/infiniband/hw/qib/qib_user

   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
  40static 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 */
  59int qib_map_page(struct pci_dev *hwdev, struct page *page, dma_addr_t *daddr)
  60{
  61        dma_addr_t phys;
  62
  63        phys = dma_map_page(&hwdev->dev, page, 0, PAGE_SIZE, DMA_FROM_DEVICE);
  64        if (dma_mapping_error(&hwdev->dev, phys))
  65                return -ENOMEM;
  66
  67        if (!phys) {
  68                dma_unmap_page(&hwdev->dev, phys, PAGE_SIZE, DMA_FROM_DEVICE);
  69                phys = dma_map_page(&hwdev->dev, page, 0, PAGE_SIZE,
  70                                    DMA_FROM_DEVICE);
  71                if (dma_mapping_error(&hwdev->dev, 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 */
  94int 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        mmap_read_lock(current->mm);
 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                        mmap_read_unlock(current->mm);
 117                        goto bail_release;
 118                }
 119        }
 120        mmap_read_unlock(current->mm);
 121
 122        return 0;
 123bail_release:
 124        __qib_release_user_pages(p, got, 0);
 125bail:
 126        atomic64_sub(num_pages, &current->mm->pinned_vm);
 127        return ret;
 128}
 129
 130void 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}
 138