drivers/infiniband/hw/ipath/ipath_mmap.c

   1 /*
   2  * Copyright (c) 2006, 2007 QLogic Corporation. All rights reserved.
   3  *
   4  * This software is available to you under a choice of one of two
   5  * licenses.  You may choose to be licensed under the terms of the GNU
   6  * General Public License (GPL) Version 2, available from the file
   7  * COPYING in the main directory of this source tree, or the
   8  * OpenIB.org BSD license below:
   9  *
  10  *     Redistribution and use in source and binary forms, with or
  11  *     without modification, are permitted provided that the following
  12  *     conditions are met:
  13  *
  14  *      - Redistributions of source code must retain the above
  15  *        copyright notice, this list of conditions and the following
  16  *        disclaimer.
  17  *
  18  *      - Redistributions in binary form must reproduce the above
  19  *        copyright notice, this list of conditions and the following
  20  *        disclaimer in the documentation and/or other materials
  21  *        provided with the distribution.
  22  *
  23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  30  * SOFTWARE.
  31  */
  32
  33 #include <linux/module.h>
  34 #include <linux/vmalloc.h>
  35 #include <linux/mm.h>
  36 #include <linux/errno.h>
  37 #include <asm/pgtable.h>
  38
  39 #include "ipath_verbs.h"
  40
  41 /**
  42  * ipath_release_mmap_info - free mmap info structure
  43  * @ref: a pointer to the kref within struct ipath_mmap_info
  44  */
  45 void ipath_release_mmap_info(struct kref *ref)
  46 {
  47         struct ipath_mmap_info *ip =
  48                 container_of(ref, struct ipath_mmap_info, ref);
  49         struct ipath_ibdev *dev = to_idev(ip->context->device);
  50
  51         spin_lock_irq(&dev->pending_lock);
  52         list_del(&ip->pending_mmaps);
  53         spin_unlock_irq(&dev->pending_lock);
  54
  55         vfree(ip->obj);
  56         kfree(ip);
  57 }
  58
  59 /*
  60  * open and close keep track of how many times the CQ is mapped,
  61  * to avoid releasing it.
  62  */
  63 static void ipath_vma_open(struct vm_area_struct *vma)
  64 {
  65         struct ipath_mmap_info *ip = vma->vm_private_data;
  66
  67         kref_get(&ip->ref);
  68 }
  69
  70 static void ipath_vma_close(struct vm_area_struct *vma)
  71 {
  72         struct ipath_mmap_info *ip = vma->vm_private_data;
  73
  74         kref_put(&ip->ref, ipath_release_mmap_info);
  75 }
  76
  77 static const struct vm_operations_struct ipath_vm_ops = {
  78         .open =     ipath_vma_open,
  79         .close =    ipath_vma_close,
  80 };
  81
  82 /**
  83  * ipath_mmap - create a new mmap region
  84  * @context: the IB user context of the process making the mmap() call
  85  * @vma: the VMA to be initialized
  86  * Return zero if the mmap is OK. Otherwise, return an errno.
  87  */
  88 int ipath_mmap(struct ib_ucontext *context, struct vm_area_struct *vma)
  89 {
  90         struct ipath_ibdev *dev = to_idev(context->device);
  91         unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
  92         unsigned long size = vma->vm_end - vma->vm_start;
  93         struct ipath_mmap_info *ip, *pp;
  94         int ret = -EINVAL;
  95
  96         /*
  97          * Search the device's list of objects waiting for a mmap call.
  98          * Normally, this list is very short since a call to create a
  99          * CQ, QP, or SRQ is soon followed by a call to mmap().
 100          */
 101         spin_lock_irq(&dev->pending_lock);
 102         list_for_each_entry_safe(ip, pp, &dev->pending_mmaps,
 103                                  pending_mmaps) {
 104                 /* Only the creator is allowed to mmap the object */
 105                 if (context != ip->context || (__u64) offset != ip->offset)
 106                         continue;
 107                 /* Don't allow a mmap larger than the object. */
 108                 if (size > ip->size)
 109                         break;
 110
 111                 list_del_init(&ip->pending_mmaps);
 112                 spin_unlock_irq(&dev->pending_lock);
 113
 114                 ret = remap_vmalloc_range(vma, ip->obj, 0);
 115                 if (ret)
 116                         goto done;
 117                 vma->vm_ops = &ipath_vm_ops;
 118                 vma->vm_private_data = ip;
 119                 ipath_vma_open(vma);
 120                 goto done;
 121         }
 122         spin_unlock_irq(&dev->pending_lock);
 123 done:
 124         return ret;
 125 }
 126
 127 /*
 128  * Allocate information for ipath_mmap
 129  */
 130 struct ipath_mmap_info *ipath_create_mmap_info(struct ipath_ibdev *dev,
 131                                                u32 size,
 132                                                struct ib_ucontext *context,
 133                                                void *obj) {
 134         struct ipath_mmap_info *ip;
 135
 136         ip = kmalloc(sizeof *ip, GFP_KERNEL);
 137         if (!ip)
 138                 goto bail;
 139
 140         size = PAGE_ALIGN(size);
 141
 142         spin_lock_irq(&dev->mmap_offset_lock);
 143         if (dev->mmap_offset == 0)
 144                 dev->mmap_offset = PAGE_SIZE;
 145         ip->offset = dev->mmap_offset;
 146         dev->mmap_offset += size;
 147         spin_unlock_irq(&dev->mmap_offset_lock);
 148
 149         INIT_LIST_HEAD(&ip->pending_mmaps);
 150         ip->size = size;
 151         ip->context = context;
 152         ip->obj = obj;
 153         kref_init(&ip->ref);
 154
 155 bail:
 156         return ip;
 157 }
 158
 159 void ipath_update_mmap_info(struct ipath_ibdev *dev,
 160                             struct ipath_mmap_info *ip,
 161                             u32 size, void *obj) {
 162         size = PAGE_ALIGN(size);
 163
 164         spin_lock_irq(&dev->mmap_offset_lock);
 165         if (dev->mmap_offset == 0)
 166                 dev->mmap_offset = PAGE_SIZE;
 167         ip->offset = dev->mmap_offset;
 168         dev->mmap_offset += size;
 169         spin_unlock_irq(&dev->mmap_offset_lock);
 170
 171         ip->size = size;
 172         ip->obj = obj;
 173 }