drivers/infiniband/hw/qib/qib_mmap.c

   1 /*
   2  * Copyright (c) 2006, 2007, 2008, 2009 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/slab.h>
  35 #include <linux/vmalloc.h>
  36 #include <linux/mm.h>
  37 #include <linux/errno.h>
  38 #include <asm/pgtable.h>
  39
  40 #include "qib_verbs.h"
  41
  42 /**
  43  * qib_release_mmap_info - free mmap info structure
  44  * @ref: a pointer to the kref within struct qib_mmap_info
  45  */
  46 void qib_release_mmap_info(struct kref *ref)
  47 {
  48         struct qib_mmap_info *ip =
  49                 container_of(ref, struct qib_mmap_info, ref);
  50         struct qib_ibdev *dev = to_idev(ip->context->device);
  51
  52         spin_lock_irq(&dev->pending_lock);
  53         list_del(&ip->pending_mmaps);
  54         spin_unlock_irq(&dev->pending_lock);
  55
  56         vfree(ip->obj);
  57         kfree(ip);
  58 }
  59
  60 /*
  61  * open and close keep track of how many times the CQ is mapped,
  62  * to avoid releasing it.
  63  */
  64 static void qib_vma_open(struct vm_area_struct *vma)
  65 {
  66         struct qib_mmap_info *ip = vma->vm_private_data;
  67
  68         kref_get(&ip->ref);
  69 }
  70
  71 static void qib_vma_close(struct vm_area_struct *vma)
  72 {
  73         struct qib_mmap_info *ip = vma->vm_private_data;
  74
  75         kref_put(&ip->ref, qib_release_mmap_info);
  76 }
  77
  78 static struct vm_operations_struct qib_vm_ops = {
  79         .open =     qib_vma_open,
  80         .close =    qib_vma_close,
  81 };
  82
  83 /**
  84  * qib_mmap - create a new mmap region
  85  * @context: the IB user context of the process making the mmap() call
  86  * @vma: the VMA to be initialized
  87  * Return zero if the mmap is OK. Otherwise, return an errno.
  88  */
  89 int qib_mmap(struct ib_ucontext *context, struct vm_area_struct *vma)
  90 {
  91         struct qib_ibdev *dev = to_idev(context->device);
  92         unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
  93         unsigned long size = vma->vm_end - vma->vm_start;
  94         struct qib_mmap_info *ip, *pp;
  95         int ret = -EINVAL;
  96
  97         /*
  98          * Search the device's list of objects waiting for a mmap call.
  99          * Normally, this list is very short since a call to create a
 100          * CQ, QP, or SRQ is soon followed by a call to mmap().
 101          */
 102         spin_lock_irq(&dev->pending_lock);
 103         list_for_each_entry_safe(ip, pp, &dev->pending_mmaps,
 104                                  pending_mmaps) {
 105                 /* Only the creator is allowed to mmap the object */
 106                 if (context != ip->context || (__u64) offset != ip->offset)
 107                         continue;
 108                 /* Don't allow a mmap larger than the object. */
 109                 if (size > ip->size)
 110                         break;
 111
 112                 list_del_init(&ip->pending_mmaps);
 113                 spin_unlock_irq(&dev->pending_lock);
 114
 115                 ret = remap_vmalloc_range(vma, ip->obj, 0);
 116                 if (ret)
 117                         goto done;
 118                 vma->vm_ops = &qib_vm_ops;
 119                 vma->vm_private_data = ip;
 120                 qib_vma_open(vma);
 121                 goto done;
 122         }
 123         spin_unlock_irq(&dev->pending_lock);
 124 done:
 125         return ret;
 126 }
 127
 128 /*
 129  * Allocate information for qib_mmap
 130  */
 131 struct qib_mmap_info *qib_create_mmap_info(struct qib_ibdev *dev,
 132                                            u32 size,
 133                                            struct ib_ucontext *context,
 134                                            void *obj) {
 135         struct qib_mmap_info *ip;
 136
 137         ip = kmalloc(sizeof *ip, GFP_KERNEL);
 138         if (!ip)
 139                 goto bail;
 140
 141         size = PAGE_ALIGN(size);
 142
 143         spin_lock_irq(&dev->mmap_offset_lock);
 144         if (dev->mmap_offset == 0)
 145                 dev->mmap_offset = PAGE_SIZE;
 146         ip->offset = dev->mmap_offset;
 147         dev->mmap_offset += size;
 148         spin_unlock_irq(&dev->mmap_offset_lock);
 149
 150         INIT_LIST_HEAD(&ip->pending_mmaps);
 151         ip->size = size;
 152         ip->context = context;
 153         ip->obj = obj;
 154         kref_init(&ip->ref);
 155
 156 bail:
 157         return ip;
 158 }
 159
 160 void qib_update_mmap_info(struct qib_ibdev *dev, struct qib_mmap_info *ip,
 161                           u32 size, void *obj)
 162 {
 163         size = PAGE_ALIGN(size);
 164
 165         spin_lock_irq(&dev->mmap_offset_lock);
 166         if (dev->mmap_offset == 0)
 167                 dev->mmap_offset = PAGE_SIZE;
 168         ip->offset = dev->mmap_offset;
 169         dev->mmap_offset += size;
 170         spin_unlock_irq(&dev->mmap_offset_lock);
 171
 172         ip->size = size;
 173         ip->obj = obj;
 174 }