drivers/infiniband/hw/ipath/ipath_mmap.c

   1 /*
   2  * Copyright (c) 2006 QLogic, Inc. 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/config.h>
  34 #include <linux/module.h>
  35 #include <linux/vmalloc.h>
  36 #include <linux/mm.h>
  37 #include <linux/errno.h>
  38 #include <asm/pgtable.h>
  39
  40 #include "ipath_verbs.h"
  41
  42 /**
  43  * ipath_release_mmap_info - free mmap info structure
  44  * @ref: a pointer to the kref within struct ipath_mmap_info
  45  */
  46 void ipath_release_mmap_info(struct kref *ref)
  47 {
  48         struct ipath_mmap_info *ip =
  49                 container_of(ref, struct ipath_mmap_info, ref);
  50
  51         vfree(ip->obj);
  52         kfree(ip);
  53 }
  54
  55 /*
  56  * open and close keep track of how many times the CQ is mapped,
  57  * to avoid releasing it.
  58  */
  59 static void ipath_vma_open(struct vm_area_struct *vma)
  60 {
  61         struct ipath_mmap_info *ip = vma->vm_private_data;
  62
  63         kref_get(&ip->ref);
  64         ip->mmap_cnt++;
  65 }
  66
  67 static void ipath_vma_close(struct vm_area_struct *vma)
  68 {
  69         struct ipath_mmap_info *ip = vma->vm_private_data;
  70
  71         ip->mmap_cnt--;
  72         kref_put(&ip->ref, ipath_release_mmap_info);
  73 }
  74
  75 static struct vm_operations_struct ipath_vm_ops = {
  76         .open =     ipath_vma_open,
  77         .close =    ipath_vma_close,
  78 };
  79
  80 /**
  81  * ipath_mmap - create a new mmap region
  82  * @context: the IB user context of the process making the mmap() call
  83  * @vma: the VMA to be initialized
  84  * Return zero if the mmap is OK. Otherwise, return an errno.
  85  */
  86 int ipath_mmap(struct ib_ucontext *context, struct vm_area_struct *vma)
  87 {
  88         struct ipath_ibdev *dev = to_idev(context->device);
  89         unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
  90         unsigned long size = vma->vm_end - vma->vm_start;
  91         struct ipath_mmap_info *ip, **pp;
  92         int ret = -EINVAL;
  93
  94         /*
  95          * Search the device's list of objects waiting for a mmap call.
  96          * Normally, this list is very short since a call to create a
  97          * CQ, QP, or SRQ is soon followed by a call to mmap().
  98          */
  99         spin_lock_irq(&dev->pending_lock);
 100         for (pp = &dev->pending_mmaps; (ip = *pp); pp = &ip->next) {
 101                 /* Only the creator is allowed to mmap the object */
 102                 if (context != ip->context || (void *) offset != ip->obj)
 103                         continue;
 104                 /* Don't allow a mmap larger than the object. */
 105                 if (size > ip->size)
 106                         break;
 107
 108                 *pp = ip->next;
 109                 spin_unlock_irq(&dev->pending_lock);
 110
 111                 ret = remap_vmalloc_range(vma, ip->obj, 0);
 112                 if (ret)
 113                         goto done;
 114                 vma->vm_ops = &ipath_vm_ops;
 115                 vma->vm_private_data = ip;
 116                 ipath_vma_open(vma);
 117                 goto done;
 118         }
 119         spin_unlock_irq(&dev->pending_lock);
 120 done:
 121         return ret;
 122 }