drivers/infiniband/sw/rxe/rxe_mmap.c

   1 // SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
   2 /*
   3  * Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
   4  * Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
   5  */
   6
   7 #include <linux/module.h>
   8 #include <linux/vmalloc.h>
   9 #include <linux/mm.h>
  10 #include <linux/errno.h>
  11 #include <rdma/uverbs_ioctl.h>
  12
  13 #include "rxe.h"
  14 #include "rxe_loc.h"
  15 #include "rxe_queue.h"
  16
  17 void rxe_mmap_release(struct kref *ref)
  18 {
  19         struct rxe_mmap_info *ip = container_of(ref,
  20                                         struct rxe_mmap_info, ref);
  21         struct rxe_dev *rxe = to_rdev(ip->context->device);
  22
  23         spin_lock_bh(&rxe->pending_lock);
  24
  25         if (!list_empty(&ip->pending_mmaps))
  26                 list_del(&ip->pending_mmaps);
  27
  28         spin_unlock_bh(&rxe->pending_lock);
  29
  30         vfree(ip->obj);         /* buf */
  31         kfree(ip);
  32 }
  33
  34 /*
  35  * open and close keep track of how many times the memory region is mapped,
  36  * to avoid releasing it.
  37  */
  38 static void rxe_vma_open(struct vm_area_struct *vma)
  39 {
  40         struct rxe_mmap_info *ip = vma->vm_private_data;
  41
  42         kref_get(&ip->ref);
  43 }
  44
  45 static void rxe_vma_close(struct vm_area_struct *vma)
  46 {
  47         struct rxe_mmap_info *ip = vma->vm_private_data;
  48
  49         kref_put(&ip->ref, rxe_mmap_release);
  50 }
  51
  52 static const struct vm_operations_struct rxe_vm_ops = {
  53         .open = rxe_vma_open,
  54         .close = rxe_vma_close,
  55 };
  56
  57 /**
  58  * rxe_mmap - create a new mmap region
  59  * @context: the IB user context of the process making the mmap() call
  60  * @vma: the VMA to be initialized
  61  * Return zero if the mmap is OK. Otherwise, return an errno.
  62  */
  63 int rxe_mmap(struct ib_ucontext *context, struct vm_area_struct *vma)
  64 {
  65         struct rxe_dev *rxe = to_rdev(context->device);
  66         unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
  67         unsigned long size = vma->vm_end - vma->vm_start;
  68         struct rxe_mmap_info *ip, *pp;
  69         int ret;
  70
  71         /*
  72          * Search the device's list of objects waiting for a mmap call.
  73          * Normally, this list is very short since a call to create a
  74          * CQ, QP, or SRQ is soon followed by a call to mmap().
  75          */
  76         spin_lock_bh(&rxe->pending_lock);
  77         list_for_each_entry_safe(ip, pp, &rxe->pending_mmaps, pending_mmaps) {
  78                 if (context != ip->context || (__u64)offset != ip->info.offset)
  79                         continue;
  80
  81                 /* Don't allow a mmap larger than the object. */
  82                 if (size > ip->info.size) {
  83                         pr_err("mmap region is larger than the object!\n");
  84                         spin_unlock_bh(&rxe->pending_lock);
  85                         ret = -EINVAL;
  86                         goto done;
  87                 }
  88
  89                 goto found_it;
  90         }
  91         pr_warn("unable to find pending mmap info\n");
  92         spin_unlock_bh(&rxe->pending_lock);
  93         ret = -EINVAL;
  94         goto done;
  95
  96 found_it:
  97         list_del_init(&ip->pending_mmaps);
  98         spin_unlock_bh(&rxe->pending_lock);
  99
 100         ret = remap_vmalloc_range(vma, ip->obj, 0);
 101         if (ret) {
 102                 pr_err("err %d from remap_vmalloc_range\n", ret);
 103                 goto done;
 104         }
 105
 106         vma->vm_ops = &rxe_vm_ops;
 107         vma->vm_private_data = ip;
 108         rxe_vma_open(vma);
 109 done:
 110         return ret;
 111 }
 112
 113 /*
 114  * Allocate information for rxe_mmap
 115  */
 116 struct rxe_mmap_info *rxe_create_mmap_info(struct rxe_dev *rxe, u32 size,
 117                                            struct ib_udata *udata, void *obj)
 118 {
 119         struct rxe_mmap_info *ip;
 120
 121         if (!udata)
 122                 return ERR_PTR(-EINVAL);
 123
 124         ip = kmalloc(sizeof(*ip), GFP_KERNEL);
 125         if (!ip)
 126                 return ERR_PTR(-ENOMEM);
 127
 128         size = PAGE_ALIGN(size);
 129
 130         spin_lock_bh(&rxe->mmap_offset_lock);
 131
 132         if (rxe->mmap_offset == 0)
 133                 rxe->mmap_offset = ALIGN(PAGE_SIZE, SHMLBA);
 134
 135         ip->info.offset = rxe->mmap_offset;
 136         rxe->mmap_offset += ALIGN(size, SHMLBA);
 137
 138         spin_unlock_bh(&rxe->mmap_offset_lock);
 139
 140         INIT_LIST_HEAD(&ip->pending_mmaps);
 141         ip->info.size = size;
 142         ip->context =
 143                 container_of(udata, struct uverbs_attr_bundle, driver_udata)
 144                         ->context;
 145         ip->obj = obj;
 146         kref_init(&ip->ref);
 147
 148         return ip;
 149 }