drivers/staging/rdma/hfi1/mmu_rb.c

   1 /*
   2  * Copyright(c) 2016 Intel Corporation.
   3  *
   4  * This file is provided under a dual BSD/GPLv2 license.  When using or
   5  * redistributing this file, you may do so under either license.
   6  *
   7  * GPL LICENSE SUMMARY
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of version 2 of the GNU General Public License as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * General Public License for more details.
  17  *
  18  * BSD LICENSE
  19  *
  20  * Redistribution and use in source and binary forms, with or without
  21  * modification, are permitted provided that the following conditions
  22  * are met:
  23  *
  24  *  - Redistributions of source code must retain the above copyright
  25  *    notice, this list of conditions and the following disclaimer.
  26  *  - Redistributions in binary form must reproduce the above copyright
  27  *    notice, this list of conditions and the following disclaimer in
  28  *    the documentation and/or other materials provided with the
  29  *    distribution.
  30  *  - Neither the name of Intel Corporation nor the names of its
  31  *    contributors may be used to endorse or promote products derived
  32  *    from this software without specific prior written permission.
  33  *
  34  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  35  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  36  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  37  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  38  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  39  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  40  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  41  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  42  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  43  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  44  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  45  *
  46  */
  47 #include <linux/list.h>
  48 #include <linux/mmu_notifier.h>
  49 #include <linux/interval_tree_generic.h>
  50
  51 #include "mmu_rb.h"
  52 #include "trace.h"
  53
  54 struct mmu_rb_handler {
  55         struct list_head list;
  56         struct mmu_notifier mn;
  57         struct rb_root *root;
  58         spinlock_t lock;        /* protect the RB tree */
  59         struct mmu_rb_ops *ops;
  60 };
  61
  62 static LIST_HEAD(mmu_rb_handlers);
  63 static DEFINE_SPINLOCK(mmu_rb_lock); /* protect mmu_rb_handlers list */
  64
  65 static unsigned long mmu_node_start(struct mmu_rb_node *);
  66 static unsigned long mmu_node_last(struct mmu_rb_node *);
  67 static struct mmu_rb_handler *find_mmu_handler(struct rb_root *);
  68 static inline void mmu_notifier_page(struct mmu_notifier *, struct mm_struct *,
  69                                      unsigned long);
  70 static inline void mmu_notifier_range_start(struct mmu_notifier *,
  71                                             struct mm_struct *,
  72                                             unsigned long, unsigned long);
  73 static void mmu_notifier_mem_invalidate(struct mmu_notifier *,
  74                                         unsigned long, unsigned long);
  75 static struct mmu_rb_node *__mmu_rb_search(struct mmu_rb_handler *,
  76                                            unsigned long, unsigned long);
  77
  78 static struct mmu_notifier_ops mn_opts = {
  79         .invalidate_page = mmu_notifier_page,
  80         .invalidate_range_start = mmu_notifier_range_start,
  81 };
  82
  83 INTERVAL_TREE_DEFINE(struct mmu_rb_node, node, unsigned long, __last,
  84                      mmu_node_start, mmu_node_last, static, __mmu_int_rb);
  85
  86 static unsigned long mmu_node_start(struct mmu_rb_node *node)
  87 {
  88         return node->addr & PAGE_MASK;
  89 }
  90
  91 static unsigned long mmu_node_last(struct mmu_rb_node *node)
  92 {
  93         return PAGE_ALIGN((node->addr & PAGE_MASK) + node->len) - 1;
  94 }
  95
  96 int hfi1_mmu_rb_register(struct rb_root *root, struct mmu_rb_ops *ops)
  97 {
  98         struct mmu_rb_handler *handlr;
  99         unsigned long flags;
 100
 101         if (!ops->invalidate)
 102                 return -EINVAL;
 103
 104         handlr = kmalloc(sizeof(*handlr), GFP_KERNEL);
 105         if (!handlr)
 106                 return -ENOMEM;
 107
 108         handlr->root = root;
 109         handlr->ops = ops;
 110         INIT_HLIST_NODE(&handlr->mn.hlist);
 111         spin_lock_init(&handlr->lock);
 112         handlr->mn.ops = &mn_opts;
 113         spin_lock_irqsave(&mmu_rb_lock, flags);
 114         list_add_tail(&handlr->list, &mmu_rb_handlers);
 115         spin_unlock_irqrestore(&mmu_rb_lock, flags);
 116
 117         return mmu_notifier_register(&handlr->mn, current->mm);
 118 }
 119
 120 void hfi1_mmu_rb_unregister(struct rb_root *root)
 121 {
 122         struct mmu_rb_handler *handler = find_mmu_handler(root);
 123         unsigned long flags;
 124
 125         if (!handler)
 126                 return;
 127
 128         spin_lock_irqsave(&mmu_rb_lock, flags);
 129         list_del(&handler->list);
 130         spin_unlock_irqrestore(&mmu_rb_lock, flags);
 131
 132         if (!RB_EMPTY_ROOT(root)) {
 133                 struct rb_node *node;
 134                 struct mmu_rb_node *rbnode;
 135
 136                 while ((node = rb_first(root))) {
 137                         rbnode = rb_entry(node, struct mmu_rb_node, node);
 138                         rb_erase(node, root);
 139                         if (handler->ops->remove)
 140                                 handler->ops->remove(root, rbnode, false);
 141                 }
 142         }
 143
 144         if (current->mm)
 145                 mmu_notifier_unregister(&handler->mn, current->mm);
 146         kfree(handler);
 147 }
 148
 149 int hfi1_mmu_rb_insert(struct rb_root *root, struct mmu_rb_node *mnode)
 150 {
 151         struct mmu_rb_handler *handler = find_mmu_handler(root);
 152         struct mmu_rb_node *node;
 153         unsigned long flags;
 154         int ret = 0;
 155
 156         if (!handler)
 157                 return -EINVAL;
 158
 159         spin_lock_irqsave(&handler->lock, flags);
 160         hfi1_cdbg(MMU, "Inserting node addr 0x%llx, len %u", mnode->addr,
 161                   mnode->len);
 162         node = __mmu_rb_search(handler, mnode->addr, mnode->len);
 163         if (node) {
 164                 ret = -EINVAL;
 165                 goto unlock;
 166         }
 167         __mmu_int_rb_insert(mnode, root);
 168
 169         if (handler->ops->insert) {
 170                 ret = handler->ops->insert(root, mnode);
 171                 if (ret)
 172                         __mmu_int_rb_remove(mnode, root);
 173         }
 174 unlock:
 175         spin_unlock_irqrestore(&handler->lock, flags);
 176         return ret;
 177 }
 178
 179 /* Caller must host handler lock */
 180 static struct mmu_rb_node *__mmu_rb_search(struct mmu_rb_handler *handler,
 181                                            unsigned long addr,
 182                                            unsigned long len)
 183 {
 184         struct mmu_rb_node *node = NULL;
 185
 186         hfi1_cdbg(MMU, "Searching for addr 0x%llx, len %u", addr, len);
 187         if (!handler->ops->filter) {
 188                 node = __mmu_int_rb_iter_first(handler->root, addr,
 189                                                (addr + len) - 1);
 190         } else {
 191                 for (node = __mmu_int_rb_iter_first(handler->root, addr,
 192                                                     (addr + len) - 1);
 193                      node;
 194                      node = __mmu_int_rb_iter_next(node, addr,
 195                                                    (addr + len) - 1)) {
 196                         if (handler->ops->filter(node, addr, len))
 197                                 return node;
 198                 }
 199         }
 200         return node;
 201 }
 202
 203 static void __mmu_rb_remove(struct mmu_rb_handler *handler,
 204                             struct mmu_rb_node *node, bool arg)
 205 {
 206         /* Validity of handler and node pointers has been checked by caller. */
 207         hfi1_cdbg(MMU, "Removing node addr 0x%llx, len %u", node->addr,
 208                   node->len);
 209         __mmu_int_rb_remove(node, handler->root);
 210         if (handler->ops->remove)
 211                 handler->ops->remove(handler->root, node, arg);
 212 }
 213
 214 struct mmu_rb_node *hfi1_mmu_rb_search(struct rb_root *root, unsigned long addr,
 215                                        unsigned long len)
 216 {
 217         struct mmu_rb_handler *handler = find_mmu_handler(root);
 218         struct mmu_rb_node *node;
 219         unsigned long flags;
 220
 221         if (!handler)
 222                 return ERR_PTR(-EINVAL);
 223
 224         spin_lock_irqsave(&handler->lock, flags);
 225         node = __mmu_rb_search(handler, addr, len);
 226         spin_unlock_irqrestore(&handler->lock, flags);
 227
 228         return node;
 229 }
 230
 231 void hfi1_mmu_rb_remove(struct rb_root *root, struct mmu_rb_node *node)
 232 {
 233         struct mmu_rb_handler *handler = find_mmu_handler(root);
 234         unsigned long flags;
 235
 236         if (!handler || !node)
 237                 return;
 238
 239         spin_lock_irqsave(&handler->lock, flags);
 240         __mmu_rb_remove(handler, node, false);
 241         spin_unlock_irqrestore(&handler->lock, flags);
 242 }
 243
 244 static struct mmu_rb_handler *find_mmu_handler(struct rb_root *root)
 245 {
 246         struct mmu_rb_handler *handler;
 247         unsigned long flags;
 248
 249         spin_lock_irqsave(&mmu_rb_lock, flags);
 250         list_for_each_entry(handler, &mmu_rb_handlers, list) {
 251                 if (handler->root == root)
 252                         goto unlock;
 253         }
 254         handler = NULL;
 255 unlock:
 256         spin_unlock_irqrestore(&mmu_rb_lock, flags);
 257         return handler;
 258 }
 259
 260 static inline void mmu_notifier_page(struct mmu_notifier *mn,
 261                                      struct mm_struct *mm, unsigned long addr)
 262 {
 263         mmu_notifier_mem_invalidate(mn, addr, addr + PAGE_SIZE);
 264 }
 265
 266 static inline void mmu_notifier_range_start(struct mmu_notifier *mn,
 267                                             struct mm_struct *mm,
 268                                             unsigned long start,
 269                                             unsigned long end)
 270 {
 271         mmu_notifier_mem_invalidate(mn, start, end);
 272 }
 273
 274 static void mmu_notifier_mem_invalidate(struct mmu_notifier *mn,
 275                                         unsigned long start, unsigned long end)
 276 {
 277         struct mmu_rb_handler *handler =
 278                 container_of(mn, struct mmu_rb_handler, mn);
 279         struct rb_root *root = handler->root;
 280         struct mmu_rb_node *node;
 281         unsigned long flags;
 282
 283         spin_lock_irqsave(&handler->lock, flags);
 284         for (node = __mmu_int_rb_iter_first(root, start, end - 1); node;
 285              node = __mmu_int_rb_iter_next(node, start, end - 1)) {
 286                 hfi1_cdbg(MMU, "Invalidating node addr 0x%llx, len %u",
 287                           node->addr, node->len);
 288                 if (handler->ops->invalidate(root, node))
 289                         __mmu_rb_remove(handler, node, true);
 290         }
 291         spin_unlock_irqrestore(&handler->lock, flags);
 292 }