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                                         struct mm_struct *,
  75                                         unsigned long, unsigned long);
  76 static struct mmu_rb_node *__mmu_rb_search(struct mmu_rb_handler *,
  77                                            unsigned long, unsigned long);
  78
  79 static struct mmu_notifier_ops mn_opts = {
  80         .invalidate_page = mmu_notifier_page,
  81         .invalidate_range_start = mmu_notifier_range_start,
  82 };
  83
  84 INTERVAL_TREE_DEFINE(struct mmu_rb_node, node, unsigned long, __last,
  85                      mmu_node_start, mmu_node_last, static, __mmu_int_rb);
  86
  87 static unsigned long mmu_node_start(struct mmu_rb_node *node)
  88 {
  89         return node->addr & PAGE_MASK;
  90 }
  91
  92 static unsigned long mmu_node_last(struct mmu_rb_node *node)
  93 {
  94         return PAGE_ALIGN((node->addr & PAGE_MASK) + node->len) - 1;
  95 }
  96
  97 int hfi1_mmu_rb_register(struct rb_root *root, struct mmu_rb_ops *ops)
  98 {
  99         struct mmu_rb_handler *handlr;
 100         unsigned long flags;
 101
 102         if (!ops->invalidate)
 103                 return -EINVAL;
 104
 105         handlr = kmalloc(sizeof(*handlr), GFP_KERNEL);
 106         if (!handlr)
 107                 return -ENOMEM;
 108
 109         handlr->root = root;
 110         handlr->ops = ops;
 111         INIT_HLIST_NODE(&handlr->mn.hlist);
 112         spin_lock_init(&handlr->lock);
 113         handlr->mn.ops = &mn_opts;
 114         spin_lock_irqsave(&mmu_rb_lock, flags);
 115         list_add_tail(&handlr->list, &mmu_rb_handlers);
 116         spin_unlock_irqrestore(&mmu_rb_lock, flags);
 117
 118         return mmu_notifier_register(&handlr->mn, current->mm);
 119 }
 120
 121 void hfi1_mmu_rb_unregister(struct rb_root *root)
 122 {
 123         struct mmu_rb_handler *handler = find_mmu_handler(root);
 124         unsigned long flags;
 125
 126         if (!handler)
 127                 return;
 128
 129         spin_lock_irqsave(&mmu_rb_lock, flags);
 130         list_del(&handler->list);
 131         spin_unlock_irqrestore(&mmu_rb_lock, flags);
 132
 133         if (!RB_EMPTY_ROOT(root)) {
 134                 struct rb_node *node;
 135                 struct mmu_rb_node *rbnode;
 136
 137                 while ((node = rb_first(root))) {
 138                         rbnode = rb_entry(node, struct mmu_rb_node, node);
 139                         rb_erase(node, root);
 140                         if (handler->ops->remove)
 141                                 handler->ops->remove(root, rbnode, NULL);
 142                 }
 143         }
 144
 145         if (current->mm)
 146                 mmu_notifier_unregister(&handler->mn, current->mm);
 147         kfree(handler);
 148 }
 149
 150 int hfi1_mmu_rb_insert(struct rb_root *root, struct mmu_rb_node *mnode)
 151 {
 152         struct mmu_rb_handler *handler = find_mmu_handler(root);
 153         struct mmu_rb_node *node;
 154         unsigned long flags;
 155         int ret = 0;
 156
 157         if (!handler)
 158                 return -EINVAL;
 159
 160         spin_lock_irqsave(&handler->lock, flags);
 161         hfi1_cdbg(MMU, "Inserting node addr 0x%llx, len %u", mnode->addr,
 162                   mnode->len);
 163         node = __mmu_rb_search(handler, mnode->addr, mnode->len);
 164         if (node) {
 165                 ret = -EINVAL;
 166                 goto unlock;
 167         }
 168         __mmu_int_rb_insert(mnode, root);
 169
 170         if (handler->ops->insert) {
 171                 ret = handler->ops->insert(root, mnode);
 172                 if (ret)
 173                         __mmu_int_rb_remove(mnode, root);
 174         }
 175 unlock:
 176         spin_unlock_irqrestore(&handler->lock, flags);
 177         return ret;
 178 }
 179
 180 /* Caller must hold handler lock */
 181 static struct mmu_rb_node *__mmu_rb_search(struct mmu_rb_handler *handler,
 182                                            unsigned long addr,
 183                                            unsigned long len)
 184 {
 185         struct mmu_rb_node *node = NULL;
 186
 187         hfi1_cdbg(MMU, "Searching for addr 0x%llx, len %u", addr, len);
 188         if (!handler->ops->filter) {
 189                 node = __mmu_int_rb_iter_first(handler->root, addr,
 190                                                (addr + len) - 1);
 191         } else {
 192                 for (node = __mmu_int_rb_iter_first(handler->root, addr,
 193                                                     (addr + len) - 1);
 194                      node;
 195                      node = __mmu_int_rb_iter_next(node, addr,
 196                                                    (addr + len) - 1)) {
 197                         if (handler->ops->filter(node, addr, len))
 198                                 return node;
 199                 }
 200         }
 201         return node;
 202 }
 203
 204 /* Caller must *not* hold handler lock. */
 205 static void __mmu_rb_remove(struct mmu_rb_handler *handler,
 206                             struct mmu_rb_node *node, struct mm_struct *mm)
 207 {
 208         unsigned long flags;
 209
 210         /* Validity of handler and node pointers has been checked by caller. */
 211         hfi1_cdbg(MMU, "Removing node addr 0x%llx, len %u", node->addr,
 212                   node->len);
 213         spin_lock_irqsave(&handler->lock, flags);
 214         __mmu_int_rb_remove(node, handler->root);
 215         spin_unlock_irqrestore(&handler->lock, flags);
 216
 217         if (handler->ops->remove)
 218                 handler->ops->remove(handler->root, node, mm);
 219 }
 220
 221 struct mmu_rb_node *hfi1_mmu_rb_search(struct rb_root *root, unsigned long addr,
 222                                        unsigned long len)
 223 {
 224         struct mmu_rb_handler *handler = find_mmu_handler(root);
 225         struct mmu_rb_node *node;
 226         unsigned long flags;
 227
 228         if (!handler)
 229                 return ERR_PTR(-EINVAL);
 230
 231         spin_lock_irqsave(&handler->lock, flags);
 232         node = __mmu_rb_search(handler, addr, len);
 233         spin_unlock_irqrestore(&handler->lock, flags);
 234
 235         return node;
 236 }
 237
 238 void hfi1_mmu_rb_remove(struct rb_root *root, struct mmu_rb_node *node)
 239 {
 240         struct mmu_rb_handler *handler = find_mmu_handler(root);
 241
 242         if (!handler || !node)
 243                 return;
 244
 245         __mmu_rb_remove(handler, node, NULL);
 246 }
 247
 248 static struct mmu_rb_handler *find_mmu_handler(struct rb_root *root)
 249 {
 250         struct mmu_rb_handler *handler;
 251         unsigned long flags;
 252
 253         spin_lock_irqsave(&mmu_rb_lock, flags);
 254         list_for_each_entry(handler, &mmu_rb_handlers, list) {
 255                 if (handler->root == root)
 256                         goto unlock;
 257         }
 258         handler = NULL;
 259 unlock:
 260         spin_unlock_irqrestore(&mmu_rb_lock, flags);
 261         return handler;
 262 }
 263
 264 static inline void mmu_notifier_page(struct mmu_notifier *mn,
 265                                      struct mm_struct *mm, unsigned long addr)
 266 {
 267         mmu_notifier_mem_invalidate(mn, mm, addr, addr + PAGE_SIZE);
 268 }
 269
 270 static inline void mmu_notifier_range_start(struct mmu_notifier *mn,
 271                                             struct mm_struct *mm,
 272                                             unsigned long start,
 273                                             unsigned long end)
 274 {
 275         mmu_notifier_mem_invalidate(mn, mm, start, end);
 276 }
 277
 278 static void mmu_notifier_mem_invalidate(struct mmu_notifier *mn,
 279                                         struct mm_struct *mm,
 280                                         unsigned long start, unsigned long end)
 281 {
 282         struct mmu_rb_handler *handler =
 283                 container_of(mn, struct mmu_rb_handler, mn);
 284         struct rb_root *root = handler->root;
 285         struct mmu_rb_node *node, *ptr = NULL;
 286         unsigned long flags;
 287
 288         spin_lock_irqsave(&handler->lock, flags);
 289         for (node = __mmu_int_rb_iter_first(root, start, end - 1);
 290              node; node = ptr) {
 291                 /* Guard against node removal. */
 292                 ptr = __mmu_int_rb_iter_next(node, start, end - 1);
 293                 hfi1_cdbg(MMU, "Invalidating node addr 0x%llx, len %u",
 294                           node->addr, node->len);
 295                 if (handler->ops->invalidate(root, node)) {
 296                         spin_unlock_irqrestore(&handler->lock, flags);
 297                         __mmu_rb_remove(handler, node, mm);
 298                         spin_lock_irqsave(&handler->lock, flags);
 299                 }
 300         }
 301         spin_unlock_irqrestore(&handler->lock, flags);
 302 }