linux/drivers/infiniband/hw/hfi1/mmu_rb.c
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   1/*
   2 * Copyright(c) 2016 - 2017 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/rculist.h>
  49#include <linux/mmu_notifier.h>
  50#include <linux/interval_tree_generic.h>
  51
  52#include "mmu_rb.h"
  53#include "trace.h"
  54
  55struct mmu_rb_handler {
  56        struct mmu_notifier mn;
  57        struct rb_root_cached root;
  58        void *ops_arg;
  59        spinlock_t lock;        /* protect the RB tree */
  60        struct mmu_rb_ops *ops;
  61        struct mm_struct *mm;
  62        struct list_head lru_list;
  63        struct work_struct del_work;
  64        struct list_head del_list;
  65        struct workqueue_struct *wq;
  66};
  67
  68static unsigned long mmu_node_start(struct mmu_rb_node *);
  69static unsigned long mmu_node_last(struct mmu_rb_node *);
  70static int mmu_notifier_range_start(struct mmu_notifier *,
  71                const struct mmu_notifier_range *);
  72static struct mmu_rb_node *__mmu_rb_search(struct mmu_rb_handler *,
  73                                           unsigned long, unsigned long);
  74static void do_remove(struct mmu_rb_handler *handler,
  75                      struct list_head *del_list);
  76static void handle_remove(struct work_struct *work);
  77
  78static const struct mmu_notifier_ops mn_opts = {
  79        .invalidate_range_start = mmu_notifier_range_start,
  80};
  81
  82INTERVAL_TREE_DEFINE(struct mmu_rb_node, node, unsigned long, __last,
  83                     mmu_node_start, mmu_node_last, static, __mmu_int_rb);
  84
  85static unsigned long mmu_node_start(struct mmu_rb_node *node)
  86{
  87        return node->addr & PAGE_MASK;
  88}
  89
  90static unsigned long mmu_node_last(struct mmu_rb_node *node)
  91{
  92        return PAGE_ALIGN(node->addr + node->len) - 1;
  93}
  94
  95int hfi1_mmu_rb_register(void *ops_arg, struct mm_struct *mm,
  96                         struct mmu_rb_ops *ops,
  97                         struct workqueue_struct *wq,
  98                         struct mmu_rb_handler **handler)
  99{
 100        struct mmu_rb_handler *handlr;
 101        int ret;
 102
 103        handlr = kmalloc(sizeof(*handlr), GFP_KERNEL);
 104        if (!handlr)
 105                return -ENOMEM;
 106
 107        handlr->root = RB_ROOT_CACHED;
 108        handlr->ops = ops;
 109        handlr->ops_arg = ops_arg;
 110        INIT_HLIST_NODE(&handlr->mn.hlist);
 111        spin_lock_init(&handlr->lock);
 112        handlr->mn.ops = &mn_opts;
 113        handlr->mm = mm;
 114        INIT_WORK(&handlr->del_work, handle_remove);
 115        INIT_LIST_HEAD(&handlr->del_list);
 116        INIT_LIST_HEAD(&handlr->lru_list);
 117        handlr->wq = wq;
 118
 119        ret = mmu_notifier_register(&handlr->mn, handlr->mm);
 120        if (ret) {
 121                kfree(handlr);
 122                return ret;
 123        }
 124
 125        *handler = handlr;
 126        return 0;
 127}
 128
 129void hfi1_mmu_rb_unregister(struct mmu_rb_handler *handler)
 130{
 131        struct mmu_rb_node *rbnode;
 132        struct rb_node *node;
 133        unsigned long flags;
 134        struct list_head del_list;
 135
 136        /* Unregister first so we don't get any more notifications. */
 137        mmu_notifier_unregister(&handler->mn, handler->mm);
 138
 139        /*
 140         * Make sure the wq delete handler is finished running.  It will not
 141         * be triggered once the mmu notifiers are unregistered above.
 142         */
 143        flush_work(&handler->del_work);
 144
 145        INIT_LIST_HEAD(&del_list);
 146
 147        spin_lock_irqsave(&handler->lock, flags);
 148        while ((node = rb_first_cached(&handler->root))) {
 149                rbnode = rb_entry(node, struct mmu_rb_node, node);
 150                rb_erase_cached(node, &handler->root);
 151                /* move from LRU list to delete list */
 152                list_move(&rbnode->list, &del_list);
 153        }
 154        spin_unlock_irqrestore(&handler->lock, flags);
 155
 156        do_remove(handler, &del_list);
 157
 158        kfree(handler);
 159}
 160
 161int hfi1_mmu_rb_insert(struct mmu_rb_handler *handler,
 162                       struct mmu_rb_node *mnode)
 163{
 164        struct mmu_rb_node *node;
 165        unsigned long flags;
 166        int ret = 0;
 167
 168        trace_hfi1_mmu_rb_insert(mnode->addr, mnode->len);
 169        spin_lock_irqsave(&handler->lock, flags);
 170        node = __mmu_rb_search(handler, mnode->addr, mnode->len);
 171        if (node) {
 172                ret = -EINVAL;
 173                goto unlock;
 174        }
 175        __mmu_int_rb_insert(mnode, &handler->root);
 176        list_add(&mnode->list, &handler->lru_list);
 177
 178        ret = handler->ops->insert(handler->ops_arg, mnode);
 179        if (ret) {
 180                __mmu_int_rb_remove(mnode, &handler->root);
 181                list_del(&mnode->list); /* remove from LRU list */
 182        }
 183unlock:
 184        spin_unlock_irqrestore(&handler->lock, flags);
 185        return ret;
 186}
 187
 188/* Caller must hold handler lock */
 189static struct mmu_rb_node *__mmu_rb_search(struct mmu_rb_handler *handler,
 190                                           unsigned long addr,
 191                                           unsigned long len)
 192{
 193        struct mmu_rb_node *node = NULL;
 194
 195        trace_hfi1_mmu_rb_search(addr, len);
 196        if (!handler->ops->filter) {
 197                node = __mmu_int_rb_iter_first(&handler->root, addr,
 198                                               (addr + len) - 1);
 199        } else {
 200                for (node = __mmu_int_rb_iter_first(&handler->root, addr,
 201                                                    (addr + len) - 1);
 202                     node;
 203                     node = __mmu_int_rb_iter_next(node, addr,
 204                                                   (addr + len) - 1)) {
 205                        if (handler->ops->filter(node, addr, len))
 206                                return node;
 207                }
 208        }
 209        return node;
 210}
 211
 212bool hfi1_mmu_rb_remove_unless_exact(struct mmu_rb_handler *handler,
 213                                     unsigned long addr, unsigned long len,
 214                                     struct mmu_rb_node **rb_node)
 215{
 216        struct mmu_rb_node *node;
 217        unsigned long flags;
 218        bool ret = false;
 219
 220        spin_lock_irqsave(&handler->lock, flags);
 221        node = __mmu_rb_search(handler, addr, len);
 222        if (node) {
 223                if (node->addr == addr && node->len == len)
 224                        goto unlock;
 225                __mmu_int_rb_remove(node, &handler->root);
 226                list_del(&node->list); /* remove from LRU list */
 227                ret = true;
 228        }
 229unlock:
 230        spin_unlock_irqrestore(&handler->lock, flags);
 231        *rb_node = node;
 232        return ret;
 233}
 234
 235void hfi1_mmu_rb_evict(struct mmu_rb_handler *handler, void *evict_arg)
 236{
 237        struct mmu_rb_node *rbnode, *ptr;
 238        struct list_head del_list;
 239        unsigned long flags;
 240        bool stop = false;
 241
 242        INIT_LIST_HEAD(&del_list);
 243
 244        spin_lock_irqsave(&handler->lock, flags);
 245        list_for_each_entry_safe_reverse(rbnode, ptr, &handler->lru_list,
 246                                         list) {
 247                if (handler->ops->evict(handler->ops_arg, rbnode, evict_arg,
 248                                        &stop)) {
 249                        __mmu_int_rb_remove(rbnode, &handler->root);
 250                        /* move from LRU list to delete list */
 251                        list_move(&rbnode->list, &del_list);
 252                }
 253                if (stop)
 254                        break;
 255        }
 256        spin_unlock_irqrestore(&handler->lock, flags);
 257
 258        while (!list_empty(&del_list)) {
 259                rbnode = list_first_entry(&del_list, struct mmu_rb_node, list);
 260                list_del(&rbnode->list);
 261                handler->ops->remove(handler->ops_arg, rbnode);
 262        }
 263}
 264
 265/*
 266 * It is up to the caller to ensure that this function does not race with the
 267 * mmu invalidate notifier which may be calling the users remove callback on
 268 * 'node'.
 269 */
 270void hfi1_mmu_rb_remove(struct mmu_rb_handler *handler,
 271                        struct mmu_rb_node *node)
 272{
 273        unsigned long flags;
 274
 275        /* Validity of handler and node pointers has been checked by caller. */
 276        trace_hfi1_mmu_rb_remove(node->addr, node->len);
 277        spin_lock_irqsave(&handler->lock, flags);
 278        __mmu_int_rb_remove(node, &handler->root);
 279        list_del(&node->list); /* remove from LRU list */
 280        spin_unlock_irqrestore(&handler->lock, flags);
 281
 282        handler->ops->remove(handler->ops_arg, node);
 283}
 284
 285static int mmu_notifier_range_start(struct mmu_notifier *mn,
 286                const struct mmu_notifier_range *range)
 287{
 288        struct mmu_rb_handler *handler =
 289                container_of(mn, struct mmu_rb_handler, mn);
 290        struct rb_root_cached *root = &handler->root;
 291        struct mmu_rb_node *node, *ptr = NULL;
 292        unsigned long flags;
 293        bool added = false;
 294
 295        spin_lock_irqsave(&handler->lock, flags);
 296        for (node = __mmu_int_rb_iter_first(root, range->start, range->end-1);
 297             node; node = ptr) {
 298                /* Guard against node removal. */
 299                ptr = __mmu_int_rb_iter_next(node, range->start,
 300                                             range->end - 1);
 301                trace_hfi1_mmu_mem_invalidate(node->addr, node->len);
 302                if (handler->ops->invalidate(handler->ops_arg, node)) {
 303                        __mmu_int_rb_remove(node, root);
 304                        /* move from LRU list to delete list */
 305                        list_move(&node->list, &handler->del_list);
 306                        added = true;
 307                }
 308        }
 309        spin_unlock_irqrestore(&handler->lock, flags);
 310
 311        if (added)
 312                queue_work(handler->wq, &handler->del_work);
 313
 314        return 0;
 315}
 316
 317/*
 318 * Call the remove function for the given handler and the list.  This
 319 * is expected to be called with a delete list extracted from handler.
 320 * The caller should not be holding the handler lock.
 321 */
 322static void do_remove(struct mmu_rb_handler *handler,
 323                      struct list_head *del_list)
 324{
 325        struct mmu_rb_node *node;
 326
 327        while (!list_empty(del_list)) {
 328                node = list_first_entry(del_list, struct mmu_rb_node, list);
 329                list_del(&node->list);
 330                handler->ops->remove(handler->ops_arg, node);
 331        }
 332}
 333
 334/*
 335 * Work queue function to remove all nodes that have been queued up to
 336 * be removed.  The key feature is that mm->mmap_sem is not being held
 337 * and the remove callback can sleep while taking it, if needed.
 338 */
 339static void handle_remove(struct work_struct *work)
 340{
 341        struct mmu_rb_handler *handler = container_of(work,
 342                                                struct mmu_rb_handler,
 343                                                del_work);
 344        struct list_head del_list;
 345        unsigned long flags;
 346
 347        /* remove anything that is queued to get removed */
 348        spin_lock_irqsave(&handler->lock, flags);
 349        list_replace_init(&handler->del_list, &del_list);
 350        spin_unlock_irqrestore(&handler->lock, flags);
 351
 352        do_remove(handler, &del_list);
 353}
 354