drivers/infiniband/hw/hfi1/mmu_rb.c

   1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
   2 /*
   3  * Copyright(c) 2020 Cornelis Networks, Inc.
   4  * Copyright(c) 2016 - 2017 Intel Corporation.
   5  */
   6
   7 #include <linux/list.h>
   8 #include <linux/rculist.h>
   9 #include <linux/mmu_notifier.h>
  10 #include <linux/interval_tree_generic.h>
  11 #include <linux/sched/mm.h>
  12
  13 #include "mmu_rb.h"
  14 #include "trace.h"
  15
  16 static unsigned long mmu_node_start(struct mmu_rb_node *);
  17 static unsigned long mmu_node_last(struct mmu_rb_node *);
  18 static int mmu_notifier_range_start(struct mmu_notifier *,
  19                 const struct mmu_notifier_range *);
  20 static struct mmu_rb_node *__mmu_rb_search(struct mmu_rb_handler *,
  21                                            unsigned long, unsigned long);
  22 static void release_immediate(struct kref *refcount);
  23 static void handle_remove(struct work_struct *work);
  24
  25 static const struct mmu_notifier_ops mn_opts = {
  26         .invalidate_range_start = mmu_notifier_range_start,
  27 };
  28
  29 INTERVAL_TREE_DEFINE(struct mmu_rb_node, node, unsigned long, __last,
  30                      mmu_node_start, mmu_node_last, static, __mmu_int_rb);
  31
  32 static unsigned long mmu_node_start(struct mmu_rb_node *node)
  33 {
  34         return node->addr & PAGE_MASK;
  35 }
  36
  37 static unsigned long mmu_node_last(struct mmu_rb_node *node)
  38 {
  39         return PAGE_ALIGN(node->addr + node->len) - 1;
  40 }
  41
  42 int hfi1_mmu_rb_register(void *ops_arg,
  43                          const struct mmu_rb_ops *ops,
  44                          struct workqueue_struct *wq,
  45                          struct mmu_rb_handler **handler)
  46 {
  47         struct mmu_rb_handler *h;
  48         void *free_ptr;
  49         int ret;
  50
  51         free_ptr = kzalloc(sizeof(*h) + cache_line_size() - 1, GFP_KERNEL);
  52         if (!free_ptr)
  53                 return -ENOMEM;
  54
  55         h = PTR_ALIGN(free_ptr, cache_line_size());
  56         h->root = RB_ROOT_CACHED;
  57         h->ops = ops;
  58         h->ops_arg = ops_arg;
  59         INIT_HLIST_NODE(&h->mn.hlist);
  60         spin_lock_init(&h->lock);
  61         h->mn.ops = &mn_opts;
  62         INIT_WORK(&h->del_work, handle_remove);
  63         INIT_LIST_HEAD(&h->del_list);
  64         INIT_LIST_HEAD(&h->lru_list);
  65         h->wq = wq;
  66         h->free_ptr = free_ptr;
  67
  68         ret = mmu_notifier_register(&h->mn, current->mm);
  69         if (ret) {
  70                 kfree(free_ptr);
  71                 return ret;
  72         }
  73
  74         *handler = h;
  75         return 0;
  76 }
  77
  78 void hfi1_mmu_rb_unregister(struct mmu_rb_handler *handler)
  79 {
  80         struct mmu_rb_node *rbnode;
  81         struct rb_node *node;
  82         unsigned long flags;
  83         struct list_head del_list;
  84
  85         /* Prevent freeing of mm until we are completely finished. */
  86         mmgrab(handler->mn.mm);
  87
  88         /* Unregister first so we don't get any more notifications. */
  89         mmu_notifier_unregister(&handler->mn, handler->mn.mm);
  90
  91         /*
  92          * Make sure the wq delete handler is finished running.  It will not
  93          * be triggered once the mmu notifiers are unregistered above.
  94          */
  95         flush_work(&handler->del_work);
  96
  97         INIT_LIST_HEAD(&del_list);
  98
  99         spin_lock_irqsave(&handler->lock, flags);
 100         while ((node = rb_first_cached(&handler->root))) {
 101                 rbnode = rb_entry(node, struct mmu_rb_node, node);
 102                 rb_erase_cached(node, &handler->root);
 103                 /* move from LRU list to delete list */
 104                 list_move(&rbnode->list, &del_list);
 105         }
 106         spin_unlock_irqrestore(&handler->lock, flags);
 107
 108         while (!list_empty(&del_list)) {
 109                 rbnode = list_first_entry(&del_list, struct mmu_rb_node, list);
 110                 list_del(&rbnode->list);
 111                 kref_put(&rbnode->refcount, release_immediate);
 112         }
 113
 114         /* Now the mm may be freed. */
 115         mmdrop(handler->mn.mm);
 116
 117         kfree(handler->free_ptr);
 118 }
 119
 120 int hfi1_mmu_rb_insert(struct mmu_rb_handler *handler,
 121                        struct mmu_rb_node *mnode)
 122 {
 123         struct mmu_rb_node *node;
 124         unsigned long flags;
 125         int ret = 0;
 126
 127         trace_hfi1_mmu_rb_insert(mnode);
 128
 129         if (current->mm != handler->mn.mm)
 130                 return -EPERM;
 131
 132         spin_lock_irqsave(&handler->lock, flags);
 133         node = __mmu_rb_search(handler, mnode->addr, mnode->len);
 134         if (node) {
 135                 ret = -EEXIST;
 136                 goto unlock;
 137         }
 138         __mmu_int_rb_insert(mnode, &handler->root);
 139         list_add_tail(&mnode->list, &handler->lru_list);
 140         mnode->handler = handler;
 141 unlock:
 142         spin_unlock_irqrestore(&handler->lock, flags);
 143         return ret;
 144 }
 145
 146 /* Caller must hold handler lock */
 147 struct mmu_rb_node *hfi1_mmu_rb_get_first(struct mmu_rb_handler *handler,
 148                                           unsigned long addr, unsigned long len)
 149 {
 150         struct mmu_rb_node *node;
 151
 152         trace_hfi1_mmu_rb_search(addr, len);
 153         node = __mmu_int_rb_iter_first(&handler->root, addr, (addr + len) - 1);
 154         if (node)
 155                 list_move_tail(&node->list, &handler->lru_list);
 156         return node;
 157 }
 158
 159 /* Caller must hold handler lock */
 160 static struct mmu_rb_node *__mmu_rb_search(struct mmu_rb_handler *handler,
 161                                            unsigned long addr,
 162                                            unsigned long len)
 163 {
 164         struct mmu_rb_node *node = NULL;
 165
 166         trace_hfi1_mmu_rb_search(addr, len);
 167         if (!handler->ops->filter) {
 168                 node = __mmu_int_rb_iter_first(&handler->root, addr,
 169                                                (addr + len) - 1);
 170         } else {
 171                 for (node = __mmu_int_rb_iter_first(&handler->root, addr,
 172                                                     (addr + len) - 1);
 173                      node;
 174                      node = __mmu_int_rb_iter_next(node, addr,
 175                                                    (addr + len) - 1)) {
 176                         if (handler->ops->filter(node, addr, len))
 177                                 return node;
 178                 }
 179         }
 180         return node;
 181 }
 182
 183 /*
 184  * Must NOT call while holding mnode->handler->lock.
 185  * mnode->handler->ops->remove() may sleep and mnode->handler->lock is a
 186  * spinlock.
 187  */
 188 static void release_immediate(struct kref *refcount)
 189 {
 190         struct mmu_rb_node *mnode =
 191                 container_of(refcount, struct mmu_rb_node, refcount);
 192         trace_hfi1_mmu_release_node(mnode);
 193         mnode->handler->ops->remove(mnode->handler->ops_arg, mnode);
 194 }
 195
 196 /* Caller must hold mnode->handler->lock */
 197 static void release_nolock(struct kref *refcount)
 198 {
 199         struct mmu_rb_node *mnode =
 200                 container_of(refcount, struct mmu_rb_node, refcount);
 201         list_move(&mnode->list, &mnode->handler->del_list);
 202         queue_work(mnode->handler->wq, &mnode->handler->del_work);
 203 }
 204
 205 /*
 206  * struct mmu_rb_node->refcount kref_put() callback.
 207  * Adds mmu_rb_node to mmu_rb_node->handler->del_list and queues
 208  * handler->del_work on handler->wq.
 209  * Does not remove mmu_rb_node from handler->lru_list or handler->rb_root.
 210  * Acquires mmu_rb_node->handler->lock; do not call while already holding
 211  * handler->lock.
 212  */
 213 void hfi1_mmu_rb_release(struct kref *refcount)
 214 {
 215         struct mmu_rb_node *mnode =
 216                 container_of(refcount, struct mmu_rb_node, refcount);
 217         struct mmu_rb_handler *handler = mnode->handler;
 218         unsigned long flags;
 219
 220         spin_lock_irqsave(&handler->lock, flags);
 221         list_move(&mnode->list, &mnode->handler->del_list);
 222         spin_unlock_irqrestore(&handler->lock, flags);
 223         queue_work(handler->wq, &handler->del_work);
 224 }
 225
 226 void hfi1_mmu_rb_evict(struct mmu_rb_handler *handler, void *evict_arg)
 227 {
 228         struct mmu_rb_node *rbnode, *ptr;
 229         struct list_head del_list;
 230         unsigned long flags;
 231         bool stop = false;
 232
 233         if (current->mm != handler->mn.mm)
 234                 return;
 235
 236         INIT_LIST_HEAD(&del_list);
 237
 238         spin_lock_irqsave(&handler->lock, flags);
 239         list_for_each_entry_safe(rbnode, ptr, &handler->lru_list, list) {
 240                 /* refcount == 1 implies mmu_rb_handler has only rbnode ref */
 241                 if (kref_read(&rbnode->refcount) > 1)
 242                         continue;
 243
 244                 if (handler->ops->evict(handler->ops_arg, rbnode, evict_arg,
 245                                         &stop)) {
 246                         __mmu_int_rb_remove(rbnode, &handler->root);
 247                         /* move from LRU list to delete list */
 248                         list_move(&rbnode->list, &del_list);
 249                 }
 250                 if (stop)
 251                         break;
 252         }
 253         spin_unlock_irqrestore(&handler->lock, flags);
 254
 255         list_for_each_entry_safe(rbnode, ptr, &del_list, list) {
 256                 trace_hfi1_mmu_rb_evict(rbnode);
 257                 kref_put(&rbnode->refcount, release_immediate);
 258         }
 259 }
 260
 261 static int mmu_notifier_range_start(struct mmu_notifier *mn,
 262                 const struct mmu_notifier_range *range)
 263 {
 264         struct mmu_rb_handler *handler =
 265                 container_of(mn, struct mmu_rb_handler, mn);
 266         struct rb_root_cached *root = &handler->root;
 267         struct mmu_rb_node *node, *ptr = NULL;
 268         unsigned long flags;
 269
 270         spin_lock_irqsave(&handler->lock, flags);
 271         for (node = __mmu_int_rb_iter_first(root, range->start, range->end-1);
 272              node; node = ptr) {
 273                 /* Guard against node removal. */
 274                 ptr = __mmu_int_rb_iter_next(node, range->start,
 275                                              range->end - 1);
 276                 trace_hfi1_mmu_mem_invalidate(node);
 277                 /* Remove from rb tree and lru_list. */
 278                 __mmu_int_rb_remove(node, root);
 279                 list_del_init(&node->list);
 280                 kref_put(&node->refcount, release_nolock);
 281         }
 282         spin_unlock_irqrestore(&handler->lock, flags);
 283
 284         return 0;
 285 }
 286
 287 /*
 288  * Work queue function to remove all nodes that have been queued up to
 289  * be removed.  The key feature is that mm->mmap_lock is not being held
 290  * and the remove callback can sleep while taking it, if needed.
 291  */
 292 static void handle_remove(struct work_struct *work)
 293 {
 294         struct mmu_rb_handler *handler = container_of(work,
 295                                                 struct mmu_rb_handler,
 296                                                 del_work);
 297         struct list_head del_list;
 298         unsigned long flags;
 299         struct mmu_rb_node *node;
 300
 301         /* remove anything that is queued to get removed */
 302         spin_lock_irqsave(&handler->lock, flags);
 303         list_replace_init(&handler->del_list, &del_list);
 304         spin_unlock_irqrestore(&handler->lock, flags);
 305
 306         while (!list_empty(&del_list)) {
 307                 node = list_first_entry(&del_list, struct mmu_rb_node, list);
 308                 list_del(&node->list);
 309                 trace_hfi1_mmu_release_node(node);
 310                 handler->ops->remove(handler->ops_arg, node);
 311         }
 312 }