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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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3e252fa7d4
Currently the lifetime of "struct item" entries in the radix tree are not controlled by RCU, but are instead deleted inline as they are removed from the tree. In the following patches we add a test which has threads iterating over items pulled from the tree and verifying them in an rcu_read_lock()/rcu_read_unlock() section. This means that though an item has been removed from the tree it could still be being worked on by other threads until the RCU grace period expires. So, we need to actually free the "struct item" structures at the end of the grace period, just as we do with "struct radix_tree_node" items. Link: http://lkml.kernel.org/r/20180503192430.7582-4-ross.zwisler@linux.intel.com Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Christoph Hellwig <hch@lst.de> Cc: CR, Sapthagirish <sapthagirish.cr@intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jan Kara <jack@suse.cz> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
335 lines
7.5 KiB
C
335 lines
7.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <stdlib.h>
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#include <assert.h>
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#include <stdio.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/bitops.h>
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#include "test.h"
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struct item *
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item_tag_set(struct radix_tree_root *root, unsigned long index, int tag)
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{
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return radix_tree_tag_set(root, index, tag);
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}
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struct item *
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item_tag_clear(struct radix_tree_root *root, unsigned long index, int tag)
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{
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return radix_tree_tag_clear(root, index, tag);
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}
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int item_tag_get(struct radix_tree_root *root, unsigned long index, int tag)
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{
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return radix_tree_tag_get(root, index, tag);
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}
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int __item_insert(struct radix_tree_root *root, struct item *item)
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{
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return __radix_tree_insert(root, item->index, item->order, item);
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}
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struct item *item_create(unsigned long index, unsigned int order)
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{
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struct item *ret = malloc(sizeof(*ret));
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ret->index = index;
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ret->order = order;
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return ret;
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}
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int item_insert_order(struct radix_tree_root *root, unsigned long index,
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unsigned order)
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{
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struct item *item = item_create(index, order);
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int err = __item_insert(root, item);
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if (err)
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free(item);
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return err;
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}
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int item_insert(struct radix_tree_root *root, unsigned long index)
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{
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return item_insert_order(root, index, 0);
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}
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void item_sanity(struct item *item, unsigned long index)
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{
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unsigned long mask;
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assert(!radix_tree_is_internal_node(item));
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assert(item->order < BITS_PER_LONG);
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mask = (1UL << item->order) - 1;
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assert((item->index | mask) == (index | mask));
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}
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int item_delete(struct radix_tree_root *root, unsigned long index)
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{
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struct item *item = radix_tree_delete(root, index);
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if (item) {
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item_sanity(item, index);
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free(item);
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return 1;
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}
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return 0;
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}
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static void item_free_rcu(struct rcu_head *head)
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{
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struct item *item = container_of(head, struct item, rcu_head);
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free(item);
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}
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int item_delete_rcu(struct radix_tree_root *root, unsigned long index)
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{
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struct item *item = radix_tree_delete(root, index);
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if (item) {
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item_sanity(item, index);
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call_rcu(&item->rcu_head, item_free_rcu);
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return 1;
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}
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return 0;
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}
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void item_check_present(struct radix_tree_root *root, unsigned long index)
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{
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struct item *item;
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item = radix_tree_lookup(root, index);
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assert(item != NULL);
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item_sanity(item, index);
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}
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struct item *item_lookup(struct radix_tree_root *root, unsigned long index)
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{
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return radix_tree_lookup(root, index);
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}
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void item_check_absent(struct radix_tree_root *root, unsigned long index)
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{
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struct item *item;
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item = radix_tree_lookup(root, index);
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assert(item == NULL);
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}
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/*
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* Scan only the passed (start, start+nr] for present items
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*/
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void item_gang_check_present(struct radix_tree_root *root,
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unsigned long start, unsigned long nr,
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int chunk, int hop)
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{
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struct item *items[chunk];
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unsigned long into;
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for (into = 0; into < nr; ) {
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int nfound;
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int nr_to_find = chunk;
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int i;
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if (nr_to_find > (nr - into))
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nr_to_find = nr - into;
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nfound = radix_tree_gang_lookup(root, (void **)items,
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start + into, nr_to_find);
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assert(nfound == nr_to_find);
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for (i = 0; i < nfound; i++)
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assert(items[i]->index == start + into + i);
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into += hop;
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}
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}
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/*
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* Scan the entire tree, only expecting present items (start, start+nr]
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*/
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void item_full_scan(struct radix_tree_root *root, unsigned long start,
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unsigned long nr, int chunk)
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{
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struct item *items[chunk];
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unsigned long into = 0;
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unsigned long this_index = start;
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int nfound;
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int i;
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// printf("%s(0x%08lx, 0x%08lx, %d)\n", __FUNCTION__, start, nr, chunk);
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while ((nfound = radix_tree_gang_lookup(root, (void **)items, into,
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chunk))) {
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// printf("At 0x%08lx, nfound=%d\n", into, nfound);
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for (i = 0; i < nfound; i++) {
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assert(items[i]->index == this_index);
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this_index++;
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}
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// printf("Found 0x%08lx->0x%08lx\n",
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// items[0]->index, items[nfound-1]->index);
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into = this_index;
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}
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if (chunk)
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assert(this_index == start + nr);
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nfound = radix_tree_gang_lookup(root, (void **)items,
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this_index, chunk);
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assert(nfound == 0);
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}
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/* Use the same pattern as tag_pages_for_writeback() in mm/page-writeback.c */
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int tag_tagged_items(struct radix_tree_root *root, pthread_mutex_t *lock,
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unsigned long start, unsigned long end, unsigned batch,
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unsigned iftag, unsigned thentag)
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{
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unsigned long tagged = 0;
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struct radix_tree_iter iter;
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void **slot;
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if (batch == 0)
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batch = 1;
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if (lock)
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pthread_mutex_lock(lock);
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radix_tree_for_each_tagged(slot, root, &iter, start, iftag) {
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if (iter.index > end)
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break;
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radix_tree_iter_tag_set(root, &iter, thentag);
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tagged++;
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if ((tagged % batch) != 0)
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continue;
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slot = radix_tree_iter_resume(slot, &iter);
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if (lock) {
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pthread_mutex_unlock(lock);
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rcu_barrier();
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pthread_mutex_lock(lock);
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}
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}
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if (lock)
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pthread_mutex_unlock(lock);
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return tagged;
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}
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/* Use the same pattern as find_swap_entry() in mm/shmem.c */
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unsigned long find_item(struct radix_tree_root *root, void *item)
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{
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struct radix_tree_iter iter;
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void **slot;
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unsigned long found = -1;
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unsigned long checked = 0;
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radix_tree_for_each_slot(slot, root, &iter, 0) {
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if (*slot == item) {
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found = iter.index;
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break;
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}
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checked++;
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if ((checked % 4) != 0)
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continue;
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slot = radix_tree_iter_resume(slot, &iter);
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}
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return found;
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}
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static int verify_node(struct radix_tree_node *slot, unsigned int tag,
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int tagged)
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{
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int anyset = 0;
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int i;
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int j;
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slot = entry_to_node(slot);
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/* Verify consistency at this level */
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for (i = 0; i < RADIX_TREE_TAG_LONGS; i++) {
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if (slot->tags[tag][i]) {
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anyset = 1;
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break;
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}
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}
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if (tagged != anyset) {
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printf("tag: %u, shift %u, tagged: %d, anyset: %d\n",
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tag, slot->shift, tagged, anyset);
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for (j = 0; j < RADIX_TREE_MAX_TAGS; j++) {
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printf("tag %d: ", j);
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for (i = 0; i < RADIX_TREE_TAG_LONGS; i++)
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printf("%016lx ", slot->tags[j][i]);
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printf("\n");
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}
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return 1;
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}
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assert(tagged == anyset);
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/* Go for next level */
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if (slot->shift > 0) {
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for (i = 0; i < RADIX_TREE_MAP_SIZE; i++)
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if (slot->slots[i])
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if (verify_node(slot->slots[i], tag,
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!!test_bit(i, slot->tags[tag]))) {
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printf("Failure at off %d\n", i);
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for (j = 0; j < RADIX_TREE_MAX_TAGS; j++) {
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printf("tag %d: ", j);
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for (i = 0; i < RADIX_TREE_TAG_LONGS; i++)
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printf("%016lx ", slot->tags[j][i]);
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printf("\n");
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}
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return 1;
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}
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}
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return 0;
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}
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void verify_tag_consistency(struct radix_tree_root *root, unsigned int tag)
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{
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struct radix_tree_node *node = root->rnode;
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if (!radix_tree_is_internal_node(node))
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return;
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verify_node(node, tag, !!root_tag_get(root, tag));
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}
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void item_kill_tree(struct radix_tree_root *root)
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{
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struct radix_tree_iter iter;
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void **slot;
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struct item *items[32];
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int nfound;
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radix_tree_for_each_slot(slot, root, &iter, 0) {
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if (radix_tree_exceptional_entry(*slot))
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radix_tree_delete(root, iter.index);
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}
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while ((nfound = radix_tree_gang_lookup(root, (void **)items, 0, 32))) {
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int i;
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for (i = 0; i < nfound; i++) {
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void *ret;
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ret = radix_tree_delete(root, items[i]->index);
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assert(ret == items[i]);
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free(items[i]);
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}
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}
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assert(radix_tree_gang_lookup(root, (void **)items, 0, 32) == 0);
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assert(root->rnode == NULL);
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}
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void tree_verify_min_height(struct radix_tree_root *root, int maxindex)
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{
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unsigned shift;
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struct radix_tree_node *node = root->rnode;
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if (!radix_tree_is_internal_node(node)) {
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assert(maxindex == 0);
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return;
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}
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node = entry_to_node(node);
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assert(maxindex <= node_maxindex(node));
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shift = node->shift;
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if (shift > 0)
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assert(maxindex > shift_maxindex(shift - RADIX_TREE_MAP_SHIFT));
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else
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assert(maxindex > 0);
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}
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