| /* |
| * Copyright (C) 2001 Momchil Velikov |
| * Portions Copyright (C) 2001 Christoph Hellwig |
| * Copyright (C) 2005 SGI, Christoph Lameter |
| * Copyright (C) 2006 Nick Piggin |
| * Copyright (C) 2012 Konstantin Khlebnikov |
| * Copyright (C) 2016 Intel, Matthew Wilcox |
| * Copyright (C) 2016 Intel, Ross Zwisler |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License as |
| * published by the Free Software Foundation; either version 2, or (at |
| * your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, but |
| * WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| */ |
| |
| #include <linux/bitmap.h> |
| #include <linux/bitops.h> |
| #include <linux/bug.h> |
| #include <linux/cpu.h> |
| #include <linux/errno.h> |
| #include <linux/export.h> |
| #include <linux/idr.h> |
| #include <linux/init.h> |
| #include <linux/kernel.h> |
| #include <linux/kmemleak.h> |
| #include <linux/percpu.h> |
| #include <linux/preempt.h> /* in_interrupt() */ |
| #include <linux/radix-tree.h> |
| #include <linux/rcupdate.h> |
| #include <linux/slab.h> |
| #include <linux/string.h> |
| |
| |
| /* Number of nodes in fully populated tree of given height */ |
| static unsigned long height_to_maxnodes[RADIX_TREE_MAX_PATH + 1] __read_mostly; |
| |
| /* |
| * Radix tree node cache. |
| */ |
| static struct kmem_cache *radix_tree_node_cachep; |
| |
| /* |
| * The radix tree is variable-height, so an insert operation not only has |
| * to build the branch to its corresponding item, it also has to build the |
| * branch to existing items if the size has to be increased (by |
| * radix_tree_extend). |
| * |
| * The worst case is a zero height tree with just a single item at index 0, |
| * and then inserting an item at index ULONG_MAX. This requires 2 new branches |
| * of RADIX_TREE_MAX_PATH size to be created, with only the root node shared. |
| * Hence: |
| */ |
| #define RADIX_TREE_PRELOAD_SIZE (RADIX_TREE_MAX_PATH * 2 - 1) |
| |
| /* |
| * The IDR does not have to be as high as the radix tree since it uses |
| * signed integers, not unsigned longs. |
| */ |
| #define IDR_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(int) - 1) |
| #define IDR_MAX_PATH (DIV_ROUND_UP(IDR_INDEX_BITS, \ |
| RADIX_TREE_MAP_SHIFT)) |
| #define IDR_PRELOAD_SIZE (IDR_MAX_PATH * 2 - 1) |
| |
| /* |
| * The IDA is even shorter since it uses a bitmap at the last level. |
| */ |
| #define IDA_INDEX_BITS (8 * sizeof(int) - 1 - ilog2(IDA_BITMAP_BITS)) |
| #define IDA_MAX_PATH (DIV_ROUND_UP(IDA_INDEX_BITS, \ |
| RADIX_TREE_MAP_SHIFT)) |
| #define IDA_PRELOAD_SIZE (IDA_MAX_PATH * 2 - 1) |
| |
| /* |
| * Per-cpu pool of preloaded nodes |
| */ |
| struct radix_tree_preload { |
| unsigned nr; |
| /* nodes->parent points to next preallocated node */ |
| struct radix_tree_node *nodes; |
| }; |
| static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, }; |
| |
| static inline struct radix_tree_node *entry_to_node(void *ptr) |
| { |
| return (void *)((unsigned long)ptr & ~RADIX_TREE_INTERNAL_NODE); |
| } |
| |
| static inline void *node_to_entry(void *ptr) |
| { |
| return (void *)((unsigned long)ptr | RADIX_TREE_INTERNAL_NODE); |
| } |
| |
| #define RADIX_TREE_RETRY node_to_entry(NULL) |
| |
| #ifdef CONFIG_RADIX_TREE_MULTIORDER |
| /* Sibling slots point directly to another slot in the same node */ |
| static inline |
| bool is_sibling_entry(const struct radix_tree_node *parent, void *node) |
| { |
| void __rcu **ptr = node; |
| return (parent->slots <= ptr) && |
| (ptr < parent->slots + RADIX_TREE_MAP_SIZE); |
| } |
| #else |
| static inline |
| bool is_sibling_entry(const struct radix_tree_node *parent, void *node) |
| { |
| return false; |
| } |
| #endif |
| |
| static inline unsigned long |
| get_slot_offset(const struct radix_tree_node *parent, void __rcu **slot) |
| { |
| return parent ? slot - parent->slots : 0; |
| } |
| |
| static unsigned int radix_tree_descend(const struct radix_tree_node *parent, |
| struct radix_tree_node **nodep, unsigned long index) |
| { |
| unsigned int offset = (index >> parent->shift) & RADIX_TREE_MAP_MASK; |
| void __rcu **entry = rcu_dereference_raw(parent->slots[offset]); |
| |
| #ifdef CONFIG_RADIX_TREE_MULTIORDER |
| if (radix_tree_is_internal_node(entry)) { |
| if (is_sibling_entry(parent, entry)) { |
| void __rcu **sibentry; |
| sibentry = (void __rcu **) entry_to_node(entry); |
| offset = get_slot_offset(parent, sibentry); |
| entry = rcu_dereference_raw(*sibentry); |
| } |
| } |
| #endif |
| |
| *nodep = (void *)entry; |
| return offset; |
| } |
| |
| static inline gfp_t root_gfp_mask(const struct radix_tree_root *root) |
| { |
| return root->gfp_mask & (__GFP_BITS_MASK & ~GFP_ZONEMASK); |
| } |
| |
| static inline void tag_set(struct radix_tree_node *node, unsigned int tag, |
| int offset) |
| { |
| __set_bit(offset, node->tags[tag]); |
| } |
| |
| static inline void tag_clear(struct radix_tree_node *node, unsigned int tag, |
| int offset) |
| { |
| __clear_bit(offset, node->tags[tag]); |
| } |
| |
| static inline int tag_get(const struct radix_tree_node *node, unsigned int tag, |
| int offset) |
| { |
| return test_bit(offset, node->tags[tag]); |
| } |
| |
| static inline void root_tag_set(struct radix_tree_root *root, unsigned tag) |
| { |
| root->gfp_mask |= (__force gfp_t)(1 << (tag + ROOT_TAG_SHIFT)); |
| } |
| |
| static inline void root_tag_clear(struct radix_tree_root *root, unsigned tag) |
| { |
| root->gfp_mask &= (__force gfp_t)~(1 << (tag + ROOT_TAG_SHIFT)); |
| } |
| |
| static inline void root_tag_clear_all(struct radix_tree_root *root) |
| { |
| root->gfp_mask &= (1 << ROOT_TAG_SHIFT) - 1; |
| } |
| |
| static inline int root_tag_get(const struct radix_tree_root *root, unsigned tag) |
| { |
| return (__force int)root->gfp_mask & (1 << (tag + ROOT_TAG_SHIFT)); |
| } |
| |
| static inline unsigned root_tags_get(const struct radix_tree_root *root) |
| { |
| return (__force unsigned)root->gfp_mask >> ROOT_TAG_SHIFT; |
| } |
| |
| static inline bool is_idr(const struct radix_tree_root *root) |
| { |
| return !!(root->gfp_mask & ROOT_IS_IDR); |
| } |
| |
| /* |
| * Returns 1 if any slot in the node has this tag set. |
| * Otherwise returns 0. |
| */ |
| static inline int any_tag_set(const struct radix_tree_node *node, |
| unsigned int tag) |
| { |
| unsigned idx; |
| for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) { |
| if (node->tags[tag][idx]) |
| return 1; |
| } |
| return 0; |
| } |
| |
| static inline void all_tag_set(struct radix_tree_node *node, unsigned int tag) |
| { |
| bitmap_fill(node->tags[tag], RADIX_TREE_MAP_SIZE); |
| } |
| |
| /** |
| * radix_tree_find_next_bit - find the next set bit in a memory region |
| * |
| * @addr: The address to base the search on |
| * @size: The bitmap size in bits |
| * @offset: The bitnumber to start searching at |
| * |
| * Unrollable variant of find_next_bit() for constant size arrays. |
| * Tail bits starting from size to roundup(size, BITS_PER_LONG) must be zero. |
| * Returns next bit offset, or size if nothing found. |
| */ |
| static __always_inline unsigned long |
| radix_tree_find_next_bit(struct radix_tree_node *node, unsigned int tag, |
| unsigned long offset) |
| { |
| const unsigned long *addr = node->tags[tag]; |
| |
| if (offset < RADIX_TREE_MAP_SIZE) { |
| unsigned long tmp; |
| |
| addr += offset / BITS_PER_LONG; |
| tmp = *addr >> (offset % BITS_PER_LONG); |
| if (tmp) |
| return __ffs(tmp) + offset; |
| offset = (offset + BITS_PER_LONG) & ~(BITS_PER_LONG - 1); |
| while (offset < RADIX_TREE_MAP_SIZE) { |
| tmp = *++addr; |
| if (tmp) |
| return __ffs(tmp) + offset; |
| offset += BITS_PER_LONG; |
| } |
| } |
| return RADIX_TREE_MAP_SIZE; |
| } |
| |
| static unsigned int iter_offset(const struct radix_tree_iter *iter) |
| { |
| return (iter->index >> iter_shift(iter)) & RADIX_TREE_MAP_MASK; |
| } |
| |
| /* |
| * The maximum index which can be stored in a radix tree |
| */ |
| static inline unsigned long shift_maxindex(unsigned int shift) |
| { |
| return (RADIX_TREE_MAP_SIZE << shift) - 1; |
| } |
| |
| static inline unsigned long node_maxindex(const struct radix_tree_node *node) |
| { |
| return shift_maxindex(node->shift); |
| } |
| |
| static unsigned long next_index(unsigned long index, |
| const struct radix_tree_node *node, |
| unsigned long offset) |
| { |
| return (index & ~node_maxindex(node)) + (offset << node->shift); |
| } |
| |
| #ifndef __KERNEL__ |
| static void dump_node(struct radix_tree_node *node, unsigned long index) |
| { |
| unsigned long i; |
| |
| pr_debug("radix node: %p offset %d indices %lu-%lu parent %p tags %lx %lx %lx shift %d count %d exceptional %d\n", |
| node, node->offset, index, index | node_maxindex(node), |
| node->parent, |
| node->tags[0][0], node->tags[1][0], node->tags[2][0], |
| node->shift, node->count, node->exceptional); |
| |
| for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) { |
| unsigned long first = index | (i << node->shift); |
| unsigned long last = first | ((1UL << node->shift) - 1); |
| void *entry = node->slots[i]; |
| if (!entry) |
| continue; |
| if (entry == RADIX_TREE_RETRY) { |
| pr_debug("radix retry offset %ld indices %lu-%lu parent %p\n", |
| i, first, last, node); |
| } else if (!radix_tree_is_internal_node(entry)) { |
| pr_debug("radix entry %p offset %ld indices %lu-%lu parent %p\n", |
| entry, i, first, last, node); |
| } else if (is_sibling_entry(node, entry)) { |
| pr_debug("radix sblng %p offset %ld indices %lu-%lu parent %p val %p\n", |
| entry, i, first, last, node, |
| *(void **)entry_to_node(entry)); |
| } else { |
| dump_node(entry_to_node(entry), first); |
| } |
| } |
| } |
| |
| /* For debug */ |
| static void radix_tree_dump(struct radix_tree_root *root) |
| { |
| pr_debug("radix root: %p rnode %p tags %x\n", |
| root, root->rnode, |
| root->gfp_mask >> ROOT_TAG_SHIFT); |
| if (!radix_tree_is_internal_node(root->rnode)) |
| return; |
| dump_node(entry_to_node(root->rnode), 0); |
| } |
| |
| static void dump_ida_node(void *entry, unsigned long index) |
| { |
| unsigned long i; |
| |
| if (!entry) |
| return; |
| |
| if (radix_tree_is_internal_node(entry)) { |
| struct radix_tree_node *node = entry_to_node(entry); |
| |
| pr_debug("ida node: %p offset %d indices %lu-%lu parent %p free %lx shift %d count %d\n", |
| node, node->offset, index * IDA_BITMAP_BITS, |
| ((index | node_maxindex(node)) + 1) * |
| IDA_BITMAP_BITS - 1, |
| node->parent, node->tags[0][0], node->shift, |
| node->count); |
| for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) |
| dump_ida_node(node->slots[i], |
| index | (i << node->shift)); |
| } else if (radix_tree_exceptional_entry(entry)) { |
| pr_debug("ida excp: %p offset %d indices %lu-%lu data %lx\n", |
| entry, (int)(index & RADIX_TREE_MAP_MASK), |
| index * IDA_BITMAP_BITS, |
| index * IDA_BITMAP_BITS + BITS_PER_LONG - |
| RADIX_TREE_EXCEPTIONAL_SHIFT, |
| (unsigned long)entry >> |
| RADIX_TREE_EXCEPTIONAL_SHIFT); |
| } else { |
| struct ida_bitmap *bitmap = entry; |
| |
| pr_debug("ida btmp: %p offset %d indices %lu-%lu data", bitmap, |
| (int)(index & RADIX_TREE_MAP_MASK), |
| index * IDA_BITMAP_BITS, |
| (index + 1) * IDA_BITMAP_BITS - 1); |
| for (i = 0; i < IDA_BITMAP_LONGS; i++) |
| pr_cont(" %lx", bitmap->bitmap[i]); |
| pr_cont("\n"); |
| } |
| } |
| |
| static void ida_dump(struct ida *ida) |
| { |
| struct radix_tree_root *root = &ida->ida_rt; |
| pr_debug("ida: %p node %p free %d\n", ida, root->rnode, |
| root->gfp_mask >> ROOT_TAG_SHIFT); |
| dump_ida_node(root->rnode, 0); |
| } |
| #endif |
| |
| /* |
| * This assumes that the caller has performed appropriate preallocation, and |
| * that the caller has pinned this thread of control to the current CPU. |
| */ |
| static struct radix_tree_node * |
| radix_tree_node_alloc(gfp_t gfp_mask, struct radix_tree_node *parent, |
| struct radix_tree_root *root, |
| unsigned int shift, unsigned int offset, |
| unsigned int count, unsigned int exceptional) |
| { |
| struct radix_tree_node *ret = NULL; |
| |
| /* |
| * Preload code isn't irq safe and it doesn't make sense to use |
| * preloading during an interrupt anyway as all the allocations have |
| * to be atomic. So just do normal allocation when in interrupt. |
| */ |
| if (!gfpflags_allow_blocking(gfp_mask) && !in_interrupt()) { |
| struct radix_tree_preload *rtp; |
| |
| /* |
| * Even if the caller has preloaded, try to allocate from the |
| * cache first for the new node to get accounted to the memory |
| * cgroup. |
| */ |
| ret = kmem_cache_alloc(radix_tree_node_cachep, |
| gfp_mask | __GFP_NOWARN); |
| if (ret) |
| goto out; |
| |
| /* |
| * Provided the caller has preloaded here, we will always |
| * succeed in getting a node here (and never reach |
| * kmem_cache_alloc) |
| */ |
| rtp = this_cpu_ptr(&radix_tree_preloads); |
| if (rtp->nr) { |
| ret = rtp->nodes; |
| rtp->nodes = ret->parent; |
| rtp->nr--; |
| } |
| /* |
| * Update the allocation stack trace as this is more useful |
| * for debugging. |
| */ |
| kmemleak_update_trace(ret); |
| goto out; |
| } |
| ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); |
| out: |
| BUG_ON(radix_tree_is_internal_node(ret)); |
| if (ret) { |
| ret->shift = shift; |
| ret->offset = offset; |
| ret->count = count; |
| ret->exceptional = exceptional; |
| ret->parent = parent; |
| ret->root = root; |
| } |
| return ret; |
| } |
| |
| static void radix_tree_node_rcu_free(struct rcu_head *head) |
| { |
| struct radix_tree_node *node = |
| container_of(head, struct radix_tree_node, rcu_head); |
| |
| /* |
| * Must only free zeroed nodes into the slab. We can be left with |
| * non-NULL entries by radix_tree_free_nodes, so clear the entries |
| * and tags here. |
| */ |
| memset(node->slots, 0, sizeof(node->slots)); |
| memset(node->tags, 0, sizeof(node->tags)); |
| INIT_LIST_HEAD(&node->private_list); |
| |
| kmem_cache_free(radix_tree_node_cachep, node); |
| } |
| |
| static inline void |
| radix_tree_node_free(struct radix_tree_node *node) |
| { |
| call_rcu(&node->rcu_head, radix_tree_node_rcu_free); |
| } |
| |
| /* |
| * Load up this CPU's radix_tree_node buffer with sufficient objects to |
| * ensure that the addition of a single element in the tree cannot fail. On |
| * success, return zero, with preemption disabled. On error, return -ENOMEM |
| * with preemption not disabled. |
| * |
| * To make use of this facility, the radix tree must be initialised without |
| * __GFP_DIRECT_RECLAIM being passed to INIT_RADIX_TREE(). |
| */ |
| static __must_check int __radix_tree_preload(gfp_t gfp_mask, unsigned nr) |
| { |
| struct radix_tree_preload *rtp; |
| struct radix_tree_node *node; |
| int ret = -ENOMEM; |
| |
| /* |
| * Nodes preloaded by one cgroup can be be used by another cgroup, so |
| * they should never be accounted to any particular memory cgroup. |
| */ |
| gfp_mask &= ~__GFP_ACCOUNT; |
| |
| preempt_disable(); |
| rtp = this_cpu_ptr(&radix_tree_preloads); |
| while (rtp->nr < nr) { |
| preempt_enable(); |
| node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); |
| if (node == NULL) |
| goto out; |
| preempt_disable(); |
| rtp = this_cpu_ptr(&radix_tree_preloads); |
| if (rtp->nr < nr) { |
| node->parent = rtp->nodes; |
| rtp->nodes = node; |
| rtp->nr++; |
| } else { |
| kmem_cache_free(radix_tree_node_cachep, node); |
| } |
| } |
| ret = 0; |
| out: |
| return ret; |
| } |
| |
| /* |
| * Load up this CPU's radix_tree_node buffer with sufficient objects to |
| * ensure that the addition of a single element in the tree cannot fail. On |
| * success, return zero, with preemption disabled. On error, return -ENOMEM |
| * with preemption not disabled. |
| * |
| * To make use of this facility, the radix tree must be initialised without |
| * __GFP_DIRECT_RECLAIM being passed to INIT_RADIX_TREE(). |
| */ |
| int radix_tree_preload(gfp_t gfp_mask) |
| { |
| /* Warn on non-sensical use... */ |
| WARN_ON_ONCE(!gfpflags_allow_blocking(gfp_mask)); |
| return __radix_tree_preload(gfp_mask, RADIX_TREE_PRELOAD_SIZE); |
| } |
| EXPORT_SYMBOL(radix_tree_preload); |
| |
| /* |
| * The same as above function, except we don't guarantee preloading happens. |
| * We do it, if we decide it helps. On success, return zero with preemption |
| * disabled. On error, return -ENOMEM with preemption not disabled. |
| */ |
| int radix_tree_maybe_preload(gfp_t gfp_mask) |
| { |
| if (gfpflags_allow_blocking(gfp_mask)) |
| return __radix_tree_preload(gfp_mask, RADIX_TREE_PRELOAD_SIZE); |
| /* Preloading doesn't help anything with this gfp mask, skip it */ |
| preempt_disable(); |
| return 0; |
| } |
| EXPORT_SYMBOL(radix_tree_maybe_preload); |
| |
| #ifdef CONFIG_RADIX_TREE_MULTIORDER |
| /* |
| * Preload with enough objects to ensure that we can split a single entry |
| * of order @old_order into many entries of size @new_order |
| */ |
| int radix_tree_split_preload(unsigned int old_order, unsigned int new_order, |
| gfp_t gfp_mask) |
| { |
| unsigned top = 1 << (old_order % RADIX_TREE_MAP_SHIFT); |
| unsigned layers = (old_order / RADIX_TREE_MAP_SHIFT) - |
| (new_order / RADIX_TREE_MAP_SHIFT); |
| unsigned nr = 0; |
| |
| WARN_ON_ONCE(!gfpflags_allow_blocking(gfp_mask)); |
| BUG_ON(new_order >= old_order); |
| |
| while (layers--) |
| nr = nr * RADIX_TREE_MAP_SIZE + 1; |
| return __radix_tree_preload(gfp_mask, top * nr); |
| } |
| #endif |
| |
| /* |
| * The same as function above, but preload number of nodes required to insert |
| * (1 << order) continuous naturally-aligned elements. |
| */ |
| int radix_tree_maybe_preload_order(gfp_t gfp_mask, int order) |
| { |
| unsigned long nr_subtrees; |
| int nr_nodes, subtree_height; |
| |
| /* Preloading doesn't help anything with this gfp mask, skip it */ |
| if (!gfpflags_allow_blocking(gfp_mask)) { |
| preempt_disable(); |
| return 0; |
| } |
| |
| /* |
| * Calculate number and height of fully populated subtrees it takes to |
| * store (1 << order) elements. |
| */ |
| nr_subtrees = 1 << order; |
| for (subtree_height = 0; nr_subtrees > RADIX_TREE_MAP_SIZE; |
| subtree_height++) |
| nr_subtrees >>= RADIX_TREE_MAP_SHIFT; |
| |
| /* |
| * The worst case is zero height tree with a single item at index 0 and |
| * then inserting items starting at ULONG_MAX - (1 << order). |
| * |
| * This requires RADIX_TREE_MAX_PATH nodes to build branch from root to |
| * 0-index item. |
| */ |
| nr_nodes = RADIX_TREE_MAX_PATH; |
| |
| /* Plus branch to fully populated subtrees. */ |
| nr_nodes += RADIX_TREE_MAX_PATH - subtree_height; |
| |
| /* Root node is shared. */ |
| nr_nodes--; |
| |
| /* Plus nodes required to build subtrees. */ |
| nr_nodes += nr_subtrees * height_to_maxnodes[subtree_height]; |
| |
| return __radix_tree_preload(gfp_mask, nr_nodes); |
| } |
| |
| static unsigned radix_tree_load_root(const struct radix_tree_root *root, |
| struct radix_tree_node **nodep, unsigned long *maxindex) |
| { |
| struct radix_tree_node *node = rcu_dereference_raw(root->rnode); |
| |
| *nodep = node; |
| |
| if (likely(radix_tree_is_internal_node(node))) { |
| node = entry_to_node(node); |
| *maxindex = node_maxindex(node); |
| return node->shift + RADIX_TREE_MAP_SHIFT; |
| } |
| |
| *maxindex = 0; |
| return 0; |
| } |
| |
| /* |
| * Extend a radix tree so it can store key @index. |
| */ |
| static int radix_tree_extend(struct radix_tree_root *root, gfp_t gfp, |
| unsigned long index, unsigned int shift) |
| { |
| void *entry; |
| unsigned int maxshift; |
| int tag; |
| |
| /* Figure out what the shift should be. */ |
| maxshift = shift; |
| while (index > shift_maxindex(maxshift)) |
| maxshift += RADIX_TREE_MAP_SHIFT; |
| |
| entry = rcu_dereference_raw(root->rnode); |
| if (!entry && (!is_idr(root) || root_tag_get(root, IDR_FREE))) |
| goto out; |
| |
| do { |
| struct radix_tree_node *node = radix_tree_node_alloc(gfp, NULL, |
| root, shift, 0, 1, 0); |
| if (!node) |
| return -ENOMEM; |
| |
| if (is_idr(root)) { |
| all_tag_set(node, IDR_FREE); |
| if (!root_tag_get(root, IDR_FREE)) { |
| tag_clear(node, IDR_FREE, 0); |
| root_tag_set(root, IDR_FREE); |
| } |
| } else { |
| /* Propagate the aggregated tag info to the new child */ |
| for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { |
| if (root_tag_get(root, tag)) |
| tag_set(node, tag, 0); |
| } |
| } |
| |
| BUG_ON(shift > BITS_PER_LONG); |
| if (radix_tree_is_internal_node(entry)) { |
| entry_to_node(entry)->parent = node; |
| } else if (radix_tree_exceptional_entry(entry)) { |
| /* Moving an exceptional root->rnode to a node */ |
| node->exceptional = 1; |
| } |
| /* |
| * entry was already in the radix tree, so we do not need |
| * rcu_assign_pointer here |
| */ |
| node->slots[0] = (void __rcu *)entry; |
| entry = node_to_entry(node); |
| rcu_assign_pointer(root->rnode, entry); |
| shift += RADIX_TREE_MAP_SHIFT; |
| } while (shift <= maxshift); |
| out: |
| return maxshift + RADIX_TREE_MAP_SHIFT; |
| } |
| |
| /** |
| * radix_tree_shrink - shrink radix tree to minimum height |
| * @root radix tree root |
| */ |
| static inline bool radix_tree_shrink(struct radix_tree_root *root, |
| radix_tree_update_node_t update_node) |
| { |
| bool shrunk = false; |
| |
| for (;;) { |
| struct radix_tree_node *node = rcu_dereference_raw(root->rnode); |
| struct radix_tree_node *child; |
| |
| if (!radix_tree_is_internal_node(node)) |
| break; |
| node = entry_to_node(node); |
| |
| /* |
| * The candidate node has more than one child, or its child |
| * is not at the leftmost slot, or the child is a multiorder |
| * entry, we cannot shrink. |
| */ |
| if (node->count != 1) |
| break; |
| child = rcu_dereference_raw(node->slots[0]); |
| if (!child) |
| break; |
| if (!radix_tree_is_internal_node(child) && node->shift) |
| break; |
| |
| if (radix_tree_is_internal_node(child)) |
| entry_to_node(child)->parent = NULL; |
| |
| /* |
| * We don't need rcu_assign_pointer(), since we are simply |
| * moving the node from one part of the tree to another: if it |
| * was safe to dereference the old pointer to it |
| * (node->slots[0]), it will be safe to dereference the new |
| * one (root->rnode) as far as dependent read barriers go. |
| */ |
| root->rnode = (void __rcu *)child; |
| if (is_idr(root) && !tag_get(node, IDR_FREE, 0)) |
| root_tag_clear(root, IDR_FREE); |
| |
| /* |
| * We have a dilemma here. The node's slot[0] must not be |
| * NULLed in case there are concurrent lookups expecting to |
| * find the item. However if this was a bottom-level node, |
| * then it may be subject to the slot pointer being visible |
| * to callers dereferencing it. If item corresponding to |
| * slot[0] is subsequently deleted, these callers would expect |
| * their slot to become empty sooner or later. |
| * |
| * For example, lockless pagecache will look up a slot, deref |
| * the page pointer, and if the page has 0 refcount it means it |
| * was concurrently deleted from pagecache so try the deref |
| * again. Fortunately there is already a requirement for logic |
| * to retry the entire slot lookup -- the indirect pointer |
| * problem (replacing direct root node with an indirect pointer |
| * also results in a stale slot). So tag the slot as indirect |
| * to force callers to retry. |
| */ |
| node->count = 0; |
| if (!radix_tree_is_internal_node(child)) { |
| node->slots[0] = (void __rcu *)RADIX_TREE_RETRY; |
| if (update_node) |
| update_node(node); |
| } |
| |
| WARN_ON_ONCE(!list_empty(&node->private_list)); |
| radix_tree_node_free(node); |
| shrunk = true; |
| } |
| |
| return shrunk; |
| } |
| |
| static bool delete_node(struct radix_tree_root *root, |
| struct radix_tree_node *node, |
| radix_tree_update_node_t update_node) |
| { |
| bool deleted = false; |
| |
| do { |
| struct radix_tree_node *parent; |
| |
| if (node->count) { |
| if (node_to_entry(node) == |
| rcu_dereference_raw(root->rnode)) |
| deleted |= radix_tree_shrink(root, |
| update_node); |
| return deleted; |
| } |
| |
| parent = node->parent; |
| if (parent) { |
| parent->slots[node->offset] = NULL; |
| parent->count--; |
| } else { |
| /* |
| * Shouldn't the tags already have all been cleared |
| * by the caller? |
| */ |
| if (!is_idr(root)) |
| root_tag_clear_all(root); |
| root->rnode = NULL; |
| } |
| |
| WARN_ON_ONCE(!list_empty(&node->private_list)); |
| radix_tree_node_free(node); |
| deleted = true; |
| |
| node = parent; |
| } while (node); |
| |
| return deleted; |
| } |
| |
| /** |
| * __radix_tree_create - create a slot in a radix tree |
| * @root: radix tree root |
| * @index: index key |
| * @order: index occupies 2^order aligned slots |
| * @nodep: returns node |
| * @slotp: returns slot |
| * |
| * Create, if necessary, and return the node and slot for an item |
| * at position @index in the radix tree @root. |
| * |
| * Until there is more than one item in the tree, no nodes are |
| * allocated and @root->rnode is used as a direct slot instead of |
| * pointing to a node, in which case *@nodep will be NULL. |
| * |
| * Returns -ENOMEM, or 0 for success. |
| */ |
| int __radix_tree_create(struct radix_tree_root *root, unsigned long index, |
| unsigned order, struct radix_tree_node **nodep, |
| void __rcu ***slotp) |
| { |
| struct radix_tree_node *node = NULL, *child; |
| void __rcu **slot = (void __rcu **)&root->rnode; |
| unsigned long maxindex; |
| unsigned int shift, offset = 0; |
| unsigned long max = index | ((1UL << order) - 1); |
| gfp_t gfp = root_gfp_mask(root); |
| |
| shift = radix_tree_load_root(root, &child, &maxindex); |
| |
| /* Make sure the tree is high enough. */ |
| if (order > 0 && max == ((1UL << order) - 1)) |
| max++; |
| if (max > maxindex) { |
| int error = radix_tree_extend(root, gfp, max, shift); |
| if (error < 0) |
| return error; |
| shift = error; |
| child = rcu_dereference_raw(root->rnode); |
| } |
| |
| while (shift > order) { |
| shift -= RADIX_TREE_MAP_SHIFT; |
| if (child == NULL) { |
| /* Have to add a child node. */ |
| child = radix_tree_node_alloc(gfp, node, root, shift, |
| offset, 0, 0); |
| if (!child) |
| return -ENOMEM; |
| rcu_assign_pointer(*slot, node_to_entry(child)); |
| if (node) |
| node->count++; |
| } else if (!radix_tree_is_internal_node(child)) |
| break; |
| |
| /* Go a level down */ |
| node = entry_to_node(child); |
| offset = radix_tree_descend(node, &child, index); |
| slot = &node->slots[offset]; |
| } |
| |
| if (nodep) |
| *nodep = node; |
| if (slotp) |
| *slotp = slot; |
| return 0; |
| } |
| |
| /* |
| * Free any nodes below this node. The tree is presumed to not need |
| * shrinking, and any user data in the tree is presumed to not need a |
| * destructor called on it. If we need to add a destructor, we can |
| * add that functionality later. Note that we may not clear tags or |
| * slots from the tree as an RCU walker may still have a pointer into |
| * this subtree. We could replace the entries with RADIX_TREE_RETRY, |
| * but we'll still have to clear those in rcu_free. |
| */ |
| static void radix_tree_free_nodes(struct radix_tree_node *node) |
| { |
| unsigned offset = 0; |
| struct radix_tree_node *child = entry_to_node(node); |
| |
| for (;;) { |
| void *entry = rcu_dereference_raw(child->slots[offset]); |
| if (radix_tree_is_internal_node(entry) && |
| !is_sibling_entry(child, entry)) { |
| child = entry_to_node(entry); |
| offset = 0; |
| continue; |
| } |
| offset++; |
| while (offset == RADIX_TREE_MAP_SIZE) { |
| struct radix_tree_node *old = child; |
| offset = child->offset + 1; |
| child = child->parent; |
| WARN_ON_ONCE(!list_empty(&old->private_list)); |
| radix_tree_node_free(old); |
| if (old == entry_to_node(node)) |
| return; |
| } |
| } |
| } |
| |
| #ifdef CONFIG_RADIX_TREE_MULTIORDER |
| static inline int insert_entries(struct radix_tree_node *node, |
| void __rcu **slot, void *item, unsigned order, bool replace) |
| { |
| struct radix_tree_node *child; |
| unsigned i, n, tag, offset, tags = 0; |
| |
| if (node) { |
| if (order > node->shift) |
| n = 1 << (order - node->shift); |
| else |
| n = 1; |
| offset = get_slot_offset(node, slot); |
| } else { |
| n = 1; |
| offset = 0; |
| } |
| |
| if (n > 1) { |
| offset = offset & ~(n - 1); |
| slot = &node->slots[offset]; |
| } |
| child = node_to_entry(slot); |
| |
| for (i = 0; i < n; i++) { |
| if (slot[i]) { |
| if (replace) { |
| node->count--; |
| for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) |
| if (tag_get(node, tag, offset + i)) |
| tags |= 1 << tag; |
| } else |
| return -EEXIST; |
| } |
| } |
| |
| for (i = 0; i < n; i++) { |
| struct radix_tree_node *old = rcu_dereference_raw(slot[i]); |
| if (i) { |
| rcu_assign_pointer(slot[i], child); |
| for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) |
| if (tags & (1 << tag)) |
| tag_clear(node, tag, offset + i); |
| } else { |
| rcu_assign_pointer(slot[i], item); |
| for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) |
| if (tags & (1 << tag)) |
| tag_set(node, tag, offset); |
| } |
| if (radix_tree_is_internal_node(old) && |
| !is_sibling_entry(node, old) && |
| (old != RADIX_TREE_RETRY)) |
| radix_tree_free_nodes(old); |
| if (radix_tree_exceptional_entry(old)) |
| node->exceptional--; |
| } |
| if (node) { |
| node->count += n; |
| if (radix_tree_exceptional_entry(item)) |
| node->exceptional += n; |
| } |
| return n; |
| } |
| #else |
| static inline int insert_entries(struct radix_tree_node *node, |
| void __rcu **slot, void *item, unsigned order, bool replace) |
| { |
| if (*slot) |
| return -EEXIST; |
| rcu_assign_pointer(*slot, item); |
| if (node) { |
| node->count++; |
| if (radix_tree_exceptional_entry(item)) |
| node->exceptional++; |
| } |
| return 1; |
| } |
| #endif |
| |
| /** |
| * __radix_tree_insert - insert into a radix tree |
| * @root: radix tree root |
| * @index: index key |
| * @order: key covers the 2^order indices around index |
| * @item: item to insert |
| * |
| * Insert an item into the radix tree at position @index. |
| */ |
| int __radix_tree_insert(struct radix_tree_root *root, unsigned long index, |
| unsigned order, void *item) |
| { |
| struct radix_tree_node *node; |
| void __rcu **slot; |
| int error; |
| |
| BUG_ON(radix_tree_is_internal_node(item)); |
| |
| error = __radix_tree_create(root, index, order, &node, &slot); |
| if (error) |
| return error; |
| |
| error = insert_entries(node, slot, item, order, false); |
| if (error < 0) |
| return error; |
| |
| if (node) { |
| unsigned offset = get_slot_offset(node, slot); |
| BUG_ON(tag_get(node, 0, offset)); |
| BUG_ON(tag_get(node, 1, offset)); |
| BUG_ON(tag_get(node, 2, offset)); |
| } else { |
| BUG_ON(root_tags_get(root)); |
| } |
| |
| return 0; |
| } |
| EXPORT_SYMBOL(__radix_tree_insert); |
| |
| /** |
| * __radix_tree_lookup - lookup an item in a radix tree |
| * @root: radix tree root |
| * @index: index key |
| * @nodep: returns node |
| * @slotp: returns slot |
| * |
| * Lookup and return the item at position @index in the radix |
| * tree @root. |
| * |
| * Until there is more than one item in the tree, no nodes are |
| * allocated and @root->rnode is used as a direct slot instead of |
| * pointing to a node, in which case *@nodep will be NULL. |
| */ |
| void *__radix_tree_lookup(const struct radix_tree_root *root, |
| unsigned long index, struct radix_tree_node **nodep, |
| void __rcu ***slotp) |
| { |
| struct radix_tree_node *node, *parent; |
| unsigned long maxindex; |
| void __rcu **slot; |
| |
| restart: |
| parent = NULL; |
| slot = (void __rcu **)&root->rnode; |
| radix_tree_load_root(root, &node, &maxindex); |
| if (index > maxindex) |
| return NULL; |
| |
| while (radix_tree_is_internal_node(node)) { |
| unsigned offset; |
| |
| if (node == RADIX_TREE_RETRY) |
| goto restart; |
| parent = entry_to_node(node); |
| offset = radix_tree_descend(parent, &node, index); |
| slot = parent->slots + offset; |
| } |
| |
| if (nodep) |
| *nodep = parent; |
| if (slotp) |
| *slotp = slot; |
| return node; |
| } |
| |
| /** |
| * radix_tree_lookup_slot - lookup a slot in a radix tree |
| * @root: radix tree root |
| * @index: index key |
| * |
| * Returns: the slot corresponding to the position @index in the |
| * radix tree @root. This is useful for update-if-exists operations. |
| * |
| * This function can be called under rcu_read_lock iff the slot is not |
| * modified by radix_tree_replace_slot, otherwise it must be called |
| * exclusive from other writers. Any dereference of the slot must be done |
| * using radix_tree_deref_slot. |
| */ |
| void __rcu **radix_tree_lookup_slot(const struct radix_tree_root *root, |
| unsigned long index) |
| { |
| void __rcu **slot; |
| |
| if (!__radix_tree_lookup(root, index, NULL, &slot)) |
| return NULL; |
| return slot; |
| } |
| EXPORT_SYMBOL(radix_tree_lookup_slot); |
| |
| /** |
| * radix_tree_lookup - perform lookup operation on a radix tree |
| * @root: radix tree root |
| * @index: index key |
| * |
| * Lookup the item at the position @index in the radix tree @root. |
| * |
| * This function can be called under rcu_read_lock, however the caller |
| * must manage lifetimes of leaf nodes (eg. RCU may also be used to free |
| * them safely). No RCU barriers are required to access or modify the |
| * returned item, however. |
| */ |
| void *radix_tree_lookup(const struct radix_tree_root *root, unsigned long index) |
| { |
| return __radix_tree_lookup(root, index, NULL, NULL); |
| } |
| EXPORT_SYMBOL(radix_tree_lookup); |
| |
| static inline void replace_sibling_entries(struct radix_tree_node *node, |
| void __rcu **slot, int count, int exceptional) |
| { |
| #ifdef CONFIG_RADIX_TREE_MULTIORDER |
| void *ptr = node_to_entry(slot); |
| unsigned offset = get_slot_offset(node, slot) + 1; |
| |
| while (offset < RADIX_TREE_MAP_SIZE) { |
| if (rcu_dereference_raw(node->slots[offset]) != ptr) |
| break; |
| if (count < 0) { |
| node->slots[offset] = NULL; |
| node->count--; |
| } |
| node->exceptional += exceptional; |
| offset++; |
| } |
| #endif |
| } |
| |
| static void replace_slot(void __rcu **slot, void *item, |
| struct radix_tree_node *node, int count, int exceptional) |
| { |
| if (WARN_ON_ONCE(radix_tree_is_internal_node(item))) |
| return; |
| |
| if (node && (count || exceptional)) { |
| node->count += count; |
| node->exceptional += exceptional; |
| replace_sibling_entries(node, slot, count, exceptional); |
| } |
| |
| rcu_assign_pointer(*slot, item); |
| } |
| |
| static bool node_tag_get(const struct radix_tree_root *root, |
| const struct radix_tree_node *node, |
| unsigned int tag, unsigned int offset) |
| { |
| if (node) |
| return tag_get(node, tag, offset); |
| return root_tag_get(root, tag); |
| } |
| |
| /* |
| * IDR users want to be able to store NULL in the tree, so if the slot isn't |
| * free, don't adjust the count, even if it's transitioning between NULL and |
| * non-NULL. For the IDA, we mark slots as being IDR_FREE while they still |
| * have empty bits, but it only stores NULL in slots when they're being |
| * deleted. |
| */ |
| static int calculate_count(struct radix_tree_root *root, |
| struct radix_tree_node *node, void __rcu **slot, |
| void *item, void *old) |
| { |
| if (is_idr(root)) { |
| unsigned offset = get_slot_offset(node, slot); |
| bool free = node_tag_get(root, node, IDR_FREE, offset); |
| if (!free) |
| return 0; |
| if (!old) |
| return 1; |
| } |
| return !!item - !!old; |
| } |
| |
| /** |
| * __radix_tree_replace - replace item in a slot |
| * @root: radix tree root |
| * @node: pointer to tree node |
| * @slot: pointer to slot in @node |
| * @item: new item to store in the slot. |
| * @update_node: callback for changing leaf nodes |
| * |
| * For use with __radix_tree_lookup(). Caller must hold tree write locked |
| * across slot lookup and replacement. |
| */ |
| void __radix_tree_replace(struct radix_tree_root *root, |
| struct radix_tree_node *node, |
| void __rcu **slot, void *item, |
| radix_tree_update_node_t update_node) |
| { |
| void *old = rcu_dereference_raw(*slot); |
| int exceptional = !!radix_tree_exceptional_entry(item) - |
| !!radix_tree_exceptional_entry(old); |
| int count = calculate_count(root, node, slot, item, old); |
| |
| /* |
| * This function supports replacing exceptional entries and |
| * deleting entries, but that needs accounting against the |
| * node unless the slot is root->rnode. |
| */ |
| WARN_ON_ONCE(!node && (slot != (void __rcu **)&root->rnode) && |
| (count || exceptional)); |
| replace_slot(slot, item, node, count, exceptional); |
| |
| if (!node) |
| return; |
| |
| if (update_node) |
| update_node(node); |
| |
| delete_node(root, node, update_node); |
| } |
| |
| /** |
| * radix_tree_replace_slot - replace item in a slot |
| * @root: radix tree root |
| * @slot: pointer to slot |
| * @item: new item to store in the slot. |
| * |
| * For use with radix_tree_lookup_slot(), radix_tree_gang_lookup_slot(), |
| * radix_tree_gang_lookup_tag_slot(). Caller must hold tree write locked |
| * across slot lookup and replacement. |
| * |
| * NOTE: This cannot be used to switch between non-entries (empty slots), |
| * regular entries, and exceptional entries, as that requires accounting |
| * inside the radix tree node. When switching from one type of entry or |
| * deleting, use __radix_tree_lookup() and __radix_tree_replace() or |
| * radix_tree_iter_replace(). |
| */ |
| void radix_tree_replace_slot(struct radix_tree_root *root, |
| void __rcu **slot, void *item) |
| { |
| __radix_tree_replace(root, NULL, slot, item, NULL); |
| } |
| EXPORT_SYMBOL(radix_tree_replace_slot); |
| |
| /** |
| * radix_tree_iter_replace - replace item in a slot |
| * @root: radix tree root |
| * @slot: pointer to slot |
| * @item: new item to store in the slot. |
| * |
| * For use with radix_tree_split() and radix_tree_for_each_slot(). |
| * Caller must hold tree write locked across split and replacement. |
| */ |
| void radix_tree_iter_replace(struct radix_tree_root *root, |
| const struct radix_tree_iter *iter, |
| void __rcu **slot, void *item) |
| { |
| __radix_tree_replace(root, iter->node, slot, item, NULL); |
| } |
| |
| #ifdef CONFIG_RADIX_TREE_MULTIORDER |
| /** |
| * radix_tree_join - replace multiple entries with one multiorder entry |
| * @root: radix tree root |
| * @index: an index inside the new entry |
| * @order: order of the new entry |
| * @item: new entry |
| * |
| * Call this function to replace several entries with one larger entry. |
| * The existing entries are presumed to not need freeing as a result of |
| * this call. |
| * |
| * The replacement entry will have all the tags set on it that were set |
| * on any of the entries it is replacing. |
| */ |
| int radix_tree_join(struct radix_tree_root *root, unsigned long index, |
| unsigned order, void *item) |
| { |
| struct radix_tree_node *node; |
| void __rcu **slot; |
| int error; |
| |
| BUG_ON(radix_tree_is_internal_node(item)); |
| |
| error = __radix_tree_create(root, index, order, &node, &slot); |
| if (!error) |
| error = insert_entries(node, slot, item, order, true); |
| if (error > 0) |
| error = 0; |
| |
| return error; |
| } |
| |
| /** |
| * radix_tree_split - Split an entry into smaller entries |
| * @root: radix tree root |
| * @index: An index within the large entry |
| * @order: Order of new entries |
| * |
| * Call this function as the first step in replacing a multiorder entry |
| * with several entries of lower order. After this function returns, |
| * loop over the relevant portion of the tree using radix_tree_for_each_slot() |
| * and call radix_tree_iter_replace() to set up each new entry. |
| * |
| * The tags from this entry are replicated to all the new entries. |
| * |
| * The radix tree should be locked against modification during the entire |
| * replacement operation. Lock-free lookups will see RADIX_TREE_RETRY which |
| * should prompt RCU walkers to restart the lookup from the root. |
| */ |
| int radix_tree_split(struct radix_tree_root *root, unsigned long index, |
| unsigned order) |
| { |
| struct radix_tree_node *parent, *node, *child; |
| void __rcu **slot; |
| unsigned int offset, end; |
| unsigned n, tag, tags = 0; |
| gfp_t gfp = root_gfp_mask(root); |
| |
| if (!__radix_tree_lookup(root, index, &parent, &slot)) |
| return -ENOENT; |
| if (!parent) |
| return -ENOENT; |
| |
| offset = get_slot_offset(parent, slot); |
| |
| for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) |
| if (tag_get(parent, tag, offset)) |
| tags |= 1 << tag; |
| |
| for (end = offset + 1; end < RADIX_TREE_MAP_SIZE; end++) { |
| if (!is_sibling_entry(parent, |
| rcu_dereference_raw(parent->slots[end]))) |
| break; |
| for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) |
| if (tags & (1 << tag)) |
| tag_set(parent, tag, end); |
| /* rcu_assign_pointer ensures tags are set before RETRY */ |
| rcu_assign_pointer(parent->slots[end], RADIX_TREE_RETRY); |
| } |
| rcu_assign_pointer(parent->slots[offset], RADIX_TREE_RETRY); |
| parent->exceptional -= (end - offset); |
| |
| if (order == parent->shift) |
| return 0; |
| if (order > parent->shift) { |
| while (offset < end) |
| offset += insert_entries(parent, &parent->slots[offset], |
| RADIX_TREE_RETRY, order, true); |
| return 0; |
| } |
| |
| node = parent; |
| |
| for (;;) { |
| if (node->shift > order) { |
| child = radix_tree_node_alloc(gfp, node, root, |
| node->shift - RADIX_TREE_MAP_SHIFT, |
| offset, 0, 0); |
| if (!child) |
| goto nomem; |
| if (node != parent) { |
| node->count++; |
| rcu_assign_pointer(node->slots[offset], |
| node_to_entry(child)); |
| for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) |
| if (tags & (1 << tag)) |
| tag_set(node, tag, offset); |
| } |
| |
| node = child; |
| offset = 0; |
| continue; |
| } |
| |
| n = insert_entries(node, &node->slots[offset], |
| RADIX_TREE_RETRY, order, false); |
| BUG_ON(n > RADIX_TREE_MAP_SIZE); |
| |
| for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) |
| if (tags & (1 << tag)) |
| tag_set(node, tag, offset); |
| offset += n; |
| |
| while (offset == RADIX_TREE_MAP_SIZE) { |
| if (node == parent) |
| break; |
| offset = node->offset; |
| child = node; |
| node = node->parent; |
| rcu_assign_pointer(node->slots[offset], |
| node_to_entry(child)); |
| offset++; |
| } |
| if ((node == parent) && (offset == end)) |
| return 0; |
| } |
| |
| nomem: |
| /* Shouldn't happen; did user forget to preload? */ |
| /* TODO: free all the allocated nodes */ |
| WARN_ON(1); |
| return -ENOMEM; |
| } |
| #endif |
| |
| static void node_tag_set(struct radix_tree_root *root, |
| struct radix_tree_node *node, |
| unsigned int tag, unsigned int offset) |
| { |
| while (node) { |
| if (tag_get(node, tag, offset)) |
| return; |
| tag_set(node, tag, offset); |
| offset = node->offset; |
| node = node->parent; |
| } |
| |
| if (!root_tag_get(root, tag)) |
| root_tag_set(root, tag); |
| } |
| |
| /** |
| * radix_tree_tag_set - set a tag on a radix tree node |
| * @root: radix tree root |
| * @index: index key |
| * @tag: tag index |
| * |
| * Set the search tag (which must be < RADIX_TREE_MAX_TAGS) |
| * corresponding to @index in the radix tree. From |
| * the root all the way down to the leaf node. |
| * |
| * Returns the address of the tagged item. Setting a tag on a not-present |
| * item is a bug. |
| */ |
| void *radix_tree_tag_set(struct radix_tree_root *root, |
| unsigned long index, unsigned int tag) |
| { |
| struct radix_tree_node *node, *parent; |
| unsigned long maxindex; |
| |
| radix_tree_load_root(root, &node, &maxindex); |
| BUG_ON(index > maxindex); |
| |
| while (radix_tree_is_internal_node(node)) { |
| unsigned offset; |
| |
| parent = entry_to_node(node); |
| offset = radix_tree_descend(parent, &node, index); |
| BUG_ON(!node); |
| |
| if (!tag_get(parent, tag, offset)) |
| tag_set(parent, tag, offset); |
| } |
| |
| /* set the root's tag bit */ |
| if (!root_tag_get(root, tag)) |
| root_tag_set(root, tag); |
| |
| return node; |
| } |
| EXPORT_SYMBOL(radix_tree_tag_set); |
| |
| /** |
| * radix_tree_iter_tag_set - set a tag on the current iterator entry |
| * @root: radix tree root |
| * @iter: iterator state |
| * @tag: tag to set |
| */ |
| void radix_tree_iter_tag_set(struct radix_tree_root *root, |
| const struct radix_tree_iter *iter, unsigned int tag) |
| { |
| node_tag_set(root, iter->node, tag, iter_offset(iter)); |
| } |
| |
| static void node_tag_clear(struct radix_tree_root *root, |
| struct radix_tree_node *node, |
| unsigned int tag, unsigned int offset) |
| { |
| while (node) { |
| if (!tag_get(node, tag, offset)) |
| return; |
| tag_clear(node, tag, offset); |
| if (any_tag_set(node, tag)) |
| return; |
| |
| offset = node->offset; |
| node = node->parent; |
| } |
| |
| /* clear the root's tag bit */ |
| if (root_tag_get(root, tag)) |
| root_tag_clear(root, tag); |
| } |
| |
| /** |
| * radix_tree_tag_clear - clear a tag on a radix tree node |
| * @root: radix tree root |
| * @index: index key |
| * @tag: tag index |
| * |
| * Clear the search tag (which must be < RADIX_TREE_MAX_TAGS) |
| * corresponding to @index in the radix tree. If this causes |
| * the leaf node to have no tags set then clear the tag in the |
| * next-to-leaf node, etc. |
| * |
| * Returns the address of the tagged item on success, else NULL. ie: |
| * has the same return value and semantics as radix_tree_lookup(). |
| */ |
| void *radix_tree_tag_clear(struct radix_tree_root *root, |
| unsigned long index, unsigned int tag) |
| { |
| struct radix_tree_node *node, *parent; |
| unsigned long maxindex; |
| int uninitialized_var(offset); |
| |
| radix_tree_load_root(root, &node, &maxindex); |
| if (index > maxindex) |
| return NULL; |
| |
| parent = NULL; |
| |
| while (radix_tree_is_internal_node(node)) { |
| parent = entry_to_node(node); |
| offset = radix_tree_descend(parent, &node, index); |
| } |
| |
| if (node) |
| node_tag_clear(root, parent, tag, offset); |
| |
| return node; |
| } |
| EXPORT_SYMBOL(radix_tree_tag_clear); |
| |
| /** |
| * radix_tree_iter_tag_clear - clear a tag on the current iterator entry |
| * @root: radix tree root |
| * @iter: iterator state |
| * @tag: tag to clear |
| */ |
| void radix_tree_iter_tag_clear(struct radix_tree_root *root, |
| const struct radix_tree_iter *iter, unsigned int tag) |
| { |
| node_tag_clear(root, iter->node, tag, iter_offset(iter)); |
| } |
| |
| /** |
| * radix_tree_tag_get - get a tag on a radix tree node |
| * @root: radix tree root |
| * @index: index key |
| * @tag: tag index (< RADIX_TREE_MAX_TAGS) |
| * |
| * Return values: |
| * |
| * 0: tag not present or not set |
| * 1: tag set |
| * |
| * Note that the return value of this function may not be relied on, even if |
| * the RCU lock is held, unless tag modification and node deletion are excluded |
| * from concurrency. |
| */ |
| int radix_tree_tag_get(const struct radix_tree_root *root, |
| unsigned long index, unsigned int tag) |
| { |
| struct radix_tree_node *node, *parent; |
| unsigned long maxindex; |
| |
| if (!root_tag_get(root, tag)) |
| return 0; |
| |
| radix_tree_load_root(root, &node, &maxindex); |
| if (index > maxindex) |
| return 0; |
| |
| while (radix_tree_is_internal_node(node)) { |
| unsigned offset; |
| |
| parent = entry_to_node(node); |
| offset = radix_tree_descend(parent, &node, index); |
| |
| if (!tag_get(parent, tag, offset)) |
| return 0; |
| if (node == RADIX_TREE_RETRY) |
| break; |
| } |
| |
| return 1; |
| } |
| EXPORT_SYMBOL(radix_tree_tag_get); |
| |
| static inline void __set_iter_shift(struct radix_tree_iter *iter, |
| unsigned int shift) |
| { |
| #ifdef CONFIG_RADIX_TREE_MULTIORDER |
| iter->shift = shift; |
| #endif |
| } |
| |
| /* Construct iter->tags bit-mask from node->tags[tag] array */ |
| static void set_iter_tags(struct radix_tree_iter *iter, |
| struct radix_tree_node *node, unsigned offset, |
| unsigned tag) |
| { |
| unsigned tag_long = offset / BITS_PER_LONG; |
| unsigned tag_bit = offset % BITS_PER_LONG; |
| |
| if (!node) { |
| iter->tags = 1; |
| return; |
| } |
| |
| iter->tags = node->tags[tag][tag_long] >> tag_bit; |
| |
| /* This never happens if RADIX_TREE_TAG_LONGS == 1 */ |
| if (tag_long < RADIX_TREE_TAG_LONGS - 1) { |
| /* Pick tags from next element */ |
| if (tag_bit) |
| iter->tags |= node->tags[tag][tag_long + 1] << |
| (BITS_PER_LONG - tag_bit); |
| /* Clip chunk size, here only BITS_PER_LONG tags */ |
| iter->next_index = __radix_tree_iter_add(iter, BITS_PER_LONG); |
| } |
| } |
| |
| #ifdef CONFIG_RADIX_TREE_MULTIORDER |
| static void __rcu **skip_siblings(struct radix_tree_node **nodep, |
| void __rcu **slot, struct radix_tree_iter *iter) |
| { |
| while (iter->index < iter->next_index) { |
| *nodep = rcu_dereference_raw(*slot); |
| if (*nodep && !is_sibling_entry(iter->node, *nodep)) |
| return slot; |
| slot++; |
| iter->index = __radix_tree_iter_add(iter, 1); |
| iter->tags >>= 1; |
| } |
| |
| *nodep = NULL; |
| return NULL; |
| } |
| |
| void __rcu **__radix_tree_next_slot(void __rcu **slot, |
| struct radix_tree_iter *iter, unsigned flags) |
| { |
| unsigned tag = flags & RADIX_TREE_ITER_TAG_MASK; |
| struct radix_tree_node *node; |
| |
| slot = skip_siblings(&node, slot, iter); |
| |
| while (radix_tree_is_internal_node(node)) { |
| unsigned offset; |
| unsigned long next_index; |
| |
| if (node == RADIX_TREE_RETRY) |
| return slot; |
| node = entry_to_node(node); |
| iter->node = node; |
| iter->shift = node->shift; |
| |
| if (flags & RADIX_TREE_ITER_TAGGED) { |
| offset = radix_tree_find_next_bit(node, tag, 0); |
| if (offset == RADIX_TREE_MAP_SIZE) |
| return NULL; |
| slot = &node->slots[offset]; |
| iter->index = __radix_tree_iter_add(iter, offset); |
| set_iter_tags(iter, node, offset, tag); |
| node = rcu_dereference_raw(*slot); |
| } else { |
| offset = 0; |
| slot = &node->slots[0]; |
| for (;;) { |
| node = rcu_dereference_raw(*slot); |
| if (node) |
| break; |
| slot++; |
| offset++; |
| if (offset == RADIX_TREE_MAP_SIZE) |
| return NULL; |
| } |
| iter->index = __radix_tree_iter_add(iter, offset); |
| } |
| if ((flags & RADIX_TREE_ITER_CONTIG) && (offset > 0)) |
| goto none; |
| next_index = (iter->index | shift_maxindex(iter->shift)) + 1; |
| if (next_index < iter->next_index) |
| iter->next_index = next_index; |
| } |
| |
| return slot; |
| none: |
| iter->next_index = 0; |
| return NULL; |
| } |
| EXPORT_SYMBOL(__radix_tree_next_slot); |
| #else |
| static void __rcu **skip_siblings(struct radix_tree_node **nodep, |
| void __rcu **slot, struct radix_tree_iter *iter) |
| { |
| return slot; |
| } |
| #endif |
| |
| void __rcu **radix_tree_iter_resume(void __rcu **slot, |
| struct radix_tree_iter *iter) |
| { |
| struct radix_tree_node *node; |
| |
| slot++; |
| iter->index = __radix_tree_iter_add(iter, 1); |
| skip_siblings(&node, slot, iter); |
| iter->next_index = iter->index; |
| iter->tags = 0; |
| return NULL; |
| } |
| EXPORT_SYMBOL(radix_tree_iter_resume); |
| |
| /** |
| * radix_tree_next_chunk - find next chunk of slots for iteration |
| * |
| * @root: radix tree root |
| * @iter: iterator state |
| * @flags: RADIX_TREE_ITER_* flags and tag index |
| * Returns: pointer to chunk first slot, or NULL if iteration is over |
| */ |
| void __rcu **radix_tree_next_chunk(const struct radix_tree_root *root, |
| struct radix_tree_iter *iter, unsigned flags) |
| { |
| unsigned tag = flags & RADIX_TREE_ITER_TAG_MASK; |
| struct radix_tree_node *node, *child; |
| unsigned long index, offset, maxindex; |
| |
| if ((flags & RADIX_TREE_ITER_TAGGED) && !root_tag_get(root, tag)) |
| return NULL; |
| |
| /* |
| * Catch next_index overflow after ~0UL. iter->index never overflows |
| * during iterating; it can be zero only at the beginning. |
| * And we cannot overflow iter->next_index in a single step, |
| * because RADIX_TREE_MAP_SHIFT < BITS_PER_LONG. |
| * |
| * This condition also used by radix_tree_next_slot() to stop |
| * contiguous iterating, and forbid switching to the next chunk. |
| */ |
| index = iter->next_index; |
| if (!index && iter->index) |
| return NULL; |
| |
| restart: |
| radix_tree_load_root(root, &child, &maxindex); |
| if (index > maxindex) |
| return NULL; |
| if (!child) |
| return NULL; |
| |
| if (!radix_tree_is_internal_node(child)) { |
| /* Single-slot tree */ |
| iter->index = index; |
| iter->next_index = maxindex + 1; |
| iter->tags = 1; |
| iter->node = NULL; |
| __set_iter_shift(iter, 0); |
| return (void __rcu **)&root->rnode; |
| } |
| |
| do { |
| node = entry_to_node(child); |
| offset = radix_tree_descend(node, &child, index); |
| |
| if ((flags & RADIX_TREE_ITER_TAGGED) ? |
| !tag_get(node, tag, offset) : !child) { |
| /* Hole detected */ |
| if (flags & RADIX_TREE_ITER_CONTIG) |
| return NULL; |
| |
| if (flags & RADIX_TREE_ITER_TAGGED) |
| offset = radix_tree_find_next_bit(node, tag, |
| offset + 1); |
| else |
| while (++offset < RADIX_TREE_MAP_SIZE) { |
| void *slot = rcu_dereference_raw( |
| node->slots[offset]); |
| if (is_sibling_entry(node, slot)) |
| continue; |
| if (slot) |
| break; |
| } |
| index &= ~node_maxindex(node); |
| index += offset << node->shift; |
| /* Overflow after ~0UL */ |
| if (!index) |
| return NULL; |
| if (offset == RADIX_TREE_MAP_SIZE) |
| goto restart; |
| child = rcu_dereference_raw(node->slots[offset]); |
| } |
| |
| if (!child) |
| goto restart; |
| if (child == RADIX_TREE_RETRY) |
| break; |
| } while (radix_tree_is_internal_node(child)); |
| |
| /* Update the iterator state */ |
| iter->index = (index &~ node_maxindex(node)) | (offset << node->shift); |
| iter->next_index = (index | node_maxindex(node)) + 1; |
| iter->node = node; |
| __set_iter_shift(iter, node->shift); |
| |
| if (flags & RADIX_TREE_ITER_TAGGED) |
| set_iter_tags(iter, node, offset, tag); |
| |
| return node->slots + offset; |
| } |
| EXPORT_SYMBOL(radix_tree_next_chunk); |
| |
| /** |
| * radix_tree_gang_lookup - perform multiple lookup on a radix tree |
| * @root: radix tree root |
| * @results: where the results of the lookup are placed |
| * @first_index: start the lookup from this key |
| * @max_items: place up to this many items at *results |
| * |
| * Performs an index-ascending scan of the tree for present items. Places |
| * them at *@results and returns the number of items which were placed at |
| * *@results. |
| * |
| * The implementation is naive. |
| * |
| * Like radix_tree_lookup, radix_tree_gang_lookup may be called under |
| * rcu_read_lock. In this case, rather than the returned results being |
| * an atomic snapshot of the tree at a single point in time, the |
| * semantics of an RCU protected gang lookup are as though multiple |
| * radix_tree_lookups have been issued in individual locks, and results |
| * stored in 'results'. |
| */ |
| unsigned int |
| radix_tree_gang_lookup(const struct radix_tree_root *root, void **results, |
| unsigned long first_index, unsigned int max_items) |
| { |
| struct radix_tree_iter iter; |
| void __rcu **slot; |
| unsigned int ret = 0; |
| |
| if (unlikely(!max_items)) |
| return 0; |
| |
| radix_tree_for_each_slot(slot, root, &iter, first_index) { |
| results[ret] = rcu_dereference_raw(*slot); |
| if (!results[ret]) |
| continue; |
| if (radix_tree_is_internal_node(results[ret])) { |
| slot = radix_tree_iter_retry(&iter); |
| continue; |
| } |
| if (++ret == max_items) |
| break; |
| } |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(radix_tree_gang_lookup); |
| |
| /** |
| * radix_tree_gang_lookup_slot - perform multiple slot lookup on radix tree |
| * @root: radix tree root |
| * @results: where the results of the lookup are placed |
| * @indices: where their indices should be placed (but usually NULL) |
| * @first_index: start the lookup from this key |
| * @max_items: place up to this many items at *results |
| * |
| * Performs an index-ascending scan of the tree for present items. Places |
| * their slots at *@results and returns the number of items which were |
| * placed at *@results. |
| * |
| * The implementation is naive. |
| * |
| * Like radix_tree_gang_lookup as far as RCU and locking goes. Slots must |
| * be dereferenced with radix_tree_deref_slot, and if using only RCU |
| * protection, radix_tree_deref_slot may fail requiring a retry. |
| */ |
| unsigned int |
| radix_tree_gang_lookup_slot(const struct radix_tree_root *root, |
| void __rcu ***results, unsigned long *indices, |
| unsigned long first_index, unsigned int max_items) |
| { |
| struct radix_tree_iter iter; |
| void __rcu **slot; |
| unsigned int ret = 0; |
| |
| if (unlikely(!max_items)) |
| return 0; |
| |
| radix_tree_for_each_slot(slot, root, &iter, first_index) { |
| results[ret] = slot; |
| if (indices) |
| indices[ret] = iter.index; |
| if (++ret == max_items) |
| break; |
| } |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(radix_tree_gang_lookup_slot); |
| |
| /** |
| * radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree |
| * based on a tag |
| * @root: radix tree root |
| * @results: where the results of the lookup are placed |
| * @first_index: start the lookup from this key |
| * @max_items: place up to this many items at *results |
| * @tag: the tag index (< RADIX_TREE_MAX_TAGS) |
| * |
| * Performs an index-ascending scan of the tree for present items which |
| * have the tag indexed by @tag set. Places the items at *@results and |
| * returns the number of items which were placed at *@results. |
| */ |
| unsigned int |
| radix_tree_gang_lookup_tag(const struct radix_tree_root *root, void **results, |
| unsigned long first_index, unsigned int max_items, |
| unsigned int tag) |
| { |
| struct radix_tree_iter iter; |
| void __rcu **slot; |
| unsigned int ret = 0; |
| |
| if (unlikely(!max_items)) |
| return 0; |
| |
| radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) { |
| results[ret] = rcu_dereference_raw(*slot); |
| if (!results[ret]) |
| continue; |
| if (radix_tree_is_internal_node(results[ret])) { |
| slot = radix_tree_iter_retry(&iter); |
| continue; |
| } |
| if (++ret == max_items) |
| break; |
| } |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(radix_tree_gang_lookup_tag); |
| |
| /** |
| * radix_tree_gang_lookup_tag_slot - perform multiple slot lookup on a |
| * radix tree based on a tag |
| * @root: radix tree root |
| * @results: where the results of the lookup are placed |
| * @first_index: start the lookup from this key |
| * @max_items: place up to this many items at *results |
| * @tag: the tag index (< RADIX_TREE_MAX_TAGS) |
| * |
| * Performs an index-ascending scan of the tree for present items which |
| * have the tag indexed by @tag set. Places the slots at *@results and |
| * returns the number of slots which were placed at *@results. |
| */ |
| unsigned int |
| radix_tree_gang_lookup_tag_slot(const struct radix_tree_root *root, |
| void __rcu ***results, unsigned long first_index, |
| unsigned int max_items, unsigned int tag) |
| { |
| struct radix_tree_iter iter; |
| void __rcu **slot; |
| unsigned int ret = 0; |
| |
| if (unlikely(!max_items)) |
| return 0; |
| |
| radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) { |
| results[ret] = slot; |
| if (++ret == max_items) |
| break; |
| } |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(radix_tree_gang_lookup_tag_slot); |
| |
| /** |
| * __radix_tree_delete_node - try to free node after clearing a slot |
| * @root: radix tree root |
| * @node: node containing @index |
| * @update_node: callback for changing leaf nodes |
| * |
| * After clearing the slot at @index in @node from radix tree |
| * rooted at @root, call this function to attempt freeing the |
| * node and shrinking the tree. |
| */ |
| void __radix_tree_delete_node(struct radix_tree_root *root, |
| struct radix_tree_node *node, |
| radix_tree_update_node_t update_node) |
| { |
| delete_node(root, node, update_node); |
| } |
| |
| static bool __radix_tree_delete(struct radix_tree_root *root, |
| struct radix_tree_node *node, void __rcu **slot) |
| { |
| void *old = rcu_dereference_raw(*slot); |
| int exceptional = radix_tree_exceptional_entry(old) ? -1 : 0; |
| unsigned offset = get_slot_offset(node, slot); |
| int tag; |
| |
| if (is_idr(root)) |
| node_tag_set(root, node, IDR_FREE, offset); |
| else |
| for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) |
| node_tag_clear(root, node, tag, offset); |
| |
| replace_slot(slot, NULL, node, -1, exceptional); |
| return node && delete_node(root, node, NULL); |
| } |
| |
| /** |
| * radix_tree_iter_delete - delete the entry at this iterator position |
| * @root: radix tree root |
| * @iter: iterator state |
| * @slot: pointer to slot |
| * |
| * Delete the entry at the position currently pointed to by the iterator. |
| * This may result in the current node being freed; if it is, the iterator |
| * is advanced so that it will not reference the freed memory. This |
| * function may be called without any locking if there are no other threads |
| * which can access this tree. |
| */ |
| void radix_tree_iter_delete(struct radix_tree_root *root, |
| struct radix_tree_iter *iter, void __rcu **slot) |
| { |
| if (__radix_tree_delete(root, iter->node, slot)) |
| iter->index = iter->next_index; |
| } |
| EXPORT_SYMBOL(radix_tree_iter_delete); |
| |
| /** |
| * radix_tree_delete_item - delete an item from a radix tree |
| * @root: radix tree root |
| * @index: index key |
| * @item: expected item |
| * |
| * Remove @item at @index from the radix tree rooted at @root. |
| * |
| * Return: the deleted entry, or %NULL if it was not present |
| * or the entry at the given @index was not @item. |
| */ |
| void *radix_tree_delete_item(struct radix_tree_root *root, |
| unsigned long index, void *item) |
| { |
| struct radix_tree_node *node = NULL; |
| void __rcu **slot = NULL; |
| void *entry; |
| |
| entry = __radix_tree_lookup(root, index, &node, &slot); |
| if (!slot) |
| return NULL; |
| if (!entry && (!is_idr(root) || node_tag_get(root, node, IDR_FREE, |
| get_slot_offset(node, slot)))) |
| return NULL; |
| |
| if (item && entry != item) |
| return NULL; |
| |
| __radix_tree_delete(root, node, slot); |
| |
| return entry; |
| } |
| EXPORT_SYMBOL(radix_tree_delete_item); |
| |
| /** |
| * radix_tree_delete - delete an entry from a radix tree |
| * @root: radix tree root |
| * @index: index key |
| * |
| * Remove the entry at @index from the radix tree rooted at @root. |
| * |
| * Return: The deleted entry, or %NULL if it was not present. |
| */ |
| void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) |
| { |
| return radix_tree_delete_item(root, index, NULL); |
| } |
| EXPORT_SYMBOL(radix_tree_delete); |
| |
| void radix_tree_clear_tags(struct radix_tree_root *root, |
| struct radix_tree_node *node, |
| void __rcu **slot) |
| { |
| if (node) { |
| unsigned int tag, offset = get_slot_offset(node, slot); |
| for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) |
| node_tag_clear(root, node, tag, offset); |
| } else { |
| root_tag_clear_all(root); |
| } |
| } |
| |
| /** |
| * radix_tree_tagged - test whether any items in the tree are tagged |
| * @root: radix tree root |
| * @tag: tag to test |
| */ |
| int radix_tree_tagged(const struct radix_tree_root *root, unsigned int tag) |
| { |
| return root_tag_get(root, tag); |
| } |
| EXPORT_SYMBOL(radix_tree_tagged); |
| |
| /** |
| * idr_preload - preload for idr_alloc() |
| * @gfp_mask: allocation mask to use for preloading |
| * |
| * Preallocate memory to use for the next call to idr_alloc(). This function |
| * returns with preemption disabled. It will be enabled by idr_preload_end(). |
| */ |
| void idr_preload(gfp_t gfp_mask) |
| { |
| if (__radix_tree_preload(gfp_mask, IDR_PRELOAD_SIZE)) |
| preempt_disable(); |
| } |
| EXPORT_SYMBOL(idr_preload); |
| |
| /** |
| * ida_pre_get - reserve resources for ida allocation |
| * @ida: ida handle |
| * @gfp: memory allocation flags |
| * |
| * This function should be called before calling ida_get_new_above(). If it |
| * is unable to allocate memory, it will return %0. On success, it returns %1. |
| */ |
| int ida_pre_get(struct ida *ida, gfp_t gfp) |
| { |
| /* |
| * The IDA API has no preload_end() equivalent. Instead, |
| * ida_get_new() can return -EAGAIN, prompting the caller |
| * to return to the ida_pre_get() step. |
| */ |
| if (!__radix_tree_preload(gfp, IDA_PRELOAD_SIZE)) |
| preempt_enable(); |
| |
| if (!this_cpu_read(ida_bitmap)) { |
| struct ida_bitmap *bitmap = kzalloc(sizeof(*bitmap), gfp); |
| if (!bitmap) |
| return 0; |
| if (this_cpu_cmpxchg(ida_bitmap, NULL, bitmap)) |
| kfree(bitmap); |
| } |
| |
| return 1; |
| } |
| EXPORT_SYMBOL(ida_pre_get); |
| |
| void __rcu **idr_get_free(struct radix_tree_root *root, |
| struct radix_tree_iter *iter, gfp_t gfp, |
| unsigned long max) |
| { |
| struct radix_tree_node *node = NULL, *child; |
| void __rcu **slot = (void __rcu **)&root->rnode; |
| unsigned long maxindex, start = iter->next_index; |
| unsigned int shift, offset = 0; |
| |
| grow: |
| shift = radix_tree_load_root(root, &child, &maxindex); |
| if (!radix_tree_tagged(root, IDR_FREE)) |
| start = max(start, maxindex + 1); |
| if (start > max) |
| return ERR_PTR(-ENOSPC); |
| |
| if (start > maxindex) { |
| int error = radix_tree_extend(root, gfp, start, shift); |
| if (error < 0) |
| return ERR_PTR(error); |
| shift = error; |
| child = rcu_dereference_raw(root->rnode); |
| } |
| |
| while (shift) { |
| shift -= RADIX_TREE_MAP_SHIFT; |
| if (child == NULL) { |
| /* Have to add a child node. */ |
| child = radix_tree_node_alloc(gfp, node, root, shift, |
| offset, 0, 0); |
| if (!child) |
| return ERR_PTR(-ENOMEM); |
| all_tag_set(child, IDR_FREE); |
| rcu_assign_pointer(*slot, node_to_entry(child)); |
| if (node) |
| node->count++; |
| } else if (!radix_tree_is_internal_node(child)) |
| break; |
| |
| node = entry_to_node(child); |
| offset = radix_tree_descend(node, &child, start); |
| if (!tag_get(node, IDR_FREE, offset)) { |
| offset = radix_tree_find_next_bit(node, IDR_FREE, |
| offset + 1); |
| start = next_index(start, node, offset); |
| if (start > max) |
| return ERR_PTR(-ENOSPC); |
| while (offset == RADIX_TREE_MAP_SIZE) { |
| offset = node->offset + 1; |
| node = node->parent; |
| if (!node) |
| goto grow; |
| shift = node->shift; |
| } |
| child = rcu_dereference_raw(node->slots[offset]); |
| } |
| slot = &node->slots[offset]; |
| } |
| |
| iter->index = start; |
| if (node) |
| iter->next_index = 1 + min(max, (start | node_maxindex(node))); |
| else |
| iter->next_index = 1; |
| iter->node = node; |
| __set_iter_shift(iter, shift); |
| set_iter_tags(iter, node, offset, IDR_FREE); |
| |
| return slot; |
| } |
| |
| /** |
| * idr_destroy - release all internal memory from an IDR |
| * @idr: idr handle |
| * |
| * After this function is called, the IDR is empty, and may be reused or |
| * the data structure containing it may be freed. |
| * |
| * A typical clean-up sequence for objects stored in an idr tree will use |
| * idr_for_each() to free all objects, if necessary, then idr_destroy() to |
| * free the memory used to keep track of those objects. |
| */ |
| void idr_destroy(struct idr *idr) |
| { |
| struct radix_tree_node *node = rcu_dereference_raw(idr->idr_rt.rnode); |
| if (radix_tree_is_internal_node(node)) |
| radix_tree_free_nodes(node); |
| idr->idr_rt.rnode = NULL; |
| root_tag_set(&idr->idr_rt, IDR_FREE); |
| } |
| EXPORT_SYMBOL(idr_destroy); |
| |
| static void |
| radix_tree_node_ctor(void *arg) |
| { |
| struct radix_tree_node *node = arg; |
| |
| memset(node, 0, sizeof(*node)); |
| INIT_LIST_HEAD(&node->private_list); |
| } |
| |
| static __init unsigned long __maxindex(unsigned int height) |
| { |
| unsigned int width = height * RADIX_TREE_MAP_SHIFT; |
| int shift = RADIX_TREE_INDEX_BITS - width; |
| |
| if (shift < 0) |
| return ~0UL; |
| if (shift >= BITS_PER_LONG) |
| return 0UL; |
| return ~0UL >> shift; |
| } |
| |
| static __init void radix_tree_init_maxnodes(void) |
| { |
| unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH + 1]; |
| unsigned int i, j; |
| |
| for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++) |
| height_to_maxindex[i] = __maxindex(i); |
| for (i = 0; i < ARRAY_SIZE(height_to_maxnodes); i++) { |
| for (j = i; j > 0; j--) |
| height_to_maxnodes[i] += height_to_maxindex[j - 1] + 1; |
| } |
| } |
| |
| static int radix_tree_cpu_dead(unsigned int cpu) |
| { |
| struct radix_tree_preload *rtp; |
| struct radix_tree_node *node; |
| |
| /* Free per-cpu pool of preloaded nodes */ |
| rtp = &per_cpu(radix_tree_preloads, cpu); |
| while (rtp->nr) { |
| node = rtp->nodes; |
| rtp->nodes = node->parent; |
| kmem_cache_free(radix_tree_node_cachep, node); |
| rtp->nr--; |
| } |
| kfree(per_cpu(ida_bitmap, cpu)); |
| per_cpu(ida_bitmap, cpu) = NULL; |
| return 0; |
| } |
| |
| void __init radix_tree_init(void) |
| { |
| int ret; |
| |
| BUILD_BUG_ON(RADIX_TREE_MAX_TAGS + __GFP_BITS_SHIFT > 32); |
| BUILD_BUG_ON(ROOT_IS_IDR & ~GFP_ZONEMASK); |
| radix_tree_node_cachep = kmem_cache_create("radix_tree_node", |
| sizeof(struct radix_tree_node), 0, |
| SLAB_PANIC | SLAB_RECLAIM_ACCOUNT, |
| radix_tree_node_ctor); |
| radix_tree_init_maxnodes(); |
| ret = cpuhp_setup_state_nocalls(CPUHP_RADIX_DEAD, "lib/radix:dead", |
| NULL, radix_tree_cpu_dead); |
| WARN_ON(ret < 0); |
| } |