diff options
Diffstat (limited to 'lib/radix-tree.c')
| -rw-r--r-- | lib/radix-tree.c | 762 |
1 files changed, 533 insertions, 229 deletions
diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 84812a9fb16f..691a9ad48497 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -22,20 +22,21 @@ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ +#include <linux/bitmap.h> +#include <linux/bitops.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/export.h> -#include <linux/radix-tree.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/kmemleak.h> -#include <linux/cpu.h> #include <linux/string.h> -#include <linux/bitops.h> -#include <linux/rcupdate.h> -#include <linux/preempt.h> /* in_interrupt() */ /* Number of nodes in fully populated tree of given height */ @@ -60,11 +61,28 @@ static struct kmem_cache *radix_tree_node_cachep; #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->private_data points to next preallocated node */ + /* nodes->parent points to next preallocated node */ struct radix_tree_node *nodes; }; static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, }; @@ -83,35 +101,38 @@ static inline void *node_to_entry(void *ptr) #ifdef CONFIG_RADIX_TREE_MULTIORDER /* Sibling slots point directly to another slot in the same node */ -static inline bool is_sibling_entry(struct radix_tree_node *parent, void *node) +static inline +bool is_sibling_entry(const struct radix_tree_node *parent, void *node) { - void **ptr = node; + void __rcu **ptr = node; return (parent->slots <= ptr) && (ptr < parent->slots + RADIX_TREE_MAP_SIZE); } #else -static inline bool is_sibling_entry(struct radix_tree_node *parent, void *node) +static inline +bool is_sibling_entry(const struct radix_tree_node *parent, void *node) { return false; } #endif -static inline unsigned long get_slot_offset(struct radix_tree_node *parent, - void **slot) +static inline unsigned long +get_slot_offset(const struct radix_tree_node *parent, void __rcu **slot) { return slot - parent->slots; } -static unsigned int radix_tree_descend(struct radix_tree_node *parent, +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 **entry = rcu_dereference_raw(parent->slots[offset]); + 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 **sibentry = (void **) entry_to_node(entry); + void __rcu **sibentry; + sibentry = (void __rcu **) entry_to_node(entry); offset = get_slot_offset(parent, sibentry); entry = rcu_dereference_raw(*sibentry); } @@ -122,7 +143,7 @@ static unsigned int radix_tree_descend(struct radix_tree_node *parent, return offset; } -static inline gfp_t root_gfp_mask(struct radix_tree_root *root) +static inline gfp_t root_gfp_mask(const struct radix_tree_root *root) { return root->gfp_mask & __GFP_BITS_MASK; } @@ -139,42 +160,48 @@ static inline void tag_clear(struct radix_tree_node *node, unsigned int tag, __clear_bit(offset, node->tags[tag]); } -static inline int tag_get(struct radix_tree_node *node, unsigned int 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 int tag) +static inline void root_tag_set(struct radix_tree_root *root, unsigned tag) { - root->gfp_mask |= (__force gfp_t)(1 << (tag + __GFP_BITS_SHIFT)); + 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 + __GFP_BITS_SHIFT)); + 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 &= __GFP_BITS_MASK; + 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 int root_tag_get(struct radix_tree_root *root, unsigned int tag) +static inline unsigned root_tags_get(const struct radix_tree_root *root) { - return (__force int)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT)); + return (__force unsigned)root->gfp_mask >> ROOT_TAG_SHIFT; } -static inline unsigned root_tags_get(struct radix_tree_root *root) +static inline bool is_idr(const struct radix_tree_root *root) { - return (__force unsigned)root->gfp_mask >> __GFP_BITS_SHIFT; + 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(struct radix_tree_node *node, unsigned int tag) +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++) { @@ -184,6 +211,11 @@ static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag) 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 * @@ -232,11 +264,18 @@ static inline unsigned long shift_maxindex(unsigned int shift) return (RADIX_TREE_MAP_SIZE << shift) - 1; } -static inline unsigned long node_maxindex(struct radix_tree_node *node) +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) { @@ -275,11 +314,59 @@ 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 >> __GFP_BITS_SHIFT); + 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 /* @@ -287,13 +374,12 @@ static void radix_tree_dump(struct radix_tree_root *root) * that the caller has pinned this thread of control to the current CPU. */ static struct radix_tree_node * -radix_tree_node_alloc(struct radix_tree_root *root, - struct radix_tree_node *parent, +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; - gfp_t gfp_mask = root_gfp_mask(root); /* * Preload code isn't irq safe and it doesn't make sense to use @@ -321,8 +407,7 @@ radix_tree_node_alloc(struct radix_tree_root *root, rtp = this_cpu_ptr(&radix_tree_preloads); if (rtp->nr) { ret = rtp->nodes; - rtp->nodes = ret->private_data; - ret->private_data = NULL; + rtp->nodes = ret->parent; rtp->nr--; } /* @@ -336,11 +421,12 @@ radix_tree_node_alloc(struct radix_tree_root *root, out: BUG_ON(radix_tree_is_internal_node(ret)); if (ret) { - ret->parent = parent; ret->shift = shift; ret->offset = offset; ret->count = count; ret->exceptional = exceptional; + ret->parent = parent; + ret->root = root; } return ret; } @@ -399,7 +485,7 @@ static int __radix_tree_preload(gfp_t gfp_mask, unsigned nr) preempt_disable(); rtp = this_cpu_ptr(&radix_tree_preloads); if (rtp->nr < nr) { - node->private_data = rtp->nodes; + node->parent = rtp->nodes; rtp->nodes = node; rtp->nr++; } else { @@ -510,7 +596,7 @@ int radix_tree_maybe_preload_order(gfp_t gfp_mask, int order) return __radix_tree_preload(gfp_mask, nr_nodes); } -static unsigned radix_tree_load_root(struct radix_tree_root *root, +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); @@ -530,10 +616,10 @@ static unsigned radix_tree_load_root(struct radix_tree_root *root, /* * Extend a radix tree so it can store key @index. */ -static int radix_tree_extend(struct radix_tree_root *root, +static int radix_tree_extend(struct radix_tree_root *root, gfp_t gfp, unsigned long index, unsigned int shift) { - struct radix_tree_node *slot; + void *entry; unsigned int maxshift; int tag; @@ -542,32 +628,44 @@ static int radix_tree_extend(struct radix_tree_root *root, while (index > shift_maxindex(maxshift)) maxshift += RADIX_TREE_MAP_SHIFT; - slot = root->rnode; - if (!slot) + 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(root, - NULL, shift, 0, 1, 0); + struct radix_tree_node *node = radix_tree_node_alloc(gfp, NULL, + root, shift, 0, 1, 0); if (!node) return -ENOMEM; - /* Propagate the aggregated tag info into the new root */ - for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { - if (root_tag_get(root, tag)) - tag_set(node, tag, 0); + 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(slot)) { - entry_to_node(slot)->parent = node; - } else if (radix_tree_exceptional_entry(slot)) { + 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; } - node->slots[0] = slot; - slot = node_to_entry(node); - rcu_assign_pointer(root->rnode, slot); + /* + * 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: @@ -578,12 +676,14 @@ out: * radix_tree_shrink - shrink radix tree to minimum height * @root radix tree root */ -static inline void radix_tree_shrink(struct radix_tree_root *root, +static inline bool radix_tree_shrink(struct radix_tree_root *root, radix_tree_update_node_t update_node, void *private) { + bool shrunk = false; + for (;;) { - struct radix_tree_node *node = root->rnode; + struct radix_tree_node *node = rcu_dereference_raw(root->rnode); struct radix_tree_node *child; if (!radix_tree_is_internal_node(node)) @@ -597,7 +697,7 @@ static inline void radix_tree_shrink(struct radix_tree_root *root, */ if (node->count != 1) break; - child = node->slots[0]; + child = rcu_dereference_raw(node->slots[0]); if (!child) break; if (!radix_tree_is_internal_node(child) && node->shift) @@ -613,7 +713,9 @@ static inline void radix_tree_shrink(struct radix_tree_root *root, * (node->slots[0]), it will be safe to dereference the new * one (root->rnode) as far as dependent read barriers go. */ - root->rnode = child; + 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 @@ -635,27 +737,34 @@ static inline void radix_tree_shrink(struct radix_tree_root *root, */ node->count = 0; if (!radix_tree_is_internal_node(child)) { - node->slots[0] = RADIX_TREE_RETRY; + node->slots[0] = (void __rcu *)RADIX_TREE_RETRY; if (update_node) update_node(node, private); } WARN_ON_ONCE(!list_empty(&node->private_list)); radix_tree_node_free(node); + shrunk = true; } + + return shrunk; } -static void delete_node(struct radix_tree_root *root, +static bool delete_node(struct radix_tree_root *root, struct radix_tree_node *node, radix_tree_update_node_t update_node, void *private) { + bool deleted = false; + do { struct radix_tree_node *parent; if (node->count) { - if (node == entry_to_node(root->rnode)) - radix_tree_shrink(root, update_node, private); - return; + if (node_to_entry(node) == + rcu_dereference_raw(root->rnode)) + deleted |= radix_tree_shrink(root, update_node, + private); + return deleted; } parent = node->parent; @@ -663,15 +772,23 @@ static void delete_node(struct radix_tree_root *root, parent->slots[node->offset] = NULL; parent->count--; } else { - root_tag_clear_all(root); + /* + * 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; } /** @@ -693,13 +810,14 @@ static void delete_node(struct radix_tree_root *root, */ int __radix_tree_create(struct radix_tree_root *root, unsigned long index, unsigned order, struct radix_tree_node **nodep, - void ***slotp) + void __rcu ***slotp) { struct radix_tree_node *node = NULL, *child; - void **slot = (void **)&root->rnode; + 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); @@ -707,18 +825,18 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index, if (order > 0 && max == ((1UL << order) - 1)) max++; if (max > maxindex) { - int error = radix_tree_extend(root, max, shift); + int error = radix_tree_extend(root, gfp, max, shift); if (error < 0) return error; shift = error; - child = root->rnode; + 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(root, node, shift, + child = radix_tree_node_alloc(gfp, node, root, shift, offset, 0, 0); if (!child) return -ENOMEM; @@ -741,7 +859,6 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index, return 0; } -#ifdef CONFIG_RADIX_TREE_MULTIORDER /* * 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 @@ -757,7 +874,7 @@ static void radix_tree_free_nodes(struct radix_tree_node *node) struct radix_tree_node *child = entry_to_node(node); for (;;) { - void *entry = child->slots[offset]; + 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); @@ -777,8 +894,9 @@ static void radix_tree_free_nodes(struct radix_tree_node *node) } } -static inline int insert_entries(struct radix_tree_node *node, void **slot, - void *item, unsigned order, bool replace) +#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; @@ -813,7 +931,7 @@ static inline int insert_entries(struct radix_tree_node *node, void **slot, } for (i = 0; i < n; i++) { - struct radix_tree_node *old = slot[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++) @@ -840,8 +958,8 @@ static inline int insert_entries(struct radix_tree_node *node, void **slot, return n; } #else -static inline int insert_entries(struct radix_tree_node *node, void **slot, - void *item, unsigned order, bool replace) +static inline int insert_entries(struct radix_tree_node *node, + void __rcu **slot, void *item, unsigned order, bool replace) { if (*slot) return -EEXIST; @@ -868,7 +986,7 @@ int __radix_tree_insert(struct radix_tree_root *root, unsigned long index, unsigned order, void *item) { struct radix_tree_node *node; - void **slot; + void __rcu **slot; int error; BUG_ON(radix_tree_is_internal_node(item)); @@ -908,16 +1026,17 @@ EXPORT_SYMBOL(__radix_tree_insert); * 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(struct radix_tree_root *root, unsigned long index, - struct radix_tree_node **nodep, void ***slotp) +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 **slot; + void __rcu **slot; restart: parent = NULL; - slot = (void **)&root->rnode; + slot = (void __rcu **)&root->rnode; radix_tree_load_root(root, &node, &maxindex); if (index > maxindex) return NULL; @@ -952,9 +1071,10 @@ void *__radix_tree_lookup(struct radix_tree_root *root, unsigned long index, * exclusive from other writers. Any dereference of the slot must be done * using radix_tree_deref_slot. */ -void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index) +void __rcu **radix_tree_lookup_slot(const struct radix_tree_root *root, + unsigned long index) { - void **slot; + void __rcu **slot; if (!__radix_tree_lookup(root, index, NULL, &slot)) return NULL; @@ -974,75 +1094,76 @@ EXPORT_SYMBOL(radix_tree_lookup_slot); * them safely). No RCU barriers are required to access or modify the * returned item, however. */ -void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index) +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 int slot_count(struct radix_tree_node *node, - void **slot) +static inline void replace_sibling_entries(struct radix_tree_node *node, + void __rcu **slot, int count, int exceptional) { - int n = 1; #ifdef CONFIG_RADIX_TREE_MULTIORDER void *ptr = node_to_entry(slot); - unsigned offset = get_slot_offset(node, slot); - int i; + unsigned offset = get_slot_offset(node, slot) + 1; - for (i = 1; offset + i < RADIX_TREE_MAP_SIZE; i++) { - if (node->slots[offset + i] != ptr) + while (offset < RADIX_TREE_MAP_SIZE) { + if (rcu_dereference_raw(node->slots[offset]) != ptr) break; - n++; + if (count < 0) { + node->slots[offset] = NULL; + node->count--; + } + node->exceptional += exceptional; + offset++; } #endif - return n; } -static void replace_slot(struct radix_tree_root *root, - struct radix_tree_node *node, - void **slot, void *item, - bool warn_typeswitch) +static void replace_slot(void __rcu **slot, void *item, + struct radix_tree_node *node, int count, int exceptional) { - void *old = rcu_dereference_raw(*slot); - int count, exceptional; - - WARN_ON_ONCE(radix_tree_is_internal_node(item)); - - count = !!item - !!old; - exceptional = !!radix_tree_exceptional_entry(item) - - !!radix_tree_exceptional_entry(old); - - WARN_ON_ONCE(warn_typeswitch && (count || exceptional)); + if (WARN_ON_ONCE(radix_tree_is_internal_node(item))) + return; - if (node) { + if (node && (count || exceptional)) { node->count += count; - if (exceptional) { - exceptional *= slot_count(node, slot); - node->exceptional += exceptional; - } + node->exceptional += exceptional; + replace_sibling_entries(node, slot, count, exceptional); } rcu_assign_pointer(*slot, item); } -static inline void delete_sibling_entries(struct radix_tree_node *node, - void **slot) +static bool node_tag_get(const struct radix_tree_root *root, + const struct radix_tree_node *node, + unsigned int tag, unsigned int offset) { -#ifdef CONFIG_RADIX_TREE_MULTIORDER - bool exceptional = radix_tree_exceptional_entry(*slot); - void *ptr = node_to_entry(slot); - unsigned offset = get_slot_offset(node, slot); - int i; + if (node) + return tag_get(node, tag, offset); + return root_tag_get(root, tag); +} - for (i = 1; offset + i < RADIX_TREE_MAP_SIZE; i++) { - if (node->slots[offset + i] != ptr) - break; - node->slots[offset + i] = NULL; - node->count--; - if (exceptional) - node->exceptional--; +/* + * 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; } -#endif + return !!item - !!old; } /** @@ -1059,18 +1180,22 @@ static inline void delete_sibling_entries(struct radix_tree_node *node, */ void __radix_tree_replace(struct radix_tree_root *root, struct radix_tree_node *node, - void **slot, void *item, + void __rcu **slot, void *item, radix_tree_update_node_t update_node, void *private) { - if (!item) - delete_sibling_entries(node, slot); + 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. */ - replace_slot(root, node, slot, item, - !node && slot != (void **)&root->rnode); + WARN_ON_ONCE(!node && (slot != (void __rcu **)&root->rnode) && + (count || exceptional)); + replace_slot(slot, item, node, count, exceptional); if (!node) return; @@ -1098,10 +1223,11 @@ void __radix_tree_replace(struct radix_tree_root *root, * radix_tree_iter_replace(). */ void radix_tree_replace_slot(struct radix_tree_root *root, - void **slot, void *item) + void __rcu **slot, void *item) { - replace_slot(root, NULL, slot, item, true); + __radix_tree_replace(root, NULL, slot, item, NULL, NULL); } +EXPORT_SYMBOL(radix_tree_replace_slot); /** * radix_tree_iter_replace - replace item in a slot @@ -1113,7 +1239,8 @@ void radix_tree_replace_slot(struct radix_tree_root *root, * 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 **slot, void *item) + const struct radix_tree_iter *iter, + void __rcu **slot, void *item) { __radix_tree_replace(root, iter->node, slot, item, NULL, NULL); } @@ -1137,7 +1264,7 @@ int radix_tree_join(struct radix_tree_root *root, unsigned long index, unsigned order, void *item) { struct radix_tree_node *node; - void **slot; + void __rcu **slot; int error; BUG_ON(radix_tree_is_internal_node(item)); @@ -1172,9 +1299,10 @@ int radix_tree_split(struct radix_tree_root *root, unsigned long index, unsigned order) { struct radix_tree_node *parent, *node, *child; - void **slot; + 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; @@ -1188,7 +1316,8 @@ int radix_tree_split(struct radix_tree_root *root, unsigned long index, tags |= 1 << tag; for (end = offset + 1; end < RADIX_TREE_MAP_SIZE; end++) { - if (!is_sibling_entry(parent, parent->slots[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)) @@ -1212,14 +1341,15 @@ int radix_tree_split(struct radix_tree_root *root, unsigned long index, for (;;) { if (node->shift > order) { - child = radix_tree_node_alloc(root, node, + 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++; - node->slots[offset] = node_to_entry(child); + 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); @@ -1261,6 +1391,22 @@ int radix_tree_split(struct radix_tree_root *root, unsigned long index, } #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 @@ -1302,6 +1448,18 @@ void *radix_tree_tag_set(struct radix_tree_root *root, } 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) @@ -1322,34 +1480,6 @@ static void node_tag_clear(struct radix_tree_root *root, root_tag_clear(root, tag); } -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_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)); -} - /** * radix_tree_tag_clear - clear a tag on a radix tree node * @root: radix tree root @@ -1390,6 +1520,18 @@ void *radix_tree_tag_clear(struct radix_tree_root *root, 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 @@ -1404,7 +1546,7 @@ EXPORT_SYMBOL(radix_tree_tag_clear); * the RCU lock is held, unless tag modification and node deletion are excluded * from concurrency. */ -int radix_tree_tag_get(struct radix_tree_root *root, +int radix_tree_tag_get(const struct radix_tree_root *root, unsigned long index, unsigned int tag) { struct radix_tree_node *node, *parent; @@ -1416,8 +1558,6 @@ int radix_tree_tag_get(struct radix_tree_root *root, radix_tree_load_root(root, &node, &maxindex); if (index > maxindex) return 0; - if (node == NULL) - return 0; while (radix_tree_is_internal_node(node)) { unsigned offset; @@ -1425,8 +1565,6 @@ int radix_tree_tag_get(struct radix_tree_root *root, parent = entry_to_node(node); offset = radix_tree_descend(parent, &node, index); - if (!node) - return 0; if (!tag_get(parent, tag, offset)) return 0; if (node == RADIX_TREE_RETRY) @@ -1453,6 +1591,11 @@ static void set_iter_tags(struct radix_tree_iter *iter, 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 */ @@ -1467,8 +1610,8 @@ static void set_iter_tags(struct radix_tree_iter *iter, } #ifdef CONFIG_RADIX_TREE_MULTIORDER -static void **skip_siblings(struct radix_tree_node **nodep, - void **slot, struct radix_tree_iter *iter) +static void __rcu **skip_siblings(struct radix_tree_node **nodep, + void __rcu **slot, struct radix_tree_iter *iter) { void *sib = node_to_entry(slot - 1); @@ -1485,8 +1628,8 @@ static void **skip_siblings(struct radix_tree_node **nodep, return NULL; } -void ** __radix_tree_next_slot(void **slot, struct radix_tree_iter *iter, - unsigned flags) +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 = rcu_dereference_raw(*slot); @@ -1539,20 +1682,20 @@ void ** __radix_tree_next_slot(void **slot, struct radix_tree_iter *iter, } EXPORT_SYMBOL(__radix_tree_next_slot); #else -static void **skip_siblings(struct radix_tree_node **nodep, - void **slot, struct radix_tree_iter *iter) +static void __rcu **skip_siblings(struct radix_tree_node **nodep, + void __rcu **slot, struct radix_tree_iter *iter) { return slot; } #endif -void **radix_tree_iter_resume(void **slot, struct radix_tree_iter *iter) +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); - node = rcu_dereference_raw(*slot); skip_siblings(&node, slot, iter); iter->next_index = iter->index; iter->tags = 0; @@ -1568,7 +1711,7 @@ EXPORT_SYMBOL(radix_tree_iter_resume); * @flags: RADIX_TREE_ITER_* flags and tag index * Returns: pointer to chunk first slot, or NULL if iteration is over */ -void **radix_tree_next_chunk(struct radix_tree_root *root, +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; @@ -1605,7 +1748,7 @@ void **radix_tree_next_chunk(struct radix_tree_root *root, iter->tags = 1; iter->node = NULL; __set_iter_shift(iter, 0); - return (void **)&root->rnode; + return (void __rcu **)&root->rnode; } do { @@ -1623,7 +1766,8 @@ void **radix_tree_next_chunk(struct radix_tree_root *root, offset + 1); else while (++offset < RADIX_TREE_MAP_SIZE) { - void *slot = node->slots[offset]; + void *slot = rcu_dereference_raw( + node->slots[offset]); if (is_sibling_entry(node, slot)) continue; if (slot) @@ -1679,11 +1823,11 @@ EXPORT_SYMBOL(radix_tree_next_chunk); * stored in 'results'. */ unsigned int -radix_tree_gang_lookup(struct radix_tree_root *root, void **results, +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 **slot; + void __rcu **slot; unsigned int ret = 0; if (unlikely(!max_items)) @@ -1724,12 +1868,12 @@ EXPORT_SYMBOL(radix_tree_gang_lookup); * protection, radix_tree_deref_slot may fail requiring a retry. */ unsigned int -radix_tree_gang_lookup_slot(struct radix_tree_root *root, - void ***results, unsigned long *indices, +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 **slot; + void __rcu **slot; unsigned int ret = 0; if (unlikely(!max_items)) @@ -1761,12 +1905,12 @@ EXPORT_SYMBOL(radix_tree_gang_lookup_slot); * returns the number of items which were placed at *@results. */ unsigned int -radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, +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 **slot; + void __rcu **slot; unsigned int ret = 0; if (unlikely(!max_items)) @@ -1802,12 +1946,12 @@ EXPORT_SYMBOL(radix_tree_gang_lookup_tag); * returns the number of slots which were placed at *@results. */ unsigned int -radix_tree_gang_lookup_tag_slot(struct radix_tree_root *root, void ***results, - unsigned long first_index, unsigned int max_items, - unsigned int tag) +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 **slot; + void __rcu **slot; unsigned int ret = 0; if (unlikely(!max_items)) @@ -1842,59 +1986,83 @@ void __radix_tree_delete_node(struct radix_tree_root *root, delete_node(root, node, update_node, private); } +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, NULL); +} + /** - * radix_tree_delete_item - delete an item from a radix tree - * @root: radix tree root - * @index: index key - * @item: expected item + * radix_tree_iter_delete - delete the entry at this iterator position + * @root: radix tree root + * @iter: iterator state + * @slot: pointer to slot * - * Remove @item at @index from the radix tree rooted at @root. + * 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; +} + +/** + * radix_tree_delete_item - delete an item from a radix tree + * @root: radix tree root + * @index: index key + * @item: expected item * - * Returns the address of the deleted item, or NULL if it was not present - * or the entry at the given @index was not @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; - unsigned int offset; - void **slot; + struct radix_tree_node *node = NULL; + void __rcu **slot; void *entry; - int tag; entry = __radix_tree_lookup(root, index, &node, &slot); - if (!entry) + 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; - if (!node) { - root_tag_clear_all(root); - root->rnode = NULL; - return entry; - } - - offset = get_slot_offset(node, slot); - - /* Clear all tags associated with the item to be deleted. */ - for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) - node_tag_clear(root, node, tag, offset); - - __radix_tree_replace(root, node, slot, NULL, NULL, NULL); + __radix_tree_delete(root, node, slot); return entry; } EXPORT_SYMBOL(radix_tree_delete_item); /** - * radix_tree_delete - delete an item from a radix tree - * @root: radix tree root - * @index: index key + * radix_tree_delete - delete an entry from a radix tree + * @root: radix tree root + * @index: index key * - * Remove the item at @index from the radix tree rooted at @root. + * Remove the entry at @index from the radix tree rooted at @root. * - * Returns the address of the deleted item, or NULL if it was not present. + * Return: The deleted entry, or %NULL if it was not present. */ void *radix_tree_delete(struct radix_tree_root *root, unsigned long index) { @@ -1904,15 +2072,14 @@ EXPORT_SYMBOL(radix_tree_delete); void radix_tree_clear_tags(struct radix_tree_root *root, struct radix_tree_node *node, - void **slot) + 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 { - /* Clear root node tags */ - root->gfp_mask &= __GFP_BITS_MASK; + root_tag_clear_all(root); } } @@ -1921,12 +2088,147 @@ void radix_tree_clear_tags(struct radix_tree_root *root, * @root: radix tree root * @tag: tag to test */ -int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag) +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) +{ + __radix_tree_preload(gfp_mask, IDR_PRELOAD_SIZE); +} +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) +{ + __radix_tree_preload(gfp, IDA_PRELOAD_SIZE); + /* + * 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. + */ + preempt_enable(); + + if (!this_cpu_read(ida_bitmap)) { + struct ida_bitmap *bitmap = kmalloc(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, int end) +{ + struct radix_tree_node *node = NULL, *child; + void __rcu **slot = (void __rcu **)&root->rnode; + unsigned long maxindex, start = iter->next_index; + unsigned long max = end > 0 ? end - 1 : INT_MAX; + 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) { @@ -1970,10 +2272,12 @@ static int radix_tree_cpu_dead(unsigned int cpu) rtp = &per_cpu(radix_tree_preloads, cpu); while (rtp->nr) { node = rtp->nodes; - rtp->nodes = node->private_data; + 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; } |