From 35534c869c62f59203c1822769bbef14e894a9e9 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Mon, 19 Dec 2016 17:43:19 -0500 Subject: [PATCH] radix tree: constify some pointers If we're just getting the value of a tag, or looking up an entry, we won't modify the radix tree, so we can declare these functions as taking a const pointer. Mostly for documentation purposes, though it might help code generation. Signed-off-by: Matthew Wilcox --- include/linux/radix-tree.h | 22 +++++++-------- lib/radix-tree.c | 57 +++++++++++++++++++++----------------- 2 files changed, 42 insertions(+), 37 deletions(-) diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h index 13d8d741ca34..32683c7c2e0d 100644 --- a/include/linux/radix-tree.h +++ b/include/linux/radix-tree.h @@ -125,7 +125,7 @@ do { \ (root)->rnode = NULL; \ } while (0) -static inline bool radix_tree_empty(struct radix_tree_root *root) +static inline bool radix_tree_empty(const struct radix_tree_root *root) { return root->rnode == NULL; } @@ -294,10 +294,10 @@ static inline int radix_tree_insert(struct radix_tree_root *root, { return __radix_tree_insert(root, index, 0, entry); } -void *__radix_tree_lookup(struct radix_tree_root *root, unsigned long index, +void *__radix_tree_lookup(const struct radix_tree_root *, unsigned long index, struct radix_tree_node **nodep, void ***slotp); -void *radix_tree_lookup(struct radix_tree_root *, unsigned long); -void **radix_tree_lookup_slot(struct radix_tree_root *, unsigned long); +void *radix_tree_lookup(const struct radix_tree_root *, unsigned long); +void **radix_tree_lookup_slot(const struct radix_tree_root *, unsigned long); typedef void (*radix_tree_update_node_t)(struct radix_tree_node *, void *); void __radix_tree_replace(struct radix_tree_root *root, struct radix_tree_node *node, @@ -316,10 +316,10 @@ void *radix_tree_delete(struct radix_tree_root *, unsigned long); void radix_tree_clear_tags(struct radix_tree_root *root, struct radix_tree_node *node, void **slot); -unsigned int radix_tree_gang_lookup(struct radix_tree_root *root, +unsigned int radix_tree_gang_lookup(const struct radix_tree_root *, void **results, unsigned long first_index, unsigned int max_items); -unsigned int radix_tree_gang_lookup_slot(struct radix_tree_root *root, +unsigned int radix_tree_gang_lookup_slot(const struct radix_tree_root *, void ***results, unsigned long *indices, unsigned long first_index, unsigned int max_items); int radix_tree_preload(gfp_t gfp_mask); @@ -330,19 +330,19 @@ void *radix_tree_tag_set(struct radix_tree_root *root, unsigned long index, unsigned int tag); void *radix_tree_tag_clear(struct radix_tree_root *root, unsigned long index, unsigned int tag); -int radix_tree_tag_get(struct radix_tree_root *root, +int radix_tree_tag_get(const struct radix_tree_root *, unsigned long index, unsigned int tag); void radix_tree_iter_tag_set(struct radix_tree_root *root, const struct radix_tree_iter *iter, unsigned int tag); unsigned int -radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, +radix_tree_gang_lookup_tag(const struct radix_tree_root *, void **results, unsigned long first_index, unsigned int max_items, unsigned int tag); unsigned int -radix_tree_gang_lookup_tag_slot(struct radix_tree_root *root, void ***results, +radix_tree_gang_lookup_tag_slot(const struct radix_tree_root *, void ***results, unsigned long first_index, unsigned int max_items, unsigned int tag); -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); static inline void radix_tree_preload_end(void) { @@ -395,7 +395,7 @@ radix_tree_iter_init(struct radix_tree_iter *iter, unsigned long start) * Also it fills @iter with data about chunk: position in the tree (index), * its end (next_index), and constructs a bit mask for tagged iterating (tags). */ -void **radix_tree_next_chunk(struct radix_tree_root *root, +void **radix_tree_next_chunk(const struct radix_tree_root *, struct radix_tree_iter *iter, unsigned flags); /** diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 84812a9fb16f..6f86fbac0e36 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -83,26 +83,28 @@ 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; 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 **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; @@ -122,7 +124,7 @@ 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; } @@ -139,13 +141,13 @@ 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)); } @@ -160,12 +162,12 @@ static inline void root_tag_clear_all(struct radix_tree_root *root) root->gfp_mask &= __GFP_BITS_MASK; } -static inline int root_tag_get(struct radix_tree_root *root, unsigned int tag) +static inline int root_tag_get(const struct radix_tree_root *root, unsigned tag) { return (__force int)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT)); } -static inline unsigned root_tags_get(struct radix_tree_root *root) +static inline unsigned root_tags_get(const struct radix_tree_root *root) { return (__force unsigned)root->gfp_mask >> __GFP_BITS_SHIFT; } @@ -174,7 +176,8 @@ static inline unsigned root_tags_get(struct radix_tree_root *root) * 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++) { @@ -232,7 +235,7 @@ 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); } @@ -510,7 +513,7 @@ 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); @@ -908,8 +911,9 @@ 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 ***slotp) { struct radix_tree_node *node, *parent; unsigned long maxindex; @@ -952,7 +956,8 @@ 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 **radix_tree_lookup_slot(const struct radix_tree_root *root, + unsigned long index) { void **slot; @@ -974,7 +979,7 @@ 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); } @@ -1404,7 +1409,7 @@ 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; @@ -1568,7 +1573,7 @@ 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 **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; @@ -1679,7 +1684,7 @@ 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; @@ -1724,7 +1729,7 @@ 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, +radix_tree_gang_lookup_slot(const struct radix_tree_root *root, void ***results, unsigned long *indices, unsigned long first_index, unsigned int max_items) { @@ -1761,7 +1766,7 @@ 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) { @@ -1802,9 +1807,9 @@ 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 ***results, unsigned long first_index, + unsigned int max_items, unsigned int tag) { struct radix_tree_iter iter; void **slot; @@ -1921,7 +1926,7 @@ 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); } -- 2.20.1