diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-16 19:50:13 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-16 19:50:13 -0700 |
commit | 517d08699b250021303f9a7cf0d758b6dc0748ed (patch) | |
tree | 5e5b0134c3fffb78fe9d8b1641a64ff28fdd7bbc /lib/radix-tree.c | |
parent | 8eeee4e2f04fc551f50c9d9847da2d73d7d33728 (diff) | |
parent | a34601c5d84134055782ee031d58d82f5440e918 (diff) |
Merge branch 'akpm'
* akpm: (182 commits)
fbdev: bf54x-lq043fb: use kzalloc over kmalloc/memset
fbdev: *bfin*: fix __dev{init,exit} markings
fbdev: *bfin*: drop unnecessary calls to memset
fbdev: bfin-t350mcqb-fb: drop unused local variables
fbdev: blackfin has __raw I/O accessors, so use them in fb.h
fbdev: s1d13xxxfb: add accelerated bitblt functions
tcx: use standard fields for framebuffer physical address and length
fbdev: add support for handoff from firmware to hw framebuffers
intelfb: fix a bug when changing video timing
fbdev: use framebuffer_release() for freeing fb_info structures
radeon: P2G2CLK_ALWAYS_ONb tested twice, should 2nd be P2G2CLK_DAC_ALWAYS_ONb?
s3c-fb: CPUFREQ frequency scaling support
s3c-fb: fix resource releasing on error during probing
carminefb: fix possible access beyond end of carmine_modedb[]
acornfb: remove fb_mmap function
mb862xxfb: use CONFIG_OF instead of CONFIG_PPC_OF
mb862xxfb: restrict compliation of platform driver to PPC
Samsung SoC Framebuffer driver: add Alpha Channel support
atmel-lcdc: fix pixclock upper bound detection
offb: use framebuffer_alloc() to allocate fb_info struct
...
Manually fix up conflicts due to kmemcheck in mm/slab.c
Diffstat (limited to 'lib/radix-tree.c')
-rw-r--r-- | lib/radix-tree.c | 110 |
1 files changed, 63 insertions, 47 deletions
diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 4bb42a0344e..23abbd93cae 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -351,20 +351,12 @@ int radix_tree_insert(struct radix_tree_root *root, } EXPORT_SYMBOL(radix_tree_insert); -/** - * 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. +/* + * is_slot == 1 : search for the slot. + * is_slot == 0 : search for the node. */ -void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index) +static void *radix_tree_lookup_element(struct radix_tree_root *root, + unsigned long index, int is_slot) { unsigned int height, shift; struct radix_tree_node *node, **slot; @@ -376,7 +368,7 @@ void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index) if (!radix_tree_is_indirect_ptr(node)) { if (index > 0) return NULL; - return (void **)&root->rnode; + return is_slot ? (void *)&root->rnode : node; } node = radix_tree_indirect_to_ptr(node); @@ -397,7 +389,25 @@ void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index) height--; } while (height > 0); - return (void **)slot; + return is_slot ? (void *)slot: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 **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index) +{ + return (void **)radix_tree_lookup_element(root, index, 1); } EXPORT_SYMBOL(radix_tree_lookup_slot); @@ -415,38 +425,7 @@ EXPORT_SYMBOL(radix_tree_lookup_slot); */ void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index) { - unsigned int height, shift; - struct radix_tree_node *node, **slot; - - node = rcu_dereference(root->rnode); - if (node == NULL) - return NULL; - - if (!radix_tree_is_indirect_ptr(node)) { - if (index > 0) - return NULL; - return node; - } - node = radix_tree_indirect_to_ptr(node); - - height = node->height; - if (index > radix_tree_maxindex(height)) - return NULL; - - shift = (height-1) * RADIX_TREE_MAP_SHIFT; - - do { - slot = (struct radix_tree_node **) - (node->slots + ((index>>shift) & RADIX_TREE_MAP_MASK)); - node = rcu_dereference(*slot); - if (node == NULL) - return NULL; - - shift -= RADIX_TREE_MAP_SHIFT; - height--; - } while (height > 0); - - return node; + return radix_tree_lookup_element(root, index, 0); } EXPORT_SYMBOL(radix_tree_lookup); @@ -666,6 +645,43 @@ unsigned long radix_tree_next_hole(struct radix_tree_root *root, } EXPORT_SYMBOL(radix_tree_next_hole); +/** + * radix_tree_prev_hole - find the prev hole (not-present entry) + * @root: tree root + * @index: index key + * @max_scan: maximum range to search + * + * Search backwards in the range [max(index-max_scan+1, 0), index] + * for the first hole. + * + * Returns: the index of the hole if found, otherwise returns an index + * outside of the set specified (in which case 'index - return >= max_scan' + * will be true). In rare cases of wrap-around, LONG_MAX will be returned. + * + * radix_tree_next_hole may be called under rcu_read_lock. However, like + * radix_tree_gang_lookup, this will not atomically search a snapshot of + * the tree at a single point in time. For example, if a hole is created + * at index 10, then subsequently a hole is created at index 5, + * radix_tree_prev_hole covering both indexes may return 5 if called under + * rcu_read_lock. + */ +unsigned long radix_tree_prev_hole(struct radix_tree_root *root, + unsigned long index, unsigned long max_scan) +{ + unsigned long i; + + for (i = 0; i < max_scan; i++) { + if (!radix_tree_lookup(root, index)) + break; + index--; + if (index == LONG_MAX) + break; + } + + return index; +} +EXPORT_SYMBOL(radix_tree_prev_hole); + static unsigned int __lookup(struct radix_tree_node *slot, void ***results, unsigned long index, unsigned int max_items, unsigned long *next_index) |