diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Kconfig.debug | 21 | ||||
| -rw-r--r-- | lib/idr.c | 11 | ||||
| -rw-r--r-- | lib/radix-tree.c | 297 | ||||
| -rw-r--r-- | lib/rbtree.c | 23 |
4 files changed, 240 insertions, 112 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 9bb7d825ba14..e40a0715f422 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -15,6 +15,21 @@ config PRINTK_TIME The behavior is also controlled by the kernel command line parameter printk.time=1. See Documentation/kernel-parameters.txt +config CONSOLE_LOGLEVEL_DEFAULT + int "Default console loglevel (1-15)" + range 1 15 + default "7" + help + Default loglevel to determine what will be printed on the console. + + Setting a default here is equivalent to passing in loglevel=<x> in + the kernel bootargs. loglevel=<x> continues to override whatever + value is specified here as well. + + Note: This does not affect the log level of un-prefixed prink() + usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT + option. + config MESSAGE_LOGLEVEL_DEFAULT int "Default message log level (1-7)" range 1 7 @@ -26,6 +41,10 @@ config MESSAGE_LOGLEVEL_DEFAULT that are auditing their logs closely may want to set it to a lower priority. + Note: This does not affect what message level gets printed on the console + by default. To change that, use loglevel=<x> in the kernel bootargs, + or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value. + config BOOT_PRINTK_DELAY bool "Delay each boot printk message by N milliseconds" depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY @@ -1986,7 +2005,7 @@ config ARCH_HAS_DEVMEM_IS_ALLOWED config STRICT_DEVMEM bool "Filter access to /dev/mem" - depends on MMU + depends on MMU && DEVMEM depends on ARCH_HAS_DEVMEM_IS_ALLOWED default y if TILE || PPC ---help--- diff --git a/lib/idr.c b/lib/idr.c index 6098336df267..52d2979a05e8 100644 --- a/lib/idr.c +++ b/lib/idr.c @@ -927,6 +927,9 @@ EXPORT_SYMBOL(ida_pre_get); * and go back to the ida_pre_get() call. If the ida is full, it will * return %-ENOSPC. * + * Note that callers must ensure that concurrent access to @ida is not possible. + * See ida_simple_get() for a varaint which takes care of locking. + * * @p_id returns a value in the range @starting_id ... %0x7fffffff. */ int ida_get_new_above(struct ida *ida, int starting_id, int *p_id) @@ -1073,6 +1076,9 @@ EXPORT_SYMBOL(ida_destroy); * Allocates an id in the range start <= id < end, or returns -ENOSPC. * On memory allocation failure, returns -ENOMEM. * + * Compared to ida_get_new_above() this function does its own locking, and + * should be used unless there are special requirements. + * * Use ida_simple_remove() to get rid of an id. */ int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end, @@ -1119,6 +1125,11 @@ EXPORT_SYMBOL(ida_simple_get); * ida_simple_remove - remove an allocated id. * @ida: the (initialized) ida. * @id: the id returned by ida_simple_get. + * + * Use to release an id allocated with ida_simple_get(). + * + * Compared to ida_remove() this function does its own locking, and should be + * used unless there are special requirements. */ void ida_simple_remove(struct ida *ida, unsigned int id) { diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 4b8bb3618b83..2e8c6f7aa56e 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -220,10 +220,10 @@ static void dump_node(struct radix_tree_node *node, unsigned long index) { unsigned long i; - pr_debug("radix node: %p offset %d tags %lx %lx %lx shift %d count %d parent %p\n", + pr_debug("radix node: %p offset %d tags %lx %lx %lx shift %d count %d exceptional %d parent %p\n", node, node->offset, node->tags[0][0], node->tags[1][0], node->tags[2][0], - node->shift, node->count, node->parent); + node->shift, node->count, node->exceptional, node->parent); for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) { unsigned long first = index | (i << node->shift); @@ -325,7 +325,6 @@ static void radix_tree_node_rcu_free(struct rcu_head *head) tag_clear(node, i, 0); node->slots[0] = NULL; - node->count = 0; kmem_cache_free(radix_tree_node_cachep, node); } @@ -522,8 +521,13 @@ static int radix_tree_extend(struct radix_tree_root *root, node->offset = 0; node->count = 1; node->parent = NULL; - if (radix_tree_is_internal_node(slot)) + if (radix_tree_is_internal_node(slot)) { entry_to_node(slot)->parent = node; + } else { + /* Moving an exceptional root->rnode to a node */ + if (radix_tree_exceptional_entry(slot)) + node->exceptional = 1; + } node->slots[0] = slot; slot = node_to_entry(node); rcu_assign_pointer(root->rnode, slot); @@ -534,6 +538,104 @@ 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, + radix_tree_update_node_t update_node, + void *private) +{ + for (;;) { + struct radix_tree_node *node = 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 = 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 = child; + + /* + * 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] = RADIX_TREE_RETRY; + if (update_node) + update_node(node, private); + } + + radix_tree_node_free(node); + } +} + +static void delete_node(struct radix_tree_root *root, + struct radix_tree_node *node, + radix_tree_update_node_t update_node, void *private) +{ + do { + struct radix_tree_node *parent; + + if (node->count) { + if (node == entry_to_node(root->rnode)) + radix_tree_shrink(root, update_node, private); + return; + } + + parent = node->parent; + if (parent) { + parent->slots[node->offset] = NULL; + parent->count--; + } else { + root_tag_clear_all(root); + root->rnode = NULL; + } + + radix_tree_node_free(node); + + node = parent; + } while (node); +} + +/** * __radix_tree_create - create a slot in a radix tree * @root: radix tree root * @index: index key @@ -649,6 +751,8 @@ int __radix_tree_insert(struct radix_tree_root *root, unsigned long index, if (node) { unsigned offset = get_slot_offset(node, slot); node->count++; + if (radix_tree_exceptional_entry(item)) + node->exceptional++; BUG_ON(tag_get(node, 0, offset)); BUG_ON(tag_get(node, 1, offset)); BUG_ON(tag_get(node, 2, offset)); @@ -746,6 +850,85 @@ void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index) } EXPORT_SYMBOL(radix_tree_lookup); +static void replace_slot(struct radix_tree_root *root, + struct radix_tree_node *node, + void **slot, void *item, + bool warn_typeswitch) +{ + 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 (node) { + node->count += count; + node->exceptional += exceptional; + } + + rcu_assign_pointer(*slot, item); +} + +/** + * __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 + * @private: private data to pass to @update_node + * + * 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 **slot, void *item, + radix_tree_update_node_t update_node, void *private) +{ + /* + * 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); + + if (!node) + return; + + if (update_node) + update_node(node, private); + + delete_node(root, node, update_node, private); +} + +/** + * 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(). + */ +void radix_tree_replace_slot(struct radix_tree_root *root, + void **slot, void *item) +{ + replace_slot(root, NULL, slot, item, true); +} + /** * radix_tree_tag_set - set a tag on a radix tree node * @root: radix tree root @@ -1394,75 +1577,6 @@ unsigned long radix_tree_locate_item(struct radix_tree_root *root, void *item) #endif /* CONFIG_SHMEM && CONFIG_SWAP */ /** - * radix_tree_shrink - shrink radix tree to minimum height - * @root radix tree root - */ -static inline bool radix_tree_shrink(struct radix_tree_root *root) -{ - bool shrunk = false; - - for (;;) { - struct radix_tree_node *node = 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 = 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 = child; - - /* - * 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. - */ - if (!radix_tree_is_internal_node(child)) - node->slots[0] = RADIX_TREE_RETRY; - - radix_tree_node_free(node); - shrunk = true; - } - - return shrunk; -} - -/** * __radix_tree_delete_node - try to free node after clearing a slot * @root: radix tree root * @node: node containing @index @@ -1470,39 +1584,11 @@ static inline bool radix_tree_shrink(struct radix_tree_root *root) * 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. - * - * Returns %true if @node was freed, %false otherwise. */ -bool __radix_tree_delete_node(struct radix_tree_root *root, +void __radix_tree_delete_node(struct radix_tree_root *root, struct radix_tree_node *node) { - bool deleted = false; - - do { - struct radix_tree_node *parent; - - if (node->count) { - if (node == entry_to_node(root->rnode)) - deleted |= radix_tree_shrink(root); - return deleted; - } - - parent = node->parent; - if (parent) { - parent->slots[node->offset] = NULL; - parent->count--; - } else { - root_tag_clear_all(root); - root->rnode = NULL; - } - - radix_tree_node_free(node); - deleted = true; - - node = parent; - } while (node); - - return deleted; + delete_node(root, node, NULL, NULL); } static inline void delete_sibling_entries(struct radix_tree_node *node, @@ -1559,10 +1645,7 @@ void *radix_tree_delete_item(struct radix_tree_root *root, node_tag_clear(root, node, tag, offset); delete_sibling_entries(node, node_to_entry(slot), offset); - node->slots[offset] = NULL; - node->count--; - - __radix_tree_delete_node(root, node); + __radix_tree_replace(root, node, slot, NULL, NULL, NULL); return entry; } diff --git a/lib/rbtree.c b/lib/rbtree.c index eb8a19fee110..1f8b112a7c35 100644 --- a/lib/rbtree.c +++ b/lib/rbtree.c @@ -296,11 +296,26 @@ ____rb_erase_color(struct rb_node *parent, struct rb_root *root, * * (p) (p) * / \ / \ - * N S --> N Sl + * N S --> N sl * / \ \ - * sl Sr s + * sl Sr S * \ * Sr + * + * Note: p might be red, and then both + * p and sl are red after rotation(which + * breaks property 4). This is fixed in + * Case 4 (in __rb_rotate_set_parents() + * which set sl the color of p + * and set p RB_BLACK) + * + * (p) (sl) + * / \ / \ + * N sl --> P S + * \ / \ + * S N Sr + * \ + * Sr */ tmp1 = tmp2->rb_right; WRITE_ONCE(sibling->rb_left, tmp1); @@ -365,7 +380,7 @@ ____rb_erase_color(struct rb_node *parent, struct rb_root *root, } break; } - /* Case 3 - right rotate at sibling */ + /* Case 3 - left rotate at sibling */ tmp1 = tmp2->rb_left; WRITE_ONCE(sibling->rb_right, tmp1); WRITE_ONCE(tmp2->rb_left, sibling); @@ -377,7 +392,7 @@ ____rb_erase_color(struct rb_node *parent, struct rb_root *root, tmp1 = sibling; sibling = tmp2; } - /* Case 4 - left rotate at parent + color flips */ + /* Case 4 - right rotate at parent + color flips */ tmp2 = sibling->rb_right; WRITE_ONCE(parent->rb_left, tmp2); WRITE_ONCE(sibling->rb_right, parent); |