函数逻辑报告

Linux Kernel

v5.5.9

Brick Technologies Co., Ltd

Source Code:lib\radix-tree.c Create Date:2022-07-27 07:10:27
Last Modify:2022-05-21 10:04:37 Copyright©Brick
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函数名称：idr_get_free

函数原型：void __rcu **idr_get_free(struct xarray *root, struct radix_tree_iter *iter, gfp_t gfp, unsigned long max)

返回类型：void

参数：

类型参数名称
struct xarray *root
struct radix_tree_iter *iter
gfp_tgfp
unsigned longmax
1490  node等于NULL
1491  void __rcu * * slot = (void __rcu * * ) & xa_head
1492  start等于next_index
1493  offset等于0
1495  grow :
1496  shift等于radix_tree_load_root(root, & child, & maxindex)
1497  如果非测试radix树上有项目则start等于max(start, maxindex + 1)
1499  如果start大于max则返回:错误号
1502  如果start大于maxindex则
1503  error等于Extend a radix tree so it can store key @index.
1504  如果error小于0则返回:错误号
1506  shift等于error
1507  child等于Dependency order vs. p above. (xa_head)
1509  如果start恒等于0且shift恒等于0则shift等于adix-tree API starts here **
1512  当shift循环
1513  shift减等于adix-tree API starts here **
1514  如果(child == NULL)则
1516  child等于This assumes that the caller has performed appropriate preallocation, and* that the caller has pinned this thread of control to the current CPU.
1518  如果非child则返回:错误号
1520  all_tag_set(child, The IDR API does not expose the tagging functionality of the radix tree* to users. Use tag 0 to track whether a node has free space below it.)
1521  cu_assign_pointer() - assign to RCU-protected pointer*@p: pointer to assign to*@v: value to assign (publish)* Assigns the specified value to the specified RCU-protected* pointer, ensuring that any concurrent RCU readers will see* any prior initialization( * slot, node_to_entry(child))
1522  如果node则count自加
1524  否则如果非radix_tree_is_internal_node(child)则退出
1527  node等于entry_to_node(child)
1528  offset等于radix_tree_descend(node, & child, start)
1529  如果非tag_get(node, The IDR API does not expose the tagging functionality of the radix tree* to users. Use tag 0 to track whether a node has free space below it., offset)则
1530  offset等于adix_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.
1532  start等于next_index(start, node, offset)
1533  如果start大于max或start恒等于0则返回:错误号
1535  当offset恒等于RADIX_TREE_MAP_SIZE循环
1536  offset等于offset加1
1537  node等于parent
1538  如果非node则转到:grow
1540  shift等于shift
1542  child等于Dependency order vs. p above. (slots[offset])
1544  slot等于slots[offset]
1547  index等于start
1548  如果node则next_index等于1加两数取小(max, (start | node_maxindex(node)))
1550  否则next_index等于1
1552  node等于node
1553  Construct iter->tags bit-mask from node->tags[tag] array
1555  返回:slot
调用者
名称描述
idr_alloc_u32
idr_alloc_u32dr_alloc_u32() - Allocate an ID.*@idr: IDR handle.*@ptr: Pointer to be associated with the new ID.*@nextid: Pointer to an ID.*@max: The maximum ID to allocate (inclusive).*@gfp: Memory allocation flags.