a3449ded12
Fixup below build error: include/linux/list_nulls.h: In function ‘hlist_nulls_del’: include/linux/list_nulls.h:84:13: error: ‘LIST_POISON2’ undeclared (first use in this function) Signed-off-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
116 lines
3.2 KiB
C
116 lines
3.2 KiB
C
#ifndef _LINUX_LIST_NULLS_H
|
|
#define _LINUX_LIST_NULLS_H
|
|
|
|
#include <linux/poison.h>
|
|
#include <linux/const.h>
|
|
|
|
/*
|
|
* Special version of lists, where end of list is not a NULL pointer,
|
|
* but a 'nulls' marker, which can have many different values.
|
|
* (up to 2^31 different values guaranteed on all platforms)
|
|
*
|
|
* In the standard hlist, termination of a list is the NULL pointer.
|
|
* In this special 'nulls' variant, we use the fact that objects stored in
|
|
* a list are aligned on a word (4 or 8 bytes alignment).
|
|
* We therefore use the last significant bit of 'ptr' :
|
|
* Set to 1 : This is a 'nulls' end-of-list marker (ptr >> 1)
|
|
* Set to 0 : This is a pointer to some object (ptr)
|
|
*/
|
|
|
|
struct hlist_nulls_head {
|
|
struct hlist_nulls_node *first;
|
|
};
|
|
|
|
struct hlist_nulls_node {
|
|
struct hlist_nulls_node *next, **pprev;
|
|
};
|
|
#define NULLS_MARKER(value) (1UL | (((long)value) << 1))
|
|
#define INIT_HLIST_NULLS_HEAD(ptr, nulls) \
|
|
((ptr)->first = (struct hlist_nulls_node *) NULLS_MARKER(nulls))
|
|
|
|
#define hlist_nulls_entry(ptr, type, member) container_of(ptr,type,member)
|
|
/**
|
|
* ptr_is_a_nulls - Test if a ptr is a nulls
|
|
* @ptr: ptr to be tested
|
|
*
|
|
*/
|
|
static inline int is_a_nulls(const struct hlist_nulls_node *ptr)
|
|
{
|
|
return ((unsigned long)ptr & 1);
|
|
}
|
|
|
|
/**
|
|
* get_nulls_value - Get the 'nulls' value of the end of chain
|
|
* @ptr: end of chain
|
|
*
|
|
* Should be called only if is_a_nulls(ptr);
|
|
*/
|
|
static inline unsigned long get_nulls_value(const struct hlist_nulls_node *ptr)
|
|
{
|
|
return ((unsigned long)ptr) >> 1;
|
|
}
|
|
|
|
static inline int hlist_nulls_unhashed(const struct hlist_nulls_node *h)
|
|
{
|
|
return !h->pprev;
|
|
}
|
|
|
|
static inline int hlist_nulls_empty(const struct hlist_nulls_head *h)
|
|
{
|
|
return is_a_nulls(h->first);
|
|
}
|
|
|
|
static inline void hlist_nulls_add_head(struct hlist_nulls_node *n,
|
|
struct hlist_nulls_head *h)
|
|
{
|
|
struct hlist_nulls_node *first = h->first;
|
|
|
|
n->next = first;
|
|
n->pprev = &h->first;
|
|
h->first = n;
|
|
if (!is_a_nulls(first))
|
|
first->pprev = &n->next;
|
|
}
|
|
|
|
static inline void __hlist_nulls_del(struct hlist_nulls_node *n)
|
|
{
|
|
struct hlist_nulls_node *next = n->next;
|
|
struct hlist_nulls_node **pprev = n->pprev;
|
|
*pprev = next;
|
|
if (!is_a_nulls(next))
|
|
next->pprev = pprev;
|
|
}
|
|
|
|
static inline void hlist_nulls_del(struct hlist_nulls_node *n)
|
|
{
|
|
__hlist_nulls_del(n);
|
|
n->pprev = LIST_POISON2;
|
|
}
|
|
|
|
/**
|
|
* hlist_nulls_for_each_entry - iterate over list of given type
|
|
* @tpos: the type * to use as a loop cursor.
|
|
* @pos: the &struct hlist_node to use as a loop cursor.
|
|
* @head: the head for your list.
|
|
* @member: the name of the hlist_node within the struct.
|
|
*
|
|
*/
|
|
#define hlist_nulls_for_each_entry(tpos, pos, head, member) \
|
|
for (pos = (head)->first; \
|
|
(!is_a_nulls(pos)) && \
|
|
({ tpos = hlist_nulls_entry(pos, typeof(*tpos), member); 1;}); \
|
|
pos = pos->next)
|
|
|
|
/**
|
|
* hlist_nulls_for_each_entry_from - iterate over a hlist continuing from current point
|
|
* @tpos: the type * to use as a loop cursor.
|
|
* @pos: the &struct hlist_node to use as a loop cursor.
|
|
* @member: the name of the hlist_node within the struct.
|
|
*
|
|
*/
|
|
#define hlist_nulls_for_each_entry_from(tpos, pos, member) \
|
|
for (; (!is_a_nulls(pos)) && \
|
|
({ tpos = hlist_nulls_entry(pos, typeof(*tpos), member); 1;}); \
|
|
pos = pos->next)
|
|
|
|
#endif
|