[igt-dev] [PATCH i-g-t v26 02/35] lib/igt_list: igt_hlist implementation.
Zbigniew Kempczyński
zbigniew.kempczynski at intel.com
Wed Mar 17 14:45:37 UTC 2021
From: Dominik Grzegorzek <dominik.grzegorzek at intel.com>
Double linked lists with a single pointer list head implementation,
based on similar in the kernel.
Signed-off-by: Dominik Grzegorzek <dominik.grzegorzek at intel.com>
Cc: Zbigniew Kempczyński <zbigniew.kempczynski at intel.com>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Acked-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
lib/igt_list.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++
lib/igt_list.h | 50 +++++++++++++++++++++++++++++++++--
2 files changed, 120 insertions(+), 2 deletions(-)
diff --git a/lib/igt_list.c b/lib/igt_list.c
index 37ae139c4..43200f9b3 100644
--- a/lib/igt_list.c
+++ b/lib/igt_list.c
@@ -22,6 +22,7 @@
*
*/
+#include "assert.h"
#include "igt_list.h"
void IGT_INIT_LIST_HEAD(struct igt_list_head *list)
@@ -81,3 +82,74 @@ bool igt_list_empty(const struct igt_list_head *head)
{
return head->next == head;
}
+
+void igt_hlist_init(struct igt_hlist_node *h)
+{
+ h->next = NULL;
+ h->pprev = NULL;
+}
+
+int igt_hlist_unhashed(const struct igt_hlist_node *h)
+{
+ return !h->pprev;
+}
+
+int igt_hlist_empty(const struct igt_hlist_head *h)
+{
+ return !h->first;
+}
+
+static void __igt_hlist_del(struct igt_hlist_node *n)
+{
+ struct igt_hlist_node *next = n->next;
+ struct igt_hlist_node **pprev = n->pprev;
+
+ *pprev = next;
+ if (next)
+ next->pprev = pprev;
+}
+
+void igt_hlist_del(struct igt_hlist_node *n)
+{
+ __igt_hlist_del(n);
+ n->next = NULL;
+ n->pprev = NULL;
+}
+
+void igt_hlist_del_init(struct igt_hlist_node *n)
+{
+ if (!igt_hlist_unhashed(n)) {
+ __igt_hlist_del(n);
+ igt_hlist_init(n);
+ }
+}
+
+void igt_hlist_add_head(struct igt_hlist_node *n, struct igt_hlist_head *h)
+{
+ struct igt_hlist_node *first = h->first;
+
+ n->next = first;
+ if (first)
+ first->pprev = &n->next;
+ h->first = n;
+ n->pprev = &h->first;
+}
+
+void igt_hlist_add_before(struct igt_hlist_node *n, struct igt_hlist_node *next)
+{
+ assert(next);
+ n->pprev = next->pprev;
+ n->next = next;
+ next->pprev = &n->next;
+ *(n->pprev) = n;
+}
+
+void igt_hlist_add_behind(struct igt_hlist_node *n, struct igt_hlist_node *prev)
+{
+ n->next = prev->next;
+ prev->next = n;
+ n->pprev = &prev->next;
+
+ if (n->next)
+ n->next->pprev = &n->next;
+}
diff --git a/lib/igt_list.h b/lib/igt_list.h
index cc93d7a0d..78e761e05 100644
--- a/lib/igt_list.h
+++ b/lib/igt_list.h
@@ -40,6 +40,10 @@
* igt_list is a doubly-linked list where an instance of igt_list_head is a
* head sentinel and has to be initialized.
*
+ * igt_hist is also an double linked lists, but with a single pointer list head.
+ * Mostly useful for hash tables where the two pointer list head is
+ * too wasteful. You lose the ability to access the tail in O(1).
+ *
* Example usage:
*
* |[<!-- language="C" -->
@@ -71,6 +75,13 @@ struct igt_list_head {
struct igt_list_head *next;
};
+struct igt_hlist_head {
+ struct igt_hlist_node *first;
+};
+
+struct igt_hlist_node {
+ struct igt_hlist_node *next, **pprev;
+};
void IGT_INIT_LIST_HEAD(struct igt_list_head *head);
void igt_list_add(struct igt_list_head *elem, struct igt_list_head *head);
@@ -81,6 +92,17 @@ void igt_list_move_tail(struct igt_list_head *elem, struct igt_list_head *list);
int igt_list_length(const struct igt_list_head *head);
bool igt_list_empty(const struct igt_list_head *head);
+void igt_hlist_init(struct igt_hlist_node *h);
+int igt_hlist_unhashed(const struct igt_hlist_node *h);
+int igt_hlist_empty(const struct igt_hlist_head *h);
+void igt_hlist_del(struct igt_hlist_node *n);
+void igt_hlist_del_init(struct igt_hlist_node *n);
+void igt_hlist_add_head(struct igt_hlist_node *n, struct igt_hlist_head *h);
+void igt_hlist_add_before(struct igt_hlist_node *n,
+ struct igt_hlist_node *next);
+void igt_hlist_add_behind(struct igt_hlist_node *n,
+ struct igt_hlist_node *prev);
+
#define igt_container_of(ptr, sample, member) \
(__typeof__(sample))((char *)(ptr) - \
offsetof(__typeof__(*sample), member))
@@ -96,9 +118,10 @@ bool igt_list_empty(const struct igt_list_head *head);
* Safe against removel of the *current* list element. To achive this it
* requires an extra helper variable `tmp` with the same type as `pos`.
*/
-#define igt_list_for_each_entry_safe(pos, tmp, head, member) \
+
+#define igt_list_for_each_entry_safe(pos, tmp, head, member) \
for (pos = igt_container_of((head)->next, pos, member), \
- tmp = igt_container_of((pos)->member.next, tmp, member); \
+ tmp = igt_container_of((pos)->member.next, tmp, member); \
&pos->member != (head); \
pos = tmp, \
tmp = igt_container_of((pos)->member.next, tmp, member))
@@ -108,6 +131,27 @@ bool igt_list_empty(const struct igt_list_head *head);
&pos->member != (head); \
pos = igt_container_of((pos)->member.prev, pos, member))
+#define igt_list_for_each_entry_safe_reverse(pos, tmp, head, member) \
+ for (pos = igt_container_of((head)->prev, pos, member), \
+ tmp = igt_container_of((pos)->member.prev, tmp, member); \
+ &pos->member != (head); \
+ pos = tmp, \
+ tmp = igt_container_of((pos)->member.prev, tmp, member))
+
+#define igt_hlist_entry_safe(ptr, sample, member) \
+ ({ typeof(ptr) ____ptr = (ptr); \
+ ____ptr ? igt_container_of(____ptr, sample, member) : NULL; \
+ })
+
+#define igt_hlist_for_each_entry(pos, head, member) \
+ for (pos = igt_hlist_entry_safe((head)->first, pos, member); \
+ pos; \
+ pos = igt_hlist_entry_safe((pos)->member.next, pos, member))
+
+#define igt_hlist_for_each_entry_safe(pos, n, head, member) \
+ for (pos = igt_hlist_entry_safe((head)->first, pos, member); \
+ pos && ({ n = pos->member.next; 1; }); \
+ pos = igt_hlist_entry_safe(n, pos, member))
/* IGT custom helpers */
@@ -127,4 +171,6 @@ bool igt_list_empty(const struct igt_list_head *head);
#define igt_list_last_entry(head, type, member) \
igt_container_of((head)->prev, (type), member)
+#define IGT_INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)
+
#endif /* IGT_LIST_H */
--
2.26.0
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