[igt-dev] [PATCH i-g-t v26 02/35] lib/igt_list: igt_hlist implementation.
Jason Ekstrand
jason at jlekstrand.net
Wed Mar 17 16:43:38 UTC 2021
Would it be better to pull the hash table implementation from Mesa?
Or use https://cgit.freedesktop.org/~anholt/hash_table/ which should
be identical, though it may be a bit out-of-date. I've poured enough
hours of my life into finding and fixing the bugs in the Mesa hash
table that IGT rolling its own doesn't really fill me with happy
feelings.
--Jason
On Wed, Mar 17, 2021 at 9:46 AM Zbigniew Kempczyński
<zbigniew.kempczynski at intel.com> wrote:
>
> 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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