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Revert "commonlib/list: Support circular list"

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This reverts commit c4be70f6ff.

Reason for revert: The CL caused a hang in Depthcharge on
Google/Quartz.

BUG=b:479143030
TEST=Verify boot on Google/Quartz.

Change-Id: I38087d0b2dd218dfb32a02c343b199708bb47d49
Signed-off-by: Kapil Porwal <kapilporwal@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/90956
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
This commit is contained in:
Subrata Banik 2026-01-27 17:13:57 +00:00
commit 4a5567071d
3 changed files with 31 additions and 84 deletions
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21
src/commonlib/include/commonlib/list.h
View file

@ -17,25 +17,14 @@ void list_remove(struct list_node *node);
// Insert list_node node after list_node after in a doubly linked list.
void list_insert_after(struct list_node *node, struct list_node *after);
// Insert list_node node before list_node before in a doubly linked list.
// `before` must not be the placeholder head node.
void list_insert_before(struct list_node *node, struct list_node *before);
// Append the node to the end of the list.
// Appends the node to the end of the list.
void list_append(struct list_node *node, struct list_node *head);
/*
* Explanation of `ptr` initialization:
* 1. head.next != NULL: This means the list isn't empty. As the implementation ensures that
* list_init() is called when the very first element is added, we can safely assume that
* the list is circular, and hence set `ptr` to the 1st element.
* 2. head.next == NULL: This means the list is empty, and list_init() hasn't been called.
* As the `head` arg might be const, we cannot simply call list_init() here. Instead, we set
* `ptr` to a special value such that `&(ptr->member) == &head`, causing the loop to
* terminate immediately.
*/
#define list_for_each(ptr, head, member) \
for ((ptr) = container_of((head).next ?: &(head), typeof(*(ptr)), member); \
(&((ptr)->member) != &(head)); \
(ptr) = container_of((ptr)->member.next, \
#define list_for_each(ptr, head, member) \
for ((ptr) = container_of((head).next, typeof(*(ptr)), member); \
(uintptr_t)ptr + (uintptr_t)offsetof(typeof(*(ptr)), member); \
(ptr) = container_of((ptr)->member.next, \
typeof(*(ptr)), member))
#endif /* __COMMONLIB_LIST_H__ */

24
src/commonlib/list.c
View file

@ -1,22 +1,10 @@
/* Taken from depthcharge: src/base/list.c */
/* SPDX-License-Identifier: GPL-2.0-or-later */
#include <assert.h>
#include <commonlib/list.h>
// Initialize a circular list, with `head` being a placeholder head node.
static void list_init(struct list_node *head)
{
if (!head->next) {
assert(!head->prev);
head->next = head->prev = head;
}
}
void list_remove(struct list_node *node)
{
/* Cannot remove the head node. */
assert(node->prev && node->next);
if (node->prev)
node->prev->next = node->next;
if (node->next)
@ -25,9 +13,6 @@ void list_remove(struct list_node *node)
void list_insert_after(struct list_node *node, struct list_node *after)
{
/* Check uninitialized head node. */
if (after->prev == NULL)
list_init(after);
node->next = after->next;
node->prev = after;
after->next = node;
@ -37,8 +22,6 @@ void list_insert_after(struct list_node *node, struct list_node *after)
void list_insert_before(struct list_node *node, struct list_node *before)
{
/* `before` cannot be an uninitialized head node. */
assert(before->prev)
node->prev = before->prev;
node->next = before;
before->prev = node;
@ -48,7 +31,8 @@ void list_insert_before(struct list_node *node, struct list_node *before)
void list_append(struct list_node *node, struct list_node *head)
{
list_init(head);
/* With a circular list, we just need to insert before the head. */
list_insert_before(node, head);
while (head->next)
head = head->next;
list_insert_after(node, head);
}