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| author | Luca Ceresoli <luca.ceresoli@bootlin.com> | 2025-08-01 20:05:23 +0300 |
|---|---|---|
| committer | Luca Ceresoli <luca.ceresoli@bootlin.com> | 2025-09-02 12:38:29 +0300 |
| commit | cb86408b1fc2e3f6fe45ebe8509a5404060e01e0 (patch) | |
| tree | 7adb860b00c73ab115c9e41d90b7dde092124682 /include/linux | |
| parent | 2a06126d1624f0661fac0833e7ee1dbdc636154e (diff) | |
| download | linux-cb86408b1fc2e3f6fe45ebe8509a5404060e01e0.tar.xz | |
list: add list_last_entry_or_null()
Add an equivalent of list_first_entry_or_null() to obtain the last element
of a list.
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20250801-drm-bridge-alloc-getput-drm_bridge_get_next_bridge-v2-1-888912b0be13@bootlin.com
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/list.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/include/linux/list.h b/include/linux/list.h index e7e28afd28f8..7f7657e41620 100644 --- a/include/linux/list.h +++ b/include/linux/list.h @@ -637,6 +637,20 @@ static inline void list_splice_tail_init(struct list_head *list, }) /** + * list_last_entry_or_null - get the last element from a list + * @ptr: the list head to take the element from. + * @type: the type of the struct this is embedded in. + * @member: the name of the list_head within the struct. + * + * Note that if the list is empty, it returns NULL. + */ +#define list_last_entry_or_null(ptr, type, member) ({ \ + struct list_head *head__ = (ptr); \ + struct list_head *pos__ = READ_ONCE(head__->prev); \ + pos__ != head__ ? list_entry(pos__, type, member) : NULL; \ +}) + +/** * list_next_entry - get the next element in list * @pos: the type * to cursor * @member: the name of the list_head within the struct. |