Commit 923d1592 authored by Dylan Yudaken's avatar Dylan Yudaken Committed by Jens Axboe
Browse files

io_uring: introduce llist helpers 



Introduce helpers to atomically switch llist.

Will later move this into common code

Signed-off-by: default avatarDylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220622134028.2013417-5-dylany@fb.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent f88262e6

io_uring/io_uring.c

+30 −0
Original line number Diff line number Diff line
@@ -1009,6 +1009,36 @@ static void handle_tw_list(struct llist_node *node, 
	} while (node);

}



/**

 * io_llist_xchg - swap all entries in a lock-less list

 * @head:	the head of lock-less list to delete all entries

 * @new:	new entry as the head of the list

 *

 * If list is empty, return NULL, otherwise, return the pointer to the first entry.

 * The order of entries returned is from the newest to the oldest added one.

 */

static inline struct llist_node *io_llist_xchg(struct llist_head *head,

					       struct llist_node *new)

{

	return xchg(&head->first, new);

}



/**

 * io_llist_cmpxchg - possibly swap all entries in a lock-less list

 * @head:	the head of lock-less list to delete all entries

 * @old:	expected old value of the first entry of the list

 * @new:	new entry as the head of the list

 *

 * perform a cmpxchg on the first entry of the list.

 */



static inline struct llist_node *io_llist_cmpxchg(struct llist_head *head,

						  struct llist_node *old,

						  struct llist_node *new)

{

	return cmpxchg(&head->first, old, new);

}



void tctx_task_work(struct callback_head *cb)

{

	bool uring_locked = false;