From: Chuck Lever <cel@kernel.org>
To: linux-nfs@vger.kernel.org
Cc: NeilBrown <neilb@suse.de>, Chuck Lever <chuck.lever@oracle.com>
Subject: [PATCH v1 08/17] llist: add interface to check if a node is on a list.
Date: Mon, 11 Sep 2023 10:39:24 -0400 [thread overview]
Message-ID: <169444316412.4327.17559564827280562621.stgit@bazille.1015granger.net> (raw)
In-Reply-To: <169444233785.4327.4365499966926096681.stgit@bazille.1015granger.net>
From: NeilBrown <neilb@suse.de>
With list.h lists, it is easy to test if a node is on a list, providing
it was initialised and that it is removed with list_del_init().
This patch provides similar functionality for llist.h lists.
init_llist_node()
marks a node as being not-on-any-list be setting the ->next pointer to
the node itself.
llist_on_list()
tests if the node is on any list.
llist_del_first_init()
remove the first element from a llist, and marks it as being off-list.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
include/linux/llist.h | 42 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 42 insertions(+)
diff --git a/include/linux/llist.h b/include/linux/llist.h
index 85bda2d02d65..dcb91e3bac1c 100644
--- a/include/linux/llist.h
+++ b/include/linux/llist.h
@@ -73,6 +73,33 @@ static inline void init_llist_head(struct llist_head *list)
list->first = NULL;
}
+/**
+ * init_llist_node - initialize lock-less list node
+ * @node: the node to be initialised
+ *
+ * In cases where there is a need to test if a node is on
+ * a list or not, this initialises the node to clearly
+ * not be on any list.
+ */
+static inline void init_llist_node(struct llist_node *node)
+{
+ node->next = node;
+}
+
+/**
+ * llist_on_list - test if a lock-list list node is on a list
+ * @node: the node to test
+ *
+ * When a node is on a list the ->next pointer will be NULL or
+ * some other node. It can never point to itself. We use that
+ * in init_llist_node() to record that a node is not on any list,
+ * and here to test whether it is on any list.
+ */
+static inline bool llist_on_list(const struct llist_node *node)
+{
+ return node->next != node;
+}
+
/**
* llist_entry - get the struct of this entry
* @ptr: the &struct llist_node pointer.
@@ -249,6 +276,21 @@ static inline struct llist_node *__llist_del_all(struct llist_head *head)
extern struct llist_node *llist_del_first(struct llist_head *head);
+/**
+ * llist_del_first_init - delete first entry from lock-list and mark is as being off-list
+ * @head: the head of lock-less list to delete from.
+ *
+ * This behave the same as llist_del_first() except that llist_init_node() is called
+ * on the returned node so that llist_on_list() will report false for the node.
+ */
+static inline struct llist_node *llist_del_first_init(struct llist_head *head)
+{
+ struct llist_node *n = llist_del_first(head);
+
+ if (n)
+ init_llist_node(n);
+ return n;
+}
struct llist_node *llist_reverse_order(struct llist_node *head);
#endif /* LLIST_H */
next prev parent reply other threads:[~2023-09-11 22:00 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-11 14:38 [PATCH v1 00/17] RPC service thread improvements Chuck Lever
2023-09-11 14:38 ` [PATCH v1 01/17] SUNRPC: move all of xprt handling into svc_xprt_handle() Chuck Lever
2023-09-11 14:38 ` [PATCH v1 02/17] SUNRPC: rename and refactor svc_get_next_xprt() Chuck Lever
2023-09-11 14:38 ` [PATCH v1 03/17] SUNRPC: Clean up bc_svc_process() Chuck Lever
2023-09-11 14:38 ` [PATCH v1 04/17] SUNRPC: integrate back-channel processing with svc_recv() Chuck Lever
2023-09-11 14:39 ` [PATCH v1 05/17] SUNRPC: change how svc threads are asked to exit Chuck Lever
2023-09-11 14:39 ` [PATCH v1 06/17] SUNRPC: add list of idle threads Chuck Lever
2023-09-11 14:39 ` [PATCH v1 07/17] SUNRPC: discard SP_CONGESTED Chuck Lever
2023-09-11 14:39 ` Chuck Lever [this message]
2023-09-11 14:39 ` [PATCH v1 09/17] SUNRPC: change service idle list to be an llist Chuck Lever
2023-09-11 14:39 ` [PATCH v1 10/17] llist: add llist_del_first_this() Chuck Lever
2023-09-11 14:39 ` [PATCH v1 11/17] lib: add light-weight queuing mechanism Chuck Lever
2023-09-11 18:13 ` Andrew Morton
2023-09-11 20:30 ` Chuck Lever III
2023-09-11 21:04 ` Andrew Morton
2023-09-11 23:19 ` NeilBrown
2023-09-12 1:30 ` Andrew Morton
2023-09-14 14:05 ` Chuck Lever III
2023-09-15 1:51 ` NeilBrown
2023-09-15 2:22 ` [PATCH 11/17 SQUASH and replace commit message] " NeilBrown
2023-09-15 15:54 ` Chuck Lever III
2023-09-12 2:37 ` [PATCH v1 11/17] " Kees Cook
2023-09-12 4:08 ` NeilBrown
2023-09-11 14:39 ` [PATCH v1 12/17] SUNRPC: rename some functions from rqst_ to svc_thread_ Chuck Lever
2023-09-11 14:39 ` [PATCH v1 13/17] SUNRPC: only have one thread waking up at a time Chuck Lever
2023-09-11 14:40 ` [PATCH v1 14/17] SUNRPC: use lwq for sp_sockets - renamed to sp_xprts Chuck Lever
2023-09-11 14:40 ` [PATCH v1 15/17] SUNRPC: change sp_nrthreads to atomic_t Chuck Lever
2023-09-11 14:40 ` [PATCH v1 16/17] SUNRPC: discard sp_lock Chuck Lever
2023-09-11 14:40 ` [PATCH v1 17/17] SUNRPC: change the back-channel queue to lwq Chuck Lever
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