From htejun@gmail.com Tue Apr 22 02:58:55 2008 From: Tejun Heo Date: Tue, 22 Apr 2008 18:58:46 +0900 Subject: klist: implement klist_add_{after|before}() To: James Bottomley , Alan Stern , Andrew Morton , Greg KH , oliver@neukum.org, Alan Cox , zaitcev@redhat.com, Linux Kernel Mailing List , linux-usb@vger.kernel.org Message-ID: <480DB6D6.5040808@gmail.com> Add klist_add_after() and klist_add_before() which puts a new node after and before an existing node, respectively. This is useful for callers which need to keep klist ordered. Note that synchronizing between simultaneous additions for ordering is the caller's responsibility. Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- include/linux/klist.h | 2 ++ lib/klist.c | 38 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 40 insertions(+) --- a/include/linux/klist.h +++ b/include/linux/klist.h @@ -46,6 +46,8 @@ struct klist_node { extern void klist_add_tail(struct klist_node * n, struct klist * k); extern void klist_add_head(struct klist_node * n, struct klist * k); +extern void klist_add_after(struct klist_node * n, struct klist_node * pos); +extern void klist_add_before(struct klist_node * n, struct klist_node * pos); extern void klist_del(struct klist_node * n); extern void klist_remove(struct klist_node * n); --- a/lib/klist.c +++ b/lib/klist.c @@ -120,6 +120,44 @@ void klist_add_tail(struct klist_node * EXPORT_SYMBOL_GPL(klist_add_tail); +/** + * klist_add_after - Init a klist_node and add it after an existing node + * @n: node we're adding. + * @pos: node to put @n after + */ + +void klist_add_after(struct klist_node * n, struct klist_node * pos) +{ + struct klist *k = pos->n_klist; + + klist_node_init(k, n); + spin_lock(&k->k_lock); + list_add(&n->n_node, &pos->n_node); + spin_unlock(&k->k_lock); +} + +EXPORT_SYMBOL_GPL(klist_add_after); + + +/** + * klist_add_before - Init a klist_node and add it before an existing node + * @n: node we're adding. + * @pos: node to put @n after + */ + +void klist_add_before(struct klist_node * n, struct klist_node * pos) +{ + struct klist *k = pos->n_klist; + + klist_node_init(k, n); + spin_lock(&k->k_lock); + list_add_tail(&n->n_node, &pos->n_node); + spin_unlock(&k->k_lock); +} + +EXPORT_SYMBOL_GPL(klist_add_before); + + static void klist_release(struct kref * kref) { struct klist_node * n = container_of(kref, struct klist_node, n_ref);