From 210272a28465a7a31bcd580d2f9529f924965aa5 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Thu, 16 Oct 2008 14:57:54 -0600 Subject: driver core: Remove completion from struct klist_node Removing the completion from klist_node reduces its size from 64 bytes to 28 on x86-64. To maintain the semantics of klist_remove(), we add a single list of klist nodes which are pending deletion and scan them. Signed-off-by: Matthew Wilcox Signed-off-by: Greg Kroah-Hartman --- lib/klist.c | 43 ++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 40 insertions(+), 3 deletions(-) (limited to 'lib/klist.c') diff --git a/lib/klist.c b/lib/klist.c index bbdd3015c2c7..573d6068a42e 100644 --- a/lib/klist.c +++ b/lib/klist.c @@ -36,6 +36,7 @@ #include #include +#include /* * Use the lowest bit of n_klist to mark deleted nodes and exclude @@ -108,7 +109,6 @@ static void add_tail(struct klist *k, struct klist_node *n) static void klist_node_init(struct klist *k, struct klist_node *n) { INIT_LIST_HEAD(&n->n_node); - init_completion(&n->n_removed); kref_init(&n->n_ref); knode_set_klist(n, k); if (k->get) @@ -171,13 +171,34 @@ void klist_add_before(struct klist_node *n, struct klist_node *pos) } EXPORT_SYMBOL_GPL(klist_add_before); +struct klist_waiter { + struct list_head list; + struct klist_node *node; + struct task_struct *process; + int woken; +}; + +static DEFINE_SPINLOCK(klist_remove_lock); +static LIST_HEAD(klist_remove_waiters); + static void klist_release(struct kref *kref) { + struct klist_waiter *waiter, *tmp; struct klist_node *n = container_of(kref, struct klist_node, n_ref); WARN_ON(!knode_dead(n)); list_del(&n->n_node); - complete(&n->n_removed); + spin_lock(&klist_remove_lock); + list_for_each_entry_safe(waiter, tmp, &klist_remove_waiters, list) { + if (waiter->node != n) + continue; + + waiter->woken = 1; + mb(); + wake_up_process(waiter->process); + list_del(&waiter->list); + } + spin_unlock(&klist_remove_lock); knode_set_klist(n, NULL); } @@ -217,8 +238,24 @@ EXPORT_SYMBOL_GPL(klist_del); */ void klist_remove(struct klist_node *n) { + struct klist_waiter waiter; + + waiter.node = n; + waiter.process = current; + waiter.woken = 0; + spin_lock(&klist_remove_lock); + list_add(&waiter.list, &klist_remove_waiters); + spin_unlock(&klist_remove_lock); + klist_del(n); - wait_for_completion(&n->n_removed); + + for (;;) { + set_current_state(TASK_UNINTERRUPTIBLE); + if (waiter.woken) + break; + schedule(); + } + __set_current_state(TASK_RUNNING); } EXPORT_SYMBOL_GPL(klist_remove); -- cgit v1.2.3-70-g09d2