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authorMatthew Wilcox <matthew@wil.cx>2008-10-16 14:57:54 -0600
committerGreg Kroah-Hartman <gregkh@suse.de>2009-01-06 10:44:30 -0800
commit210272a28465a7a31bcd580d2f9529f924965aa5 (patch)
treebd368e8f27c7691b12deaafc1a52c79db1fa1cc9 /lib/klist.c
parent929d2fa5955ab27aa21fac615b23e0e92e8dc3a0 (diff)
downloadlwn-210272a28465a7a31bcd580d2f9529f924965aa5.tar.gz
lwn-210272a28465a7a31bcd580d2f9529f924965aa5.zip
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 <willy@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'lib/klist.c')
-rw-r--r--lib/klist.c43
1 files changed, 40 insertions, 3 deletions
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 <linux/klist.h>
#include <linux/module.h>
+#include <linux/sched.h>
/*
* 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);