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authorOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>2006-04-18 09:45:18 +0200
committerJens Axboe <axboe@suse.de>2006-04-18 09:45:18 +0200
commitdbecf3ab40b5a6cc4499543778cd9f9682c0abad (patch)
tree56dcd8c30835472b54017e1cb5fd852386ee9e49 /block
parentfba822722e3f9d438fca8fd9541d7ddd447d7a48 (diff)
downloadlinux-linaro-stable-dbecf3ab40b5a6cc4499543778cd9f9682c0abad.tar.gz
[PATCH 2/2] cfq: fix cic's rbtree traversal
When queue dies, we set cic->key=NULL as dead mark. So, when we traverse a rbtree, we must check whether it's still valid key. if it was invalidated, drop it, then restart the traversal from top. Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Signed-off-by: Jens Axboe <axboe@suse.de>
Diffstat (limited to 'block')
-rw-r--r--block/cfq-iosched.c33
1 files changed, 27 insertions, 6 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 01820b1094e9..246feae16c60 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1472,15 +1472,31 @@ out:
return cfqq;
}
+static void
+cfq_drop_dead_cic(struct io_context *ioc, struct cfq_io_context *cic)
+{
+ read_lock(&cfq_exit_lock);
+ rb_erase(&cic->rb_node, &ioc->cic_root);
+ read_unlock(&cfq_exit_lock);
+ kmem_cache_free(cfq_ioc_pool, cic);
+ atomic_dec(&ioc_count);
+}
+
static struct cfq_io_context *
cfq_cic_rb_lookup(struct cfq_data *cfqd, struct io_context *ioc)
{
- struct rb_node *n = ioc->cic_root.rb_node;
+ struct rb_node *n;
struct cfq_io_context *cic;
void *key = cfqd;
+restart:
+ n = ioc->cic_root.rb_node;
while (n) {
cic = rb_entry(n, struct cfq_io_context, rb_node);
+ if (unlikely(!cic->key)) {
+ cfq_drop_dead_cic(ioc, cic);
+ goto restart;
+ }
if (key < cic->key)
n = n->rb_left;
@@ -1497,20 +1513,24 @@ static inline void
cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc,
struct cfq_io_context *cic)
{
- struct rb_node **p = &ioc->cic_root.rb_node;
- struct rb_node *parent = NULL;
+ struct rb_node **p;
+ struct rb_node *parent;
struct cfq_io_context *__cic;
- read_lock(&cfq_exit_lock);
-
cic->ioc = ioc;
cic->key = cfqd;
ioc->set_ioprio = cfq_ioc_set_ioprio;
-
+restart:
+ parent = NULL;
+ p = &ioc->cic_root.rb_node;
while (*p) {
parent = *p;
__cic = rb_entry(parent, struct cfq_io_context, rb_node);
+ if (unlikely(!__cic->key)) {
+ cfq_drop_dead_cic(ioc, cic);
+ goto restart;
+ }
if (cic->key < __cic->key)
p = &(*p)->rb_left;
@@ -1520,6 +1540,7 @@ cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc,
BUG();
}
+ read_lock(&cfq_exit_lock);
rb_link_node(&cic->rb_node, parent, p);
rb_insert_color(&cic->rb_node, &ioc->cic_root);
list_add(&cic->queue_list, &cfqd->cic_list);