Commit 1c605d67 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'for-linus' of git://brick.kernel.dk/data/git/linux-2.6-block

* 'for-linus' of git://brick.kernel.dk/data/git/linux-2.6-block:
  [PATCH] cfq: Further rbtree traversal and cfq_exit_queue() race fix
  [PATCH 2/2] cfq: fix cic's rbtree traversal
  [PATCH 1/2] iosched: fix typo and barrier()
parents 6fbe85f9 be3b0753
......@@ -1844,9 +1844,10 @@ static void __exit as_exit(void)
DECLARE_COMPLETION(all_gone);
elv_unregister(&iosched_as);
ioc_gone = &all_gone;
barrier();
/* ioc_gone's update must be visible before reading ioc_count */
smp_wmb();
if (atomic_read(&ioc_count))
complete(ioc_gone);
wait_for_completion(ioc_gone);
synchronize_rcu();
kmem_cache_destroy(arq_pool);
}
......
......@@ -1472,19 +1472,37 @@ 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;
void *k, *key = cfqd;
restart:
n = ioc->cic_root.rb_node;
while (n) {
cic = rb_entry(n, struct cfq_io_context, rb_node);
/* ->key must be copied to avoid race with cfq_exit_queue() */
k = cic->key;
if (unlikely(!k)) {
cfq_drop_dead_cic(ioc, cic);
goto restart;
}
if (key < cic->key)
if (key < k)
n = n->rb_left;
else if (key > cic->key)
else if (key > k)
n = n->rb_right;
else
return cic;
......@@ -1497,29 +1515,37 @@ 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);
void *k;
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);
/* ->key must be copied to avoid race with cfq_exit_queue() */
k = __cic->key;
if (unlikely(!k)) {
cfq_drop_dead_cic(ioc, cic);
goto restart;
}
if (cic->key < __cic->key)
if (cic->key < k)
p = &(*p)->rb_left;
else if (cic->key > __cic->key)
else if (cic->key > k)
p = &(*p)->rb_right;
else
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);
......@@ -2439,9 +2465,10 @@ static void __exit cfq_exit(void)
DECLARE_COMPLETION(all_gone);
elv_unregister(&iosched_cfq);
ioc_gone = &all_gone;
barrier();
/* ioc_gone's update must be visible before reading ioc_count */
smp_wmb();
if (atomic_read(&ioc_count))
complete(ioc_gone);
wait_for_completion(ioc_gone);
synchronize_rcu();
cfq_slab_kill();
}
......
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