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[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>
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parent
fba822722e
commit
dbecf3ab40
1 changed files with 27 additions and 6 deletions
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@ -1472,15 +1472,31 @@ cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk,
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return cfqq;
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return cfqq;
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}
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}
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static void
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cfq_drop_dead_cic(struct io_context *ioc, struct cfq_io_context *cic)
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{
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read_lock(&cfq_exit_lock);
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rb_erase(&cic->rb_node, &ioc->cic_root);
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read_unlock(&cfq_exit_lock);
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kmem_cache_free(cfq_ioc_pool, cic);
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atomic_dec(&ioc_count);
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}
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static struct cfq_io_context *
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static struct cfq_io_context *
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cfq_cic_rb_lookup(struct cfq_data *cfqd, struct io_context *ioc)
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cfq_cic_rb_lookup(struct cfq_data *cfqd, struct io_context *ioc)
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{
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{
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struct rb_node *n = ioc->cic_root.rb_node;
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struct rb_node *n;
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struct cfq_io_context *cic;
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struct cfq_io_context *cic;
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void *key = cfqd;
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void *key = cfqd;
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restart:
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n = ioc->cic_root.rb_node;
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while (n) {
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while (n) {
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cic = rb_entry(n, struct cfq_io_context, rb_node);
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cic = rb_entry(n, struct cfq_io_context, rb_node);
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if (unlikely(!cic->key)) {
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cfq_drop_dead_cic(ioc, cic);
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goto restart;
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}
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if (key < cic->key)
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if (key < cic->key)
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n = n->rb_left;
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n = n->rb_left;
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@ -1497,20 +1513,24 @@ static inline void
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cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc,
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cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc,
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struct cfq_io_context *cic)
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struct cfq_io_context *cic)
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{
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{
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struct rb_node **p = &ioc->cic_root.rb_node;
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struct rb_node **p;
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struct rb_node *parent = NULL;
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struct rb_node *parent;
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struct cfq_io_context *__cic;
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struct cfq_io_context *__cic;
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read_lock(&cfq_exit_lock);
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cic->ioc = ioc;
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cic->ioc = ioc;
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cic->key = cfqd;
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cic->key = cfqd;
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ioc->set_ioprio = cfq_ioc_set_ioprio;
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ioc->set_ioprio = cfq_ioc_set_ioprio;
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restart:
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parent = NULL;
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p = &ioc->cic_root.rb_node;
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while (*p) {
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while (*p) {
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parent = *p;
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parent = *p;
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__cic = rb_entry(parent, struct cfq_io_context, rb_node);
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__cic = rb_entry(parent, struct cfq_io_context, rb_node);
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if (unlikely(!__cic->key)) {
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cfq_drop_dead_cic(ioc, cic);
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goto restart;
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}
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if (cic->key < __cic->key)
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if (cic->key < __cic->key)
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p = &(*p)->rb_left;
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p = &(*p)->rb_left;
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@ -1520,6 +1540,7 @@ cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc,
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BUG();
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BUG();
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}
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}
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read_lock(&cfq_exit_lock);
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rb_link_node(&cic->rb_node, parent, p);
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rb_link_node(&cic->rb_node, parent, p);
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rb_insert_color(&cic->rb_node, &ioc->cic_root);
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rb_insert_color(&cic->rb_node, &ioc->cic_root);
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list_add(&cic->queue_list, &cfqd->cic_list);
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list_add(&cic->queue_list, &cfqd->cic_list);
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