#ifndef IOCONTEXT_H
#define IOCONTEXT_H
+#include <linux/radix-tree.h>
+#include <linux/rcupdate.h>
+
/*
* This is the per-process anticipatory I/O scheduler state.
*/
struct cfq_queue;
struct cfq_io_context {
- struct rb_node rb_node;
void *key;
+ unsigned long dead_key;
struct cfq_queue *cfqq[2];
sector_t seek_mean;
struct list_head queue_list;
+ struct hlist_node cic_list;
void (*dtor)(struct io_context *); /* destructor */
void (*exit)(struct io_context *); /* called on task exit */
+
+ struct rcu_head rcu_head;
};
/*
- * This is the per-process I/O subsystem state. It is refcounted and
- * kmalloc'ed. Currently all fields are modified in process io context
- * (apart from the atomic refcount), so require no locking.
+ * I/O subsystem state of the associated processes. It is refcounted
+ * and kmalloc'ed. These could be shared between processes.
*/
struct io_context {
atomic_t refcount;
- struct task_struct *task;
+ atomic_t nr_tasks;
+
+ /* all the fields below are protected by this lock */
+ spinlock_t lock;
unsigned short ioprio;
unsigned short ioprio_changed;
int nr_batch_requests; /* Number of requests left in the batch */
struct as_io_context *aic;
- struct rb_root cic_root;
+ struct radix_tree_root radix_root;
+ struct hlist_head cic_list;
void *ioc_data;
};
+static inline struct io_context *ioc_task_link(struct io_context *ioc)
+{
+ /*
+ * if ref count is zero, don't allow sharing (ioc is going away, it's
+ * a race).
+ */
+ if (ioc && atomic_inc_not_zero(&ioc->refcount)) {
+ atomic_inc(&ioc->nr_tasks);
+ return ioc;
+ }
+
+ return NULL;
+}
+
#endif