1 files changed, 91 insertions, 0 deletions
diff --git a/include/linux/iocontext.h b/include/linux/iocontext.h
new file mode 100644
index 00000000..b2eee896
--- /dev/null
+++ b/include/linux/iocontext.h
@@ -0,0 +1,91 @@
+#ifndef IOCONTEXT_H
+#define IOCONTEXT_H
+
+#include <linux/radix-tree.h>
+#include <linux/rcupdate.h>
+
+struct cfq_queue;
+struct cfq_io_context {
+	void *key;
+
+	struct cfq_queue *cfqq[2];
+
+	struct io_context *ioc;
+
+	unsigned long last_end_request;
+
+	unsigned long ttime_total;
+	unsigned long ttime_samples;
+	unsigned long ttime_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;
+};
+
+/*
+ * I/O subsystem state of the associated processes.  It is refcounted
+ * and kmalloc'ed. These could be shared between processes.
+ */
+struct io_context {
+	atomic_long_t refcount;
+	atomic_t nr_tasks;
+
+	/* all the fields below are protected by this lock */
+	spinlock_t lock;
+
+	unsigned short ioprio;
+	unsigned short ioprio_changed;
+
+#if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
+	unsigned short cgroup_changed;
+#endif
+
+	/*
+	 * For request batching
+	 */
+	int nr_batch_requests;     /* Number of requests left in the batch */
+	unsigned long last_waited; /* Time last woken after wait for request */
+
+	struct radix_tree_root radix_root;
+	struct hlist_head cic_list;
+	void __rcu *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_long_inc_not_zero(&ioc->refcount)) {
+		atomic_inc(&ioc->nr_tasks);
+		return ioc;
+	}
+
+	return NULL;
+}
+
+struct task_struct;
+#ifdef CONFIG_BLOCK
+int put_io_context(struct io_context *ioc);
+void exit_io_context(struct task_struct *task);
+struct io_context *get_io_context(gfp_t gfp_flags, int node);
+struct io_context *alloc_io_context(gfp_t gfp_flags, int node);
+#else
+static inline void exit_io_context(struct task_struct *task)
+{
+}
+
+struct io_context;
+static inline int put_io_context(struct io_context *ioc)
+{
+	return 1;
+}
+#endif
+
+#endif