1 files changed, 95 insertions, 0 deletions

diff --git a/include/linux/iocontext.h b/include/linux/iocontext.h
new file mode 100644
index 000000000000..593b222d9dcc
--- /dev/null
+++ b/include/linux/iocontext.h
@@ -0,0 +1,95 @@
+#ifndef IOCONTEXT_H
+#define IOCONTEXT_H
+
+#include <linux/radix-tree.h>
+
+/*
+ * This is the per-process anticipatory I/O scheduler state.
+ */
+struct as_io_context {
+        spinlock_t lock;
+
+        void (*dtor)(struct as_io_context *aic); /* destructor */
+        void (*exit)(struct as_io_context *aic); /* called on task exit */
+
+        unsigned long state;
+        atomic_t nr_queued; /* queued reads & sync writes */
+        atomic_t nr_dispatched; /* number of requests gone to the drivers */
+
+        /* IO History tracking */
+        /* Thinktime */
+        unsigned long last_end_request;
+        unsigned long ttime_total;
+        unsigned long ttime_samples;
+        unsigned long ttime_mean;
+        /* Layout pattern */
+        unsigned int seek_samples;
+        sector_t last_request_pos;
+        u64 seek_total;
+        sector_t seek_mean;
+};
+
+struct cfq_queue;
+struct cfq_io_context {
+        void *key;
+        unsigned long dead_key;
+
+        struct cfq_queue *cfqq[2];
+
+        struct io_context *ioc;
+
+        unsigned long last_end_request;
+        sector_t last_request_pos;
+
+        unsigned long ttime_total;
+        unsigned long ttime_samples;
+        unsigned long ttime_mean;
+
+        unsigned int seek_samples;
+        u64 seek_total;
+        sector_t seek_mean;
+
+        struct list_head queue_list;
+
+        void (*dtor)(struct io_context *); /* destructor */
+        void (*exit)(struct io_context *); /* called on task exit */
+};
+
+/*
+ * 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;
+        atomic_t nr_tasks;
+
+        /* all the fields below are protected by this lock */
+        spinlock_t lock;
+
+        unsigned short ioprio;
+        unsigned short ioprio_changed;
+
+        /*
+         * For request batching
+         */
+        unsigned long last_waited; /* Time last woken after wait for request */
+        int nr_batch_requests;     /* Number of requests left in the batch */
+
+        struct as_io_context *aic;
+        struct radix_tree_root radix_root;
+        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))
+                return ioc;
+
+        return NULL;
+}
+
+#endif