Merge branch 'for-linus' of git://linux-nfs.org/~bfields/linux

[linux-2.6] / include / linux / iocontext.h

diff --git a/include/linux/iocontext.h b/include/linux/iocontext.h
index 186807ea62e21d6bbceb8ba1bd1701e358a72b16..593b222d9dcc25334be5ca6d05dc0a5ab413f5f5 100644 (file)
--- a/include/linux/iocontext.h
+++ b/include/linux/iocontext.h
@@ -1,6 +1,8 @@
 #ifndef IOCONTEXT_H
 #define IOCONTEXT_H
 
+#include <linux/radix-tree.h>
+
 /*
  * This is the per-process anticipatory I/O scheduler state.
  */
@@ -29,8 +31,8 @@ struct as_io_context {
 
 struct cfq_queue;
 struct cfq_io_context {
-       struct rb_node rb_node;
        void *key;
+       unsigned long dead_key;
 
        struct cfq_queue *cfqq[2];
 
@@ -54,13 +56,15 @@ struct cfq_io_context {
 };
 
 /*
- * 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;
@@ -72,8 +76,20 @@ struct io_context {
        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;
        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