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-rw-r--r--include/linux/iocontext.h39
1 files changed, 22 insertions, 17 deletions
diff --git a/include/linux/iocontext.h b/include/linux/iocontext.h
index 1a3018063034..df38db2ef45b 100644
--- a/include/linux/iocontext.h
+++ b/include/linux/iocontext.h
@@ -6,11 +6,7 @@
#include <linux/workqueue.h>
enum {
- ICQ_IOPRIO_CHANGED = 1 << 0,
- ICQ_CGROUP_CHANGED = 1 << 1,
ICQ_EXITED = 1 << 2,
-
- ICQ_CHANGED_MASK = ICQ_IOPRIO_CHANGED | ICQ_CGROUP_CHANGED,
};
/*
@@ -100,6 +96,7 @@ struct io_cq {
*/
struct io_context {
atomic_long_t refcount;
+ atomic_t active_ref;
atomic_t nr_tasks;
/* all the fields below are protected by this lock */
@@ -120,29 +117,37 @@ struct io_context {
struct work_struct release_work;
};
-static inline struct io_context *ioc_task_link(struct io_context *ioc)
+/**
+ * get_io_context_active - get active reference on ioc
+ * @ioc: ioc of interest
+ *
+ * Only iocs with active reference can issue new IOs. This function
+ * acquires an active reference on @ioc. The caller must already have an
+ * active reference on @ioc.
+ */
+static inline void get_io_context_active(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;
- }
+ WARN_ON_ONCE(atomic_long_read(&ioc->refcount) <= 0);
+ WARN_ON_ONCE(atomic_read(&ioc->active_ref) <= 0);
+ atomic_long_inc(&ioc->refcount);
+ atomic_inc(&ioc->active_ref);
+}
+
+static inline void ioc_task_link(struct io_context *ioc)
+{
+ get_io_context_active(ioc);
- return NULL;
+ WARN_ON_ONCE(atomic_read(&ioc->nr_tasks) <= 0);
+ atomic_inc(&ioc->nr_tasks);
}
struct task_struct;
#ifdef CONFIG_BLOCK
void put_io_context(struct io_context *ioc);
+void put_io_context_active(struct io_context *ioc);
void exit_io_context(struct task_struct *task);
struct io_context *get_task_io_context(struct task_struct *task,
gfp_t gfp_flags, int node);
-void ioc_ioprio_changed(struct io_context *ioc, int ioprio);
-void ioc_cgroup_changed(struct io_context *ioc);
-unsigned int icq_get_changed(struct io_cq *icq);
#else
struct io_context;
static inline void put_io_context(struct io_context *ioc) { }