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linux-next/include/linux/iocontext.h
Tejun Heo 42ec57a8f6 block: misc ioc cleanups
* int return from put_io_context() wasn't used by anybody.  Make it
  return void like other put functions and docbook-fy the function
  comment.

* Reorder dummy declarations for !CONFIG_BLOCK case a bit.

* Make alloc_ioc_context() use __GFP_ZERO allocation, take init out of
  if block and drop 0'ing.

* Docbook-fy current_io_context() comment.

This patch doesn't introduce any functional change.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-12-14 00:33:37 +01:00

90 lines
2.0 KiB
C

#ifndef IOCONTEXT_H
#define IOCONTEXT_H
#include <linux/radix-tree.h>
#include <linux/rcupdate.h>
struct cfq_queue;
struct cfq_ttime {
unsigned long last_end_request;
unsigned long ttime_total;
unsigned long ttime_samples;
unsigned long ttime_mean;
};
struct cfq_io_context {
void *key;
struct cfq_queue *cfqq[2];
struct io_context *ioc;
struct cfq_ttime ttime;
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
void 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
struct io_context;
static inline void put_io_context(struct io_context *ioc) { }
static inline void exit_io_context(struct task_struct *task) { }
#endif
#endif