1#ifndef IOCONTEXT_H 2#define IOCONTEXT_H 3 4#include <linux/radix-tree.h> 5#include <linux/rcupdate.h> 6 7struct cfq_queue; 8struct cfq_io_context { 9 void *key; 10 11 struct cfq_queue *cfqq[2]; 12 13 struct io_context *ioc; 14 15 unsigned long last_end_request; 16 17 unsigned long ttime_total; 18 unsigned long ttime_samples; 19 unsigned long ttime_mean; 20 21 struct list_head queue_list; 22 struct hlist_node cic_list; 23 24 void (*dtor)(struct io_context *); /* destructor */ 25 void (*exit)(struct io_context *); /* called on task exit */ 26 27 struct rcu_head rcu_head; 28}; 29 30/* 31 * I/O subsystem state of the associated processes. It is refcounted 32 * and kmalloc'ed. These could be shared between processes. 33 */ 34struct io_context { 35 atomic_long_t refcount; 36 atomic_t nr_tasks; 37 38 /* all the fields below are protected by this lock */ 39 spinlock_t lock; 40 41 unsigned short ioprio; 42 unsigned short ioprio_changed; 43 44#if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE) 45 unsigned short cgroup_changed; 46#endif 47 48 /* 49 * For request batching 50 */ 51 int nr_batch_requests; /* Number of requests left in the batch */ 52 unsigned long last_waited; /* Time last woken after wait for request */ 53 54 struct radix_tree_root radix_root; 55 struct hlist_head cic_list; 56 void *ioc_data; 57}; 58 59static inline struct io_context *ioc_task_link(struct io_context *ioc) 60{ 61 /* 62 * if ref count is zero, don't allow sharing (ioc is going away, it's 63 * a race). 64 */ 65 if (ioc && atomic_long_inc_not_zero(&ioc->refcount)) { 66 atomic_inc(&ioc->nr_tasks); 67 return ioc; 68 } 69 70 return NULL; 71} 72 73struct task_struct; 74#ifdef CONFIG_BLOCK 75int put_io_context(struct io_context *ioc); 76void exit_io_context(struct task_struct *task); 77struct io_context *get_io_context(gfp_t gfp_flags, int node); 78struct io_context *alloc_io_context(gfp_t gfp_flags, int node); 79void copy_io_context(struct io_context **pdst, struct io_context **psrc); 80#else 81static inline void exit_io_context(struct task_struct *task) 82{ 83} 84 85struct io_context; 86static inline int put_io_context(struct io_context *ioc) 87{ 88 return 1; 89} 90#endif 91 92#endif 93