1 #ifndef IOCONTEXT_H 2 #define IOCONTEXT_H 3 4 #include <linux/radix-tree.h> 5 #include <linux/rcupdate.h> 6 7 struct cfq_queue; 8 struct cfq_io_context { 9 void *key; 10 unsigned long dead_key; 11 12 struct cfq_queue *cfqq[2]; 13 14 struct io_context *ioc; 15 16 unsigned long last_end_request; 17 18 unsigned long ttime_total; 19 unsigned long ttime_samples; 20 unsigned long ttime_mean; 21 22 struct list_head queue_list; 23 struct hlist_node cic_list; 24 25 void (*dtor)(struct io_context *); /* destructor */ 26 void (*exit)(struct io_context *); /* called on task exit */ 27 28 struct rcu_head rcu_head; 29 }; 30 31 /* 32 * I/O subsystem state of the associated processes. It is refcounted 33 * and kmalloc'ed. These could be shared between processes. 34 */ 35 struct io_context { 36 atomic_long_t refcount; 37 atomic_t nr_tasks; 38 39 /* all the fields below are protected by this lock */ 40 spinlock_t lock; 41 42 unsigned short ioprio; 43 unsigned short ioprio_changed; 44 45 #ifdef CONFIG_BLK_CGROUP 46 unsigned short cgroup_changed; 47 #endif 48 49 /* 50 * For request batching 51 */ 52 unsigned long last_waited; /* Time last woken after wait for request */ 53 int nr_batch_requests; /* Number of requests left in the batch */ 54 55 struct radix_tree_root radix_root; 56 struct hlist_head cic_list; 57 void *ioc_data; 58 }; 59 60 static inline struct io_context *ioc_task_link(struct io_context *ioc) 61 { 62 /* 63 * if ref count is zero, don't allow sharing (ioc is going away, it's 64 * a race). 65 */ 66 if (ioc && atomic_long_inc_not_zero(&ioc->refcount)) { 67 atomic_inc(&ioc->nr_tasks); 68 return ioc; 69 } 70 71 return NULL; 72 } 73 74 struct task_struct; 75 #ifdef CONFIG_BLOCK 76 int put_io_context(struct io_context *ioc); 77 void exit_io_context(struct task_struct *task); 78 struct io_context *get_io_context(gfp_t gfp_flags, int node); 79 struct io_context *alloc_io_context(gfp_t gfp_flags, int node); 80 void copy_io_context(struct io_context **pdst, struct io_context **psrc); 81 #else 82 static inline void exit_io_context(struct task_struct *task) 83 { 84 } 85 86 struct io_context; 87 static inline int put_io_context(struct io_context *ioc) 88 { 89 return 1; 90 } 91 #endif 92 93 #endif 94