include/linux/iocontext.h

   1 #ifndef IOCONTEXT_H
   2 #define IOCONTEXT_H
   3
   4 #include <linux/radix-tree.h>
   5 #include <linux/rcupdate.h>
   6 #include <linux/workqueue.h>
   7
   8 struct cfq_queue;
   9 struct cfq_ttime {
  10         unsigned long last_end_request;
  11
  12         unsigned long ttime_total;
  13         unsigned long ttime_samples;
  14         unsigned long ttime_mean;
  15 };
  16
  17 enum {
  18         CIC_IOPRIO_CHANGED,
  19         CIC_CGROUP_CHANGED,
  20 };
  21
  22 struct cfq_io_context {
  23         void *key;
  24         struct request_queue *q;
  25
  26         struct cfq_queue *cfqq[2];
  27
  28         struct io_context *ioc;
  29
  30         struct cfq_ttime ttime;
  31
  32         struct list_head queue_list;
  33         struct hlist_node cic_list;
  34
  35         unsigned long changed;
  36
  37         void (*exit)(struct cfq_io_context *);
  38         void (*release)(struct cfq_io_context *);
  39
  40         struct rcu_head rcu_head;
  41 };
  42
  43 /*
  44  * I/O subsystem state of the associated processes.  It is refcounted
  45  * and kmalloc'ed. These could be shared between processes.
  46  */
  47 struct io_context {
  48         atomic_long_t refcount;
  49         atomic_t nr_tasks;
  50
  51         /* all the fields below are protected by this lock */
  52         spinlock_t lock;
  53
  54         unsigned short ioprio;
  55
  56         /*
  57          * For request batching
  58          */
  59         int nr_batch_requests;     /* Number of requests left in the batch */
  60         unsigned long last_waited; /* Time last woken after wait for request */
  61
  62         struct radix_tree_root radix_root;
  63         struct hlist_head cic_list;
  64         void __rcu *ioc_data;
  65
  66         struct work_struct release_work;
  67 };
  68
  69 static inline struct io_context *ioc_task_link(struct io_context *ioc)
  70 {
  71         /*
  72          * if ref count is zero, don't allow sharing (ioc is going away, it's
  73          * a race).
  74          */
  75         if (ioc && atomic_long_inc_not_zero(&ioc->refcount)) {
  76                 atomic_inc(&ioc->nr_tasks);
  77                 return ioc;
  78         }
  79
  80         return NULL;
  81 }
  82
  83 struct task_struct;
  84 #ifdef CONFIG_BLOCK
  85 void put_io_context(struct io_context *ioc, struct request_queue *locked_q);
  86 void exit_io_context(struct task_struct *task);
  87 struct io_context *get_task_io_context(struct task_struct *task,
  88                                        gfp_t gfp_flags, int node);
  89 void ioc_ioprio_changed(struct io_context *ioc, int ioprio);
  90 void ioc_cgroup_changed(struct io_context *ioc);
  91 #else
  92 struct io_context;
  93 static inline void put_io_context(struct io_context *ioc,
  94                                   struct request_queue *locked_q) { }
  95 static inline void exit_io_context(struct task_struct *task) { }
  96 #endif
  97
  98 #endif