include/linux/sunrpc/sched.h

   1 /*
   2  * linux/include/linux/sunrpc/sched.h
   3  *
   4  * Scheduling primitives for kernel Sun RPC.
   5  *
   6  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
   7  */
   8
   9 #ifndef _LINUX_SUNRPC_SCHED_H_
  10 #define _LINUX_SUNRPC_SCHED_H_
  11
  12 #include <linux/timer.h>
  13 #include <linux/sunrpc/types.h>
  14 #include <linux/rcupdate.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/wait.h>
  17 #include <linux/workqueue.h>
  18 #include <linux/sunrpc/xdr.h>
  19
  20 /*
  21  * This is the actual RPC procedure call info.
  22  */
  23 struct rpc_procinfo;
  24 struct rpc_message {
  25         struct rpc_procinfo *   rpc_proc;       /* Procedure information */
  26         void *                  rpc_argp;       /* Arguments */
  27         void *                  rpc_resp;       /* Result */
  28         struct rpc_cred *       rpc_cred;       /* Credentials */
  29 };
  30
  31 struct rpc_call_ops;
  32 struct rpc_wait_queue;
  33 struct rpc_wait {
  34         struct list_head        list;           /* wait queue links */
  35         struct list_head        links;          /* Links to related tasks */
  36 };
  37
  38 /*
  39  * This is the RPC task struct
  40  */
  41 struct rpc_task {
  42 #ifdef RPC_DEBUG
  43         unsigned long           tk_magic;       /* 0xf00baa */
  44 #endif
  45         atomic_t                tk_count;       /* Reference count */
  46         struct list_head        tk_task;        /* global list of tasks */
  47         struct rpc_clnt *       tk_client;      /* RPC client */
  48         struct rpc_rqst *       tk_rqstp;       /* RPC request */
  49         int                     tk_status;      /* result of last operation */
  50
  51         /*
  52          * RPC call state
  53          */
  54         struct rpc_message      tk_msg;         /* RPC call info */
  55         __u8                    tk_garb_retry;
  56         __u8                    tk_cred_retry;
  57
  58         /*
  59          * timeout_fn   to be executed by timer bottom half
  60          * callback     to be executed after waking up
  61          * action       next procedure for async tasks
  62          * tk_ops       caller callbacks
  63          */
  64         void                    (*tk_timeout_fn)(struct rpc_task *);
  65         void                    (*tk_callback)(struct rpc_task *);
  66         void                    (*tk_action)(struct rpc_task *);
  67         const struct rpc_call_ops *tk_ops;
  68         void *                  tk_calldata;
  69
  70         /*
  71          * tk_timer is used for async processing by the RPC scheduling
  72          * primitives. You should not access this directly unless
  73          * you have a pathological interest in kernel oopses.
  74          */
  75         struct timer_list       tk_timer;       /* kernel timer */
  76         unsigned long           tk_timeout;     /* timeout for rpc_sleep() */
  77         unsigned short          tk_flags;       /* misc flags */
  78         unsigned long           tk_runstate;    /* Task run status */
  79         struct workqueue_struct *tk_workqueue;  /* Normally rpciod, but could
  80                                                  * be any workqueue
  81                                                  */
  82         struct rpc_wait_queue   *tk_waitqueue;  /* RPC wait queue we're on */
  83         union {
  84                 struct work_struct      tk_work;        /* Async task work queue */
  85                 struct rpc_wait         tk_wait;        /* RPC wait */
  86                 struct rcu_head         tk_rcu;         /* for task deletion */
  87         } u;
  88
  89         unsigned short          tk_timeouts;    /* maj timeouts */
  90         size_t                  tk_bytes_sent;  /* total bytes sent */
  91         unsigned long           tk_start;       /* RPC task init timestamp */
  92         long                    tk_rtt;         /* round-trip time (jiffies) */
  93
  94         pid_t                   tk_owner;       /* Process id for batching tasks */
  95         unsigned char           tk_priority : 2;/* Task priority */
  96
  97 #ifdef RPC_DEBUG
  98         unsigned short          tk_pid;         /* debugging aid */
  99 #endif
 100 };
 101 #define tk_xprt                 tk_client->cl_xprt
 102
 103 /* support walking a list of tasks on a wait queue */
 104 #define task_for_each(task, pos, head) \
 105         list_for_each(pos, head) \
 106                 if ((task=list_entry(pos, struct rpc_task, u.tk_wait.list)),1)
 107
 108 #define task_for_first(task, head) \
 109         if (!list_empty(head) &&  \
 110             ((task=list_entry((head)->next, struct rpc_task, u.tk_wait.list)),1))
 111
 112 typedef void                    (*rpc_action)(struct rpc_task *);
 113
 114 struct rpc_call_ops {
 115         void (*rpc_call_prepare)(struct rpc_task *, void *);
 116         void (*rpc_call_done)(struct rpc_task *, void *);
 117         void (*rpc_release)(void *);
 118 };
 119
 120 struct rpc_task_setup {
 121         struct rpc_task *task;
 122         struct rpc_clnt *rpc_client;
 123         const struct rpc_message *rpc_message;
 124         const struct rpc_call_ops *callback_ops;
 125         void *callback_data;
 126         struct workqueue_struct *workqueue;
 127         unsigned short flags;
 128         signed char priority;
 129 };
 130
 131 /*
 132  * RPC task flags
 133  */
 134 #define RPC_TASK_ASYNC          0x0001          /* is an async task */
 135 #define RPC_TASK_SWAPPER        0x0002          /* is swapping in/out */
 136 #define RPC_CALL_MAJORSEEN      0x0020          /* major timeout seen */
 137 #define RPC_TASK_ROOTCREDS      0x0040          /* force root creds */
 138 #define RPC_TASK_DYNAMIC        0x0080          /* task was kmalloc'ed */
 139 #define RPC_TASK_KILLED         0x0100          /* task was killed */
 140 #define RPC_TASK_SOFT           0x0200          /* Use soft timeouts */
 141
 142 #define RPC_IS_ASYNC(t)         ((t)->tk_flags & RPC_TASK_ASYNC)
 143 #define RPC_IS_SWAPPER(t)       ((t)->tk_flags & RPC_TASK_SWAPPER)
 144 #define RPC_DO_ROOTOVERRIDE(t)  ((t)->tk_flags & RPC_TASK_ROOTCREDS)
 145 #define RPC_ASSASSINATED(t)     ((t)->tk_flags & RPC_TASK_KILLED)
 146 #define RPC_DO_CALLBACK(t)      ((t)->tk_callback != NULL)
 147 #define RPC_IS_SOFT(t)          ((t)->tk_flags & RPC_TASK_SOFT)
 148
 149 #define RPC_TASK_RUNNING        0
 150 #define RPC_TASK_QUEUED         1
 151 #define RPC_TASK_WAKEUP         2
 152 #define RPC_TASK_HAS_TIMER      3
 153 #define RPC_TASK_ACTIVE         4
 154
 155 #define RPC_IS_RUNNING(t)       test_bit(RPC_TASK_RUNNING, &(t)->tk_runstate)
 156 #define rpc_set_running(t)      set_bit(RPC_TASK_RUNNING, &(t)->tk_runstate)
 157 #define rpc_test_and_set_running(t) \
 158                                 test_and_set_bit(RPC_TASK_RUNNING, &(t)->tk_runstate)
 159 #define rpc_clear_running(t)    \
 160         do { \
 161                 smp_mb__before_clear_bit(); \
 162                 clear_bit(RPC_TASK_RUNNING, &(t)->tk_runstate); \
 163                 smp_mb__after_clear_bit(); \
 164         } while (0)
 165
 166 #define RPC_IS_QUEUED(t)        test_bit(RPC_TASK_QUEUED, &(t)->tk_runstate)
 167 #define rpc_set_queued(t)       set_bit(RPC_TASK_QUEUED, &(t)->tk_runstate)
 168 #define rpc_clear_queued(t)     \
 169         do { \
 170                 smp_mb__before_clear_bit(); \
 171                 clear_bit(RPC_TASK_QUEUED, &(t)->tk_runstate); \
 172                 smp_mb__after_clear_bit(); \
 173         } while (0)
 174
 175 #define rpc_start_wakeup(t) \
 176         (test_and_set_bit(RPC_TASK_WAKEUP, &(t)->tk_runstate) == 0)
 177 #define rpc_finish_wakeup(t) \
 178         do { \
 179                 smp_mb__before_clear_bit(); \
 180                 clear_bit(RPC_TASK_WAKEUP, &(t)->tk_runstate); \
 181                 smp_mb__after_clear_bit(); \
 182         } while (0)
 183
 184 #define RPC_IS_ACTIVATED(t)     test_bit(RPC_TASK_ACTIVE, &(t)->tk_runstate)
 185
 186 /*
 187  * Task priorities.
 188  * Note: if you change these, you must also change
 189  * the task initialization definitions below.
 190  */
 191 #define RPC_PRIORITY_LOW        (-1)
 192 #define RPC_PRIORITY_NORMAL     (0)
 193 #define RPC_PRIORITY_HIGH       (1)
 194 #define RPC_NR_PRIORITY         (1 + RPC_PRIORITY_HIGH - RPC_PRIORITY_LOW)
 195
 196 /*
 197  * RPC synchronization objects
 198  */
 199 struct rpc_wait_queue {
 200         spinlock_t              lock;
 201         struct list_head        tasks[RPC_NR_PRIORITY]; /* task queue for each priority level */
 202         pid_t                   owner;                  /* process id of last task serviced */
 203         unsigned char           maxpriority;            /* maximum priority (0 if queue is not a priority queue) */
 204         unsigned char           priority;               /* current priority */
 205         unsigned char           count;                  /* # task groups remaining serviced so far */
 206         unsigned char           nr;                     /* # tasks remaining for cookie */
 207         unsigned short          qlen;                   /* total # tasks waiting in queue */
 208 #ifdef RPC_DEBUG
 209         const char *            name;
 210 #endif
 211 };
 212
 213 /*
 214  * This is the # requests to send consecutively
 215  * from a single cookie.  The aim is to improve
 216  * performance of NFS operations such as read/write.
 217  */
 218 #define RPC_BATCH_COUNT                 16
 219 #define RPC_IS_PRIORITY(q)              ((q)->maxpriority > 0)
 220
 221 /*
 222  * Function prototypes
 223  */
 224 struct rpc_task *rpc_new_task(const struct rpc_task_setup *);
 225 struct rpc_task *rpc_run_task(const struct rpc_task_setup *);
 226 void            rpc_put_task(struct rpc_task *);
 227 void            rpc_exit_task(struct rpc_task *);
 228 void            rpc_release_calldata(const struct rpc_call_ops *, void *);
 229 void            rpc_killall_tasks(struct rpc_clnt *);
 230 void            rpc_execute(struct rpc_task *);
 231 void            rpc_init_priority_wait_queue(struct rpc_wait_queue *, const char *);
 232 void            rpc_init_wait_queue(struct rpc_wait_queue *, const char *);
 233 void            rpc_sleep_on(struct rpc_wait_queue *, struct rpc_task *,
 234                                         rpc_action action, rpc_action timer);
 235 void            rpc_wake_up_queued_task(struct rpc_wait_queue *,
 236                                         struct rpc_task *);
 237 void            rpc_wake_up(struct rpc_wait_queue *);
 238 struct rpc_task *rpc_wake_up_next(struct rpc_wait_queue *);
 239 void            rpc_wake_up_status(struct rpc_wait_queue *, int);
 240 void            rpc_delay(struct rpc_task *, unsigned long);
 241 void *          rpc_malloc(struct rpc_task *, size_t);
 242 void            rpc_free(void *);
 243 int             rpciod_up(void);
 244 void            rpciod_down(void);
 245 int             __rpc_wait_for_completion_task(struct rpc_task *task, int (*)(void *));
 246 #ifdef RPC_DEBUG
 247 void            rpc_show_tasks(void);
 248 #endif
 249 int             rpc_init_mempool(void);
 250 void            rpc_destroy_mempool(void);
 251 extern struct workqueue_struct *rpciod_workqueue;
 252
 253 static inline void rpc_exit(struct rpc_task *task, int status)
 254 {
 255         task->tk_status = status;
 256         task->tk_action = rpc_exit_task;
 257 }
 258
 259 static inline int rpc_wait_for_completion_task(struct rpc_task *task)
 260 {
 261         return __rpc_wait_for_completion_task(task, NULL);
 262 }
 263
 264 #ifdef RPC_DEBUG
 265 static inline const char * rpc_qname(struct rpc_wait_queue *q)
 266 {
 267         return ((q && q->name) ? q->name : "unknown");
 268 }
 269 #endif
 270
 271 #endif /* _LINUX_SUNRPC_SCHED_H_ */