sched.h

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/*
 * linux/include/linux/sunrpc/sched.h
 *
 * Scheduling primitives for kernel Sun RPC.
 *
 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
 */

#ifndef _LINUX_SUNRPC_SCHED_H_
#define _LINUX_SUNRPC_SCHED_H_

#include <linux/timer.h>
#include <linux/ktime.h>
#include <linux/sunrpc/types.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <linux/workqueue.h>
#include <linux/sunrpc/xdr.h>

/*
 * This is the actual RPC procedure call info.
 */
struct rpc_procinfo;
struct rpc_message {
    struct rpc_procinfo *   rpc_proc;   /* Procedure information */
    void *          rpc_argp;   /* Arguments */
    void *          rpc_resp;   /* Result */
    struct rpc_cred *   rpc_cred;   /* Credentials */
};

struct rpc_call_ops;
struct rpc_wait_queue;
struct rpc_wait {
    struct list_head    list;       /* wait queue links */
    struct list_head    links;      /* Links to related tasks */
    struct list_head    timer_list; /* Timer list */
    unsigned long       expires;
};

/*
 * This is the RPC task struct
 */
struct rpc_task {
    atomic_t        tk_count;   /* Reference count */
    struct list_head    tk_task;    /* global list of tasks */
    struct rpc_clnt *   tk_client;  /* RPC client */
    struct rpc_rqst *   tk_rqstp;   /* RPC request */

    /*
     * RPC call state
     */
    struct rpc_message  tk_msg;     /* RPC call info */

    /*
     * callback to be executed after waking up
     * action   next procedure for async tasks
     * tk_ops   caller callbacks
     */
    void            (*tk_callback)(struct rpc_task *);
    void            (*tk_action)(struct rpc_task *);
    const struct rpc_call_ops *tk_ops;
    void *          tk_calldata;

    unsigned long       tk_timeout; /* timeout for rpc_sleep() */
    unsigned long       tk_runstate;    /* Task run status */
    struct workqueue_struct *tk_workqueue;  /* Normally rpciod, but could
                         * be any workqueue
                         */
    struct rpc_wait_queue   *tk_waitqueue;  /* RPC wait queue we're on */
    union {
        struct work_struct  tk_work;    /* Async task work queue */
        struct rpc_wait     tk_wait;    /* RPC wait */
    } u;

    ktime_t         tk_start;   /* RPC task init timestamp */

    pid_t           tk_owner;   /* Process id for batching tasks */
    int         tk_status;  /* result of last operation */
    unsigned short      tk_flags;   /* misc flags */
    unsigned short      tk_timeouts;    /* maj timeouts */

#ifdef RPC_DEBUG
    unsigned short      tk_pid;     /* debugging aid */
#endif
    unsigned char       tk_priority : 2,/* Task priority */
                tk_garb_retry : 2,
                tk_cred_retry : 2,
                tk_rebind_retry : 2;
};
#define tk_xprt         tk_client->cl_xprt

/* support walking a list of tasks on a wait queue */
#define task_for_each(task, pos, head) \
    list_for_each(pos, head) \
        if ((task=list_entry(pos, struct rpc_task, u.tk_wait.list)),1)

#define task_for_first(task, head) \
    if (!list_empty(head) &&  \
        ((task=list_entry((head)->next, struct rpc_task, u.tk_wait.list)),1))

typedef void            (*rpc_action)(struct rpc_task *);

struct rpc_call_ops {
    void (*rpc_call_prepare)(struct rpc_task *, void *);
    void (*rpc_call_done)(struct rpc_task *, void *);
    void (*rpc_count_stats)(struct rpc_task *, void *);
    void (*rpc_release)(void *);
};

struct rpc_task_setup {
    struct rpc_task *task;
    struct rpc_clnt *rpc_client;
    const struct rpc_message *rpc_message;
    const struct rpc_call_ops *callback_ops;
    void *callback_data;
    struct workqueue_struct *workqueue;
    unsigned short flags;
    signed char priority;
};

/*
 * RPC task flags
 */
#define RPC_TASK_ASYNC      0x0001      /* is an async task */
#define RPC_TASK_SWAPPER    0x0002      /* is swapping in/out */
#define RPC_CALL_MAJORSEEN  0x0020      /* major timeout seen */
#define RPC_TASK_ROOTCREDS  0x0040      /* force root creds */
#define RPC_TASK_DYNAMIC    0x0080      /* task was kmalloc'ed */
#define RPC_TASK_KILLED     0x0100      /* task was killed */
#define RPC_TASK_SOFT       0x0200      /* Use soft timeouts */
#define RPC_TASK_SOFTCONN   0x0400      /* Fail if can't connect */
#define RPC_TASK_SENT       0x0800      /* message was sent */
#define RPC_TASK_TIMEOUT    0x1000      /* fail with ETIMEDOUT on timeout */

#define RPC_IS_ASYNC(t)     ((t)->tk_flags & RPC_TASK_ASYNC)
#define RPC_IS_SWAPPER(t)   ((t)->tk_flags & RPC_TASK_SWAPPER)
#define RPC_DO_ROOTOVERRIDE(t)  ((t)->tk_flags & RPC_TASK_ROOTCREDS)
#define RPC_ASSASSINATED(t) ((t)->tk_flags & RPC_TASK_KILLED)
#define RPC_IS_SOFT(t)      ((t)->tk_flags & (RPC_TASK_SOFT|RPC_TASK_TIMEOUT))
#define RPC_IS_SOFTCONN(t)  ((t)->tk_flags & RPC_TASK_SOFTCONN)
#define RPC_WAS_SENT(t)     ((t)->tk_flags & RPC_TASK_SENT)

#define RPC_TASK_RUNNING    0
#define RPC_TASK_QUEUED     1
#define RPC_TASK_ACTIVE     2

#define RPC_IS_RUNNING(t)   test_bit(RPC_TASK_RUNNING, &(t)->tk_runstate)
#define rpc_set_running(t)  set_bit(RPC_TASK_RUNNING, &(t)->tk_runstate)
#define rpc_test_and_set_running(t) \
                test_and_set_bit(RPC_TASK_RUNNING, &(t)->tk_runstate)
#define rpc_clear_running(t)    \
    do { \
        smp_mb__before_clear_bit(); \
        clear_bit(RPC_TASK_RUNNING, &(t)->tk_runstate); \
        smp_mb__after_clear_bit(); \
    } while (0)

#define RPC_IS_QUEUED(t)    test_bit(RPC_TASK_QUEUED, &(t)->tk_runstate)
#define rpc_set_queued(t)   set_bit(RPC_TASK_QUEUED, &(t)->tk_runstate)
#define rpc_clear_queued(t) \
    do { \
        smp_mb__before_clear_bit(); \
        clear_bit(RPC_TASK_QUEUED, &(t)->tk_runstate); \
        smp_mb__after_clear_bit(); \
    } while (0)

#define RPC_IS_ACTIVATED(t) test_bit(RPC_TASK_ACTIVE, &(t)->tk_runstate)

/*
 * Task priorities.
 * Note: if you change these, you must also change
 * the task initialization definitions below.
 */
#define RPC_PRIORITY_LOW    (-1)
#define RPC_PRIORITY_NORMAL (0)
#define RPC_PRIORITY_HIGH   (1)
#define RPC_PRIORITY_PRIVILEGED (2)
#define RPC_NR_PRIORITY     (1 + RPC_PRIORITY_PRIVILEGED - RPC_PRIORITY_LOW)

struct rpc_timer {
    struct timer_list timer;
    struct list_head list;
    unsigned long expires;
};

/*
 * RPC synchronization objects
 */
struct rpc_wait_queue {
    spinlock_t      lock;
    struct list_head    tasks[RPC_NR_PRIORITY]; /* task queue for each priority level */
    pid_t           owner;          /* process id of last task serviced */
    unsigned char       maxpriority;        /* maximum priority (0 if queue is not a priority queue) */
    unsigned char       priority;       /* current priority */
    unsigned char       count;          /* # task groups remaining serviced so far */
    unsigned char       nr;         /* # tasks remaining for cookie */
    unsigned short      qlen;           /* total # tasks waiting in queue */
    struct rpc_timer    timer_list;
#if defined(RPC_DEBUG) || defined(RPC_TRACEPOINTS)
    const char *        name;
#endif
};

/*
 * This is the # requests to send consecutively
 * from a single cookie.  The aim is to improve
 * performance of NFS operations such as read/write.
 */
#define RPC_BATCH_COUNT         16
#define RPC_IS_PRIORITY(q)      ((q)->maxpriority > 0)

/*
 * Function prototypes
 */
struct rpc_task *rpc_new_task(const struct rpc_task_setup *);
struct rpc_task *rpc_run_task(const struct rpc_task_setup *);
struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req,
                const struct rpc_call_ops *ops);
void        rpc_put_task(struct rpc_task *);
void        rpc_put_task_async(struct rpc_task *);
void        rpc_exit_task(struct rpc_task *);
void        rpc_exit(struct rpc_task *, int);
void        rpc_release_calldata(const struct rpc_call_ops *, void *);
void        rpc_killall_tasks(struct rpc_clnt *);
void        rpc_execute(struct rpc_task *);
void        rpc_init_priority_wait_queue(struct rpc_wait_queue *, const char *);
void        rpc_init_wait_queue(struct rpc_wait_queue *, const char *);
void        rpc_destroy_wait_queue(struct rpc_wait_queue *);
void        rpc_sleep_on(struct rpc_wait_queue *, struct rpc_task *,
                    rpc_action action);
void        rpc_sleep_on_priority(struct rpc_wait_queue *,
                    struct rpc_task *,
                    rpc_action action,
                    int priority);
void        rpc_wake_up_queued_task(struct rpc_wait_queue *,
                    struct rpc_task *);
void        rpc_wake_up(struct rpc_wait_queue *);
struct rpc_task *rpc_wake_up_next(struct rpc_wait_queue *);
struct rpc_task *rpc_wake_up_first(struct rpc_wait_queue *,
                    bool (*)(struct rpc_task *, void *),
                    void *);
void        rpc_wake_up_status(struct rpc_wait_queue *, int);
int     rpc_queue_empty(struct rpc_wait_queue *);
void        rpc_delay(struct rpc_task *, unsigned long);
void *      rpc_malloc(struct rpc_task *, size_t);
void        rpc_free(void *);
int     rpciod_up(void);
void        rpciod_down(void);
int     __rpc_wait_for_completion_task(struct rpc_task *task, int (*)(void *));
#ifdef RPC_DEBUG
struct net;
void        rpc_show_tasks(struct net *);
#endif
int     rpc_init_mempool(void);
void        rpc_destroy_mempool(void);
extern struct workqueue_struct *rpciod_workqueue;
void        rpc_prepare_task(struct rpc_task *task);

static inline int rpc_wait_for_completion_task(struct rpc_task *task)
{
    return __rpc_wait_for_completion_task(task, NULL);
}

static inline void rpc_task_set_priority(struct rpc_task *task, unsigned char prio)
{
    task->tk_priority = prio - RPC_PRIORITY_LOW;
}

static inline int rpc_task_has_priority(struct rpc_task *task, unsigned char prio)
{
    return (task->tk_priority + RPC_PRIORITY_LOW == prio);
}

#if defined(RPC_DEBUG) || defined (RPC_TRACEPOINTS)
static inline const char * rpc_qname(const struct rpc_wait_queue *q)
{
    return ((q && q->name) ? q->name : "unknown");
}

static inline void rpc_assign_waitqueue_name(struct rpc_wait_queue *q,
        const char *name)
{
    q->name = name;
}
#else
static inline void rpc_assign_waitqueue_name(struct rpc_wait_queue *q,
        const char *name)
{
}
#endif

#endif /* _LINUX_SUNRPC_SCHED_H_ */