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      1 /*
      2  * linux/include/linux/sunrpc/sched.h
      3  *
      4  * Scheduling primitives for kernel Sun RPC.
      5  *
      6  * Copyright (C) 1996, Olaf Kirch <okir (at) 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/spinlock.h>
     15 #include <linux/wait.h>
     16 #include <linux/workqueue.h>
     17 #include <linux/sunrpc/xdr.h>
     18 
     19 /*
     20  * This is the actual RPC procedure call info.
     21  */
     22 struct rpc_procinfo;
     23 struct rpc_message {
     24 	struct rpc_procinfo *	rpc_proc;	/* Procedure information */
     25 	void *			rpc_argp;	/* Arguments */
     26 	void *			rpc_resp;	/* Result */
     27 	struct rpc_cred *	rpc_cred;	/* Credentials */
     28 };
     29 
     30 struct rpc_call_ops;
     31 struct rpc_wait_queue;
     32 struct rpc_wait {
     33 	struct list_head	list;		/* wait queue links */
     34 	struct list_head	links;		/* Links to related tasks */
     35 	struct rpc_wait_queue *	rpc_waitq;	/* RPC wait queue we're on */
     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 	unsigned long		tk_cookie;	/* Cookie for batching tasks */
     59 
     60 	/*
     61 	 * timeout_fn   to be executed by timer bottom half
     62 	 * callback	to be executed after waking up
     63 	 * action	next procedure for async tasks
     64 	 * tk_ops	caller callbacks
     65 	 */
     66 	void			(*tk_timeout_fn)(struct rpc_task *);
     67 	void			(*tk_callback)(struct rpc_task *);
     68 	void			(*tk_action)(struct rpc_task *);
     69 	const struct rpc_call_ops *tk_ops;
     70 	void *			tk_calldata;
     71 
     72 	/*
     73 	 * tk_timer is used for async processing by the RPC scheduling
     74 	 * primitives. You should not access this directly unless
     75 	 * you have a pathological interest in kernel oopses.
     76 	 */
     77 	struct timer_list	tk_timer;	/* kernel timer */
     78 	unsigned long		tk_timeout;	/* timeout for rpc_sleep() */
     79 	unsigned short		tk_flags;	/* misc flags */
     80 	unsigned char		tk_priority : 2;/* Task priority */
     81 	unsigned long		tk_runstate;	/* Task run status */
     82 	struct workqueue_struct	*tk_workqueue;	/* Normally rpciod, but could
     83 						 * be any workqueue
     84 						 */
     85 	union {
     86 		struct work_struct	tk_work;	/* Async task work queue */
     87 		struct rpc_wait		tk_wait;	/* RPC wait */
     88 	} u;
     89 
     90 	unsigned short		tk_timeouts;	/* maj timeouts */
     91 	size_t			tk_bytes_sent;	/* total bytes sent */
     92 	unsigned long		tk_start;	/* RPC task init timestamp */
     93 	long			tk_rtt;		/* round-trip time (jiffies) */
     94 
     95 #ifdef RPC_DEBUG
     96 	unsigned short		tk_pid;		/* debugging aid */
     97 #endif
     98 };
     99 #define tk_auth			tk_client->cl_auth
    100 #define tk_xprt			tk_client->cl_xprt
    101 
    102 /* support walking a list of tasks on a wait queue */
    103 #define	task_for_each(task, pos, head) \
    104 	list_for_each(pos, head) \
    105 		if ((task=list_entry(pos, struct rpc_task, u.tk_wait.list)),1)
    106 
    107 #define	task_for_first(task, head) \
    108 	if (!list_empty(head) &&  \
    109 	    ((task=list_entry((head)->next, struct rpc_task, u.tk_wait.list)),1))
    110 
    111 /* .. and walking list of all tasks */
    112 #define	alltask_for_each(task, pos, head) \
    113 	list_for_each(pos, head) \
    114 		if ((task=list_entry(pos, struct rpc_task, tk_task)),1)
    115 
    116 typedef void			(*rpc_action)(struct rpc_task *);
    117 
    118 struct rpc_call_ops {
    119 	void (*rpc_call_prepare)(struct rpc_task *, void *);
    120 	void (*rpc_call_done)(struct rpc_task *, void *);
    121 	void (*rpc_release)(void *);
    122 };
    123 
    124 
    125 /*
    126  * RPC task flags
    127  */
    128 #define RPC_TASK_ASYNC		0x0001		/* is an async task */
    129 #define RPC_TASK_SWAPPER	0x0002		/* is swapping in/out */
    130 #define RPC_TASK_CHILD		0x0008		/* is child of other task */
    131 #define RPC_CALL_MAJORSEEN	0x0020		/* major timeout seen */
    132 #define RPC_TASK_ROOTCREDS	0x0040		/* force root creds */
    133 #define RPC_TASK_DYNAMIC	0x0080		/* task was kmalloc'ed */
    134 #define RPC_TASK_KILLED		0x0100		/* task was killed */
    135 #define RPC_TASK_SOFT		0x0200		/* Use soft timeouts */
    136 #define RPC_TASK_NOINTR		0x0400		/* uninterruptible task */
    137 
    138 #define RPC_IS_ASYNC(t)		((t)->tk_flags & RPC_TASK_ASYNC)
    139 #define RPC_IS_CHILD(t)		((t)->tk_flags & RPC_TASK_CHILD)
    140 #define RPC_IS_SWAPPER(t)	((t)->tk_flags & RPC_TASK_SWAPPER)
    141 #define RPC_DO_ROOTOVERRIDE(t)	((t)->tk_flags & RPC_TASK_ROOTCREDS)
    142 #define RPC_ASSASSINATED(t)	((t)->tk_flags & RPC_TASK_KILLED)
    143 #define RPC_DO_CALLBACK(t)	((t)->tk_callback != NULL)
    144 #define RPC_IS_SOFT(t)		((t)->tk_flags & RPC_TASK_SOFT)
    145 #define RPC_TASK_UNINTERRUPTIBLE(t) ((t)->tk_flags & RPC_TASK_NOINTR)
    146 
    147 #define RPC_TASK_RUNNING	0
    148 #define RPC_TASK_QUEUED		1
    149 #define RPC_TASK_WAKEUP		2
    150 #define RPC_TASK_HAS_TIMER	3
    151 #define RPC_TASK_ACTIVE		4
    152 
    153 #define RPC_IS_RUNNING(t)	(test_bit(RPC_TASK_RUNNING, &(t)->tk_runstate))
    154 #define rpc_set_running(t)	(set_bit(RPC_TASK_RUNNING, &(t)->tk_runstate))
    155 #define rpc_test_and_set_running(t) \
    156 				(test_and_set_bit(RPC_TASK_RUNNING, &(t)->tk_runstate))
    157 #define rpc_clear_running(t)	\
    158 	do { \
    159 		smp_mb__before_clear_bit(); \
    160 		clear_bit(RPC_TASK_RUNNING, &(t)->tk_runstate); \
    161 		smp_mb__after_clear_bit(); \
    162 	} while (0)
    163 
    164 #define RPC_IS_QUEUED(t)	(test_bit(RPC_TASK_QUEUED, &(t)->tk_runstate))
    165 #define rpc_set_queued(t)	(set_bit(RPC_TASK_QUEUED, &(t)->tk_runstate))
    166 #define rpc_clear_queued(t)	\
    167 	do { \
    168 		smp_mb__before_clear_bit(); \
    169 		clear_bit(RPC_TASK_QUEUED, &(t)->tk_runstate); \
    170 		smp_mb__after_clear_bit(); \
    171 	} while (0)
    172 
    173 #define rpc_start_wakeup(t) \
    174 	(test_and_set_bit(RPC_TASK_WAKEUP, &(t)->tk_runstate) == 0)
    175 #define rpc_finish_wakeup(t) \
    176 	do { \
    177 		smp_mb__before_clear_bit(); \
    178 		clear_bit(RPC_TASK_WAKEUP, &(t)->tk_runstate); \
    179 		smp_mb__after_clear_bit(); \
    180 	} while (0)
    181 
    182 #define RPC_IS_ACTIVATED(t)	(test_bit(RPC_TASK_ACTIVE, &(t)->tk_runstate))
    183 #define rpc_set_active(t)	(set_bit(RPC_TASK_ACTIVE, &(t)->tk_runstate))
    184 #define rpc_clear_active(t)	\
    185 	do { \
    186 		smp_mb__before_clear_bit(); \
    187 		clear_bit(RPC_TASK_ACTIVE, &(t)->tk_runstate); \
    188 		smp_mb__after_clear_bit(); \
    189 	} while(0)
    190 
    191 /*
    192  * Task priorities.
    193  * Note: if you change these, you must also change
    194  * the task initialization definitions below.
    195  */
    196 #define RPC_PRIORITY_LOW	0
    197 #define RPC_PRIORITY_NORMAL	1
    198 #define RPC_PRIORITY_HIGH	2
    199 #define RPC_NR_PRIORITY		(RPC_PRIORITY_HIGH+1)
    200 
    201 /*
    202  * RPC synchronization objects
    203  */
    204 struct rpc_wait_queue {
    205 	spinlock_t		lock;
    206 	struct list_head	tasks[RPC_NR_PRIORITY];	/* task queue for each priority level */
    207 	unsigned long		cookie;			/* cookie of last task serviced */
    208 	unsigned char		maxpriority;		/* maximum priority (0 if queue is not a priority queue) */
    209 	unsigned char		priority;		/* current priority */
    210 	unsigned char		count;			/* # task groups remaining serviced so far */
    211 	unsigned char		nr;			/* # tasks remaining for cookie */
    212 	unsigned short		qlen;			/* total # tasks waiting in queue */
    213 #ifdef RPC_DEBUG
    214 	const char *		name;
    215 #endif
    216 };
    217 
    218 /*
    219  * This is the # requests to send consecutively
    220  * from a single cookie.  The aim is to improve
    221  * performance of NFS operations such as read/write.
    222  */
    223 #define RPC_BATCH_COUNT			16
    224 
    225 #ifndef RPC_DEBUG
    226 # define RPC_WAITQ_INIT(var,qname) { \
    227 		.lock = SPIN_LOCK_UNLOCKED, \
    228 		.tasks = { \
    229 			[0] = LIST_HEAD_INIT(var.tasks[0]), \
    230 			[1] = LIST_HEAD_INIT(var.tasks[1]), \
    231 			[2] = LIST_HEAD_INIT(var.tasks[2]), \
    232 		}, \
    233 	}
    234 #else
    235 # define RPC_WAITQ_INIT(var,qname) { \
    236 		.lock = SPIN_LOCK_UNLOCKED, \
    237 		.tasks = { \
    238 			[0] = LIST_HEAD_INIT(var.tasks[0]), \
    239 			[1] = LIST_HEAD_INIT(var.tasks[1]), \
    240 			[2] = LIST_HEAD_INIT(var.tasks[2]), \
    241 		}, \
    242 		.name = qname, \
    243 	}
    244 #endif
    245 # define RPC_WAITQ(var,qname)      struct rpc_wait_queue var = RPC_WAITQ_INIT(var,qname)
    246 
    247 #define RPC_IS_PRIORITY(q)		((q)->maxpriority > 0)
    248 
    249 /*
    250  * Function prototypes
    251  */
    252 struct rpc_task *rpc_new_task(struct rpc_clnt *, int flags,
    253 				const struct rpc_call_ops *ops, void *data);
    254 struct rpc_task *rpc_run_task(struct rpc_clnt *clnt, int flags,
    255 				const struct rpc_call_ops *ops, void *data);
    256 struct rpc_task *rpc_new_child(struct rpc_clnt *, struct rpc_task *parent);
    257 void		rpc_init_task(struct rpc_task *task, struct rpc_clnt *clnt,
    258 				int flags, const struct rpc_call_ops *ops,
    259 				void *data);
    260 void		rpc_release_task(struct rpc_task *);
    261 void		rpc_exit_task(struct rpc_task *);
    262 void		rpc_killall_tasks(struct rpc_clnt *);
    263 int		rpc_execute(struct rpc_task *);
    264 void		rpc_run_child(struct rpc_task *parent, struct rpc_task *child,
    265 					rpc_action action);
    266 void		rpc_init_priority_wait_queue(struct rpc_wait_queue *, const char *);
    267 void		rpc_init_wait_queue(struct rpc_wait_queue *, const char *);
    268 void		rpc_sleep_on(struct rpc_wait_queue *, struct rpc_task *,
    269 					rpc_action action, rpc_action timer);
    270 void		rpc_wake_up_task(struct rpc_task *);
    271 void		rpc_wake_up(struct rpc_wait_queue *);
    272 struct rpc_task *rpc_wake_up_next(struct rpc_wait_queue *);
    273 void		rpc_wake_up_status(struct rpc_wait_queue *, int);
    274 void		rpc_delay(struct rpc_task *, unsigned long);
    275 void *		rpc_malloc(struct rpc_task *, size_t);
    276 void		rpc_free(struct rpc_task *);
    277 int		rpciod_up(void);
    278 void		rpciod_down(void);
    279 int		__rpc_wait_for_completion_task(struct rpc_task *task, int (*)(void *));
    280 #ifdef RPC_DEBUG
    281 void		rpc_show_tasks(void);
    282 #endif
    283 int		rpc_init_mempool(void);
    284 void		rpc_destroy_mempool(void);
    285 extern struct workqueue_struct *rpciod_workqueue;
    286 
    287 static inline void rpc_exit(struct rpc_task *task, int status)
    288 {
    289 	task->tk_status = status;
    290 	task->tk_action = rpc_exit_task;
    291 }
    292 
    293 static inline int rpc_wait_for_completion_task(struct rpc_task *task)
    294 {
    295 	return __rpc_wait_for_completion_task(task, NULL);
    296 }
    297 
    298 #ifdef RPC_DEBUG
    299 static inline const char * rpc_qname(struct rpc_wait_queue *q)
    300 {
    301 	return ((q && q->name) ? q->name : "unknown");
    302 }
    303 #endif
    304 
    305 #endif /* _LINUX_SUNRPC_SCHED_H_ */
    306