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       1                 :            : /* SPDX-License-Identifier: GPL-2.0 */
       2                 :            : /*
       3                 :            :  * Common header file for generic dynamic events.
       4                 :            :  */
       5                 :            : 
       6                 :            : #ifndef _TRACE_DYNEVENT_H
       7                 :            : #define _TRACE_DYNEVENT_H
       8                 :            : 
       9                 :            : #include <linux/kernel.h>
      10                 :            : #include <linux/list.h>
      11                 :            : #include <linux/mutex.h>
      12                 :            : #include <linux/seq_file.h>
      13                 :            : 
      14                 :            : #include "trace.h"
      15                 :            : 
      16                 :            : struct dyn_event;
      17                 :            : 
      18                 :            : /**
      19                 :            :  * struct dyn_event_operations - Methods for each type of dynamic events
      20                 :            :  *
      21                 :            :  * These methods must be set for each type, since there is no default method.
      22                 :            :  * Before using this for dyn_event_init(), it must be registered by
      23                 :            :  * dyn_event_register().
      24                 :            :  *
      25                 :            :  * @create: Parse and create event method. This is invoked when user passes
      26                 :            :  *  a event definition to dynamic_events interface. This must not destruct
      27                 :            :  *  the arguments and return -ECANCELED if given arguments doesn't match its
      28                 :            :  *  command prefix.
      29                 :            :  * @show: Showing method. This is invoked when user reads the event definitions
      30                 :            :  *  via dynamic_events interface.
      31                 :            :  * @is_busy: Check whether given event is busy so that it can not be deleted.
      32                 :            :  *  Return true if it is busy, otherwides false.
      33                 :            :  * @free: Delete the given event. Return 0 if success, otherwides error.
      34                 :            :  * @match: Check whether given event and system name match this event. The argc
      35                 :            :  *  and argv is used for exact match. Return true if it matches, otherwides
      36                 :            :  *  false.
      37                 :            :  *
      38                 :            :  * Except for @create, these methods are called under holding event_mutex.
      39                 :            :  */
      40                 :            : struct dyn_event_operations {
      41                 :            :         struct list_head        list;
      42                 :            :         int (*create)(int argc, const char *argv[]);
      43                 :            :         int (*show)(struct seq_file *m, struct dyn_event *ev);
      44                 :            :         bool (*is_busy)(struct dyn_event *ev);
      45                 :            :         int (*free)(struct dyn_event *ev);
      46                 :            :         bool (*match)(const char *system, const char *event,
      47                 :            :                       int argc, const char **argv, struct dyn_event *ev);
      48                 :            : };
      49                 :            : 
      50                 :            : /* Register new dyn_event type -- must be called at first */
      51                 :            : int dyn_event_register(struct dyn_event_operations *ops);
      52                 :            : 
      53                 :            : /**
      54                 :            :  * struct dyn_event - Dynamic event list header
      55                 :            :  *
      56                 :            :  * The dyn_event structure encapsulates a list and a pointer to the operators
      57                 :            :  * for making a global list of dynamic events.
      58                 :            :  * User must includes this in each event structure, so that those events can
      59                 :            :  * be added/removed via dynamic_events interface.
      60                 :            :  */
      61                 :            : struct dyn_event {
      62                 :            :         struct list_head                list;
      63                 :            :         struct dyn_event_operations     *ops;
      64                 :            : };
      65                 :            : 
      66                 :            : extern struct list_head dyn_event_list;
      67                 :            : 
      68                 :            : static inline
      69                 :            : int dyn_event_init(struct dyn_event *ev, struct dyn_event_operations *ops)
      70                 :            : {
      71         [ #  # ]:          0 :         if (!ev || !ops)
      72                 :            :                 return -EINVAL;
      73                 :            : 
      74                 :          0 :         INIT_LIST_HEAD(&ev->list);
      75                 :          0 :         ev->ops = ops;
      76                 :            :         return 0;
      77                 :            : }
      78                 :            : 
      79                 :            : static inline int dyn_event_add(struct dyn_event *ev)
      80                 :            : {
      81                 :            :         lockdep_assert_held(&event_mutex);
      82                 :            : 
      83   [ #  #  #  #  :          0 :         if (!ev || !ev->ops)
             #  #  #  # ]
      84                 :            :                 return -EINVAL;
      85                 :            : 
      86                 :          0 :         list_add_tail(&ev->list, &dyn_event_list);
      87                 :            :         return 0;
      88                 :            : }
      89                 :            : 
      90                 :            : static inline void dyn_event_remove(struct dyn_event *ev)
      91                 :            : {
      92                 :            :         lockdep_assert_held(&event_mutex);
      93                 :          0 :         list_del_init(&ev->list);
      94                 :            : }
      95                 :            : 
      96                 :            : void *dyn_event_seq_start(struct seq_file *m, loff_t *pos);
      97                 :            : void *dyn_event_seq_next(struct seq_file *m, void *v, loff_t *pos);
      98                 :            : void dyn_event_seq_stop(struct seq_file *m, void *v);
      99                 :            : int dyn_events_release_all(struct dyn_event_operations *type);
     100                 :            : int dyn_event_release(int argc, char **argv, struct dyn_event_operations *type);
     101                 :            : 
     102                 :            : /*
     103                 :            :  * for_each_dyn_event   -       iterate over the dyn_event list
     104                 :            :  * @pos:        the struct dyn_event * to use as a loop cursor
     105                 :            :  *
     106                 :            :  * This is just a basement of for_each macro. Wrap this for
     107                 :            :  * each actual event structure with ops filtering.
     108                 :            :  */
     109                 :            : #define for_each_dyn_event(pos) \
     110                 :            :         list_for_each_entry(pos, &dyn_event_list, list)
     111                 :            : 
     112                 :            : /*
     113                 :            :  * for_each_dyn_event   -       iterate over the dyn_event list safely
     114                 :            :  * @pos:        the struct dyn_event * to use as a loop cursor
     115                 :            :  * @n:          the struct dyn_event * to use as temporary storage
     116                 :            :  */
     117                 :            : #define for_each_dyn_event_safe(pos, n) \
     118                 :            :         list_for_each_entry_safe(pos, n, &dyn_event_list, list)
     119                 :            : 
     120                 :            : #endif