include/linux/poll.h

   1 #ifndef _LINUX_POLL_H
   2 #define _LINUX_POLL_H
   3
   4 #include <asm/poll.h>
   5
   6 #ifdef __KERNEL__
   7
   8 #include <linux/compiler.h>
   9 #include <linux/wait.h>
  10 #include <linux/string.h>
  11 #include <linux/fs.h>
  12 #include <linux/sched.h>
  13 #include <asm/uaccess.h>
  14
  15 /* ~832 bytes of stack space used max in sys_select/sys_poll before allocating
  16    additional memory. */
  17 #define MAX_STACK_ALLOC 832
  18 #define FRONTEND_STACK_ALLOC    256
  19 #define SELECT_STACK_ALLOC      FRONTEND_STACK_ALLOC
  20 #define POLL_STACK_ALLOC        FRONTEND_STACK_ALLOC
  21 #define WQUEUES_STACK_ALLOC     (MAX_STACK_ALLOC - FRONTEND_STACK_ALLOC)
  22 #define N_INLINE_POLL_ENTRIES   (WQUEUES_STACK_ALLOC / sizeof(struct poll_table_entry))
  23
  24 #define DEFAULT_POLLMASK (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)
  25
  26 struct poll_table_struct;
  27
  28 /*
  29  * structures and helpers for f_op->poll implementations
  30  */
  31 typedef void (*poll_queue_proc)(struct file *, wait_queue_head_t *, struct poll_table_struct *);
  32
  33 typedef struct poll_table_struct {
  34         poll_queue_proc qproc;
  35 } poll_table;
  36
  37 static inline void poll_wait(struct file * filp, wait_queue_head_t * wait_address, poll_table *p)
  38 {
  39         if (p && wait_address)
  40                 p->qproc(filp, wait_address, p);
  41 }
  42
  43 static inline void init_poll_funcptr(poll_table *pt, poll_queue_proc qproc)
  44 {
  45         pt->qproc = qproc;
  46 }
  47
  48 struct poll_table_entry {
  49         struct file *filp;
  50         wait_queue_t wait;
  51         wait_queue_head_t *wait_address;
  52 };
  53
  54 /*
  55  * Structures and helpers for sys_poll/sys_poll
  56  */
  57 struct poll_wqueues {
  58         poll_table pt;
  59         struct poll_table_page *table;
  60         struct task_struct *polling_task;
  61         int triggered;
  62         int error;
  63         int inline_index;
  64         struct poll_table_entry inline_entries[N_INLINE_POLL_ENTRIES];
  65 };
  66
  67 extern void poll_initwait(struct poll_wqueues *pwq);
  68 extern void poll_freewait(struct poll_wqueues *pwq);
  69 extern int poll_schedule_timeout(struct poll_wqueues *pwq, int state,
  70                                  ktime_t *expires, unsigned long slack);
  71
  72 static inline int poll_schedule(struct poll_wqueues *pwq, int state)
  73 {
  74         return poll_schedule_timeout(pwq, state, NULL, 0);
  75 }
  76
  77 /*
  78  * Scaleable version of the fd_set.
  79  */
  80
  81 typedef struct {
  82         unsigned long *in, *out, *ex;
  83         unsigned long *res_in, *res_out, *res_ex;
  84 } fd_set_bits;
  85
  86 /*
  87  * How many longwords for "nr" bits?
  88  */
  89 #define FDS_BITPERLONG  (8*sizeof(long))
  90 #define FDS_LONGS(nr)   (((nr)+FDS_BITPERLONG-1)/FDS_BITPERLONG)
  91 #define FDS_BYTES(nr)   (FDS_LONGS(nr)*sizeof(long))
  92
  93 /*
  94  * We do a VERIFY_WRITE here even though we are only reading this time:
  95  * we'll write to it eventually..
  96  *
  97  * Use "unsigned long" accesses to let user-mode fd_set's be long-aligned.
  98  */
  99 static inline
 100 int get_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
 101 {
 102         nr = FDS_BYTES(nr);
 103         if (ufdset)
 104                 return copy_from_user(fdset, ufdset, nr) ? -EFAULT : 0;
 105
 106         memset(fdset, 0, nr);
 107         return 0;
 108 }
 109
 110 static inline unsigned long __must_check
 111 set_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
 112 {
 113         if (ufdset)
 114                 return __copy_to_user(ufdset, fdset, FDS_BYTES(nr));
 115         return 0;
 116 }
 117
 118 static inline
 119 void zero_fd_set(unsigned long nr, unsigned long *fdset)
 120 {
 121         memset(fdset, 0, FDS_BYTES(nr));
 122 }
 123
 124 #define MAX_INT64_SECONDS (((s64)(~((u64)0)>>1)/HZ)-1)
 125
 126 extern int do_select(int n, fd_set_bits *fds, struct timespec *end_time);
 127 extern int do_sys_poll(struct pollfd __user * ufds, unsigned int nfds,
 128                        struct timespec *end_time);
 129 extern int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
 130                            fd_set __user *exp, struct timespec *end_time);
 131
 132 extern int poll_select_set_timeout(struct timespec *to, long sec, long nsec);
 133
 134 #endif /* KERNEL */
 135
 136 #endif /* _LINUX_POLL_H */