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/ktime.h> 10 #include <linux/wait.h> 11 #include <linux/string.h> 12 #include <linux/fs.h> 13 #include <linux/sysctl.h> 14 #include <asm/uaccess.h> 15 16 extern struct ctl_table epoll_table[]; /* for sysctl */ 17 /* ~832 bytes of stack space used max in sys_select/sys_poll before allocating 18 additional memory. */ 19 #define MAX_STACK_ALLOC 832 20 #define FRONTEND_STACK_ALLOC 256 21 #define SELECT_STACK_ALLOC FRONTEND_STACK_ALLOC 22 #define POLL_STACK_ALLOC FRONTEND_STACK_ALLOC 23 #define WQUEUES_STACK_ALLOC (MAX_STACK_ALLOC - FRONTEND_STACK_ALLOC) 24 #define N_INLINE_POLL_ENTRIES (WQUEUES_STACK_ALLOC / sizeof(struct poll_table_entry)) 25 26 #define DEFAULT_POLLMASK (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM) 27 28 struct poll_table_struct; 29 30 /* 31 * structures and helpers for f_op->poll implementations 32 */ 33 typedef void (*poll_queue_proc)(struct file *, wait_queue_head_t *, struct poll_table_struct *); 34 35 /* 36 * Do not touch the structure directly, use the access functions 37 * poll_does_not_wait() and poll_requested_events() instead. 38 */ 39 typedef struct poll_table_struct { 40 poll_queue_proc _qproc; 41 unsigned long _key; 42 } poll_table; 43 44 static inline void poll_wait(struct file * filp, wait_queue_head_t * wait_address, poll_table *p) 45 { 46 if (p && p->_qproc && wait_address) 47 p->_qproc(filp, wait_address, p); 48 } 49 50 /* 51 * Return true if it is guaranteed that poll will not wait. This is the case 52 * if the poll() of another file descriptor in the set got an event, so there 53 * is no need for waiting. 54 */ 55 static inline bool poll_does_not_wait(const poll_table *p) 56 { 57 return p == NULL || p->_qproc == NULL; 58 } 59 60 /* 61 * Return the set of events that the application wants to poll for. 62 * This is useful for drivers that need to know whether a DMA transfer has 63 * to be started implicitly on poll(). You typically only want to do that 64 * if the application is actually polling for POLLIN and/or POLLOUT. 65 */ 66 static inline unsigned long poll_requested_events(const poll_table *p) 67 { 68 return p ? p->_key : ~0UL; 69 } 70 71 static inline void init_poll_funcptr(poll_table *pt, poll_queue_proc qproc) 72 { 73 pt->_qproc = qproc; 74 pt->_key = ~0UL; /* all events enabled */ 75 } 76 77 struct poll_table_entry { 78 struct file *filp; 79 unsigned long key; 80 wait_queue_t wait; 81 wait_queue_head_t *wait_address; 82 }; 83 84 /* 85 * Structures and helpers for select/poll syscall 86 */ 87 struct poll_wqueues { 88 poll_table pt; 89 struct poll_table_page *table; 90 struct task_struct *polling_task; 91 int triggered; 92 int error; 93 int inline_index; 94 struct poll_table_entry inline_entries[N_INLINE_POLL_ENTRIES]; 95 }; 96 97 extern void poll_initwait(struct poll_wqueues *pwq); 98 extern void poll_freewait(struct poll_wqueues *pwq); 99 extern int poll_schedule_timeout(struct poll_wqueues *pwq, int state, 100 ktime_t *expires, unsigned long slack); 101 extern long select_estimate_accuracy(struct timespec *tv); 102 103 104 static inline int poll_schedule(struct poll_wqueues *pwq, int state) 105 { 106 return poll_schedule_timeout(pwq, state, NULL, 0); 107 } 108 109 /* 110 * Scalable version of the fd_set. 111 */ 112 113 typedef struct { 114 unsigned long *in, *out, *ex; 115 unsigned long *res_in, *res_out, *res_ex; 116 } fd_set_bits; 117 118 /* 119 * How many longwords for "nr" bits? 120 */ 121 #define FDS_BITPERLONG (8*sizeof(long)) 122 #define FDS_LONGS(nr) (((nr)+FDS_BITPERLONG-1)/FDS_BITPERLONG) 123 #define FDS_BYTES(nr) (FDS_LONGS(nr)*sizeof(long)) 124 125 /* 126 * We do a VERIFY_WRITE here even though we are only reading this time: 127 * we'll write to it eventually.. 128 * 129 * Use "unsigned long" accesses to let user-mode fd_set's be long-aligned. 130 */ 131 static inline 132 int get_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset) 133 { 134 nr = FDS_BYTES(nr); 135 if (ufdset) 136 return copy_from_user(fdset, ufdset, nr) ? -EFAULT : 0; 137 138 memset(fdset, 0, nr); 139 return 0; 140 } 141 142 static inline unsigned long __must_check 143 set_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset) 144 { 145 if (ufdset) 146 return __copy_to_user(ufdset, fdset, FDS_BYTES(nr)); 147 return 0; 148 } 149 150 static inline 151 void zero_fd_set(unsigned long nr, unsigned long *fdset) 152 { 153 memset(fdset, 0, FDS_BYTES(nr)); 154 } 155 156 #define MAX_INT64_SECONDS (((s64)(~((u64)0)>>1)/HZ)-1) 157 158 extern int do_select(int n, fd_set_bits *fds, struct timespec *end_time); 159 extern int do_sys_poll(struct pollfd __user * ufds, unsigned int nfds, 160 struct timespec *end_time); 161 extern int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp, 162 fd_set __user *exp, struct timespec *end_time); 163 164 extern int poll_select_set_timeout(struct timespec *to, long sec, long nsec); 165 166 #endif /* KERNEL */ 167 168 #endif /* _LINUX_POLL_H */ 169