| /* SPDX-License-Identifier: GPL-2.0 */ |
| #ifndef _LINUX_POLL_H |
| #define _LINUX_POLL_H |
| |
| |
| #include <linux/compiler.h> |
| #include <linux/ktime.h> |
| #include <linux/wait.h> |
| #include <linux/string.h> |
| #include <linux/fs.h> |
| #include <linux/uaccess.h> |
| #include <uapi/linux/poll.h> |
| #include <uapi/linux/eventpoll.h> |
| |
| /* ~832 bytes of stack space used max in sys_select/sys_poll before allocating |
| additional memory. */ |
| #define MAX_STACK_ALLOC 832 |
| #define FRONTEND_STACK_ALLOC 256 |
| #define SELECT_STACK_ALLOC FRONTEND_STACK_ALLOC |
| #define POLL_STACK_ALLOC FRONTEND_STACK_ALLOC |
| #define WQUEUES_STACK_ALLOC (MAX_STACK_ALLOC - FRONTEND_STACK_ALLOC) |
| #define N_INLINE_POLL_ENTRIES (WQUEUES_STACK_ALLOC / sizeof(struct poll_table_entry)) |
| |
| #define DEFAULT_POLLMASK (EPOLLIN | EPOLLOUT | EPOLLRDNORM | EPOLLWRNORM) |
| |
| struct poll_table_struct; |
| |
| /* |
| * structures and helpers for f_op->poll implementations |
| */ |
| typedef void (*poll_queue_proc)(struct file *, wait_queue_head_t *, struct poll_table_struct *); |
| |
| /* |
| * Do not touch the structure directly, use the access functions |
| * poll_does_not_wait() and poll_requested_events() instead. |
| */ |
| typedef struct poll_table_struct { |
| poll_queue_proc _qproc; |
| __poll_t _key; |
| } poll_table; |
| |
| static inline void poll_wait(struct file * filp, wait_queue_head_t * wait_address, poll_table *p) |
| { |
| if (p && p->_qproc && wait_address) |
| p->_qproc(filp, wait_address, p); |
| } |
| |
| /* |
| * Return true if it is guaranteed that poll will not wait. This is the case |
| * if the poll() of another file descriptor in the set got an event, so there |
| * is no need for waiting. |
| */ |
| static inline bool poll_does_not_wait(const poll_table *p) |
| { |
| return p == NULL || p->_qproc == NULL; |
| } |
| |
| /* |
| * Return the set of events that the application wants to poll for. |
| * This is useful for drivers that need to know whether a DMA transfer has |
| * to be started implicitly on poll(). You typically only want to do that |
| * if the application is actually polling for POLLIN and/or POLLOUT. |
| */ |
| static inline __poll_t poll_requested_events(const poll_table *p) |
| { |
| return p ? p->_key : ~(__poll_t)0; |
| } |
| |
| static inline void init_poll_funcptr(poll_table *pt, poll_queue_proc qproc) |
| { |
| pt->_qproc = qproc; |
| pt->_key = ~(__poll_t)0; /* all events enabled */ |
| } |
| |
| static inline bool file_can_poll(struct file *file) |
| { |
| return file->f_op->poll; |
| } |
| |
| static inline __poll_t vfs_poll(struct file *file, struct poll_table_struct *pt) |
| { |
| if (unlikely(!file->f_op->poll)) |
| return DEFAULT_POLLMASK; |
| return file->f_op->poll(file, pt); |
| } |
| |
| struct poll_table_entry { |
| struct file *filp; |
| __poll_t key; |
| wait_queue_entry_t wait; |
| wait_queue_head_t *wait_address; |
| }; |
| |
| /* |
| * Structures and helpers for select/poll syscall |
| */ |
| struct poll_wqueues { |
| poll_table pt; |
| struct poll_table_page *table; |
| struct task_struct *polling_task; |
| int triggered; |
| int error; |
| int inline_index; |
| struct poll_table_entry inline_entries[N_INLINE_POLL_ENTRIES]; |
| }; |
| |
| extern void poll_initwait(struct poll_wqueues *pwq); |
| extern void poll_freewait(struct poll_wqueues *pwq); |
| extern u64 select_estimate_accuracy(struct timespec64 *tv); |
| |
| #define MAX_INT64_SECONDS (((s64)(~((u64)0)>>1)/HZ)-1) |
| |
| extern int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp, |
| fd_set __user *exp, struct timespec64 *end_time); |
| |
| extern int poll_select_set_timeout(struct timespec64 *to, time64_t sec, |
| long nsec); |
| |
| #define __MAP(v, from, to) \ |
| (from < to ? (v & from) * (to/from) : (v & from) / (from/to)) |
| |
| static inline __u16 mangle_poll(__poll_t val) |
| { |
| __u16 v = (__force __u16)val; |
| #define M(X) __MAP(v, (__force __u16)EPOLL##X, POLL##X) |
| return M(IN) | M(OUT) | M(PRI) | M(ERR) | M(NVAL) | |
| M(RDNORM) | M(RDBAND) | M(WRNORM) | M(WRBAND) | |
| M(HUP) | M(RDHUP) | M(MSG); |
| #undef M |
| } |
| |
| static inline __poll_t demangle_poll(u16 val) |
| { |
| #define M(X) (__force __poll_t)__MAP(val, POLL##X, (__force __u16)EPOLL##X) |
| return M(IN) | M(OUT) | M(PRI) | M(ERR) | M(NVAL) | |
| M(RDNORM) | M(RDBAND) | M(WRNORM) | M(WRBAND) | |
| M(HUP) | M(RDHUP) | M(MSG); |
| #undef M |
| } |
| #undef __MAP |
| |
| |
| #endif /* _LINUX_POLL_H */ |