diff options
Diffstat (limited to 'include/linux/poll.h')
| -rw-r--r-- | include/linux/poll.h | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/include/linux/poll.h b/include/linux/poll.h new file mode 100644 index 000000000..a9e0e1c2d --- /dev/null +++ b/include/linux/poll.h @@ -0,0 +1,147 @@ +/* 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. */ +#ifdef __clang__ +#define MAX_STACK_ALLOC 768 +#else +#define MAX_STACK_ALLOC 832 +#endif +#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 */ |