diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/poll.h | 37 | ||||
| -rw-r--r-- | include/net/sock.h | 2 |
2 files changed, 32 insertions, 7 deletions
diff --git a/include/linux/poll.h b/include/linux/poll.h index cf40010ce0cd..48fe8bc398d1 100644 --- a/include/linux/poll.h +++ b/include/linux/poll.h @@ -32,21 +32,46 @@ struct poll_table_struct; */ 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; - unsigned long key; + poll_queue_proc _qproc; + unsigned long _key; } poll_table; static inline void poll_wait(struct file * filp, wait_queue_head_t * wait_address, poll_table *p) { - if (p && wait_address) - p->qproc(filp, wait_address, 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 unsigned long poll_requested_events(const poll_table *p) +{ + return p ? p->_key : ~0UL; } static inline void init_poll_funcptr(poll_table *pt, poll_queue_proc qproc) { - pt->qproc = qproc; - pt->key = ~0UL; /* all events enabled */ + pt->_qproc = qproc; + pt->_key = ~0UL; /* all events enabled */ } struct poll_table_entry { diff --git a/include/net/sock.h b/include/net/sock.h index 04bc0b30e9e9..a6ba1f8871fd 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1854,7 +1854,7 @@ static inline bool wq_has_sleeper(struct socket_wq *wq) static inline void sock_poll_wait(struct file *filp, wait_queue_head_t *wait_address, poll_table *p) { - if (p && wait_address) { + if (!poll_does_not_wait(p) && wait_address) { poll_wait(filp, wait_address, p); /* * We need to be sure we are in sync with the |