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epoll: convert internal api to timespec64
Patch series "add epoll_pwait2 syscall", v4. Enable nanosecond timeouts for epoll. Analogous to pselect and ppoll, introduce an epoll_wait syscall variant that takes a struct timespec instead of int timeout. This patch (of 4): Make epoll more consistent with select/poll: pass along the timeout as timespec64 pointer. In anticipation of additional changes affecting all three polling mechanisms: - add epoll_pwait2 syscall with timespec semantics, and share poll_select_set_timeout implementation. - compute slack before conversion to absolute time, to save one ktime_get_ts64 call. Link: https://lkml.kernel.org/r/20201121144401.3727659-1-willemdebruijn.kernel@gmail.com Link: https://lkml.kernel.org/r/20201121144401.3727659-2-willemdebruijn.kernel@gmail.com Signed-off-by: Willem de Bruijn <willemb@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -1712,15 +1712,25 @@ static int ep_send_events(struct eventpoll *ep,
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return res;
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}
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static inline struct timespec64 ep_set_mstimeout(long ms)
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static struct timespec64 *ep_timeout_to_timespec(struct timespec64 *to, long ms)
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{
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struct timespec64 now, ts = {
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.tv_sec = ms / MSEC_PER_SEC,
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.tv_nsec = NSEC_PER_MSEC * (ms % MSEC_PER_SEC),
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};
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struct timespec64 now;
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if (ms < 0)
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return NULL;
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if (!ms) {
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to->tv_sec = 0;
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to->tv_nsec = 0;
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return to;
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}
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to->tv_sec = ms / MSEC_PER_SEC;
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to->tv_nsec = NSEC_PER_MSEC * (ms % MSEC_PER_SEC);
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ktime_get_ts64(&now);
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return timespec64_add_safe(now, ts);
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*to = timespec64_add_safe(now, *to);
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return to;
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}
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/**
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@ -1732,8 +1742,8 @@ static inline struct timespec64 ep_set_mstimeout(long ms)
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* stored.
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* @maxevents: Size (in terms of number of events) of the caller event buffer.
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* @timeout: Maximum timeout for the ready events fetch operation, in
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* milliseconds. If the @timeout is zero, the function will not block,
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* while if the @timeout is less than zero, the function will block
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* timespec. If the timeout is zero, the function will not block,
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* while if the @timeout ptr is NULL, the function will block
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* until at least one event has been retrieved (or an error
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* occurred).
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*
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@ -1741,7 +1751,7 @@ static inline struct timespec64 ep_set_mstimeout(long ms)
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* error code, in case of error.
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*/
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static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events,
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int maxevents, long timeout)
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int maxevents, struct timespec64 *timeout)
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{
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int res, eavail, timed_out = 0;
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u64 slack = 0;
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@ -1750,13 +1760,11 @@ static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events,
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lockdep_assert_irqs_enabled();
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if (timeout > 0) {
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struct timespec64 end_time = ep_set_mstimeout(timeout);
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slack = select_estimate_accuracy(&end_time);
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if (timeout && (timeout->tv_sec | timeout->tv_nsec)) {
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slack = select_estimate_accuracy(timeout);
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to = &expires;
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*to = timespec64_to_ktime(end_time);
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} else if (timeout == 0) {
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*to = timespec64_to_ktime(*timeout);
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} else if (timeout) {
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/*
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* Avoid the unnecessary trip to the wait queue loop, if the
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* caller specified a non blocking operation.
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@ -2175,7 +2183,7 @@ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd,
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* part of the user space epoll_wait(2).
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*/
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static int do_epoll_wait(int epfd, struct epoll_event __user *events,
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int maxevents, int timeout)
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int maxevents, struct timespec64 *to)
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{
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int error;
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struct fd f;
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@ -2209,7 +2217,7 @@ static int do_epoll_wait(int epfd, struct epoll_event __user *events,
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ep = f.file->private_data;
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/* Time to fish for events ... */
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error = ep_poll(ep, events, maxevents, timeout);
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error = ep_poll(ep, events, maxevents, to);
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error_fput:
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fdput(f);
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@ -2219,7 +2227,10 @@ static int do_epoll_wait(int epfd, struct epoll_event __user *events,
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SYSCALL_DEFINE4(epoll_wait, int, epfd, struct epoll_event __user *, events,
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int, maxevents, int, timeout)
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{
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return do_epoll_wait(epfd, events, maxevents, timeout);
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struct timespec64 to;
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return do_epoll_wait(epfd, events, maxevents,
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ep_timeout_to_timespec(&to, timeout));
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}
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/*
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@ -2230,6 +2241,7 @@ SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct epoll_event __user *, events,
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int, maxevents, int, timeout, const sigset_t __user *, sigmask,
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size_t, sigsetsize)
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{
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struct timespec64 to;
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int error;
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/*
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@ -2240,7 +2252,9 @@ SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct epoll_event __user *, events,
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if (error)
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return error;
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error = do_epoll_wait(epfd, events, maxevents, timeout);
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error = do_epoll_wait(epfd, events, maxevents,
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ep_timeout_to_timespec(&to, timeout));
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restore_saved_sigmask_unless(error == -EINTR);
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return error;
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@ -2253,6 +2267,7 @@ COMPAT_SYSCALL_DEFINE6(epoll_pwait, int, epfd,
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const compat_sigset_t __user *, sigmask,
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compat_size_t, sigsetsize)
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{
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struct timespec64 to;
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long err;
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/*
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@ -2263,7 +2278,9 @@ COMPAT_SYSCALL_DEFINE6(epoll_pwait, int, epfd,
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if (err)
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return err;
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err = do_epoll_wait(epfd, events, maxevents, timeout);
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err = do_epoll_wait(epfd, events, maxevents,
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ep_timeout_to_timespec(&to, timeout));
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restore_saved_sigmask_unless(err == -EINTR);
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return err;
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