Commit 58169a52 authored by Willem de Bruijn's avatar Willem de Bruijn Committed by Linus Torvalds
Browse files

epoll: add syscall epoll_pwait2 

Add syscall epoll_pwait2, an epoll_wait variant with nsec resolution that
replaces int timeout with struct timespec.  It is equivalent otherwise.

    int epoll_pwait2(int fd, struct epoll_event *events,
                     int maxevents,
                     const struct timespec *timeout,
                     const sigset_t *sigset);

The underlying hrtimer is already programmed with nsec resolution.
pselect and ppoll also set nsec resolution timeout with timespec.

The sigset_t in epoll_pwait has a compat variant. epoll_pwait2 needs
the same.

For timespec, only support this new interface on 2038 aware platforms
that define __kernel_timespec_t. So no CONFIG_COMPAT_32BIT_TIME.

Link: https://lkml.kernel.org/r/20201121144401.3727659-3-willemdebruijn.kernel@gmail.com


Signed-off-by: default avatarWillem de Bruijn <willemb@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7cdf7c20

fs/eventpoll.c

+73 −14
Original line number Diff line number Diff line
@@ -2237,11 +2237,10 @@ SYSCALL_DEFINE4(epoll_wait, int, epfd, struct epoll_event __user *, events, 
 * Implement the event wait interface for the eventpoll file. It is the kernel

 * part of the user space epoll_pwait(2).

 */

SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct epoll_event __user *, events,

		int, maxevents, int, timeout, const sigset_t __user *, sigmask,

		size_t, sigsetsize)

static int do_epoll_pwait(int epfd, struct epoll_event __user *events,

			  int maxevents, struct timespec64 *to,

			  const sigset_t __user *sigmask, size_t sigsetsize)

{

	struct timespec64 to;

	int error;



	/*
@@ -2252,22 +2251,48 @@ SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct epoll_event __user *, events, 
	if (error)

		return error;



	error = do_epoll_wait(epfd, events, maxevents,

			      ep_timeout_to_timespec(&to, timeout));

	error = do_epoll_wait(epfd, events, maxevents, to);



	restore_saved_sigmask_unless(error == -EINTR);



	return error;

}



#ifdef CONFIG_COMPAT

COMPAT_SYSCALL_DEFINE6(epoll_pwait, int, epfd,

			struct epoll_event __user *, events,

			int, maxevents, int, timeout,

			const compat_sigset_t __user *, sigmask,

			compat_size_t, sigsetsize)

SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct epoll_event __user *, events,

		int, maxevents, int, timeout, const sigset_t __user *, sigmask,

		size_t, sigsetsize)

{

	struct timespec64 to;



	return do_epoll_pwait(epfd, events, maxevents,

			      ep_timeout_to_timespec(&to, timeout),

			      sigmask, sigsetsize);

}



SYSCALL_DEFINE6(epoll_pwait2, int, epfd, struct epoll_event __user *, events,

		int, maxevents, const struct __kernel_timespec __user *, timeout,

		const sigset_t __user *, sigmask, size_t, sigsetsize)

{

	struct timespec64 ts, *to = NULL;



	if (timeout) {

		if (get_timespec64(&ts, timeout))

			return -EFAULT;

		to = &ts;

		if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))

			return -EINVAL;

	}



	return do_epoll_pwait(epfd, events, maxevents, to,

			      sigmask, sigsetsize);

}



#ifdef CONFIG_COMPAT

static int do_compat_epoll_pwait(int epfd, struct epoll_event __user *events,

				 int maxevents, struct timespec64 *timeout,

				 const compat_sigset_t __user *sigmask,

				 compat_size_t sigsetsize)

{

	long err;



	/*
@@ -2278,13 +2303,47 @@ COMPAT_SYSCALL_DEFINE6(epoll_pwait, int, epfd, 
	if (err)

		return err;



	err = do_epoll_wait(epfd, events, maxevents,

			    ep_timeout_to_timespec(&to, timeout));

	err = do_epoll_wait(epfd, events, maxevents, timeout);



	restore_saved_sigmask_unless(err == -EINTR);



	return err;

}



COMPAT_SYSCALL_DEFINE6(epoll_pwait, int, epfd,

		       struct epoll_event __user *, events,

		       int, maxevents, int, timeout,

		       const compat_sigset_t __user *, sigmask,

		       compat_size_t, sigsetsize)

{

	struct timespec64 to;



	return do_compat_epoll_pwait(epfd, events, maxevents,

				     ep_timeout_to_timespec(&to, timeout),

				     sigmask, sigsetsize);

}



COMPAT_SYSCALL_DEFINE6(epoll_pwait2, int, epfd,

		       struct epoll_event __user *, events,

		       int, maxevents,

		       const struct __kernel_timespec __user *, timeout,

		       const compat_sigset_t __user *, sigmask,

		       compat_size_t, sigsetsize)

{

	struct timespec64 ts, *to = NULL;



	if (timeout) {

		if (get_timespec64(&ts, timeout))

			return -EFAULT;

		to = &ts;

		if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))

			return -EINVAL;

	}



	return do_compat_epoll_pwait(epfd, events, maxevents, to,

				     sigmask, sigsetsize);

}



#endif



static int __init eventpoll_init(void)

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