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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: Willem 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
zero-sugar-mainline-defconfig
Willem de Bruijn 2020-12-18 14:05:38 -08:00 committed by Linus Torvalds
parent 7cdf7c20e9
commit 58169a52eb
1 changed files with 73 additions and 14 deletions
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87
fs/eventpoll.c
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@ -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)