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Date: Wed, 18 Nov 2020 09:46:15 -0500
From: Willem de Bruijn <willemdebruijn.kernel@...il.com>
To: linux-fsdevel@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, viro@...iv.linux.org.uk,
akpm@...ux-foundation.org, soheil.kdev@...il.com, arnd@...db.de,
shuochen@...gle.com, linux-man@...r.kernel.org,
Willem de Bruijn <willemb@...gle.com>
Subject: [PATCH v3 1/2] epoll: add nsec timeout support with epoll_pwait2
From: Willem de Bruijn <willemb@...gle.com>
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.
Changes
v3:
- rewrite: add epoll_pwait2 syscall instead of epoll_create1 flag
v2:
- cast to s64: avoid overflow on 32-bit platforms (Shuo Chen)
- minor commit message rewording
Signed-off-by: Willem de Bruijn <willemb@...gle.com>
---
This version applies cleanly to linux-next-20201117.
---
arch/alpha/kernel/syscalls/syscall.tbl | 1 +
arch/arm/tools/syscall.tbl | 1 +
arch/arm64/include/asm/unistd.h | 2 +-
arch/arm64/include/asm/unistd32.h | 2 +
arch/ia64/kernel/syscalls/syscall.tbl | 1 +
arch/m68k/kernel/syscalls/syscall.tbl | 1 +
arch/microblaze/kernel/syscalls/syscall.tbl | 1 +
arch/mips/kernel/syscalls/syscall_n32.tbl | 1 +
arch/mips/kernel/syscalls/syscall_n64.tbl | 1 +
arch/mips/kernel/syscalls/syscall_o32.tbl | 1 +
arch/parisc/kernel/syscalls/syscall.tbl | 1 +
arch/powerpc/kernel/syscalls/syscall.tbl | 1 +
arch/s390/kernel/syscalls/syscall.tbl | 1 +
arch/sh/kernel/syscalls/syscall.tbl | 1 +
arch/sparc/kernel/syscalls/syscall.tbl | 1 +
arch/x86/entry/syscalls/syscall_32.tbl | 1 +
arch/x86/entry/syscalls/syscall_64.tbl | 1 +
arch/xtensa/kernel/syscalls/syscall.tbl | 1 +
fs/eventpoll.c | 106 ++++++++++++++++----
include/linux/compat.h | 6 ++
include/linux/syscalls.h | 5 +
include/uapi/asm-generic/unistd.h | 4 +-
kernel/sys_ni.c | 2 +
23 files changed, 123 insertions(+), 20 deletions(-)
diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl
index c5cc5bfa2062..e0a599bfb0e1 100644
--- a/arch/alpha/kernel/syscalls/syscall.tbl
+++ b/arch/alpha/kernel/syscalls/syscall.tbl
@@ -481,3 +481,4 @@
549 common faccessat2 sys_faccessat2
550 common process_madvise sys_process_madvise
551 common watch_mount sys_watch_mount
+552 common epoll_pwait2 sys_epoll_pwait2
diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
index 47325b3b661a..dbde88a855b6 100644
--- a/arch/arm/tools/syscall.tbl
+++ b/arch/arm/tools/syscall.tbl
@@ -455,3 +455,4 @@
439 common faccessat2 sys_faccessat2
440 common process_madvise sys_process_madvise
441 common watch_mount sys_watch_mount
+443 common epoll_pwait2 sys_epoll_pwait2
diff --git a/arch/arm64/include/asm/unistd.h b/arch/arm64/include/asm/unistd.h
index 949788f5ba40..d1f7d35f986e 100644
--- a/arch/arm64/include/asm/unistd.h
+++ b/arch/arm64/include/asm/unistd.h
@@ -38,7 +38,7 @@
#define __ARM_NR_compat_set_tls (__ARM_NR_COMPAT_BASE + 5)
#define __ARM_NR_COMPAT_END (__ARM_NR_COMPAT_BASE + 0x800)
-#define __NR_compat_syscalls 443
+#define __NR_compat_syscalls 444
#endif
#define __ARCH_WANT_SYS_CLONE
diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
index c71c3fe0b6cd..b84e24a7e2c0 100644
--- a/arch/arm64/include/asm/unistd32.h
+++ b/arch/arm64/include/asm/unistd32.h
@@ -893,6 +893,8 @@ __SYSCALL(__NR_process_madvise, sys_process_madvise)
__SYSCALL(__NR_watch_mount, sys_watch_mount)
#define __NR_memfd_secret 442
__SYSCALL(__NR_memfd_secret, sys_memfd_secret)
+#define __NR_epoll_pwait2 443
+__SYSCALL(__NR_epoll_pwait2, sys_epoll_pwait2)
/*
* Please add new compat syscalls above this comment and update
diff --git a/arch/ia64/kernel/syscalls/syscall.tbl b/arch/ia64/kernel/syscalls/syscall.tbl
index 033244462350..c8809959636f 100644
--- a/arch/ia64/kernel/syscalls/syscall.tbl
+++ b/arch/ia64/kernel/syscalls/syscall.tbl
@@ -362,3 +362,4 @@
439 common faccessat2 sys_faccessat2
440 common process_madvise sys_process_madvise
441 common watch_mount sys_watch_mount
+443 common epoll_pwait2 sys_epoll_pwait2
diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl
index efd3ecb3cdfc..dde585616bf8 100644
--- a/arch/m68k/kernel/syscalls/syscall.tbl
+++ b/arch/m68k/kernel/syscalls/syscall.tbl
@@ -441,3 +441,4 @@
439 common faccessat2 sys_faccessat2
440 common process_madvise sys_process_madvise
441 common watch_mount sys_watch_mount
+443 common epoll_pwait2 sys_epoll_pwait2
diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl
index 67ae5a5e4d21..4c09f27fedd0 100644
--- a/arch/microblaze/kernel/syscalls/syscall.tbl
+++ b/arch/microblaze/kernel/syscalls/syscall.tbl
@@ -447,3 +447,4 @@
439 common faccessat2 sys_faccessat2
440 common process_madvise sys_process_madvise
441 common watch_mount sys_watch_mount
+443 common epoll_pwait2 sys_epoll_pwait2
diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
index c59bc6acc47a..00921244242d 100644
--- a/arch/mips/kernel/syscalls/syscall_n32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
@@ -380,3 +380,4 @@
439 n32 faccessat2 sys_faccessat2
440 n32 process_madvise sys_process_madvise
441 n32 watch_mount sys_watch_mount
+443 n32 epoll_pwait2 sys_epoll_pwait2
diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl
index 50bbb9517052..b7920f76358d 100644
--- a/arch/mips/kernel/syscalls/syscall_n64.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n64.tbl
@@ -356,3 +356,4 @@
439 n64 faccessat2 sys_faccessat2
440 n64 process_madvise sys_process_madvise
441 n64 watch_mount sys_watch_mount
+443 n64 epoll_pwait2 sys_epoll_pwait2
diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
index 1d5644e221b4..2ab5ed500113 100644
--- a/arch/mips/kernel/syscalls/syscall_o32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
@@ -429,3 +429,4 @@
439 o32 faccessat2 sys_faccessat2
440 o32 process_madvise sys_process_madvise
441 o32 watch_mount sys_watch_mount
+443 o32 epoll_pwait2 sys_epoll_pwait2 compat_sys_epoll_pwait2
diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
index 4492cc2fce23..9caf7d969846 100644
--- a/arch/parisc/kernel/syscalls/syscall.tbl
+++ b/arch/parisc/kernel/syscalls/syscall.tbl
@@ -439,3 +439,4 @@
439 common faccessat2 sys_faccessat2
440 common process_madvise sys_process_madvise
441 common watch_mount sys_watch_mount
+443 common epoll_pwait2 sys_epoll_pwait2 compat_sys_epoll_pwait2
diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
index ee122bfc2ddc..dce635420226 100644
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -531,3 +531,4 @@
439 common faccessat2 sys_faccessat2
440 common process_madvise sys_process_madvise
441 common watch_mount sys_watch_mount
+443 common epoll_pwait2 sys_epoll_pwait2 compat_sys_epoll_pwait2
diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
index b467b57d66d1..dedfa6db9f8d 100644
--- a/arch/s390/kernel/syscalls/syscall.tbl
+++ b/arch/s390/kernel/syscalls/syscall.tbl
@@ -444,3 +444,4 @@
439 common faccessat2 sys_faccessat2 sys_faccessat2
440 common process_madvise sys_process_madvise sys_process_madvise
441 common watch_mount sys_watch_mount sys_watch_mount
+443 common epoll_pwait2 sys_epoll_pwait2 sys_epoll_pwait2
diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl
index f9c7ca5cb969..f7a383ae2c48 100644
--- a/arch/sh/kernel/syscalls/syscall.tbl
+++ b/arch/sh/kernel/syscalls/syscall.tbl
@@ -444,3 +444,4 @@
439 common faccessat2 sys_faccessat2
440 common process_madvise sys_process_madvise
441 common watch_mount sys_watch_mount
+443 common epoll_pwait2 sys_epoll_pwait2
diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
index 341fd4ba053b..a6cdf450d0f4 100644
--- a/arch/sparc/kernel/syscalls/syscall.tbl
+++ b/arch/sparc/kernel/syscalls/syscall.tbl
@@ -487,3 +487,4 @@
439 common faccessat2 sys_faccessat2
440 common process_madvise sys_process_madvise
441 common watch_mount sys_watch_mount
+443 common epoll_pwait2 sys_epoll_pwait2
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 109e6681b8fa..9a4e8ec207fc 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -447,3 +447,4 @@
440 i386 process_madvise sys_process_madvise
441 i386 watch_mount sys_watch_mount
442 i386 memfd_secret sys_memfd_secret
+443 i386 epoll_pwait2 sys_epoll_pwait2 compat_sys_epoll_pwait2
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 742cf17d7725..e2cb5f87e760 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -364,6 +364,7 @@
440 common process_madvise sys_process_madvise
441 common watch_mount sys_watch_mount
442 common memfd_secret sys_memfd_secret
+443 common epoll_pwait2 sys_epoll_pwait2
#
# Due to a historical design error, certain syscalls are numbered differently
diff --git a/arch/xtensa/kernel/syscalls/syscall.tbl b/arch/xtensa/kernel/syscalls/syscall.tbl
index 6225d87be81f..1c8ae5fd026e 100644
--- a/arch/xtensa/kernel/syscalls/syscall.tbl
+++ b/arch/xtensa/kernel/syscalls/syscall.tbl
@@ -412,3 +412,4 @@
439 common faccessat2 sys_faccessat2
440 common process_madvise sys_process_madvise
441 common watch_mount sys_watch_mount
+443 common epoll_pwait2 sys_epoll_pwait2
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 297aeb0ee9d1..0f0543e1cc6f 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -1714,13 +1714,11 @@ static int ep_send_events(struct eventpoll *ep,
return res;
}
-static inline struct timespec64 ep_set_mstimeout(long ms)
+static inline struct timespec64 ep_set_nstimeout(s64 timeout)
{
- struct timespec64 now, ts = {
- .tv_sec = ms / MSEC_PER_SEC,
- .tv_nsec = NSEC_PER_MSEC * (ms % MSEC_PER_SEC),
- };
+ struct timespec64 now, ts;
+ ts = ns_to_timespec64(timeout);
ktime_get_ts64(&now);
return timespec64_add_safe(now, ts);
}
@@ -1734,7 +1732,7 @@ static inline struct timespec64 ep_set_mstimeout(long ms)
* stored.
* @maxevents: Size (in terms of number of events) of the caller event buffer.
* @timeout: Maximum timeout for the ready events fetch operation, in
- * milliseconds. If the @timeout is zero, the function will not block,
+ * nanoseconds. If the @timeout is zero, the function will not block,
* while if the @timeout is less than zero, the function will block
* until at least one event has been retrieved (or an error
* occurred).
@@ -1743,7 +1741,7 @@ static inline struct timespec64 ep_set_mstimeout(long ms)
* error code, in case of error.
*/
static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events,
- int maxevents, long timeout)
+ int maxevents, s64 timeout)
{
int res, eavail, timed_out = 0;
u64 slack = 0;
@@ -1753,7 +1751,7 @@ static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events,
lockdep_assert_irqs_enabled();
if (timeout > 0) {
- struct timespec64 end_time = ep_set_mstimeout(timeout);
+ struct timespec64 end_time = ep_set_nstimeout(timeout);
slack = select_estimate_accuracy(&end_time);
to = &expires;
@@ -2177,7 +2175,7 @@ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd,
* part of the user space epoll_wait(2).
*/
static int do_epoll_wait(int epfd, struct epoll_event __user *events,
- int maxevents, int timeout)
+ int maxevents, s64 timeout)
{
int error;
struct fd f;
@@ -2218,19 +2216,27 @@ static int do_epoll_wait(int epfd, struct epoll_event __user *events,
return error;
}
+static s64 timeout_to_ns(int timeout)
+{
+ if (timeout <= 0)
+ return timeout;
+ else
+ return timeout * (s64)NSEC_PER_MSEC;
+}
+
SYSCALL_DEFINE4(epoll_wait, int, epfd, struct epoll_event __user *, events,
int, maxevents, int, timeout)
{
- return do_epoll_wait(epfd, events, maxevents, timeout);
+ return do_epoll_wait(epfd, events, maxevents, timeout_to_ns(timeout));
}
/*
* 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, s64 timeout,
+ const sigset_t __user *sigmask, size_t sigsetsize)
{
int error;
@@ -2248,12 +2254,40 @@ SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct epoll_event __user *, events,
return error;
}
+SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct epoll_event __user *, events,
+ int, maxevents, int, timeout, const sigset_t __user *, sigmask,
+ size_t, sigsetsize)
+{
+ return do_epoll_pwait(epfd, events, maxevents, timeout_to_ns(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;
+ s64 timeout_ns;
+
+ if (timeout) {
+ if (get_timespec64(&ts, timeout))
+ return -EFAULT;
+ if (!timespec64_valid(&ts))
+ return -EINVAL;
+ timeout_ns = timespec64_to_ns(&ts);
+ } else {
+ timeout_ns = -1;
+ }
+
+ return do_epoll_pwait(epfd, events, maxevents, timeout_ns,
+ sigmask, sigsetsize);
+}
+
#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)
+static int do_compat_epoll_pwait(int epfd, struct epoll_event __user *events,
+ int maxevents, s64 timeout,
+ const compat_sigset_t __user *sigmask,
+ compat_size_t sigsetsize)
{
long err;
@@ -2270,6 +2304,42 @@ COMPAT_SYSCALL_DEFINE6(epoll_pwait, int, epfd,
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)
+{
+ return do_compat_epoll_pwait(epfd, events, maxevents,
+ timeout_to_ns(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;
+ s64 timeout_ns;
+
+ if (timeout) {
+ if (get_timespec64(&ts, timeout))
+ return -EFAULT;
+ if (!timespec64_valid(&ts))
+ return -EINVAL;
+ timeout_ns = timespec64_to_ns(&ts);
+ } else {
+ timeout_ns = -1;
+ }
+
+ return do_compat_epoll_pwait(epfd, events, maxevents, timeout_ns,
+ sigmask, sigsetsize);
+}
+
#endif
static int __init eventpoll_init(void)
diff --git a/include/linux/compat.h b/include/linux/compat.h
index 14d514233e1d..76dc28a2e7f1 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -505,6 +505,12 @@ asmlinkage long compat_sys_epoll_pwait(int epfd,
int maxevents, int timeout,
const compat_sigset_t __user *sigmask,
compat_size_t sigsetsize);
+asmlinkage long compat_sys_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);
/* fs/fcntl.c */
asmlinkage long compat_sys_fcntl(unsigned int fd, unsigned int cmd,
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index e87a96ace85b..2ba45fb7874c 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -362,6 +362,11 @@ asmlinkage long sys_epoll_pwait(int epfd, struct epoll_event __user *events,
int maxevents, int timeout,
const sigset_t __user *sigmask,
size_t sigsetsize);
+asmlinkage long sys_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);
/* fs/fcntl.c */
asmlinkage long sys_dup(unsigned int fildes);
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index 3bc087d14535..aa883388700e 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -865,9 +865,11 @@ __SYSCALL(__NR_watch_mount, sys_watch_mount)
#define __NR_memfd_secret 442
__SYSCALL(__NR_memfd_secret, sys_memfd_secret)
#endif
+#define __NR_epoll_pwait2 443
+__SC_COMP(__NR_epoll_pwait2, sys_epoll_pwait2, compat_sys_epoll_pwait2)
#undef __NR_syscalls
-#define __NR_syscalls 443
+#define __NR_syscalls 444
/*
* 32 bit systems traditionally used different
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index 805fd7a668be..869aa6b5bf34 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -68,6 +68,8 @@ COND_SYSCALL(epoll_create1);
COND_SYSCALL(epoll_ctl);
COND_SYSCALL(epoll_pwait);
COND_SYSCALL_COMPAT(epoll_pwait);
+COND_SYSCALL(epoll_pwait2);
+COND_SYSCALL_COMPAT(epoll_pwait2);
/* fs/fcntl.c */
--
2.29.2.454.gaff20da3a2-goog
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