[PATCH RFC v3 6/7] epoll: Add implementation for epoll_pwait1

Fam Zheng
2015-02-13T09:07:09Z

This is the new implementation for poll which has a flags parameter and
packs a number of parameters into a structure.

The main advantage of it over existing epoll_pwait is about timeout:
epoll_pwait expects a relative millisecond value, while epoll_pwait1
accepts 1) a timespec which is in nanosecond granularity; 2) a clockid
to allow using a clock other than CLOCK_MONOTONIC.

The 'flags' field in params is reserved for now and must be zero. The
next step would be allowing absolute timeout value.

Signed-off-by: Fam Zheng <famz@redhat.com>
---
fs/eventpoll.c | 27 +++++++++++++++++++++++++++
include/linux/syscalls.h | 5 +++++
include/uapi/linux/eventpoll.h | 7 +++++++
3 files changed, 39 insertions(+)

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 12e2e63..cc51e8c 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -2117,6 +2117,33 @@ out:
return ret;
}

+SYSCALL_DEFINE5(epoll_pwait1, int, epfd, int, flags,
+ struct epoll_event __user *, events,
+ int, maxevents,
+ struct epoll_wait_params __user *, params)
+{
+ struct epoll_wait_params p;
+ ktime_t kt = { 0 };
+ sigset_t sigmask;
+
+ if (flags)
+ return -EINVAL;
+ if (!params)
+ return -EINVAL;
+ if (copy_from_user(&p, params, sizeof(p)))
+ return -EFAULT;
+ if (p.sigmask) {
+ if (copy_from_user(&sigmask, p.sigmask, sizeof(sigmask)))
+ return -EFAULT;
+ if (p.sigsetsize != sizeof(p.sigmask))
+ return -EINVAL;
+ }
+ kt = timespec_to_ktime(p.timeout);
+
+ return epoll_pwait_do(epfd, events, maxevents, p.clockid,
+ kt, p.sigmask ? &sigmask : NULL);
+}
+
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE6(epoll_pwait, int, epfd,
struct epoll_event __user *, events,
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 7d784e3..a4823d9 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -13,6 +13,7 @@

struct epoll_event;
struct epoll_ctl_cmd;
+struct epoll_wait_params;
struct iattr;
struct inode;
struct iocb;
@@ -635,6 +636,10 @@ 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_pwait1(int epfd, int flags,
+ struct epoll_event __user *events,
+ int maxevents,
+ struct epoll_wait_params __user *params);
asmlinkage long sys_epoll_ctl_batch(int epfd, int flags,
int ncmds,
struct epoll_ctl_cmd __user *cmds);
diff --git a/include/uapi/linux/eventpoll.h b/include/uapi/linux/eventpoll.h
index 4e18b17..d35c591 100644
--- a/include/uapi/linux/eventpoll.h
+++ b/include/uapi/linux/eventpoll.h
@@ -72,6 +72,13 @@ struct epoll_ctl_cmd {
int result;
} EPOLL_PACKED;

+struct epoll_wait_params {
+ int clockid;
+ struct timespec timeout;
+ sigset_t *sigmask;
+ size_t sigsetsize;
+} EPOLL_PACKED;
+
#ifdef CONFIG_PM_SLEEP
static inline void ep_take_care_of_epollwakeup(struct epoll_event *epev)
{
--
1.9.3