[PATCH 052/109] fs: add do_epoll_*() helpers; remove internal calls to sys_epoll_*()

From: Dominik Brodowski
Date: Thu Mar 29 2018 - 07:55:52 EST


Using the helper functions do_epoll_create() and do_epoll_wait() allows us
to remove in-kernel calls to the related syscall functions.

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@xxxxxxxxxxxxxxxxxxxxxxxxxx

Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx>
---
fs/eventpoll.c | 23 +++++++++++++++++------
1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 0f3494ed3ed0..602ca4285b2e 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -1936,7 +1936,7 @@ static void clear_tfile_check_list(void)
/*
* Open an eventpoll file descriptor.
*/
-SYSCALL_DEFINE1(epoll_create1, int, flags)
+static int do_epoll_create(int flags)
{
int error, fd;
struct eventpoll *ep = NULL;
@@ -1979,12 +1979,17 @@ SYSCALL_DEFINE1(epoll_create1, int, flags)
return error;
}

+SYSCALL_DEFINE1(epoll_create1, int, flags)
+{
+ return do_epoll_create(flags);
+}
+
SYSCALL_DEFINE1(epoll_create, int, size)
{
if (size <= 0)
return -EINVAL;

- return sys_epoll_create1(0);
+ return do_epoll_create(0);
}

/*
@@ -2148,8 +2153,8 @@ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd,
* Implement the event wait interface for the eventpoll file. It is the kernel
* part of the user space epoll_wait(2).
*/
-SYSCALL_DEFINE4(epoll_wait, int, epfd, struct epoll_event __user *, events,
- int, maxevents, int, timeout)
+static int do_epoll_wait(int epfd, struct epoll_event __user *events,
+ int maxevents, int timeout)
{
int error;
struct fd f;
@@ -2190,6 +2195,12 @@ SYSCALL_DEFINE4(epoll_wait, int, epfd, struct epoll_event __user *, events,
return error;
}

+SYSCALL_DEFINE4(epoll_wait, int, epfd, struct epoll_event __user *, events,
+ int, maxevents, int, timeout)
+{
+ return do_epoll_wait(epfd, events, maxevents, timeout);
+}
+
/*
* Implement the event wait interface for the eventpoll file. It is the kernel
* part of the user space epoll_pwait(2).
@@ -2214,7 +2225,7 @@ SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct epoll_event __user *, events,
set_current_blocked(&ksigmask);
}

- error = sys_epoll_wait(epfd, events, maxevents, timeout);
+ error = do_epoll_wait(epfd, events, maxevents, timeout);

/*
* If we changed the signal mask, we need to restore the original one.
@@ -2257,7 +2268,7 @@ COMPAT_SYSCALL_DEFINE6(epoll_pwait, int, epfd,
set_current_blocked(&ksigmask);
}

- err = sys_epoll_wait(epfd, events, maxevents, timeout);
+ err = do_epoll_wait(epfd, events, maxevents, timeout);

/*
* If we changed the signal mask, we need to restore the original one.
--
2.16.3