[PATCH v3 13/13] epoll: implement epoll_create2() syscall

Roman Penyaev
2019-05-16T08:58:40Z

epoll_create2() is needed to accept EPOLL_USERPOLL flags
and size, i.e. this patch wires up polling from userspace.

Signed-off-by: Roman Penyaev <rpenyaev@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 4cd5f982b1e5..f0d271875f4e 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -438,3 +438,4 @@
425 i386 io_uring_setup sys_io_uring_setup __ia32_sys_io_uring_setup
426 i386 io_uring_enter sys_io_uring_enter __ia32_sys_io_uring_enter
427 i386 io_uring_register sys_io_uring_register __ia32_sys_io_uring_register
+428 i386 epoll_create2 sys_epoll_create2 __ia32_sys_epoll_create2
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 64ca0d06259a..5ee9bb31a552 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -355,6 +355,7 @@
425 common io_uring_setup __x64_sys_io_uring_setup
426 common io_uring_enter __x64_sys_io_uring_enter
427 common io_uring_register __x64_sys_io_uring_register
+428 common epoll_create2 __x64_sys_epoll_create2

#
# x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 9ff666ce7cb5..b44c3a0c4ad0 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -2614,6 +2614,14 @@ static int do_epoll_create(int flags, size_t size)
return error;
}

+SYSCALL_DEFINE2(epoll_create2, int, flags, size_t, size)
+{
+ if (size == 0)
+ return -EINVAL;
+
+ return do_epoll_create(flags, size);
+}
+
SYSCALL_DEFINE1(epoll_create1, int, flags)
{
return do_epoll_create(flags, 0);
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index e2870fe1be5b..5049b0d16949 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -358,6 +358,7 @@ asmlinkage long sys_eventfd2(unsigned int count, int flags);

/* fs/eventpoll.c */
asmlinkage long sys_epoll_create1(int flags);
+asmlinkage long sys_epoll_create2(int flags, size_t size);
asmlinkage long sys_epoll_ctl(int epfd, int op, int fd,
struct epoll_event __user *event);
asmlinkage long sys_epoll_pwait(int epfd, struct epoll_event __user *events,
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index dee7292e1df6..fccfaab366ee 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -832,9 +832,11 @@ __SYSCALL(__NR_io_uring_setup, sys_io_uring_setup)
__SYSCALL(__NR_io_uring_enter, sys_io_uring_enter)
#define __NR_io_uring_register 427
__SYSCALL(__NR_io_uring_register, sys_io_uring_register)
+#define __NR_epoll_create2 428
+__SYSCALL(__NR_epoll_create2, sys_epoll_create2)

#undef __NR_syscalls
-#define __NR_syscalls 428
+#define __NR_syscalls 429

/*
* 32 bit systems traditionally used different
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index 4d9ae5ea6caf..665908b8a326 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -65,6 +65,7 @@ COND_SYSCALL(eventfd2);

/* fs/eventfd.c */
COND_SYSCALL(epoll_create1);
+COND_SYSCALL(epoll_create2);
COND_SYSCALL(epoll_ctl);
COND_SYSCALL(epoll_pwait);
COND_SYSCALL_COMPAT(epoll_pwait);
--
2.21.0