fs: add ksys_truncate() wrapper; remove in-kernel calls to sys_truncate()

Using the ksys_truncate() wrapper allows us to get rid of in-kernel
calls to the sys_truncate() syscall. The ksys_ prefix denotes that this
function is meant as a drop-in replacement for the syscall. In
particular, it uses the same calling convention as sys_truncate().

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@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/fs/open.c b/fs/open.c
index 8a42a2961130..2e816fc7bd56 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -128,7 +128,7 @@ out:
 }
 EXPORT_SYMBOL_GPL(vfs_truncate);
 
-static long do_sys_truncate(const char __user *pathname, loff_t length)
+long do_sys_truncate(const char __user *pathname, loff_t length)
 {
 	unsigned int lookup_flags = LOOKUP_FOLLOW;
 	struct path path;