fs: add ksys_ftruncate() wrapper; remove in-kernel calls to sys_ftruncate()
Using the ksys_ftruncate() wrapper allows us to get rid of in-kernel
calls to the sys_ftruncate() 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_ftruncate().
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>
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index df0d1e8..4102317 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1038,4 +1038,11 @@ static inline long ksys_lchown(const char __user *filename, uid_t user,
AT_SYMLINK_NOFOLLOW);
}
+extern long do_sys_ftruncate(unsigned int fd, loff_t length, int small);
+
+static inline long ksys_ftruncate(unsigned int fd, unsigned long length)
+{
+ return do_sys_ftruncate(fd, length, 1);
+}
+
#endif