fs: add ksys_sync_file_range helper(); remove in-kernel calls to syscall
Using this helper allows us to avoid the in-kernel calls to the
sys_sync_file_range() 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_sync_file_range().
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 4dd685e..331da76 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -963,6 +963,8 @@ ssize_t ksys_read(unsigned int fd, char __user *buf, size_t count);
void ksys_sync(void);
int ksys_unshare(unsigned long unshare_flags);
int ksys_setsid(void);
+int ksys_sync_file_range(int fd, loff_t offset, loff_t nbytes,
+ unsigned int flags);
/*
* The following kernel syscall equivalents are just wrappers to fs-internal