fs: add do_linkat() helper and ksys_link() wrapper; remove in-kernel calls to syscall

Using the fs-internal do_linkat() helper allows us to get rid of
fs-internal calls to the sys_linkat() syscall.

Introducing the ksys_link() wrapper allows us to avoid the in-kernel
calls to sys_link() 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_link().

In the near future, the only fs-external user of ksys_link() should be
converted to use vfs_link() instead.

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/[email protected]

Cc: Al Viro <[email protected]>
Cc: Andrew Morton <[email protected]>
Signed-off-by: Dominik Brodowski <[email protected]>
This commit is contained in:
Dominik Brodowski 2018-03-11 11:34:53 +01:00
commit 46ea89eb65
4 changed files with 21 additions and 4 deletions

View file

@ -62,6 +62,8 @@ long do_rmdir(int dfd, const char __user *pathname);
long do_unlinkat(int dfd, struct filename *name);
long do_symlinkat(const char __user *oldname, int newdfd,
const char __user *newname);
int do_linkat(int olddfd, const char __user *oldname, int newdfd,
const char __user *newname, int flags);
/*
* namespace.c