[RFC PATCH 00/35] remove in-kernel syscall invocations

[RFC PATCH 00/35] remove in-kernel syscall invocations

[Dominik Brodowski]

Here is a first set of patches which reduce the number of syscall invocations
from within the kernel.

The rationale for this change is described in patch 1 as follows:

	The syscall entry points to the kernel defined by SYSCALL_DEFINEx()
	and COMPAT_SYSCALL_DEFINEx() should only be called from userspace
	through kernel entry points, but not from the kernel itself. This
	will allow cleanups and optimizations to the entry paths *and* to
	the parts of the kernel code which currently need to pretend to be
	userspace in order to make use of syscalls.

Two patches make use of existing kernel functions which can be used instead
of sys_xyzzy():

	syscalls: use kernel_wait4() instead of sys_wait4()
	syscalls: mm_release(): use do_futex() instead of sys_futex()

Another set of patches is closely limited in scope, as all callers were in
the same file:

	syscalls: do not call sys_getpgid() within the kernel
	syscalls: do not call sys_readlinkat() within the kernel
	syscalls: do not call sys_pipe2() within the kernel
	syscalls: do not call sys_renameat2() within the kernel
	syscalls: do not call sys_futimesat() within the kernel
	syscalls: do not call sys_epoll_*() within the kernel
	syscalls: do not call sys_signalfd4() within the kernel
	syscalls: do not call sys_eventfd2() within the kernel

A few special cases:

	syscalls: do not call sys_rt_sigpending() within the kernel
	syscalls: do not call sys_ioperm() within the kernel
	hostfs: rename do_rmdir() to hostfs_do_rmdir()

Then, a few patches are simple wrappers/indirections, with ksys_xyzzy() to
be called within the kernel.

	syscalls: do not call sys_mount() within the kernel
	syscalls: do not call sys_umount() within the kernel
	syscalls: do not call sys_dup{,3}() within the kernel
	syscalls: do not call sys_chroot() within the kernel
	syscalls: do not call sys_write() within the kernel
	syscalls: do not call sys_unshare() within the kernel
	syscalls: do not call sys_fadvise64{,_64}() within the kernel
	syscalls: do not call sys_mmap_pgoff() within the kernel
	syscalls: do not call sys_chdir() within the kernel
	syscalls: do not call sys_sync_file_range() within the kernel

I'm a bit more unsure about these remaining patches. They use inline stubs
named ksys_xyzzy() which (mostly) call fs-internal functions. Another
alternative would be to define these in fs/*, but then we'd get more and
more indirections.

	syscalls: do not call sys_unlink() within the kernel
	syscalls: do not call sys_rmdir() within the kernel
	syscalls: do not call sys_mkdir{,at}() within the kernel
	syscalls: do not call sys_symlink{,at}() within the kernel
	syscalls: do not call sys_mknod{,at}() within the kernel
	syscalls: do not call sys_link{,at}() within the kernel
	syscalls: do not call sys_{f,}chmod{at,}() within the kernel
	syscalls: do not call sys_{f,}access{,at}() within the kernel
	syscalls: do not call sys_ftruncate() within the kernel
	syscalls: do not call sys_{,l,f}chown() within the kernel
	syscalls: do not call sys_close() within the kernel

Thanks,
	Dominik

Dominik Brodowski (35):
  syscalls: define goal to not call sys_xyzzy() from within the kernel
  syscalls: use kernel_wait4() instead of sys_wait4()
  syscalls: mm_release(): use do_futex() instead of sys_futex()
  syscalls: do not call sys_getpgid() within the kernel
  syscalls: do not call sys_readlinkat() within the kernel
  syscalls: do not call sys_pipe2() within the kernel
  syscalls: do not call sys_renameat2() within the kernel
  syscalls: do not call sys_futimesat() within the kernel
  syscalls: do not call sys_epoll_*() within the kernel
  syscalls: do not call sys_signalfd4() within the kernel
  syscalls: do not call sys_eventfd2() within the kernel
  syscalls: do not call sys_rt_sigpending() within the kernel
  syscalls: do not call sys_ioperm() within the kernel
  syscalls: do not call sys_mount() within the kernel
  syscalls: do not call sys_umount() within the kernel
  syscalls: do not call sys_dup{,3}() within the kernel
  syscalls: do not call sys_chroot() within the kernel
  syscalls: do not call sys_write() within the kernel
  syscalls: do not call sys_unshare() within the kernel
  syscalls: do not call sys_fadvise64{,_64}() within the kernel
  syscalls: do not call sys_mmap_pgoff() within the kernel
  syscalls: do not call sys_chdir() within the kernel
  syscalls: do not call sys_sync_file_range() within the kernel
  syscalls: do not call sys_unlink() within the kernel
  hostfs: rename do_rmdir() to hostfs_do_rmdir()
  syscalls: do not call sys_rmdir() within the kernel
  syscalls: do not call sys_mkdir{,at}() within the kernel
  syscalls: do not call sys_symlink{,at}() within the kernel
  syscalls: do not call sys_mknod{,at}() within the kernel
  syscalls: do not call sys_link{,at}() within the kernel
  syscalls: do not call sys_{f,}chmod{at,}() within the kernel
  syscalls: do not call sys_{f,}access{,at}() within the kernel
  syscalls: do not call sys_ftruncate() within the kernel
  syscalls: do not call sys_{,l,f}chown() within the kernel
  syscalls: do not call sys_close() within the kernel

 Documentation/process/adding-syscalls.rst |  14 ----
 arch/alpha/kernel/osf_sys.c               |   2 +-
 arch/arm/kernel/sys_arm.c                 |   2 +-
 arch/arm64/kernel/sys.c                   |   2 +-
 arch/cris/kernel/sys_cris.c               |   2 +-
 arch/frv/kernel/sys_frv.c                 |   4 +-
 arch/ia64/kernel/sys_ia64.c               |   4 +-
 arch/m68k/kernel/sys_m68k.c               |   2 +-
 arch/metag/kernel/sys_metag.c             |   8 +--
 arch/microblaze/kernel/sys_microblaze.c   |   6 +-
 arch/mips/kernel/linux32.c                |  10 +--
 arch/mips/kernel/syscall.c                |   6 +-
 arch/mn10300/kernel/sys_mn10300.c         |   3 +-
 arch/parisc/kernel/sys_parisc.c           |  14 ++--
 arch/powerpc/kernel/sys_ppc32.c           |   8 +--
 arch/powerpc/kernel/syscalls.c            |   6 +-
 arch/riscv/kernel/sys_riscv.c             |   4 +-
 arch/s390/kernel/compat_linux.c           |  23 ++++---
 arch/s390/kernel/sys_s390.c               |   2 +-
 arch/score/kernel/sys_score.c             |   5 +-
 arch/sh/kernel/sys_sh.c                   |   4 +-
 arch/sh/kernel/sys_sh32.c                 |   8 +--
 arch/sparc/kernel/sys_sparc32.c           |  14 ++--
 arch/sparc/kernel/sys_sparc_32.c          |   6 +-
 arch/sparc/kernel/sys_sparc_64.c          |   2 +-
 arch/tile/kernel/compat.c                 |   4 +-
 arch/tile/kernel/sys.c                    |  12 ++--
 arch/um/kernel/syscall.c                  |   2 +-
 arch/x86/ia32/sys_ia32.c                  |  22 +++---
 arch/x86/include/asm/syscalls.h           |   1 +
 arch/x86/kernel/ioport.c                  |   7 +-
 arch/x86/kernel/sys_x86_64.c              |   2 +-
 arch/xtensa/kernel/syscall.c              |   2 +-
 drivers/base/devtmpfs.c                   |  11 +--
 drivers/tty/vt/vt_ioctl.c                 |   6 +-
 fs/autofs4/dev-ioctl.c                    |   2 +-
 fs/binfmt_misc.c                          |   2 +-
 fs/eventfd.c                              |   9 ++-
 fs/eventpoll.c                            |  23 +++++--
 fs/file.c                                 |  17 ++++-
 fs/hostfs/hostfs.h                        |   2 +-
 fs/hostfs/hostfs_kern.c                   |   2 +-
 fs/hostfs/hostfs_user.c                   |   2 +-
 fs/internal.h                             |  14 ++++
 fs/namei.c                                |  61 ++++++++++++-----
 fs/namespace.c                            |  19 ++++--
 fs/open.c                                 |  67 ++++++++++++++----
 fs/pipe.c                                 |   9 ++-
 fs/read_write.c                           |   9 ++-
 fs/signalfd.c                             |  14 ++--
 fs/stat.c                                 |  12 +++-
 fs/sync.c                                 |  12 +++-
 fs/utimes.c                               |  13 +++-
 include/linux/syscalls.h                  | 109 +++++++++++++++++++++++++++++-
 init/do_mounts.c                          |  12 ++--
 init/do_mounts.h                          |   4 +-
 init/do_mounts_initrd.c                   |  34 +++++-----
 init/do_mounts_md.c                       |   8 +--
 init/do_mounts_rd.c                       |  12 ++--
 init/initramfs.c                          |  42 ++++++------
 init/main.c                               |   7 +-
 init/noinitramfs.c                        |   6 +-
 kernel/exit.c                             |   2 +-
 kernel/fork.c                             |  11 ++-
 kernel/pid_namespace.c                    |   6 +-
 kernel/signal.c                           |  13 +++-
 kernel/sys.c                              |   9 ++-
 kernel/uid16.c                            |   6 +-
 kernel/umh.c                              |   2 +-
 mm/fadvise.c                              |  10 ++-
 mm/mmap.c                                 |  17 +++--
 mm/nommu.c                                |  17 +++--
 72 files changed, 572 insertions(+), 274 deletions(-)

-- 
2.16.2

[RFC PATCH 01/35] syscalls: define goal to not call sys_xyzzy() from within the kernel

[Dominik Brodowski]

The syscall entry points to the kernel defined by SYSCALL_DEFINEx()
and COMPAT_SYSCALL_DEFINEx() should only be called from userspace
through kernel entry points, but not from the kernel itself. This
will allow cleanups and optimizations to the entry paths *and* to
the parts of the kernel code which currently need to pretend to be
userspace in order to make use of syscalls.

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 Documentation/process/adding-syscalls.rst | 14 --------------
 include/linux/syscalls.h                  |  7 +++++++
 2 files changed, 7 insertions(+), 14 deletions(-)

diff --git a/Documentation/process/adding-syscalls.rst b/Documentation/process/adding-syscalls.rst
index 8cc25a06f353..35a14b730da9 100644
--- a/Documentation/process/adding-syscalls.rst
+++ b/Documentation/process/adding-syscalls.rst
@@ -201,12 +201,6 @@ followed by the (type, name) pairs for the parameters as arguments.  Using
 this macro allows metadata about the new system call to be made available for
 other tools.
 
-The new entry point also needs a corresponding function prototype, in
-``include/linux/syscalls.h``, marked as asmlinkage to match the way that system
-calls are invoked::
-
-    asmlinkage long sys_xyzzy(...);
-
 Some architectures (e.g. x86) have their own architecture-specific syscall
 tables, but several other architectures share a generic syscall table. Add your
 new system call to the generic list by adding an entry to the list in
@@ -240,7 +234,6 @@ To summarize, you need a commit that includes:
 
  - ``CONFIG`` option for the new function, normally in ``init/Kconfig``
  - ``SYSCALL_DEFINEn(xyzzy, ...)`` for the entry point
- - corresponding prototype in ``include/linux/syscalls.h``
  - generic table entry in ``include/uapi/asm-generic/unistd.h``
  - fallback stub in ``kernel/sys_ni.c``
 
@@ -302,12 +295,6 @@ needed to deal with them.  (Typically, the ``compat_sys_`` version converts the
 values to 64-bit versions and either calls on to the ``sys_`` version, or both of
 them call a common inner implementation function.)
 
-The compat entry point also needs a corresponding function prototype, in
-``include/linux/compat.h``, marked as asmlinkage to match the way that system
-calls are invoked::
-
-    asmlinkage long compat_sys_xyzzy(...);
-
 If the system call involves a structure that is laid out differently on 32-bit
 and 64-bit systems, say ``struct xyzzy_args``, then the include/linux/compat.h
 header file should also include a compat version of the structure (``struct
@@ -344,7 +331,6 @@ version; the entry in ``include/uapi/asm-generic/unistd.h`` should use
 To summarize, you need:
 
  - a ``COMPAT_SYSCALL_DEFINEn(xyzzy, ...)`` for the compat entry point
- - corresponding prototype in ``include/linux/compat.h``
  - (if needed) 32-bit mapping struct in ``include/linux/compat.h``
  - instance of ``__SC_COMP`` not ``__SYSCALL`` in
    ``include/uapi/asm-generic/unistd.h``
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index a78186d826d7..700a83a9c1ad 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -941,4 +941,11 @@ asmlinkage long sys_pkey_free(int pkey);
 asmlinkage long sys_statx(int dfd, const char __user *path, unsigned flags,
 			  unsigned mask, struct statx __user *buffer);
 
+
+/*
+ * The kernel should not use call syscalls (i.e., sys_xyzyyz()) directly.
+ * Instead, use one of the following functions which work equivalent to
+ * the syscall they are named for.
+ */
+
 #endif
-- 
2.16.2

[RFC PATCH 02/35] syscalls: use kernel_wait4() instead of sys_wait4()

[Dominik Brodowski]

All call sites of sys_wait4() set *rusage to NULL. Therefore, there is
no need for the copy_to_user() handling of *rusage, and we can use
kernel_wait4() directly.

CC: Luis R. Rodriguez <mcgrof@kernel.org>
CC: Al Viro <viro@zeniv.linux.org.uk>
CC: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 kernel/exit.c          | 2 +-
 kernel/pid_namespace.c | 6 +++---
 kernel/umh.c           | 2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/kernel/exit.c b/kernel/exit.c
index 995453d9fb55..c3c7ac560114 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1691,7 +1691,7 @@ SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr,
  */
 SYSCALL_DEFINE3(waitpid, pid_t, pid, int __user *, stat_addr, int, options)
 {
-	return sys_wait4(pid, stat_addr, options, NULL);
+	return kernel_wait4(pid, stat_addr, options, NULL);
 }
 
 #endif
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 0b53eef7d34b..93b57f026688 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -242,16 +242,16 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns)
 
 	/*
 	 * Reap the EXIT_ZOMBIE children we had before we ignored SIGCHLD.
-	 * sys_wait4() will also block until our children traced from the
+	 * kernel_wait4() will also block until our children traced from the
 	 * parent namespace are detached and become EXIT_DEAD.
 	 */
 	do {
 		clear_thread_flag(TIF_SIGPENDING);
-		rc = sys_wait4(-1, NULL, __WALL, NULL);
+		rc = kernel_wait4(-1, NULL, __WALL, NULL);
 	} while (rc != -ECHILD);
 
 	/*
-	 * sys_wait4() above can't reap the EXIT_DEAD children but we do not
+	 * kernel_wait4() above can't reap the EXIT_DEAD children but we do not
 	 * really care, we could reparent them to the global init. We could
 	 * exit and reap ->child_reaper even if it is not the last thread in
 	 * this pid_ns, free_pid(pid_allocated == 0) calls proc_cleanup_work(),
diff --git a/kernel/umh.c b/kernel/umh.c
index 18e5fa4b0e71..f4b557cadf08 100644
--- a/kernel/umh.c
+++ b/kernel/umh.c
@@ -135,7 +135,7 @@ static void call_usermodehelper_exec_sync(struct subprocess_info *sub_info)
 		 *
 		 * Thus the __user pointer cast is valid here.
 		 */
-		sys_wait4(pid, (int __user *)&ret, 0, NULL);
+		kernel_wait4(pid, (int __user *)&ret, 0, NULL);
 
 		/*
 		 * If ret is 0, either call_usermodehelper_exec_async failed and
-- 
2.16.2

[RFC PATCH 03/35] syscalls: mm_release(): use do_futex() instead of sys_futex()

[Dominik Brodowski]

sys_futex() is a wrapper to do_futex() which does not modify any
values here:

- uaddr, val and val3 are kept the same

- op is masked with FUTEX_CMD_MASK, but is always set to FUTEX_WAKE.
  Therefore, val2 is always 0.

- as utime is set to NULL, *timeout is NULL

CC: Thomas Gleixner <tglx@linutronix.de>
CC: Ingo Molnar <mingo@redhat.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Darren Hart <dvhart@infradead.org>
CC: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 kernel/fork.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/fork.c b/kernel/fork.c
index e5d9d405ae4e..b1e031aac9db 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1198,8 +1198,8 @@ void mm_release(struct task_struct *tsk, struct mm_struct *mm)
 			 * not set up a proper pointer then tough luck.
 			 */
 			put_user(0, tsk->clear_child_tid);
-			sys_futex(tsk->clear_child_tid, FUTEX_WAKE,
-					1, NULL, NULL, 0);
+			do_futex(tsk->clear_child_tid, FUTEX_WAKE,
+					1, NULL, NULL, 0, 0);
 		}
 		tsk->clear_child_tid = NULL;
 	}
-- 
2.16.2

[RFC PATCH 04/35] syscalls: do not call sys_getpgid() within the kernel

[Dominik Brodowski]

CC: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 kernel/sys.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/kernel/sys.c b/kernel/sys.c
index f2289de20e19..ebb138b841c8 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1027,7 +1027,7 @@ SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
 	return err;
 }
 
-SYSCALL_DEFINE1(getpgid, pid_t, pid)
+static int do_getpgid(pid_t pid)
 {
 	struct task_struct *p;
 	struct pid *grp;
@@ -1055,11 +1055,16 @@ SYSCALL_DEFINE1(getpgid, pid_t, pid)
 	return retval;
 }
 
+SYSCALL_DEFINE1(getpgid, pid_t, pid)
+{
+	return do_getpgid(pid);
+}
+
 #ifdef __ARCH_WANT_SYS_GETPGRP
 
 SYSCALL_DEFINE0(getpgrp)
 {
-	return sys_getpgid(0);
+	return do_getpgid(0);
 }
 
 #endif
-- 
2.16.2

[RFC PATCH 05/35] syscalls: do not call sys_readlinkat() within the kernel

[Dominik Brodowski]

CC: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/stat.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/fs/stat.c b/fs/stat.c
index 873785dae022..f8e6fb2c3657 100644
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -379,8 +379,8 @@ SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf)
 	return error;
 }
 
-SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
-		char __user *, buf, int, bufsiz)
+static int do_readlinkat(int dfd, const char __user *pathname,
+			 char __user *buf, int bufsiz)
 {
 	struct path path;
 	int error;
@@ -415,10 +415,16 @@ SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
 	return error;
 }
 
+SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
+		char __user *, buf, int, bufsiz)
+{
+	return do_readlinkat(dfd, pathname, buf, bufsiz);
+}
+
 SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf,
 		int, bufsiz)
 {
-	return sys_readlinkat(AT_FDCWD, path, buf, bufsiz);
+	return do_readlinkat(AT_FDCWD, path, buf, bufsiz);
 }
 
 
-- 
2.16.2

[RFC PATCH 06/35] syscalls: do not call sys_pipe2() within the kernel

[Dominik Brodowski]

CC: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/pipe.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/pipe.c b/fs/pipe.c
index 7b1954caf388..39d6f431da83 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -841,7 +841,7 @@ int do_pipe_flags(int *fd, int flags)
  * sys_pipe() is the normal C calling standard for creating
  * a pipe. It's not the way Unix traditionally does this, though.
  */
-SYSCALL_DEFINE2(pipe2, int __user *, fildes, int, flags)
+static int do_pipe2(int __user *fildes, int flags)
 {
 	struct file *files[2];
 	int fd[2];
@@ -863,9 +863,14 @@ SYSCALL_DEFINE2(pipe2, int __user *, fildes, int, flags)
 	return error;
 }
 
+SYSCALL_DEFINE2(pipe2, int __user *, fildes, int, flags)
+{
+	return do_pipe2(fildes, flags);
+}
+
 SYSCALL_DEFINE1(pipe, int __user *, fildes)
 {
-	return sys_pipe2(fildes, 0);
+	return do_pipe2(fildes, 0);
 }
 
 static int wait_for_partner(struct pipe_inode_info *pipe, unsigned int *cnt)
-- 
2.16.2

[RFC PATCH 07/35] syscalls: do not call sys_renameat2() within the kernel

[Dominik Brodowski]

CC: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/namei.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 921ae32dbc80..524e829ffc7d 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -4478,8 +4478,8 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 }
 EXPORT_SYMBOL(vfs_rename);
 
-SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname,
-		int, newdfd, const char __user *, newname, unsigned int, flags)
+static int do_renameat2(int olddfd, const char __user *oldname, int newdfd,
+			const char __user *newname, unsigned int flags)
 {
 	struct dentry *old_dentry, *new_dentry;
 	struct dentry *trap;
@@ -4621,15 +4621,21 @@ SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname,
 	return error;
 }
 
+SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname,
+		int, newdfd, const char __user *, newname, unsigned int, flags)
+{
+	return do_renameat2(olddfd, oldname, newdfd, newname, flags);
+}
+
 SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname,
 		int, newdfd, const char __user *, newname)
 {
-	return sys_renameat2(olddfd, oldname, newdfd, newname, 0);
+	return do_renameat2(olddfd, oldname, newdfd, newname, 0);
 }
 
 SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newname)
 {
-	return sys_renameat2(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
+	return do_renameat2(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
 }
 
 int vfs_whiteout(struct inode *dir, struct dentry *dentry)
-- 
2.16.2

[RFC PATCH 08/35] syscalls: do not call sys_futimesat() within the kernel

[Dominik Brodowski]

CC: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/utimes.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/fs/utimes.c b/fs/utimes.c
index e4b3d7c2c9f5..5be035ed26c0 100644
--- a/fs/utimes.c
+++ b/fs/utimes.c
@@ -184,8 +184,8 @@ SYSCALL_DEFINE4(utimensat, int, dfd, const char __user *, filename,
 	return do_utimes(dfd, filename, utimes ? tstimes : NULL, flags);
 }
 
-SYSCALL_DEFINE3(futimesat, int, dfd, const char __user *, filename,
-		struct timeval __user *, utimes)
+static long do_futimesat(int dfd, const char __user *filename,
+			 struct timeval __user *utimes)
 {
 	struct timeval times[2];
 	struct timespec64 tstimes[2];
@@ -212,10 +212,17 @@ SYSCALL_DEFINE3(futimesat, int, dfd, const char __user *, filename,
 	return do_utimes(dfd, filename, utimes ? tstimes : NULL, 0);
 }
 
+
+SYSCALL_DEFINE3(futimesat, int, dfd, const char __user *, filename,
+		struct timeval __user *, utimes)
+{
+	return do_futimesat(dfd, filename, utimes);
+}
+
 SYSCALL_DEFINE2(utimes, char __user *, filename,
 		struct timeval __user *, utimes)
 {
-	return sys_futimesat(AT_FDCWD, filename, utimes);
+	return do_futimesat(AT_FDCWD, filename, utimes);
 }
 
 #ifdef CONFIG_COMPAT
-- 
2.16.2

[RFC PATCH 09/35] syscalls: do not call sys_epoll_*() within the kernel

[Dominik Brodowski]

CC: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/eventpoll.c | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 0f3494ed3ed0..602ca4285b2e 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -1936,7 +1936,7 @@ static void clear_tfile_check_list(void)
 /*
  * Open an eventpoll file descriptor.
  */
-SYSCALL_DEFINE1(epoll_create1, int, flags)
+static int do_epoll_create(int flags)
 {
 	int error, fd;
 	struct eventpoll *ep = NULL;
@@ -1979,12 +1979,17 @@ SYSCALL_DEFINE1(epoll_create1, int, flags)
 	return error;
 }
 
+SYSCALL_DEFINE1(epoll_create1, int, flags)
+{
+	return do_epoll_create(flags);
+}
+
 SYSCALL_DEFINE1(epoll_create, int, size)
 {
 	if (size <= 0)
 		return -EINVAL;
 
-	return sys_epoll_create1(0);
+	return do_epoll_create(0);
 }
 
 /*
@@ -2148,8 +2153,8 @@ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd,
  * Implement the event wait interface for the eventpoll file. It is the kernel
  * part of the user space epoll_wait(2).
  */
-SYSCALL_DEFINE4(epoll_wait, int, epfd, struct epoll_event __user *, events,
-		int, maxevents, int, timeout)
+static int do_epoll_wait(int epfd, struct epoll_event __user *events,
+			 int maxevents, int timeout)
 {
 	int error;
 	struct fd f;
@@ -2190,6 +2195,12 @@ SYSCALL_DEFINE4(epoll_wait, int, epfd, struct epoll_event __user *, events,
 	return error;
 }
 
+SYSCALL_DEFINE4(epoll_wait, int, epfd, struct epoll_event __user *, events,
+		int, maxevents, int, timeout)
+{
+	return do_epoll_wait(epfd, events, maxevents, timeout);
+}
+
 /*
  * Implement the event wait interface for the eventpoll file. It is the kernel
  * part of the user space epoll_pwait(2).
@@ -2214,7 +2225,7 @@ SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct epoll_event __user *, events,
 		set_current_blocked(&ksigmask);
 	}
 
-	error = sys_epoll_wait(epfd, events, maxevents, timeout);
+	error = do_epoll_wait(epfd, events, maxevents, timeout);
 
 	/*
 	 * If we changed the signal mask, we need to restore the original one.
@@ -2257,7 +2268,7 @@ COMPAT_SYSCALL_DEFINE6(epoll_pwait, int, epfd,
 		set_current_blocked(&ksigmask);
 	}
 
-	err = sys_epoll_wait(epfd, events, maxevents, timeout);
+	err = do_epoll_wait(epfd, events, maxevents, timeout);
 
 	/*
 	 * If we changed the signal mask, we need to restore the original one.
-- 
2.16.2

[RFC PATCH 10/35] syscalls: do not call sys_signalfd4() within the kernel

[Dominik Brodowski]

CC: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/signalfd.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/fs/signalfd.c b/fs/signalfd.c
index 76bf9cc62074..501c41f3351f 100644
--- a/fs/signalfd.c
+++ b/fs/signalfd.c
@@ -256,8 +256,8 @@ static const struct file_operations signalfd_fops = {
 	.llseek		= noop_llseek,
 };
 
-SYSCALL_DEFINE4(signalfd4, int, ufd, sigset_t __user *, user_mask,
-		size_t, sizemask, int, flags)
+static int do_signalfd4(int ufd, sigset_t __user *user_mask, size_t sizemask,
+			int flags)
 {
 	sigset_t sigmask;
 	struct signalfd_ctx *ctx;
@@ -310,10 +310,16 @@ SYSCALL_DEFINE4(signalfd4, int, ufd, sigset_t __user *, user_mask,
 	return ufd;
 }
 
+SYSCALL_DEFINE4(signalfd4, int, ufd, sigset_t __user *, user_mask,
+		size_t, sizemask, int, flags)
+{
+	return do_signalfd4(ufd, user_mask, sizemask, flags);
+}
+
 SYSCALL_DEFINE3(signalfd, int, ufd, sigset_t __user *, user_mask,
 		size_t, sizemask)
 {
-	return sys_signalfd4(ufd, user_mask, sizemask, 0);
+	return do_signalfd4(ufd, user_mask, sizemask, 0);
 }
 
 #ifdef CONFIG_COMPAT
@@ -333,7 +339,7 @@ COMPAT_SYSCALL_DEFINE4(signalfd4, int, ufd,
 	if (copy_to_user(ksigmask, &tmp, sizeof(sigset_t)))
 		return -EFAULT;
 
-	return sys_signalfd4(ufd, ksigmask, sizeof(sigset_t), flags);
+	return do_signalfd4(ufd, ksigmask, sizeof(sigset_t), flags);
 }
 
 COMPAT_SYSCALL_DEFINE3(signalfd, int, ufd,
-- 
2.16.2

[RFC PATCH 11/35] syscalls: do not call sys_eventfd2() within the kernel

[Dominik Brodowski]

CC: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/eventfd.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/eventfd.c b/fs/eventfd.c
index 012f5bd46dfa..08d3bd602f73 100644
--- a/fs/eventfd.c
+++ b/fs/eventfd.c
@@ -380,7 +380,7 @@ struct eventfd_ctx *eventfd_ctx_fileget(struct file *file)
 }
 EXPORT_SYMBOL_GPL(eventfd_ctx_fileget);
 
-SYSCALL_DEFINE2(eventfd2, unsigned int, count, int, flags)
+static int do_eventfd(unsigned int count, int flags)
 {
 	struct eventfd_ctx *ctx;
 	int fd;
@@ -409,8 +409,13 @@ SYSCALL_DEFINE2(eventfd2, unsigned int, count, int, flags)
 	return fd;
 }
 
+SYSCALL_DEFINE2(eventfd2, unsigned int, count, int, flags)
+{
+	return do_eventfd(count, flags);
+}
+
 SYSCALL_DEFINE1(eventfd, unsigned int, count)
 {
-	return sys_eventfd2(count, 0);
+	return do_eventfd(count, 0);
 }
 
-- 
2.16.2

[RFC PATCH 12/35] syscalls: do not call sys_rt_sigpending() within the kernel

[Dominik Brodowski]

A similar code path is already open-coded three times (in sys_rt_sigpending
and in the two compat stubs), so do it a fourth time here.

CC: Al Viro <viro@zeniv.linux.org.uk>
CC: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 include/linux/syscalls.h |  2 +-
 kernel/signal.c          | 13 +++++++++++--
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 700a83a9c1ad..79c46c46603b 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -288,7 +288,7 @@ asmlinkage long sys_capset(cap_user_header_t header,
 				const cap_user_data_t data);
 asmlinkage long sys_personality(unsigned int personality);
 
-asmlinkage long sys_sigpending(old_sigset_t __user *set);
+asmlinkage long sys_sigpending(old_sigset_t __user *uset);
 asmlinkage long sys_sigprocmask(int how, old_sigset_t __user *set,
 				old_sigset_t __user *oset);
 asmlinkage long sys_sigaltstack(const struct sigaltstack __user *uss,
diff --git a/kernel/signal.c b/kernel/signal.c
index c6e4c83dc090..fe0906d1d3cc 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3631,9 +3631,18 @@ int __compat_save_altstack(compat_stack_t __user *uss, unsigned long sp)
  *  sys_sigpending - examine pending signals
  *  @set: where mask of pending signal is returned
  */
-SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set)
+SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, uset)
 {
-	return sys_rt_sigpending((sigset_t __user *)set, sizeof(old_sigset_t)); 
+	sigset_t set;
+	int err;
+
+	if (sizeof(old_sigset_t) > sizeof(*uset))
+		return -EINVAL;
+
+	err = do_sigpending(&set);
+	if (!err && copy_to_user(uset, &set, sizeof(old_sigset_t)))
+		err = -EFAULT;
+	return err;
 }
 
 #ifdef CONFIG_COMPAT
-- 
2.16.2

[RFC PATCH 13/35] syscalls: do not call sys_ioperm() within the kernel

[Dominik Brodowski]

While at it, use SYSCALL_DEFINE3() instead of a hand-crafted syscall
definition.

CC: Thomas Gleixner <tglx@linutronix.de>
CC: Ingo Molnar <mingo@redhat.com>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: Jiri Slaby <jslaby@suse.com>
CC: x86@kernel.org
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 arch/x86/include/asm/syscalls.h | 1 +
 arch/x86/kernel/ioport.c        | 7 ++++++-
 drivers/tty/vt/vt_ioctl.c       | 6 +++---
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/syscalls.h b/arch/x86/include/asm/syscalls.h
index bad25bb80679..1c0bebbd039e 100644
--- a/arch/x86/include/asm/syscalls.h
+++ b/arch/x86/include/asm/syscalls.h
@@ -17,6 +17,7 @@
 
 /* Common in X86_32 and X86_64 */
 /* kernel/ioport.c */
+long ksys_ioperm(unsigned long from, unsigned long num, int turn_on);
 asmlinkage long sys_ioperm(unsigned long, unsigned long, int);
 asmlinkage long sys_iopl(unsigned int);
 
diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c
index 2f723301eb58..0fe1c8782208 100644
--- a/arch/x86/kernel/ioport.c
+++ b/arch/x86/kernel/ioport.c
@@ -23,7 +23,7 @@
 /*
  * this changes the io permissions bitmap in the current task.
  */
-asmlinkage long sys_ioperm(unsigned long from, unsigned long num, int turn_on)
+long ksys_ioperm(unsigned long from, unsigned long num, int turn_on)
 {
 	struct thread_struct *t = &current->thread;
 	struct tss_struct *tss;
@@ -96,6 +96,11 @@ asmlinkage long sys_ioperm(unsigned long from, unsigned long num, int turn_on)
 	return 0;
 }
 
+SYSCALL_DEFINE3(ioperm, unsigned long, from, unsigned long, num, int, turn_on)
+{
+	return ksys_ioperm(from, num, turn_on);
+}
+
 /*
  * sys_iopl has to be used when you want to access the IO ports
  * beyond the 0x3ff range: to get the full 65536 ports bitmapped
diff --git a/drivers/tty/vt/vt_ioctl.c b/drivers/tty/vt/vt_ioctl.c
index d61be307256a..a78ad10a119b 100644
--- a/drivers/tty/vt/vt_ioctl.c
+++ b/drivers/tty/vt/vt_ioctl.c
@@ -57,7 +57,7 @@ extern struct tty_driver *console_driver;
  */
 
 #ifdef CONFIG_X86
-#include <linux/syscalls.h>
+#include <asm/syscalls.h>
 #endif
 
 static void complete_change_console(struct vc_data *vc);
@@ -420,12 +420,12 @@ int vt_ioctl(struct tty_struct *tty,
 			ret = -EINVAL;
 			break;
 		}
-		ret = sys_ioperm(arg, 1, (cmd == KDADDIO)) ? -ENXIO : 0;
+		ret = ksys_ioperm(arg, 1, (cmd == KDADDIO)) ? -ENXIO : 0;
 		break;
 
 	case KDENABIO:
 	case KDDISABIO:
-		ret = sys_ioperm(GPFIRST, GPNUM,
+		ret = ksys_ioperm(GPFIRST, GPNUM,
 				  (cmd == KDENABIO)) ? -ENXIO : 0;
 		break;
 #endif
-- 
2.16.2

[RFC PATCH 14/35] syscalls: do not call sys_mount() within the kernel

[Dominik Brodowski]

CC: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 drivers/base/devtmpfs.c  |  5 +++--
 fs/namespace.c           | 10 ++++++++--
 include/linux/syscalls.h |  3 +++
 init/do_mounts.c         |  4 ++--
 init/do_mounts_initrd.c  |  6 +++---
 5 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index 50025d7959cb..4afb04686c8e 100644
--- a/drivers/base/devtmpfs.c
+++ b/drivers/base/devtmpfs.c
@@ -356,7 +356,8 @@ int devtmpfs_mount(const char *mntdir)
 	if (!thread)
 		return 0;
 
-	err = sys_mount("devtmpfs", (char *)mntdir, "devtmpfs", MS_SILENT, NULL);
+	err = ksys_mount("devtmpfs", (char *)mntdir, "devtmpfs", MS_SILENT,
+			 NULL);
 	if (err)
 		printk(KERN_INFO "devtmpfs: error mounting %i\n", err);
 	else
@@ -382,7 +383,7 @@ static int devtmpfsd(void *p)
 	*err = sys_unshare(CLONE_NEWNS);
 	if (*err)
 		goto out;
-	*err = sys_mount("devtmpfs", "/", "devtmpfs", MS_SILENT, options);
+	*err = ksys_mount("devtmpfs", "/", "devtmpfs", MS_SILENT, options);
 	if (*err)
 		goto out;
 	sys_chdir("/.."); /* will traverse into overmounted root */
diff --git a/fs/namespace.c b/fs/namespace.c
index 9d1374ab6e06..642b8b229944 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -3032,8 +3032,8 @@ struct dentry *mount_subtree(struct vfsmount *mnt, const char *name)
 }
 EXPORT_SYMBOL(mount_subtree);
 
-SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name,
-		char __user *, type, unsigned long, flags, void __user *, data)
+int ksys_mount(char __user *dev_name, char __user *dir_name, char __user *type,
+	       unsigned long flags, void __user *data)
 {
 	int ret;
 	char *kernel_type;
@@ -3066,6 +3066,12 @@ SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name,
 	return ret;
 }
 
+SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name,
+		char __user *, type, unsigned long, flags, void __user *, data)
+{
+	return ksys_mount(dev_name, dir_name, type, flags, data);
+}
+
 /*
  * Return true if path is reachable from root
  *
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 79c46c46603b..63625d2cbcb8 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -948,4 +948,7 @@ asmlinkage long sys_statx(int dfd, const char __user *path, unsigned flags,
  * the syscall they are named for.
  */
 
+int ksys_mount(char __user *dev_name, char __user *dir_name, char __user *type,
+	       unsigned long flags, void __user *data);
+
 #endif
diff --git a/init/do_mounts.c b/init/do_mounts.c
index 7cf4f6dafd5f..eb768de43d84 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -363,7 +363,7 @@ static void __init get_fs_names(char *page)
 static int __init do_mount_root(char *name, char *fs, int flags, void *data)
 {
 	struct super_block *s;
-	int err = sys_mount(name, "/root", fs, flags, data);
+	int err = ksys_mount(name, "/root", fs, flags, data);
 	if (err)
 		return err;
 
@@ -599,7 +599,7 @@ void __init prepare_namespace(void)
 	mount_root();
 out:
 	devtmpfs_mount("dev");
-	sys_mount(".", "/", NULL, MS_MOVE, NULL);
+	ksys_mount(".", "/", NULL, MS_MOVE, NULL);
 	sys_chroot(".");
 }
 
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index 53d4f0f326e7..7868a6039fb4 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -43,7 +43,7 @@ static int init_linuxrc(struct subprocess_info *info, struct cred *new)
 	sys_dup(0);
 	/* move initrd over / and chdir/chroot in initrd root */
 	sys_chdir("/root");
-	sys_mount(".", "/", NULL, MS_MOVE, NULL);
+	ksys_mount(".", "/", NULL, MS_MOVE, NULL);
 	sys_chroot(".");
 	sys_setsid();
 	return 0;
@@ -81,7 +81,7 @@ static void __init handle_initrd(void)
 	current->flags &= ~PF_FREEZER_SKIP;
 
 	/* move initrd to rootfs' /old */
-	sys_mount("..", ".", NULL, MS_MOVE, NULL);
+	ksys_mount("..", ".", NULL, MS_MOVE, NULL);
 	/* switch root and cwd back to / of rootfs */
 	sys_chroot("..");
 
@@ -95,7 +95,7 @@ static void __init handle_initrd(void)
 	mount_root();
 
 	printk(KERN_NOTICE "Trying to move old root to /initrd ... ");
-	error = sys_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);
+	error = ksys_mount("/old", "/root/initrd", NULL, MS_MOVE, NULL);
 	if (!error)
 		printk("okay\n");
 	else {
-- 
2.16.2

[RFC PATCH 15/35] syscalls: do not call sys_umount() within the kernel

[Dominik Brodowski]

CC: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/namespace.c           | 9 +++++++--
 include/linux/syscalls.h | 1 +
 init/do_mounts_initrd.c  | 2 +-
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/fs/namespace.c b/fs/namespace.c
index 642b8b229944..e398f32d7541 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1680,7 +1680,7 @@ static inline bool may_mandlock(void)
  * unixes. Our API is identical to OSF/1 to avoid making a mess of AMD
  */
 
-SYSCALL_DEFINE2(umount, char __user *, name, int, flags)
+int ksys_umount(char __user *name, int flags)
 {
 	struct path path;
 	struct mount *mnt;
@@ -1720,6 +1720,11 @@ SYSCALL_DEFINE2(umount, char __user *, name, int, flags)
 	return retval;
 }
 
+SYSCALL_DEFINE2(umount, char __user *, name, int, flags)
+{
+	return ksys_umount(name, flags);
+}
+
 #ifdef __ARCH_WANT_SYS_OLDUMOUNT
 
 /*
@@ -1727,7 +1732,7 @@ SYSCALL_DEFINE2(umount, char __user *, name, int, flags)
  */
 SYSCALL_DEFINE1(oldumount, char __user *, name)
 {
-	return sys_umount(name, 0);
+	return ksys_umount(name, 0);
 }
 
 #endif
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 63625d2cbcb8..d509f4992d2e 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -950,5 +950,6 @@ asmlinkage long sys_statx(int dfd, const char __user *path, unsigned flags,
 
 int ksys_mount(char __user *dev_name, char __user *dir_name, char __user *type,
 	       unsigned long flags, void __user *data);
+int ksys_umount(char __user *name, int flags);
 
 #endif
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index 7868a6039fb4..1c4da8353332 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -105,7 +105,7 @@ static void __init handle_initrd(void)
 		else
 			printk("failed\n");
 		printk(KERN_NOTICE "Unmounting old root\n");
-		sys_umount("/old", MNT_DETACH);
+		ksys_umount("/old", MNT_DETACH);
 		printk(KERN_NOTICE "Trying to free ramdisk memory ... ");
 		if (fd < 0) {
 			error = fd;
-- 
2.16.2

[RFC PATCH 16/35] syscalls: do not call sys_dup{,3}() within the kernel

[Dominik Brodowski]

CC: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/file.c                | 16 +++++++++++++---
 include/linux/syscalls.h |  1 +
 init/do_mounts_initrd.c  |  4 ++--
 init/main.c              |  4 ++--
 4 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/fs/file.c b/fs/file.c
index 42f0db4bd0fb..d304004f0b65 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -870,7 +870,7 @@ int replace_fd(unsigned fd, struct file *file, unsigned flags)
 	return err;
 }
 
-SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags)
+static int ksys_dup3(unsigned int oldfd, unsigned int newfd, int flags)
 {
 	int err = -EBADF;
 	struct file *file;
@@ -904,6 +904,11 @@ SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags)
 	return err;
 }
 
+SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags)
+{
+	return ksys_dup3(oldfd, newfd, flags);
+}
+
 SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd)
 {
 	if (unlikely(newfd == oldfd)) { /* corner case */
@@ -916,10 +921,10 @@ SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd)
 		rcu_read_unlock();
 		return retval;
 	}
-	return sys_dup3(oldfd, newfd, 0);
+	return ksys_dup3(oldfd, newfd, 0);
 }
 
-SYSCALL_DEFINE1(dup, unsigned int, fildes)
+int ksys_dup(unsigned int fildes)
 {
 	int ret = -EBADF;
 	struct file *file = fget_raw(fildes);
@@ -934,6 +939,11 @@ SYSCALL_DEFINE1(dup, unsigned int, fildes)
 	return ret;
 }
 
+SYSCALL_DEFINE1(dup, unsigned int, fildes)
+{
+	return ksys_dup(fildes);
+}
+
 int f_dupfd(unsigned int from, struct file *file, unsigned flags)
 {
 	int err;
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index d509f4992d2e..986e91d5a2ea 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -951,5 +951,6 @@ asmlinkage long sys_statx(int dfd, const char __user *path, unsigned flags,
 int ksys_mount(char __user *dev_name, char __user *dir_name, char __user *type,
 	       unsigned long flags, void __user *data);
 int ksys_umount(char __user *name, int flags);
+int ksys_dup(unsigned int fildes);
 
 #endif
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index 1c4da8353332..e8573e1776f6 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -39,8 +39,8 @@ static int init_linuxrc(struct subprocess_info *info, struct cred *new)
 	sys_unshare(CLONE_FS | CLONE_FILES);
 	/* stdin/stdout/stderr for /linuxrc */
 	sys_open("/dev/console", O_RDWR, 0);
-	sys_dup(0);
-	sys_dup(0);
+	ksys_dup(0);
+	ksys_dup(0);
 	/* move initrd over / and chdir/chroot in initrd root */
 	sys_chdir("/root");
 	ksys_mount(".", "/", NULL, MS_MOVE, NULL);
diff --git a/init/main.c b/init/main.c
index 969eaf140ef0..b8649d1466e1 100644
--- a/init/main.c
+++ b/init/main.c
@@ -1077,8 +1077,8 @@ static noinline void __init kernel_init_freeable(void)
 	if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
 		pr_err("Warning: unable to open an initial console.\n");
 
-	(void) sys_dup(0);
-	(void) sys_dup(0);
+	(void) ksys_dup(0);
+	(void) ksys_dup(0);
 	/*
 	 * check if there is an early userspace init.  If yes, let it do all
 	 * the work
-- 
2.16.2

[RFC PATCH 17/35] syscalls: do not call sys_chroot() within the kernel

[Dominik Brodowski]

CC: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 drivers/base/devtmpfs.c  | 2 +-
 fs/open.c                | 7 ++++++-
 include/linux/syscalls.h | 1 +
 init/do_mounts.c         | 2 +-
 init/do_mounts_initrd.c  | 4 ++--
 5 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index 4afb04686c8e..5743f04014ca 100644
--- a/drivers/base/devtmpfs.c
+++ b/drivers/base/devtmpfs.c
@@ -387,7 +387,7 @@ static int devtmpfsd(void *p)
 	if (*err)
 		goto out;
 	sys_chdir("/.."); /* will traverse into overmounted root */
-	sys_chroot(".");
+	ksys_chroot(".");
 	complete(&setup_done);
 	while (1) {
 		spin_lock(&req_lock);
diff --git a/fs/open.c b/fs/open.c
index 7ea118471dce..7a475e8a2e41 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -479,7 +479,7 @@ SYSCALL_DEFINE1(fchdir, unsigned int, fd)
 	return error;
 }
 
-SYSCALL_DEFINE1(chroot, const char __user *, filename)
+int ksys_chroot(const char __user *filename)
 {
 	struct path path;
 	int error;
@@ -512,6 +512,11 @@ SYSCALL_DEFINE1(chroot, const char __user *, filename)
 	return error;
 }
 
+SYSCALL_DEFINE1(chroot, const char __user *, filename)
+{
+	return ksys_chroot(filename);
+}
+
 static int chmod_common(const struct path *path, umode_t mode)
 {
 	struct inode *inode = path->dentry->d_inode;
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 986e91d5a2ea..c3416f8e8e29 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -952,5 +952,6 @@ int ksys_mount(char __user *dev_name, char __user *dir_name, char __user *type,
 	       unsigned long flags, void __user *data);
 int ksys_umount(char __user *name, int flags);
 int ksys_dup(unsigned int fildes);
+int ksys_chroot(const char __user *filename);
 
 #endif
diff --git a/init/do_mounts.c b/init/do_mounts.c
index eb768de43d84..2f06f7827b0c 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -600,7 +600,7 @@ void __init prepare_namespace(void)
 out:
 	devtmpfs_mount("dev");
 	ksys_mount(".", "/", NULL, MS_MOVE, NULL);
-	sys_chroot(".");
+	ksys_chroot(".");
 }
 
 static bool is_tmpfs;
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index e8573e1776f6..71293265ac4b 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -44,7 +44,7 @@ static int init_linuxrc(struct subprocess_info *info, struct cred *new)
 	/* move initrd over / and chdir/chroot in initrd root */
 	sys_chdir("/root");
 	ksys_mount(".", "/", NULL, MS_MOVE, NULL);
-	sys_chroot(".");
+	ksys_chroot(".");
 	sys_setsid();
 	return 0;
 }
@@ -83,7 +83,7 @@ static void __init handle_initrd(void)
 	/* move initrd to rootfs' /old */
 	ksys_mount("..", ".", NULL, MS_MOVE, NULL);
 	/* switch root and cwd back to / of rootfs */
-	sys_chroot("..");
+	ksys_chroot("..");
 
 	if (new_decode_dev(real_root_dev) == Root_RAM0) {
 		sys_chdir("/old");
-- 
2.16.2

[RFC PATCH 18/35] syscalls: do not call sys_write() within the kernel

[Dominik Brodowski]

CC: Alexander Viro <viro@zeniv.linux.org.uk>
CC: linux-s390@vger.kernel.org
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 arch/s390/kernel/compat_linux.c | 2 +-
 fs/read_write.c                 | 9 +++++++--
 include/linux/syscalls.h        | 1 +
 init/do_mounts_rd.c             | 4 ++--
 init/initramfs.c                | 2 +-
 5 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/arch/s390/kernel/compat_linux.c b/arch/s390/kernel/compat_linux.c
index 79b7a3438d54..5a9cfde5fc28 100644
--- a/arch/s390/kernel/compat_linux.c
+++ b/arch/s390/kernel/compat_linux.c
@@ -468,7 +468,7 @@ COMPAT_SYSCALL_DEFINE3(s390_write, unsigned int, fd, const char __user *, buf, c
 	if ((compat_ssize_t) count < 0)
 		return -EINVAL; 
 
-	return sys_write(fd, buf, count);
+	return ksys_write(fd, buf, count);
 }
 
 /*
diff --git a/fs/read_write.c b/fs/read_write.c
index f8547b82dfb3..8e8f0b4f52e2 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -578,8 +578,7 @@ SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count)
 	return ret;
 }
 
-SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf,
-		size_t, count)
+ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count)
 {
 	struct fd f = fdget_pos(fd);
 	ssize_t ret = -EBADF;
@@ -595,6 +594,12 @@ SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf,
 	return ret;
 }
 
+SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf,
+		size_t, count)
+{
+	return ksys_write(fd, buf, count);
+}
+
 SYSCALL_DEFINE4(pread64, unsigned int, fd, char __user *, buf,
 			size_t, count, loff_t, pos)
 {
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index c3416f8e8e29..51dd1e9185e1 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -953,5 +953,6 @@ int ksys_mount(char __user *dev_name, char __user *dir_name, char __user *type,
 int ksys_umount(char __user *name, int flags);
 int ksys_dup(unsigned int fildes);
 int ksys_chroot(const char __user *filename);
+ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count);
 
 #endif
diff --git a/init/do_mounts_rd.c b/init/do_mounts_rd.c
index 99e0b649fc0e..2d365c398ccc 100644
--- a/init/do_mounts_rd.c
+++ b/init/do_mounts_rd.c
@@ -270,7 +270,7 @@ int __init rd_load_image(char *from)
 			printk("Loading disk #%d... ", disk);
 		}
 		sys_read(in_fd, buf, BLOCK_SIZE);
-		sys_write(out_fd, buf, BLOCK_SIZE);
+		ksys_write(out_fd, buf, BLOCK_SIZE);
 #if !defined(CONFIG_S390)
 		if (!(i % 16)) {
 			pr_cont("%c\b", rotator[rotate & 0x3]);
@@ -317,7 +317,7 @@ static long __init compr_fill(void *buf, unsigned long len)
 
 static long __init compr_flush(void *window, unsigned long outcnt)
 {
-	long written = sys_write(crd_outfd, window, outcnt);
+	long written = ksys_write(crd_outfd, window, outcnt);
 	if (written != outcnt) {
 		if (decompress_error == 0)
 			printk(KERN_ERR
diff --git a/init/initramfs.c b/init/initramfs.c
index 7e99a0038942..6f972df15bf2 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -27,7 +27,7 @@ static ssize_t __init xwrite(int fd, const char *p, size_t count)
 
 	/* sys_write only can write MAX_RW_COUNT aka 2G-4K bytes at most */
 	while (count) {
-		ssize_t rv = sys_write(fd, p, count);
+		ssize_t rv = ksys_write(fd, p, count);
 
 		if (rv < 0) {
 			if (rv == -EINTR || rv == -EAGAIN)
-- 
2.16.2

[RFC PATCH 19/35] syscalls: do not call sys_unshare() within the kernel

[Dominik Brodowski]

CC: Al Viro <viro@zeniv.linux.org.uk>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 drivers/base/devtmpfs.c  | 2 +-
 include/linux/syscalls.h | 1 +
 init/do_mounts_initrd.c  | 2 +-
 kernel/fork.c            | 7 ++++++-
 4 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index 5743f04014ca..d6f37537275c 100644
--- a/drivers/base/devtmpfs.c
+++ b/drivers/base/devtmpfs.c
@@ -380,7 +380,7 @@ static int devtmpfsd(void *p)
 {
 	char options[] = "mode=0755";
 	int *err = p;
-	*err = sys_unshare(CLONE_NEWNS);
+	*err = ksys_unshare(CLONE_NEWNS);
 	if (*err)
 		goto out;
 	*err = ksys_mount("devtmpfs", "/", "devtmpfs", MS_SILENT, options);
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 51dd1e9185e1..1a17128394b7 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -954,5 +954,6 @@ int ksys_umount(char __user *name, int flags);
 int ksys_dup(unsigned int fildes);
 int ksys_chroot(const char __user *filename);
 ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count);
+int ksys_unshare(unsigned long unshare_flags);
 
 #endif
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index 71293265ac4b..414284dadc64 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -36,7 +36,7 @@ __setup("noinitrd", no_initrd);
 
 static int init_linuxrc(struct subprocess_info *info, struct cred *new)
 {
-	sys_unshare(CLONE_FS | CLONE_FILES);
+	ksys_unshare(CLONE_FS | CLONE_FILES);
 	/* stdin/stdout/stderr for /linuxrc */
 	sys_open("/dev/console", O_RDWR, 0);
 	ksys_dup(0);
diff --git a/kernel/fork.c b/kernel/fork.c
index b1e031aac9db..f71b67dc156d 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2354,7 +2354,7 @@ static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp
  * constructed. Here we are modifying the current, active,
  * task_struct.
  */
-SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags)
+int ksys_unshare(unsigned long unshare_flags)
 {
 	struct fs_struct *fs, *new_fs = NULL;
 	struct files_struct *fd, *new_fd = NULL;
@@ -2470,6 +2470,11 @@ SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags)
 	return err;
 }
 
+SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags)
+{
+	return ksys_unshare(unshare_flags);
+}
+
 /*
  *	Helper to unshare the files of the current task.
  *	We don't want to expose copy_files internals to
-- 
2.16.2

[RFC PATCH 20/35] syscalls: do not call sys_fadvise64{,_64}() within the kernel

[Dominik Brodowski]

Some compat stubs called sys_fadvise64(), which then just passed
through the arguments to sys_fadvise64_64(). Get rid of this
indirection.

CC: Andrew Morton <akpm@linux-foundation.org>
CC: linux-mm@kvack.org
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 arch/arm/kernel/sys_arm.c       |  2 +-
 arch/metag/kernel/sys_metag.c   |  2 +-
 arch/mips/kernel/linux32.c      |  2 +-
 arch/parisc/kernel/sys_parisc.c |  2 +-
 arch/powerpc/kernel/sys_ppc32.c |  4 ++--
 arch/powerpc/kernel/syscalls.c  |  4 ++--
 arch/s390/kernel/compat_linux.c |  5 +++--
 arch/sh/kernel/sys_sh32.c       |  8 ++++----
 arch/sparc/kernel/sys_sparc32.c | 10 +++++-----
 arch/tile/kernel/sys.c          |  4 ++--
 arch/x86/ia32/sys_ia32.c        | 12 ++++++------
 arch/xtensa/kernel/syscall.c    |  2 +-
 include/linux/syscalls.h        |  1 +
 mm/fadvise.c                    | 10 ++++++++--
 14 files changed, 38 insertions(+), 30 deletions(-)

diff --git a/arch/arm/kernel/sys_arm.c b/arch/arm/kernel/sys_arm.c
index 3151f5623d0e..bdf7514204ab 100644
--- a/arch/arm/kernel/sys_arm.c
+++ b/arch/arm/kernel/sys_arm.c
@@ -35,5 +35,5 @@
 asmlinkage long sys_arm_fadvise64_64(int fd, int advice,
 				     loff_t offset, loff_t len)
 {
-	return sys_fadvise64_64(fd, offset, len, advice);
+	return ksys_fadvise64_64(fd, offset, len, advice);
 }
diff --git a/arch/metag/kernel/sys_metag.c b/arch/metag/kernel/sys_metag.c
index 27d96499dd38..b949f917ab8b 100644
--- a/arch/metag/kernel/sys_metag.c
+++ b/arch/metag/kernel/sys_metag.c
@@ -122,7 +122,7 @@ asmlinkage long sys_fadvise64_64_metag(int fd, unsigned long offs_lo,
 				       unsigned long len_lo,
 				       unsigned long len_hi, int advice)
 {
-	return sys_fadvise64_64(fd, merge_64(offs_hi, offs_lo),
+	return ksys_fadvise64_64(fd, merge_64(offs_hi, offs_lo),
 				merge_64(len_hi, len_lo), advice);
 }
 
diff --git a/arch/mips/kernel/linux32.c b/arch/mips/kernel/linux32.c
index b332f6fc1e72..b8a3cf5d5950 100644
--- a/arch/mips/kernel/linux32.c
+++ b/arch/mips/kernel/linux32.c
@@ -149,7 +149,7 @@ asmlinkage long sys32_fadvise64_64(int fd, int __pad,
 	unsigned long a4, unsigned long a5,
 	int flags)
 {
-	return sys_fadvise64_64(fd,
+	return ksys_fadvise64_64(fd,
 			merge_64(a2, a3), merge_64(a4, a5),
 			flags);
 }
diff --git a/arch/parisc/kernel/sys_parisc.c b/arch/parisc/kernel/sys_parisc.c
index 378a754ca186..da1c27ea8e1a 100644
--- a/arch/parisc/kernel/sys_parisc.c
+++ b/arch/parisc/kernel/sys_parisc.c
@@ -352,7 +352,7 @@ asmlinkage long parisc_fadvise64_64(int fd,
 			unsigned int high_off, unsigned int low_off,
 			unsigned int high_len, unsigned int low_len, int advice)
 {
-	return sys_fadvise64_64(fd, (loff_t)high_off << 32 | low_off,
+	return ksys_fadvise64_64(fd, (loff_t)high_off << 32 | low_off,
 			(loff_t)high_len << 32 | low_len, advice);
 }
 
diff --git a/arch/powerpc/kernel/sys_ppc32.c b/arch/powerpc/kernel/sys_ppc32.c
index 15f216d022e2..93df264ab76c 100644
--- a/arch/powerpc/kernel/sys_ppc32.c
+++ b/arch/powerpc/kernel/sys_ppc32.c
@@ -113,8 +113,8 @@ asmlinkage int compat_sys_ftruncate64(unsigned int fd, u32 reg4, unsigned long h
 long ppc32_fadvise64(int fd, u32 unused, u32 offset_high, u32 offset_low,
 		     size_t len, int advice)
 {
-	return sys_fadvise64(fd, (u64)offset_high << 32 | offset_low, len,
-			     advice);
+	return ksys_fadvise64_64(fd, (u64)offset_high << 32 | offset_low, len,
+				 advice);
 }
 
 asmlinkage long compat_sys_sync_file_range2(int fd, unsigned int flags,
diff --git a/arch/powerpc/kernel/syscalls.c b/arch/powerpc/kernel/syscalls.c
index a877bf8269fe..ecb981eea74b 100644
--- a/arch/powerpc/kernel/syscalls.c
+++ b/arch/powerpc/kernel/syscalls.c
@@ -119,8 +119,8 @@ long ppc64_personality(unsigned long personality)
 long ppc_fadvise64_64(int fd, int advice, u32 offset_high, u32 offset_low,
 		      u32 len_high, u32 len_low)
 {
-	return sys_fadvise64(fd, (u64)offset_high << 32 | offset_low,
-			     (u64)len_high << 32 | len_low, advice);
+	return ksys_fadvise64_64(fd, (u64)offset_high << 32 | offset_low,
+				 (u64)len_high << 32 | len_low, advice);
 }
 
 long sys_switch_endian(void)
diff --git a/arch/s390/kernel/compat_linux.c b/arch/s390/kernel/compat_linux.c
index 5a9cfde5fc28..357a66934a98 100644
--- a/arch/s390/kernel/compat_linux.c
+++ b/arch/s390/kernel/compat_linux.c
@@ -483,7 +483,8 @@ COMPAT_SYSCALL_DEFINE5(s390_fadvise64, int, fd, u32, high, u32, low, compat_size
 		advise = POSIX_FADV_DONTNEED;
 	else if (advise == 5)
 		advise = POSIX_FADV_NOREUSE;
-	return sys_fadvise64(fd, (unsigned long)high << 32 | low, len, advise);
+	return ksys_fadvise64_64(fd, (unsigned long)high << 32 | low, len,
+				 advise);
 }
 
 struct fadvise64_64_args {
@@ -503,7 +504,7 @@ COMPAT_SYSCALL_DEFINE1(s390_fadvise64_64, struct fadvise64_64_args __user *, arg
 		a.advice = POSIX_FADV_DONTNEED;
 	else if (a.advice == 5)
 		a.advice = POSIX_FADV_NOREUSE;
-	return sys_fadvise64_64(a.fd, a.offset, a.len, a.advice);
+	return ksys_fadvise64_64(a.fd, a.offset, a.len, a.advice);
 }
 
 COMPAT_SYSCALL_DEFINE6(s390_sync_file_range, int, fd, u32, offhigh, u32, offlow,
diff --git a/arch/sh/kernel/sys_sh32.c b/arch/sh/kernel/sys_sh32.c
index f8dc8bfd4606..4d55318e0899 100644
--- a/arch/sh/kernel/sys_sh32.c
+++ b/arch/sh/kernel/sys_sh32.c
@@ -52,10 +52,10 @@ asmlinkage int sys_fadvise64_64_wrapper(int fd, u32 offset0, u32 offset1,
 				u32 len0, u32 len1, int advice)
 {
 #ifdef  __LITTLE_ENDIAN__
-	return sys_fadvise64_64(fd, (u64)offset1 << 32 | offset0,
-				(u64)len1 << 32 | len0,	advice);
+	return ksys_fadvise64_64(fd, (u64)offset1 << 32 | offset0,
+				 (u64)len1 << 32 | len0, advice);
 #else
-	return sys_fadvise64_64(fd, (u64)offset0 << 32 | offset1,
-				(u64)len0 << 32 | len1,	advice);
+	return ksys_fadvise64_64(fd, (u64)offset0 << 32 | offset1,
+				 (u64)len0 << 32 | len1, advice);
 #endif
 }
diff --git a/arch/sparc/kernel/sys_sparc32.c b/arch/sparc/kernel/sys_sparc32.c
index 6d964bdefbaa..08261bc15d30 100644
--- a/arch/sparc/kernel/sys_sparc32.c
+++ b/arch/sparc/kernel/sys_sparc32.c
@@ -225,7 +225,7 @@ long compat_sys_fadvise64(int fd,
 			  unsigned long offlo,
 			  compat_size_t len, int advice)
 {
-	return sys_fadvise64_64(fd, (offhi << 32) | offlo, len, advice);
+	return ksys_fadvise64_64(fd, (offhi << 32) | offlo, len, advice);
 }
 
 long compat_sys_fadvise64_64(int fd,
@@ -233,10 +233,10 @@ long compat_sys_fadvise64_64(int fd,
 			     unsigned long lenhi, unsigned long lenlo,
 			     int advice)
 {
-	return sys_fadvise64_64(fd,
-				(offhi << 32) | offlo,
-				(lenhi << 32) | lenlo,
-				advice);
+	return ksys_fadvise64_64(fd,
+				 (offhi << 32) | offlo,
+				 (lenhi << 32) | lenlo,
+				 advice);
 }
 
 long sys32_sync_file_range(unsigned int fd, unsigned long off_high, unsigned long off_low, unsigned long nb_high, unsigned long nb_low, unsigned int flags)
diff --git a/arch/tile/kernel/sys.c b/arch/tile/kernel/sys.c
index c7418dcbbb08..9e74b736b5f7 100644
--- a/arch/tile/kernel/sys.c
+++ b/arch/tile/kernel/sys.c
@@ -74,8 +74,8 @@ ssize_t sys32_readahead(int fd, SYSCALL_PAIR(offset), u32 count)
 int sys32_fadvise64_64(int fd, SYSCALL_PAIR(offset),
 		       SYSCALL_PAIR(len), int advice)
 {
-	return sys_fadvise64_64(fd, ((loff_t)offset_hi << 32) | offset_lo,
-				((loff_t)len_hi << 32) | len_lo, advice);
+	return ksys_fadvise64_64(fd, ((loff_t)offset_hi << 32) | offset_lo,
+				 ((loff_t)len_hi << 32) | len_lo, advice);
 }
 
 #endif /* 32-bit syscall wrappers */
diff --git a/arch/x86/ia32/sys_ia32.c b/arch/x86/ia32/sys_ia32.c
index 96cd33bbfc85..c412b14ed385 100644
--- a/arch/x86/ia32/sys_ia32.c
+++ b/arch/x86/ia32/sys_ia32.c
@@ -196,10 +196,10 @@ asmlinkage long sys32_pwrite(unsigned int fd, const char __user *ubuf,
 long sys32_fadvise64_64(int fd, __u32 offset_low, __u32 offset_high,
 			__u32 len_low, __u32 len_high, int advice)
 {
-	return sys_fadvise64_64(fd,
-			       (((u64)offset_high)<<32) | offset_low,
-			       (((u64)len_high)<<32) | len_low,
-				advice);
+	return ksys_fadvise64_64(fd,
+				 (((u64)offset_high)<<32) | offset_low,
+				 (((u64)len_high)<<32) | len_low,
+				 advice);
 }
 
 asmlinkage ssize_t sys32_readahead(int fd, unsigned off_lo, unsigned off_hi,
@@ -219,8 +219,8 @@ asmlinkage long sys32_sync_file_range(int fd, unsigned off_low, unsigned off_hi,
 asmlinkage long sys32_fadvise64(int fd, unsigned offset_lo, unsigned offset_hi,
 				size_t len, int advice)
 {
-	return sys_fadvise64_64(fd, ((u64)offset_hi << 32) | offset_lo,
-				len, advice);
+	return ksys_fadvise64_64(fd, ((u64)offset_hi << 32) | offset_lo,
+				 len, advice);
 }
 
 asmlinkage long sys32_fallocate(int fd, int mode, unsigned offset_lo,
diff --git a/arch/xtensa/kernel/syscall.c b/arch/xtensa/kernel/syscall.c
index 74afbf02d07e..8201748da05b 100644
--- a/arch/xtensa/kernel/syscall.c
+++ b/arch/xtensa/kernel/syscall.c
@@ -55,7 +55,7 @@ asmlinkage long xtensa_shmat(int shmid, char __user *shmaddr, int shmflg)
 asmlinkage long xtensa_fadvise64_64(int fd, int advice,
 		unsigned long long offset, unsigned long long len)
 {
-	return sys_fadvise64_64(fd, offset, len, advice);
+	return ksys_fadvise64_64(fd, offset, len, advice);
 }
 
 #ifdef CONFIG_MMU
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 1a17128394b7..bf489173ddc2 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -955,5 +955,6 @@ int ksys_dup(unsigned int fildes);
 int ksys_chroot(const char __user *filename);
 ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count);
 int ksys_unshare(unsigned long unshare_flags);
+int ksys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice);
 
 #endif
diff --git a/mm/fadvise.c b/mm/fadvise.c
index 767887f5f3bf..afa41491d324 100644
--- a/mm/fadvise.c
+++ b/mm/fadvise.c
@@ -26,7 +26,8 @@
  * POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could
  * deactivate the pages and clear PG_Referenced.
  */
-SYSCALL_DEFINE4(fadvise64_64, int, fd, loff_t, offset, loff_t, len, int, advice)
+
+int ksys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
 {
 	struct fd f = fdget(fd);
 	struct inode *inode;
@@ -185,11 +186,16 @@ SYSCALL_DEFINE4(fadvise64_64, int, fd, loff_t, offset, loff_t, len, int, advice)
 	return ret;
 }
 
+SYSCALL_DEFINE4(fadvise64_64, int, fd, loff_t, offset, loff_t, len, int, advice)
+{
+	return ksys_fadvise64_64(fd, offset, len, advice);
+}
+
 #ifdef __ARCH_WANT_SYS_FADVISE64
 
 SYSCALL_DEFINE4(fadvise64, int, fd, loff_t, offset, size_t, len, int, advice)
 {
-	return sys_fadvise64_64(fd, offset, len, advice);
+	return ksys_fadvise64_64(fd, offset, len, advice);
 }
 
 #endif
-- 
2.16.2

[RFC PATCH 21/35] syscalls: do not call sys_mmap_pgoff() within the kernel

[Dominik Brodowski]

CC: Andrew Morton <akpm@linux-foundation.org>
CC: linux-mm@kvack.org
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 arch/alpha/kernel/osf_sys.c             |  2 +-
 arch/arm64/kernel/sys.c                 |  2 +-
 arch/cris/kernel/sys_cris.c             |  2 +-
 arch/frv/kernel/sys_frv.c               |  4 ++--
 arch/ia64/kernel/sys_ia64.c             |  4 ++--
 arch/m68k/kernel/sys_m68k.c             |  2 +-
 arch/metag/kernel/sys_metag.c           |  2 +-
 arch/microblaze/kernel/sys_microblaze.c |  6 +++---
 arch/mips/kernel/linux32.c              |  4 ++--
 arch/mips/kernel/syscall.c              |  6 ++++--
 arch/mn10300/kernel/sys_mn10300.c       |  3 ++-
 arch/parisc/kernel/sys_parisc.c         |  6 +++---
 arch/powerpc/kernel/syscalls.c          |  2 +-
 arch/riscv/kernel/sys_riscv.c           |  4 ++--
 arch/s390/kernel/compat_linux.c         |  6 +++---
 arch/s390/kernel/sys_s390.c             |  2 +-
 arch/score/kernel/sys_score.c           |  5 +++--
 arch/sh/kernel/sys_sh.c                 |  4 ++--
 arch/sparc/kernel/sys_sparc_32.c        |  6 +++---
 arch/sparc/kernel/sys_sparc_64.c        |  2 +-
 arch/tile/kernel/sys.c                  |  8 ++++----
 arch/um/kernel/syscall.c                |  2 +-
 arch/x86/ia32/sys_ia32.c                |  2 +-
 arch/x86/kernel/sys_x86_64.c            |  2 +-
 include/linux/syscalls.h                |  3 +++
 mm/mmap.c                               | 17 ++++++++++++-----
 mm/nommu.c                              | 17 ++++++++++++-----
 27 files changed, 73 insertions(+), 52 deletions(-)

diff --git a/arch/alpha/kernel/osf_sys.c b/arch/alpha/kernel/osf_sys.c
index fa1a392ca9a2..89faa6f4de47 100644
--- a/arch/alpha/kernel/osf_sys.c
+++ b/arch/alpha/kernel/osf_sys.c
@@ -189,7 +189,7 @@ SYSCALL_DEFINE6(osf_mmap, unsigned long, addr, unsigned long, len,
 		goto out;
 	if (off & ~PAGE_MASK)
 		goto out;
-	ret = sys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
+	ret = ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
  out:
 	return ret;
 }
diff --git a/arch/arm64/kernel/sys.c b/arch/arm64/kernel/sys.c
index 26fe8ea93ea2..72981bae10eb 100644
--- a/arch/arm64/kernel/sys.c
+++ b/arch/arm64/kernel/sys.c
@@ -34,7 +34,7 @@ asmlinkage long sys_mmap(unsigned long addr, unsigned long len,
 	if (offset_in_page(off) != 0)
 		return -EINVAL;
 
-	return sys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
 }
 
 SYSCALL_DEFINE1(arm64_personality, unsigned int, personality)
diff --git a/arch/cris/kernel/sys_cris.c b/arch/cris/kernel/sys_cris.c
index ecea13f1d760..f1f8db552ea9 100644
--- a/arch/cris/kernel/sys_cris.c
+++ b/arch/cris/kernel/sys_cris.c
@@ -32,5 +32,5 @@ sys_mmap2(unsigned long addr, unsigned long len, unsigned long prot,
           unsigned long flags, unsigned long fd, unsigned long pgoff)
 {
 	/* bug(?): 8Kb pages here */
-        return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
 }
diff --git a/arch/frv/kernel/sys_frv.c b/arch/frv/kernel/sys_frv.c
index f80cc8b9bd45..6817b929469e 100644
--- a/arch/frv/kernel/sys_frv.c
+++ b/arch/frv/kernel/sys_frv.c
@@ -39,6 +39,6 @@ asmlinkage long sys_mmap2(unsigned long addr, unsigned long len,
 	if (pgoff & ((1 << (PAGE_SHIFT - 12)) - 1))
 		return -EINVAL;
 
-	return sys_mmap_pgoff(addr, len, prot, flags, fd,
-			      pgoff >> (PAGE_SHIFT - 12));
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd,
+			       pgoff >> (PAGE_SHIFT - 12));
 }
diff --git a/arch/ia64/kernel/sys_ia64.c b/arch/ia64/kernel/sys_ia64.c
index 085adfcc74a4..9ebe1d633abc 100644
--- a/arch/ia64/kernel/sys_ia64.c
+++ b/arch/ia64/kernel/sys_ia64.c
@@ -139,7 +139,7 @@ int ia64_mmap_check(unsigned long addr, unsigned long len,
 asmlinkage unsigned long
 sys_mmap2 (unsigned long addr, unsigned long len, int prot, int flags, int fd, long pgoff)
 {
-	addr = sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
+	addr = ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
 	if (!IS_ERR((void *) addr))
 		force_successful_syscall_return();
 	return addr;
@@ -151,7 +151,7 @@ sys_mmap (unsigned long addr, unsigned long len, int prot, int flags, int fd, lo
 	if (offset_in_page(off) != 0)
 		return -EINVAL;
 
-	addr = sys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
+	addr = ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
 	if (!IS_ERR((void *) addr))
 		force_successful_syscall_return();
 	return addr;
diff --git a/arch/m68k/kernel/sys_m68k.c b/arch/m68k/kernel/sys_m68k.c
index 27e10af5153a..6363ec83a290 100644
--- a/arch/m68k/kernel/sys_m68k.c
+++ b/arch/m68k/kernel/sys_m68k.c
@@ -46,7 +46,7 @@ asmlinkage long sys_mmap2(unsigned long addr, unsigned long len,
 	 * so we need to shift the argument down by 1; m68k mmap64(3)
 	 * (in libc) expects the last argument of mmap2 in 4Kb units.
 	 */
-	return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
 }
 
 /* Convert virtual (user) address VADDR to physical address PADDR */
diff --git a/arch/metag/kernel/sys_metag.c b/arch/metag/kernel/sys_metag.c
index b949f917ab8b..b2d9f278bd79 100644
--- a/arch/metag/kernel/sys_metag.c
+++ b/arch/metag/kernel/sys_metag.c
@@ -48,7 +48,7 @@ asmlinkage long sys_mmap2(unsigned long addr, unsigned long len,
 
 	pgoff >>= PAGE_SHIFT - 12;
 
-	return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
 }
 
 asmlinkage int sys_metag_setglobalbit(char __user *addr, int mask)
diff --git a/arch/microblaze/kernel/sys_microblaze.c b/arch/microblaze/kernel/sys_microblaze.c
index f1e1f666ddde..ed9f34da1a2a 100644
--- a/arch/microblaze/kernel/sys_microblaze.c
+++ b/arch/microblaze/kernel/sys_microblaze.c
@@ -40,7 +40,7 @@ SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
 	if (pgoff & ~PAGE_MASK)
 		return -EINVAL;
 
-	return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff >> PAGE_SHIFT);
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff >> PAGE_SHIFT);
 }
 
 SYSCALL_DEFINE6(mmap2, unsigned long, addr, unsigned long, len,
@@ -50,6 +50,6 @@ SYSCALL_DEFINE6(mmap2, unsigned long, addr, unsigned long, len,
 	if (pgoff & (~PAGE_MASK >> 12))
 		return -EINVAL;
 
-	return sys_mmap_pgoff(addr, len, prot, flags, fd,
-			      pgoff >> (PAGE_SHIFT - 12));
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd,
+			       pgoff >> (PAGE_SHIFT - 12));
 }
diff --git a/arch/mips/kernel/linux32.c b/arch/mips/kernel/linux32.c
index b8a3cf5d5950..0ce4f7240f69 100644
--- a/arch/mips/kernel/linux32.c
+++ b/arch/mips/kernel/linux32.c
@@ -67,8 +67,8 @@ SYSCALL_DEFINE6(32_mmap2, unsigned long, addr, unsigned long, len,
 {
 	if (pgoff & (~PAGE_MASK >> 12))
 		return -EINVAL;
-	return sys_mmap_pgoff(addr, len, prot, flags, fd,
-			      pgoff >> (PAGE_SHIFT-12));
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd,
+			       pgoff >> (PAGE_SHIFT-12));
 }
 
 #define RLIM_INFINITY32 0x7fffffff
diff --git a/arch/mips/kernel/syscall.c b/arch/mips/kernel/syscall.c
index 58c6f634b550..69c17b549fd3 100644
--- a/arch/mips/kernel/syscall.c
+++ b/arch/mips/kernel/syscall.c
@@ -63,7 +63,8 @@ SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
 {
 	if (offset & ~PAGE_MASK)
 		return -EINVAL;
-	return sys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd,
+			       offset >> PAGE_SHIFT);
 }
 
 SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
@@ -73,7 +74,8 @@ SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
 	if (pgoff & (~PAGE_MASK >> 12))
 		return -EINVAL;
 
-	return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff >> (PAGE_SHIFT-12));
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd,
+			       pgoff >> (PAGE_SHIFT - 12));
 }
 
 save_static_function(sys_fork);
diff --git a/arch/mn10300/kernel/sys_mn10300.c b/arch/mn10300/kernel/sys_mn10300.c
index f999981e55c0..3c3256dc0382 100644
--- a/arch/mn10300/kernel/sys_mn10300.c
+++ b/arch/mn10300/kernel/sys_mn10300.c
@@ -29,5 +29,6 @@ asmlinkage long old_mmap(unsigned long addr, unsigned long len,
 {
 	if (offset & ~PAGE_MASK)
 		return -EINVAL;
-	return sys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd,
+			       offset >> PAGE_SHIFT);
 }
diff --git a/arch/parisc/kernel/sys_parisc.c b/arch/parisc/kernel/sys_parisc.c
index da1c27ea8e1a..572feeea834c 100644
--- a/arch/parisc/kernel/sys_parisc.c
+++ b/arch/parisc/kernel/sys_parisc.c
@@ -270,8 +270,8 @@ asmlinkage unsigned long sys_mmap2(unsigned long addr, unsigned long len,
 {
 	/* Make sure the shift for mmap2 is constant (12), no matter what PAGE_SIZE
 	   we have. */
-	return sys_mmap_pgoff(addr, len, prot, flags, fd,
-			      pgoff >> (PAGE_SHIFT - 12));
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd,
+			       pgoff >> (PAGE_SHIFT - 12));
 }
 
 asmlinkage unsigned long sys_mmap(unsigned long addr, unsigned long len,
@@ -279,7 +279,7 @@ asmlinkage unsigned long sys_mmap(unsigned long addr, unsigned long len,
 		unsigned long offset)
 {
 	if (!(offset & ~PAGE_MASK)) {
-		return sys_mmap_pgoff(addr, len, prot, flags, fd,
+		return ksys_mmap_pgoff(addr, len, prot, flags, fd,
 					offset >> PAGE_SHIFT);
 	} else {
 		return -EINVAL;
diff --git a/arch/powerpc/kernel/syscalls.c b/arch/powerpc/kernel/syscalls.c
index ecb981eea74b..1ef3b80b62a6 100644
--- a/arch/powerpc/kernel/syscalls.c
+++ b/arch/powerpc/kernel/syscalls.c
@@ -57,7 +57,7 @@ static inline long do_mmap2(unsigned long addr, size_t len,
 		off >>= shift;
 	}
 
-	ret = sys_mmap_pgoff(addr, len, prot, flags, fd, off);
+	ret = ksys_mmap_pgoff(addr, len, prot, flags, fd, off);
 out:
 	return ret;
 }
diff --git a/arch/riscv/kernel/sys_riscv.c b/arch/riscv/kernel/sys_riscv.c
index 79c78668258e..f7181ed8aafc 100644
--- a/arch/riscv/kernel/sys_riscv.c
+++ b/arch/riscv/kernel/sys_riscv.c
@@ -24,8 +24,8 @@ static long riscv_sys_mmap(unsigned long addr, unsigned long len,
 {
 	if (unlikely(offset & (~PAGE_MASK >> page_shift_offset)))
 		return -EINVAL;
-	return sys_mmap_pgoff(addr, len, prot, flags, fd,
-			      offset >> (PAGE_SHIFT - page_shift_offset));
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd,
+			       offset >> (PAGE_SHIFT - page_shift_offset));
 }
 
 #ifdef CONFIG_64BIT
diff --git a/arch/s390/kernel/compat_linux.c b/arch/s390/kernel/compat_linux.c
index 357a66934a98..a47995a5174c 100644
--- a/arch/s390/kernel/compat_linux.c
+++ b/arch/s390/kernel/compat_linux.c
@@ -442,8 +442,8 @@ COMPAT_SYSCALL_DEFINE1(s390_old_mmap, struct mmap_arg_struct_emu31 __user *, arg
 		return -EFAULT;
 	if (a.offset & ~PAGE_MASK)
 		return -EINVAL;
-	return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
-			      a.offset >> PAGE_SHIFT);
+	return ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
+			       a.offset >> PAGE_SHIFT);
 }
 
 COMPAT_SYSCALL_DEFINE1(s390_mmap2, struct mmap_arg_struct_emu31 __user *, arg)
@@ -452,7 +452,7 @@ COMPAT_SYSCALL_DEFINE1(s390_mmap2, struct mmap_arg_struct_emu31 __user *, arg)
 
 	if (copy_from_user(&a, arg, sizeof(a)))
 		return -EFAULT;
-	return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, a.offset);
+	return ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, a.offset);
 }
 
 COMPAT_SYSCALL_DEFINE3(s390_read, unsigned int, fd, char __user *, buf, compat_size_t, count)
diff --git a/arch/s390/kernel/sys_s390.c b/arch/s390/kernel/sys_s390.c
index 0090037ab148..31cefe0c28c0 100644
--- a/arch/s390/kernel/sys_s390.c
+++ b/arch/s390/kernel/sys_s390.c
@@ -53,7 +53,7 @@ SYSCALL_DEFINE1(mmap2, struct s390_mmap_arg_struct __user *, arg)
 
 	if (copy_from_user(&a, arg, sizeof(a)))
 		goto out;
-	error = sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, a.offset);
+	error = ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, a.offset);
 out:
 	return error;
 }
diff --git a/arch/score/kernel/sys_score.c b/arch/score/kernel/sys_score.c
index 47c20ba46167..76ca9d49df4b 100644
--- a/arch/score/kernel/sys_score.c
+++ b/arch/score/kernel/sys_score.c
@@ -37,7 +37,7 @@ asmlinkage long
 sys_mmap2(unsigned long addr, unsigned long len, unsigned long prot,
 	  unsigned long flags, unsigned long fd, unsigned long pgoff)
 {
-	return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
 }
 
 asmlinkage long
@@ -46,5 +46,6 @@ sys_mmap(unsigned long addr, unsigned long len, unsigned long prot,
 {
 	if (unlikely(offset & ~PAGE_MASK))
 		return -EINVAL;
-	return sys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd,
+			       offset >> PAGE_SHIFT);
 }
diff --git a/arch/sh/kernel/sys_sh.c b/arch/sh/kernel/sys_sh.c
index 724911c59e7d..f8afc014e084 100644
--- a/arch/sh/kernel/sys_sh.c
+++ b/arch/sh/kernel/sys_sh.c
@@ -35,7 +35,7 @@ asmlinkage int old_mmap(unsigned long addr, unsigned long len,
 {
 	if (off & ~PAGE_MASK)
 		return -EINVAL;
-	return sys_mmap_pgoff(addr, len, prot, flags, fd, off>>PAGE_SHIFT);
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd, off>>PAGE_SHIFT);
 }
 
 asmlinkage long sys_mmap2(unsigned long addr, unsigned long len,
@@ -51,7 +51,7 @@ asmlinkage long sys_mmap2(unsigned long addr, unsigned long len,
 
 	pgoff >>= PAGE_SHIFT - 12;
 
-	return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
 }
 
 /* sys_cacheflush -- flush (part of) the processor cache.  */
diff --git a/arch/sparc/kernel/sys_sparc_32.c b/arch/sparc/kernel/sys_sparc_32.c
index 990703b7cf4d..d980da4ffd7b 100644
--- a/arch/sparc/kernel/sys_sparc_32.c
+++ b/arch/sparc/kernel/sys_sparc_32.c
@@ -104,8 +104,8 @@ asmlinkage long sys_mmap2(unsigned long addr, unsigned long len,
 {
 	/* Make sure the shift for mmap2 is constant (12), no matter what PAGE_SIZE
 	   we have. */
-	return sys_mmap_pgoff(addr, len, prot, flags, fd,
-			      pgoff >> (PAGE_SHIFT - 12));
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd,
+			       pgoff >> (PAGE_SHIFT - 12));
 }
 
 asmlinkage long sys_mmap(unsigned long addr, unsigned long len,
@@ -113,7 +113,7 @@ asmlinkage long sys_mmap(unsigned long addr, unsigned long len,
 	unsigned long off)
 {
 	/* no alignment check? */
-	return sys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
 }
 
 long sparc_remap_file_pages(unsigned long start, unsigned long size,
diff --git a/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c
index 55416db482ad..ebb84dc8a5a7 100644
--- a/arch/sparc/kernel/sys_sparc_64.c
+++ b/arch/sparc/kernel/sys_sparc_64.c
@@ -458,7 +458,7 @@ SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
 		goto out;
 	if (off & ~PAGE_MASK)
 		goto out;
-	retval = sys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
+	retval = ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
 out:
 	return retval;
 }
diff --git a/arch/tile/kernel/sys.c b/arch/tile/kernel/sys.c
index 9e74b736b5f7..803c312193bc 100644
--- a/arch/tile/kernel/sys.c
+++ b/arch/tile/kernel/sys.c
@@ -88,8 +88,8 @@ SYSCALL_DEFINE6(mmap2, unsigned long, addr, unsigned long, len,
 #define PAGE_ADJUST (PAGE_SHIFT - 12)
 	if (off_4k & ((1 << PAGE_ADJUST) - 1))
 		return -EINVAL;
-	return sys_mmap_pgoff(addr, len, prot, flags, fd,
-			      off_4k >> PAGE_ADJUST);
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd,
+			       off_4k >> PAGE_ADJUST);
 }
 
 #ifdef __tilegx__
@@ -99,8 +99,8 @@ SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
 {
 	if (offset & ((1 << PAGE_SHIFT) - 1))
 		return -EINVAL;
-	return sys_mmap_pgoff(addr, len, prot, flags, fd,
-			      offset >> PAGE_SHIFT);
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd,
+			       offset >> PAGE_SHIFT);
 }
 #endif
 
diff --git a/arch/um/kernel/syscall.c b/arch/um/kernel/syscall.c
index 6258676bed85..35f7047bdebc 100644
--- a/arch/um/kernel/syscall.c
+++ b/arch/um/kernel/syscall.c
@@ -22,7 +22,7 @@ long old_mmap(unsigned long addr, unsigned long len,
 	if (offset & ~PAGE_MASK)
 		goto out;
 
-	err = sys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
+	err = ksys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
  out:
 	return err;
 }
diff --git a/arch/x86/ia32/sys_ia32.c b/arch/x86/ia32/sys_ia32.c
index c412b14ed385..f115378bebec 100644
--- a/arch/x86/ia32/sys_ia32.c
+++ b/arch/x86/ia32/sys_ia32.c
@@ -163,7 +163,7 @@ asmlinkage long sys32_mmap(struct mmap_arg_struct32 __user *arg)
 	if (a.offset & ~PAGE_MASK)
 		return -EINVAL;
 
-	return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
+	return ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
 			       a.offset>>PAGE_SHIFT);
 }
 
diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
index 676774b9bb8d..a3f15ed545b5 100644
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c
@@ -97,7 +97,7 @@ SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
 	if (off & ~PAGE_MASK)
 		goto out;
 
-	error = sys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
+	error = ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
 out:
 	return error;
 }
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index bf489173ddc2..197c622d0b9f 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -956,5 +956,8 @@ int ksys_chroot(const char __user *filename);
 ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count);
 int ksys_unshare(unsigned long unshare_flags);
 int ksys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice);
+unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
+			      unsigned long prot, unsigned long flags,
+			      unsigned long fd, unsigned long pgoff);
 
 #endif
diff --git a/mm/mmap.c b/mm/mmap.c
index 9efdc021ad22..aa0dc8231c0d 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1488,9 +1488,9 @@ unsigned long do_mmap(struct file *file, unsigned long addr,
 	return addr;
 }
 
-SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
-		unsigned long, prot, unsigned long, flags,
-		unsigned long, fd, unsigned long, pgoff)
+unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
+			      unsigned long prot, unsigned long flags,
+			      unsigned long fd, unsigned long pgoff)
 {
 	struct file *file = NULL;
 	unsigned long retval;
@@ -1537,6 +1537,13 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
 	return retval;
 }
 
+SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
+		unsigned long, prot, unsigned long, flags,
+		unsigned long, fd, unsigned long, pgoff)
+{
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
+}
+
 #ifdef __ARCH_WANT_SYS_OLD_MMAP
 struct mmap_arg_struct {
 	unsigned long addr;
@@ -1556,8 +1563,8 @@ SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
 	if (offset_in_page(a.offset))
 		return -EINVAL;
 
-	return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
-			      a.offset >> PAGE_SHIFT);
+	return ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
+			       a.offset >> PAGE_SHIFT);
 }
 #endif /* __ARCH_WANT_SYS_OLD_MMAP */
 
diff --git a/mm/nommu.c b/mm/nommu.c
index ebb6e618dade..cad329629530 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1423,9 +1423,9 @@ unsigned long do_mmap(struct file *file,
 	return -ENOMEM;
 }
 
-SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
-		unsigned long, prot, unsigned long, flags,
-		unsigned long, fd, unsigned long, pgoff)
+unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
+			      unsigned long prot, unsigned long flags,
+			      unsigned long fd, unsigned long pgoff)
 {
 	struct file *file = NULL;
 	unsigned long retval = -EBADF;
@@ -1447,6 +1447,13 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
 	return retval;
 }
 
+SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
+		unsigned long, prot, unsigned long, flags,
+		unsigned long, fd, unsigned long, pgoff)
+{
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
+}
+
 #ifdef __ARCH_WANT_SYS_OLD_MMAP
 struct mmap_arg_struct {
 	unsigned long addr;
@@ -1466,8 +1473,8 @@ SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
 	if (offset_in_page(a.offset))
 		return -EINVAL;
 
-	return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
-			      a.offset >> PAGE_SHIFT);
+	return ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
+			       a.offset >> PAGE_SHIFT);
 }
 #endif /* __ARCH_WANT_SYS_OLD_MMAP */
 
-- 
2.16.2

[RFC PATCH 22/35] syscalls: do not call sys_chdir() within the kernel

[Dominik Brodowski]

CC: Al Viro <viro@zeniv.linux.org.uk>
CC: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 drivers/base/devtmpfs.c  | 2 +-
 fs/open.c                | 7 ++++++-
 include/linux/syscalls.h | 1 +
 init/do_mounts.c         | 2 +-
 init/do_mounts_initrd.c  | 8 ++++----
 5 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index d6f37537275c..f7768077e817 100644
--- a/drivers/base/devtmpfs.c
+++ b/drivers/base/devtmpfs.c
@@ -386,7 +386,7 @@ static int devtmpfsd(void *p)
 	*err = ksys_mount("devtmpfs", "/", "devtmpfs", MS_SILENT, options);
 	if (*err)
 		goto out;
-	sys_chdir("/.."); /* will traverse into overmounted root */
+	ksys_chdir("/.."); /* will traverse into overmounted root */
 	ksys_chroot(".");
 	complete(&setup_done);
 	while (1) {
diff --git a/fs/open.c b/fs/open.c
index 7a475e8a2e41..a19b8277c439 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -431,7 +431,7 @@ SYSCALL_DEFINE2(access, const char __user *, filename, int, mode)
 	return sys_faccessat(AT_FDCWD, filename, mode);
 }
 
-SYSCALL_DEFINE1(chdir, const char __user *, filename)
+int ksys_chdir(const char __user *filename)
 {
 	struct path path;
 	int error;
@@ -457,6 +457,11 @@ SYSCALL_DEFINE1(chdir, const char __user *, filename)
 	return error;
 }
 
+SYSCALL_DEFINE1(chdir, const char __user *, filename)
+{
+	return ksys_chdir(filename);
+}
+
 SYSCALL_DEFINE1(fchdir, unsigned int, fd)
 {
 	struct fd f = fdget_raw(fd);
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 197c622d0b9f..03c70fa26852 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -959,5 +959,6 @@ int ksys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice);
 unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
 			      unsigned long prot, unsigned long flags,
 			      unsigned long fd, unsigned long pgoff);
+int ksys_chdir(const char __user *filename);
 
 #endif
diff --git a/init/do_mounts.c b/init/do_mounts.c
index 2f06f7827b0c..89f18985fa90 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -367,7 +367,7 @@ static int __init do_mount_root(char *name, char *fs, int flags, void *data)
 	if (err)
 		return err;
 
-	sys_chdir("/root");
+	ksys_chdir("/root");
 	s = current->fs->pwd.dentry->d_sb;
 	ROOT_DEV = s->s_dev;
 	printk(KERN_INFO
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index 414284dadc64..c19d9070134e 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -42,7 +42,7 @@ static int init_linuxrc(struct subprocess_info *info, struct cred *new)
 	ksys_dup(0);
 	ksys_dup(0);
 	/* move initrd over / and chdir/chroot in initrd root */
-	sys_chdir("/root");
+	ksys_chdir("/root");
 	ksys_mount(".", "/", NULL, MS_MOVE, NULL);
 	ksys_chroot(".");
 	sys_setsid();
@@ -61,7 +61,7 @@ static void __init handle_initrd(void)
 	/* mount initrd on rootfs' /root */
 	mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY);
 	sys_mkdir("/old", 0700);
-	sys_chdir("/old");
+	ksys_chdir("/old");
 
 	/* try loading default modules from initrd */
 	load_default_modules();
@@ -86,11 +86,11 @@ static void __init handle_initrd(void)
 	ksys_chroot("..");
 
 	if (new_decode_dev(real_root_dev) == Root_RAM0) {
-		sys_chdir("/old");
+		ksys_chdir("/old");
 		return;
 	}
 
-	sys_chdir("/");
+	ksys_chdir("/");
 	ROOT_DEV = new_decode_dev(real_root_dev);
 	mount_root();
 
-- 
2.16.2

[RFC PATCH 23/35] syscalls: do not call sys_sync_file_range() within the kernel

[Dominik Brodowski]

CC: Al Viro <viro@zeniv.linux.org.uk>
CC: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 arch/metag/kernel/sys_metag.c   |  4 ++--
 arch/mips/kernel/linux32.c      |  2 +-
 arch/parisc/kernel/sys_parisc.c |  2 +-
 arch/powerpc/kernel/sys_ppc32.c |  2 +-
 arch/s390/kernel/compat_linux.c |  2 +-
 arch/sparc/kernel/sys_sparc32.c |  2 +-
 arch/tile/kernel/compat.c       |  2 +-
 arch/x86/ia32/sys_ia32.c        |  6 +++---
 fs/sync.c                       | 12 +++++++++---
 include/linux/syscalls.h        |  2 ++
 10 files changed, 22 insertions(+), 14 deletions(-)

diff --git a/arch/metag/kernel/sys_metag.c b/arch/metag/kernel/sys_metag.c
index b2d9f278bd79..d2ae5fcb9f80 100644
--- a/arch/metag/kernel/sys_metag.c
+++ b/arch/metag/kernel/sys_metag.c
@@ -152,8 +152,8 @@ asmlinkage long sys_sync_file_range_metag(int fd, unsigned long offs_lo,
 					  unsigned long len_hi,
 					  unsigned int flags)
 {
-	return sys_sync_file_range(fd, merge_64(offs_hi, offs_lo),
-				   merge_64(len_hi, len_lo), flags);
+	return ksys_sync_file_range(fd, merge_64(offs_hi, offs_lo),
+				    merge_64(len_hi, len_lo), flags);
 }
 
 /* Provide the actual syscall number to call mapping. */
diff --git a/arch/mips/kernel/linux32.c b/arch/mips/kernel/linux32.c
index 0ce4f7240f69..db895771ab06 100644
--- a/arch/mips/kernel/linux32.c
+++ b/arch/mips/kernel/linux32.c
@@ -139,7 +139,7 @@ asmlinkage long sys32_sync_file_range(int fd, int __pad,
 	unsigned long a4, unsigned long a5,
 	int flags)
 {
-	return sys_sync_file_range(fd,
+	return ksys_sync_file_range(fd,
 			merge_64(a2, a3), merge_64(a4, a5),
 			flags);
 }
diff --git a/arch/parisc/kernel/sys_parisc.c b/arch/parisc/kernel/sys_parisc.c
index 572feeea834c..0b0e1cfb4bd9 100644
--- a/arch/parisc/kernel/sys_parisc.c
+++ b/arch/parisc/kernel/sys_parisc.c
@@ -360,7 +360,7 @@ asmlinkage long parisc_sync_file_range(int fd,
 			u32 hi_off, u32 lo_off, u32 hi_nbytes, u32 lo_nbytes,
 			unsigned int flags)
 {
-	return sys_sync_file_range(fd, (loff_t)hi_off << 32 | lo_off,
+	return ksys_sync_file_range(fd, (loff_t)hi_off << 32 | lo_off,
 			(loff_t)hi_nbytes << 32 | lo_nbytes, flags);
 }
 
diff --git a/arch/powerpc/kernel/sys_ppc32.c b/arch/powerpc/kernel/sys_ppc32.c
index 93df264ab76c..3871aa9267e6 100644
--- a/arch/powerpc/kernel/sys_ppc32.c
+++ b/arch/powerpc/kernel/sys_ppc32.c
@@ -124,5 +124,5 @@ asmlinkage long compat_sys_sync_file_range2(int fd, unsigned int flags,
 	loff_t offset = ((loff_t)offset_hi << 32) | offset_lo;
 	loff_t nbytes = ((loff_t)nbytes_hi << 32) | nbytes_lo;
 
-	return sys_sync_file_range(fd, offset, nbytes, flags);
+	return ksys_sync_file_range(fd, offset, nbytes, flags);
 }
diff --git a/arch/s390/kernel/compat_linux.c b/arch/s390/kernel/compat_linux.c
index a47995a5174c..82e99bf3b00e 100644
--- a/arch/s390/kernel/compat_linux.c
+++ b/arch/s390/kernel/compat_linux.c
@@ -510,7 +510,7 @@ COMPAT_SYSCALL_DEFINE1(s390_fadvise64_64, struct fadvise64_64_args __user *, arg
 COMPAT_SYSCALL_DEFINE6(s390_sync_file_range, int, fd, u32, offhigh, u32, offlow,
 		       u32, nhigh, u32, nlow, unsigned int, flags)
 {
-	return sys_sync_file_range(fd, ((loff_t)offhigh << 32) + offlow,
+	return ksys_sync_file_range(fd, ((loff_t)offhigh << 32) + offlow,
 				   ((u64)nhigh << 32) + nlow, flags);
 }
 
diff --git a/arch/sparc/kernel/sys_sparc32.c b/arch/sparc/kernel/sys_sparc32.c
index 08261bc15d30..c56f43893283 100644
--- a/arch/sparc/kernel/sys_sparc32.c
+++ b/arch/sparc/kernel/sys_sparc32.c
@@ -241,7 +241,7 @@ long compat_sys_fadvise64_64(int fd,
 
 long sys32_sync_file_range(unsigned int fd, unsigned long off_high, unsigned long off_low, unsigned long nb_high, unsigned long nb_low, unsigned int flags)
 {
-	return sys_sync_file_range(fd,
+	return ksys_sync_file_range(fd,
 				   (off_high << 32) | off_low,
 				   (nb_high << 32) | nb_low,
 				   flags);
diff --git a/arch/tile/kernel/compat.c b/arch/tile/kernel/compat.c
index bdaf71d31a4a..24414d4d592d 100644
--- a/arch/tile/kernel/compat.c
+++ b/arch/tile/kernel/compat.c
@@ -68,7 +68,7 @@ COMPAT_SYSCALL_DEFINE6(pwrite64, unsigned int, fd, char __user *, ubuf,
 COMPAT_SYSCALL_DEFINE6(sync_file_range2, int, fd, unsigned int, flags,
 		       SYSCALL_PAIR(offset), SYSCALL_PAIR(nbytes))
 {
-	return sys_sync_file_range(fd, ((loff_t)offset_hi << 32) | offset_lo,
+	return ksys_sync_file_range(fd, ((loff_t)offset_hi << 32) | offset_lo,
 				   ((loff_t)nbytes_hi << 32) | nbytes_lo,
 				   flags);
 }
diff --git a/arch/x86/ia32/sys_ia32.c b/arch/x86/ia32/sys_ia32.c
index f115378bebec..42badedd5ebc 100644
--- a/arch/x86/ia32/sys_ia32.c
+++ b/arch/x86/ia32/sys_ia32.c
@@ -211,9 +211,9 @@ asmlinkage ssize_t sys32_readahead(int fd, unsigned off_lo, unsigned off_hi,
 asmlinkage long sys32_sync_file_range(int fd, unsigned off_low, unsigned off_hi,
 				      unsigned n_low, unsigned n_hi,  int flags)
 {
-	return sys_sync_file_range(fd,
-				   ((u64)off_hi << 32) | off_low,
-				   ((u64)n_hi << 32) | n_low, flags);
+	return ksys_sync_file_range(fd,
+				    ((u64)off_hi << 32) | off_low,
+				    ((u64)n_hi << 32) | n_low, flags);
 }
 
 asmlinkage long sys32_fadvise64(int fd, unsigned offset_lo, unsigned offset_hi,
diff --git a/fs/sync.c b/fs/sync.c
index 6e0a2cbaf6de..ff947c30a6c0 100644
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -280,8 +280,8 @@ SYSCALL_DEFINE1(fdatasync, unsigned int, fd)
  * already-instantiated disk blocks, there are no guarantees here that the data
  * will be available after a crash.
  */
-SYSCALL_DEFINE4(sync_file_range, int, fd, loff_t, offset, loff_t, nbytes,
-				unsigned int, flags)
+int ksys_sync_file_range(int fd, loff_t offset, loff_t nbytes,
+			 unsigned int flags)
 {
 	int ret;
 	struct fd f;
@@ -359,10 +359,16 @@ SYSCALL_DEFINE4(sync_file_range, int, fd, loff_t, offset, loff_t, nbytes,
 	return ret;
 }
 
+SYSCALL_DEFINE4(sync_file_range, int, fd, loff_t, offset, loff_t, nbytes,
+				unsigned int, flags)
+{
+	return ksys_sync_file_range(fd, offset, nbytes, flags);
+}
+
 /* It would be nice if people remember that not all the world's an i386
    when they introduce new system calls */
 SYSCALL_DEFINE4(sync_file_range2, int, fd, unsigned int, flags,
 				 loff_t, offset, loff_t, nbytes)
 {
-	return sys_sync_file_range(fd, offset, nbytes, flags);
+	return ksys_sync_file_range(fd, offset, nbytes, flags);
 }
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 03c70fa26852..5b17c3c64a52 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -960,5 +960,7 @@ unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
 			      unsigned long prot, unsigned long flags,
 			      unsigned long fd, unsigned long pgoff);
 int ksys_chdir(const char __user *filename);
+int ksys_sync_file_range(int fd, loff_t offset, loff_t nbytes,
+			 unsigned int flags);
 
 #endif
-- 
2.16.2

[RFC PATCH 24/35] syscalls: do not call sys_unlink() within the kernel

[Dominik Brodowski]

CC: Al Viro <viro@zeniv.linux.org.uk>
CC: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 include/linux/syscalls.h | 10 ++++++++++
 init/do_mounts.h         |  2 +-
 init/do_mounts_initrd.c  |  4 ++--
 init/do_mounts_rd.c      |  2 +-
 init/initramfs.c         |  4 ++--
 5 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 5b17c3c64a52..452be95ab9ca 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -963,4 +963,14 @@ int ksys_chdir(const char __user *filename);
 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
+ * functions. Therefore, provide stubs to be inlined at the callsites.
+ */
+extern long do_unlinkat(int dfd, struct filename *name);
+static inline long ksys_unlink(const char __user *pathname)
+{
+	return do_unlinkat(AT_FDCWD, getname(pathname));
+}
+
 #endif
diff --git a/init/do_mounts.h b/init/do_mounts.h
index 5b05c8f93f47..401f90ee1eeb 100644
--- a/init/do_mounts.h
+++ b/init/do_mounts.h
@@ -16,7 +16,7 @@ extern int root_mountflags;
 
 static inline int create_dev(char *name, dev_t dev)
 {
-	sys_unlink(name);
+	ksys_unlink(name);
 	return sys_mknod(name, S_IFBLK|0600, new_encode_dev(dev));
 }
 
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index c19d9070134e..784576b633fd 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -128,11 +128,11 @@ bool __init initrd_load(void)
 		 * mounted in the normal path.
 		 */
 		if (rd_load_image("/initrd.image") && ROOT_DEV != Root_RAM0) {
-			sys_unlink("/initrd.image");
+			ksys_unlink("/initrd.image");
 			handle_initrd();
 			return true;
 		}
 	}
-	sys_unlink("/initrd.image");
+	ksys_unlink("/initrd.image");
 	return false;
 }
diff --git a/init/do_mounts_rd.c b/init/do_mounts_rd.c
index 2d365c398ccc..5b69056f610a 100644
--- a/init/do_mounts_rd.c
+++ b/init/do_mounts_rd.c
@@ -288,7 +288,7 @@ int __init rd_load_image(char *from)
 	sys_close(out_fd);
 out:
 	kfree(buf);
-	sys_unlink("/dev/ram");
+	ksys_unlink("/dev/ram");
 	return res;
 }
 
diff --git a/init/initramfs.c b/init/initramfs.c
index 6f972df15bf2..08eb551168a8 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -319,7 +319,7 @@ static void __init clean_path(char *path, umode_t fmode)
 		if (S_ISDIR(st.mode))
 			sys_rmdir(path);
 		else
-			sys_unlink(path);
+			ksys_unlink(path);
 	}
 }
 
@@ -591,7 +591,7 @@ static void __init clean_rootfs(void)
 				if (S_ISDIR(st.mode))
 					sys_rmdir(dirp->d_name);
 				else
-					sys_unlink(dirp->d_name);
+					ksys_unlink(dirp->d_name);
 			}
 
 			num -= dirp->d_reclen;
-- 
2.16.2

[RFC PATCH 25/35] hostfs: rename do_rmdir() to hostfs_do_rmdir()

[Dominik Brodowski]

do_rmdir() is used in the VFS layer at fs/namei.c, so use a different
name in hostfs.

CC: Jeff Dike <jdike@addtoit.com>
CC: Richard Weinberger <richard@nod.at>
CC: user-mode-linux-devel@lists.sourceforge.net
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/hostfs/hostfs.h      | 2 +-
 fs/hostfs/hostfs_kern.c | 2 +-
 fs/hostfs/hostfs_user.c | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/hostfs/hostfs.h b/fs/hostfs/hostfs.h
index ffaec2e7526c..cb8374af08a6 100644
--- a/fs/hostfs/hostfs.h
+++ b/fs/hostfs/hostfs.h
@@ -84,7 +84,7 @@ extern int set_attr(const char *file, struct hostfs_iattr *attrs, int fd);
 extern int make_symlink(const char *from, const char *to);
 extern int unlink_file(const char *file);
 extern int do_mkdir(const char *file, int mode);
-extern int do_rmdir(const char *file);
+extern int hostfs_do_rmdir(const char *file);
 extern int do_mknod(const char *file, int mode, unsigned int major,
 		    unsigned int minor);
 extern int link_file(const char *from, const char *to);
diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c
index c148e7f4f451..3cd85eb5bbb1 100644
--- a/fs/hostfs/hostfs_kern.c
+++ b/fs/hostfs/hostfs_kern.c
@@ -706,7 +706,7 @@ static int hostfs_rmdir(struct inode *ino, struct dentry *dentry)
 
 	if ((file = dentry_name(dentry)) == NULL)
 		return -ENOMEM;
-	err = do_rmdir(file);
+	err = hostfs_do_rmdir(file);
 	__putname(file);
 	return err;
 }
diff --git a/fs/hostfs/hostfs_user.c b/fs/hostfs/hostfs_user.c
index 9c1e0f019880..5ecc4706172b 100644
--- a/fs/hostfs/hostfs_user.c
+++ b/fs/hostfs/hostfs_user.c
@@ -304,7 +304,7 @@ int do_mkdir(const char *file, int mode)
 	return 0;
 }
 
-int do_rmdir(const char *file)
+int hostfs_do_rmdir(const char *file)
 {
 	int err;
 
-- 
2.16.2

[RFC PATCH 26/35] syscalls: do not call sys_rmdir() within the kernel

[Dominik Brodowski]

CC: Al Viro <viro@zeniv.linux.org.uk>
CC: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/internal.h            | 1 +
 fs/namei.c               | 2 +-
 include/linux/syscalls.h | 6 ++++++
 init/initramfs.c         | 4 ++--
 4 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/fs/internal.h b/fs/internal.h
index df262f41a0ef..0eda35fa1743 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -55,6 +55,7 @@ extern void __init chrdev_init(void);
 extern int user_path_mountpoint_at(int, const char __user *, unsigned int, struct path *);
 extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
 			   const char *, unsigned int, struct path *);
+long do_rmdir(int dfd, const char __user *pathname);
 long do_unlinkat(int dfd, struct filename *name);
 
 /*
diff --git a/fs/namei.c b/fs/namei.c
index 524e829ffc7d..8545151f74e9 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3872,7 +3872,7 @@ int vfs_rmdir(struct inode *dir, struct dentry *dentry)
 }
 EXPORT_SYMBOL(vfs_rmdir);
 
-static long do_rmdir(int dfd, const char __user *pathname)
+long do_rmdir(int dfd, const char __user *pathname)
 {
 	int error = 0;
 	struct filename *name;
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 452be95ab9ca..bb610042a1ec 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -973,4 +973,10 @@ static inline long ksys_unlink(const char __user *pathname)
 	return do_unlinkat(AT_FDCWD, getname(pathname));
 }
 
+extern long do_rmdir(int dfd, const char __user *pathname);
+static inline long ksys_rmdir(const char __user *pathname)
+{
+	return do_rmdir(AT_FDCWD, pathname);
+}
+
 #endif
diff --git a/init/initramfs.c b/init/initramfs.c
index 08eb551168a8..73bbb227f868 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -317,7 +317,7 @@ static void __init clean_path(char *path, umode_t fmode)
 
 	if (!vfs_lstat(path, &st) && (st.mode ^ fmode) & S_IFMT) {
 		if (S_ISDIR(st.mode))
-			sys_rmdir(path);
+			ksys_rmdir(path);
 		else
 			ksys_unlink(path);
 	}
@@ -589,7 +589,7 @@ static void __init clean_rootfs(void)
 			WARN_ON_ONCE(ret);
 			if (!ret) {
 				if (S_ISDIR(st.mode))
-					sys_rmdir(dirp->d_name);
+					ksys_rmdir(dirp->d_name);
 				else
 					ksys_unlink(dirp->d_name);
 			}
-- 
2.16.2

[RFC PATCH 27/35] syscalls: do not call sys_mkdir{,at}() within the kernel

[Dominik Brodowski]

CC: Al Viro <viro@zeniv.linux.org.uk>
CC: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/internal.h            | 1 +
 fs/namei.c               | 9 +++++++--
 include/linux/syscalls.h | 6 ++++++
 init/do_mounts_initrd.c  | 2 +-
 init/initramfs.c         | 2 +-
 init/noinitramfs.c       | 4 ++--
 6 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/fs/internal.h b/fs/internal.h
index 0eda35fa1743..53846bd4d9d7 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -55,6 +55,7 @@ extern void __init chrdev_init(void);
 extern int user_path_mountpoint_at(int, const char __user *, unsigned int, struct path *);
 extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
 			   const char *, unsigned int, struct path *);
+long do_mkdirat(int dfd, const char __user *pathname, umode_t mode);
 long do_rmdir(int dfd, const char __user *pathname);
 long do_unlinkat(int dfd, struct filename *name);
 
diff --git a/fs/namei.c b/fs/namei.c
index 8545151f74e9..dcf506227509 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3803,7 +3803,7 @@ int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 }
 EXPORT_SYMBOL(vfs_mkdir);
 
-SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode)
+long do_mkdirat(int dfd, const char __user *pathname, umode_t mode)
 {
 	struct dentry *dentry;
 	struct path path;
@@ -3828,9 +3828,14 @@ SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode)
 	return error;
 }
 
+SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode)
+{
+	return do_mkdirat(dfd, pathname, mode);
+}
+
 SYSCALL_DEFINE2(mkdir, const char __user *, pathname, umode_t, mode)
 {
-	return sys_mkdirat(AT_FDCWD, pathname, mode);
+	return do_mkdirat(AT_FDCWD, pathname, mode);
 }
 
 int vfs_rmdir(struct inode *dir, struct dentry *dentry)
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index bb610042a1ec..e7fb0295dbfc 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -979,4 +979,10 @@ static inline long ksys_rmdir(const char __user *pathname)
 	return do_rmdir(AT_FDCWD, pathname);
 }
 
+extern long do_mkdirat(int dfd, const char __user *pathname, umode_t mode);
+static inline long ksys_mkdir(const char __user *pathname, umode_t mode)
+{
+	return do_mkdirat(AT_FDCWD, pathname, mode);
+}
+
 #endif
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index 784576b633fd..d30db6bbf014 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -60,7 +60,7 @@ static void __init handle_initrd(void)
 	create_dev("/dev/root.old", Root_RAM0);
 	/* mount initrd on rootfs' /root */
 	mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY);
-	sys_mkdir("/old", 0700);
+	ksys_mkdir("/old", 0700);
 	ksys_chdir("/old");
 
 	/* try loading default modules from initrd */
diff --git a/init/initramfs.c b/init/initramfs.c
index 73bbb227f868..ca538a5f9fa9 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -352,7 +352,7 @@ static int __init do_name(void)
 			}
 		}
 	} else if (S_ISDIR(mode)) {
-		sys_mkdir(collected, mode);
+		ksys_mkdir(collected, mode);
 		sys_chown(collected, uid, gid);
 		sys_chmod(collected, mode);
 		dir_add(collected, mtime);
diff --git a/init/noinitramfs.c b/init/noinitramfs.c
index 267739d85179..a08a9d937e60 100644
--- a/init/noinitramfs.c
+++ b/init/noinitramfs.c
@@ -29,7 +29,7 @@ static int __init default_rootfs(void)
 {
 	int err;
 
-	err = sys_mkdir((const char __user __force *) "/dev", 0755);
+	err = ksys_mkdir((const char __user __force *) "/dev", 0755);
 	if (err < 0)
 		goto out;
 
@@ -39,7 +39,7 @@ static int __init default_rootfs(void)
 	if (err < 0)
 		goto out;
 
-	err = sys_mkdir((const char __user __force *) "/root", 0700);
+	err = ksys_mkdir((const char __user __force *) "/root", 0700);
 	if (err < 0)
 		goto out;
 
-- 
2.16.2

[RFC PATCH 28/35] syscalls: do not call sys_symlink{,at}() within the kernel

[Dominik Brodowski]

CC: Al Viro <viro@zeniv.linux.org.uk>
CC: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/internal.h            |  2 ++
 fs/namei.c               | 12 +++++++++---
 include/linux/syscalls.h |  8 ++++++++
 init/initramfs.c         |  2 +-
 4 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/fs/internal.h b/fs/internal.h
index 53846bd4d9d7..a3f04ca2a08b 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -58,6 +58,8 @@ extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
 long do_mkdirat(int dfd, const char __user *pathname, umode_t mode);
 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);
 
 /*
  * namespace.c
diff --git a/fs/namei.c b/fs/namei.c
index dcf506227509..e15da92209d5 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -4113,8 +4113,8 @@ int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)
 }
 EXPORT_SYMBOL(vfs_symlink);
 
-SYSCALL_DEFINE3(symlinkat, const char __user *, oldname,
-		int, newdfd, const char __user *, newname)
+long do_symlinkat(const char __user *oldname, int newdfd,
+		  const char __user *newname)
 {
 	int error;
 	struct filename *from;
@@ -4144,9 +4144,15 @@ SYSCALL_DEFINE3(symlinkat, const char __user *, oldname,
 	return error;
 }
 
+SYSCALL_DEFINE3(symlinkat, const char __user *, oldname,
+		int, newdfd, const char __user *, newname)
+{
+	return do_symlinkat(oldname, newdfd, newname);
+}
+
 SYSCALL_DEFINE2(symlink, const char __user *, oldname, const char __user *, newname)
 {
-	return sys_symlinkat(oldname, AT_FDCWD, newname);
+	return do_symlinkat(oldname, AT_FDCWD, newname);
 }
 
 /**
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index e7fb0295dbfc..178d1321a037 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -985,4 +985,12 @@ static inline long ksys_mkdir(const char __user *pathname, umode_t mode)
 	return do_mkdirat(AT_FDCWD, pathname, mode);
 }
 
+extern long do_symlinkat(const char __user *oldname, int newdfd,
+			 const char __user *newname);
+static inline long ksys_symlink(const char __user *oldname,
+				const char __user *newname)
+{
+	return do_symlinkat(oldname, AT_FDCWD, newname);
+}
+
 #endif
diff --git a/init/initramfs.c b/init/initramfs.c
index ca538a5f9fa9..cd9571a113b6 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -392,7 +392,7 @@ static int __init do_symlink(void)
 {
 	collected[N_ALIGN(name_len) + body_len] = '\0';
 	clean_path(collected, 0);
-	sys_symlink(collected + N_ALIGN(name_len), collected);
+	ksys_symlink(collected + N_ALIGN(name_len), collected);
 	sys_lchown(collected, uid, gid);
 	do_utime(collected, mtime);
 	state = SkipIt;
-- 
2.16.2

[RFC PATCH 29/35] syscalls: do not call sys_mknod{,at}() within the kernel

[Dominik Brodowski]

CC: Al Viro <viro@zeniv.linux.org.uk>
CC: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/internal.h            |  2 ++
 fs/namei.c               | 12 +++++++++---
 include/linux/syscalls.h |  8 ++++++++
 init/do_mounts.h         |  2 +-
 init/initramfs.c         |  2 +-
 init/noinitramfs.c       |  2 +-
 6 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/fs/internal.h b/fs/internal.h
index a3f04ca2a08b..4f0b67054c54 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -55,6 +55,8 @@ extern void __init chrdev_init(void);
 extern int user_path_mountpoint_at(int, const char __user *, unsigned int, struct path *);
 extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
 			   const char *, unsigned int, struct path *);
+long do_mknodat(int dfd, const char __user *filename, umode_t mode,
+		unsigned int dev);
 long do_mkdirat(int dfd, const char __user *pathname, umode_t mode);
 long do_rmdir(int dfd, const char __user *pathname);
 long do_unlinkat(int dfd, struct filename *name);
diff --git a/fs/namei.c b/fs/namei.c
index e15da92209d5..8459a18cdd18 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3728,8 +3728,8 @@ static int may_mknod(umode_t mode)
 	}
 }
 
-SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode,
-		unsigned, dev)
+long do_mknodat(int dfd, const char __user *filename, umode_t mode,
+		unsigned int dev)
 {
 	struct dentry *dentry;
 	struct path path;
@@ -3772,9 +3772,15 @@ SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode,
 	return error;
 }
 
+SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode,
+		unsigned int, dev)
+{
+	return do_mknodat(dfd, filename, mode, dev);
+}
+
 SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, dev)
 {
-	return sys_mknodat(AT_FDCWD, filename, mode, dev);
+	return do_mknodat(AT_FDCWD, filename, mode, dev);
 }
 
 int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 178d1321a037..617f72c0aae8 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -993,4 +993,12 @@ static inline long ksys_symlink(const char __user *oldname,
 	return do_symlinkat(oldname, AT_FDCWD, newname);
 }
 
+extern long do_mknodat(int dfd, const char __user *filename, umode_t mode,
+		       unsigned int dev);
+static inline long ksys_mknod(const char __user *filename, umode_t mode,
+			      unsigned int dev)
+{
+	return do_mknodat(AT_FDCWD, filename, mode, dev);
+}
+
 #endif
diff --git a/init/do_mounts.h b/init/do_mounts.h
index 401f90ee1eeb..0bb0806de4ce 100644
--- a/init/do_mounts.h
+++ b/init/do_mounts.h
@@ -17,7 +17,7 @@ extern int root_mountflags;
 static inline int create_dev(char *name, dev_t dev)
 {
 	ksys_unlink(name);
-	return sys_mknod(name, S_IFBLK|0600, new_encode_dev(dev));
+	return ksys_mknod(name, S_IFBLK|0600, new_encode_dev(dev));
 }
 
 static inline u32 bstat(char *name)
diff --git a/init/initramfs.c b/init/initramfs.c
index cd9571a113b6..2972ed0ab399 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -359,7 +359,7 @@ static int __init do_name(void)
 	} else if (S_ISBLK(mode) || S_ISCHR(mode) ||
 		   S_ISFIFO(mode) || S_ISSOCK(mode)) {
 		if (maybe_link() == 0) {
-			sys_mknod(collected, mode, rdev);
+			ksys_mknod(collected, mode, rdev);
 			sys_chown(collected, uid, gid);
 			sys_chmod(collected, mode);
 			do_utime(collected, mtime);
diff --git a/init/noinitramfs.c b/init/noinitramfs.c
index a08a9d937e60..f4bad8436c93 100644
--- a/init/noinitramfs.c
+++ b/init/noinitramfs.c
@@ -33,7 +33,7 @@ static int __init default_rootfs(void)
 	if (err < 0)
 		goto out;
 
-	err = sys_mknod((const char __user __force *) "/dev/console",
+	err = ksys_mknod((const char __user __force *) "/dev/console",
 			S_IFCHR | S_IRUSR | S_IWUSR,
 			new_encode_dev(MKDEV(5, 1)));
 	if (err < 0)
-- 
2.16.2

[RFC PATCH 30/35] syscalls: do not call sys_link{,at}() within the kernel

[Dominik Brodowski]

CC: Al Viro <viro@zeniv.linux.org.uk>
CC: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/internal.h            |  2 ++
 fs/namei.c               | 12 +++++++++---
 include/linux/syscalls.h |  8 ++++++++
 init/initramfs.c         |  2 +-
 4 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/fs/internal.h b/fs/internal.h
index 4f0b67054c54..91e6fc93fcb5 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -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
diff --git a/fs/namei.c b/fs/namei.c
index 8459a18cdd18..10148235829f 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -4250,8 +4250,8 @@ EXPORT_SYMBOL(vfs_link);
  * with linux 2.0, and to avoid hard-linking to directories
  * and other special files.  --ADM
  */
-SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
-		int, newdfd, const char __user *, newname, int, flags)
+int do_linkat(int olddfd, const char __user *oldname, int newdfd,
+	      const char __user *newname, int flags)
 {
 	struct dentry *new_dentry;
 	struct path old_path, new_path;
@@ -4315,9 +4315,15 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
 	return error;
 }
 
+SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
+		int, newdfd, const char __user *, newname, int, flags)
+{
+	return do_linkat(olddfd, oldname, newdfd, newname, flags);
+}
+
 SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname)
 {
-	return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
+	return do_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
 }
 
 /**
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 617f72c0aae8..27620caed7e4 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1001,4 +1001,12 @@ static inline long ksys_mknod(const char __user *filename, umode_t mode,
 	return do_mknodat(AT_FDCWD, filename, mode, dev);
 }
 
+extern int do_linkat(int olddfd, const char __user *oldname, int newdfd,
+		     const char __user *newname, int flags);
+static inline long ksys_link(const char __user *oldname,
+			     const char __user *newname)
+{
+	return do_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
+}
+
 #endif
diff --git a/init/initramfs.c b/init/initramfs.c
index 2972ed0ab399..5855ab632b4e 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -306,7 +306,7 @@ static int __init maybe_link(void)
 	if (nlink >= 2) {
 		char *old = find_link(major, minor, ino, mode, collected);
 		if (old)
-			return (sys_link(old, collected) < 0) ? -1 : 1;
+			return (ksys_link(old, collected) < 0) ? -1 : 1;
 	}
 	return 0;
 }
-- 
2.16.2

[RFC PATCH 31/35] syscalls: do not call sys_{f,}chmod{at,}() within the kernel

[Dominik Brodowski]

CC: Al Viro <viro@zeniv.linux.org.uk>
CC: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/internal.h            |  2 ++
 fs/open.c                | 17 ++++++++++++++---
 include/linux/syscalls.h |  7 +++++++
 init/initramfs.c         |  6 +++---
 4 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/fs/internal.h b/fs/internal.h
index 91e6fc93fcb5..2474bf460f96 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -119,6 +119,8 @@ extern struct file *do_filp_open(int dfd, struct filename *pathname,
 extern struct file *do_file_open_root(struct dentry *, struct vfsmount *,
 		const char *, const struct open_flags *);
 
+int do_fchmodat(int dfd, const char __user *filename, umode_t mode);
+
 extern int open_check_o_direct(struct file *f);
 extern int vfs_open(const struct path *, struct file *, const struct cred *);
 extern struct file *filp_clone_open(struct file *);
diff --git a/fs/open.c b/fs/open.c
index a19b8277c439..6037f2bf418c 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -551,7 +551,7 @@ static int chmod_common(const struct path *path, umode_t mode)
 	return error;
 }
 
-SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode)
+int ksys_fchmod(unsigned int fd, umode_t mode)
 {
 	struct fd f = fdget(fd);
 	int err = -EBADF;
@@ -564,7 +564,12 @@ SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode)
 	return err;
 }
 
-SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, umode_t, mode)
+SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode)
+{
+	return ksys_fchmod(fd, mode);
+}
+
+int do_fchmodat(int dfd, const char __user *filename, umode_t mode)
 {
 	struct path path;
 	int error;
@@ -582,9 +587,15 @@ SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, umode_t, mode
 	return error;
 }
 
+SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename,
+		umode_t, mode)
+{
+	return do_fchmodat(dfd, filename, mode);
+}
+
 SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode)
 {
-	return sys_fchmodat(AT_FDCWD, filename, mode);
+	return do_fchmodat(AT_FDCWD, filename, mode);
 }
 
 static int chown_common(const struct path *path, uid_t user, gid_t group)
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 27620caed7e4..87feef73c077 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -962,6 +962,7 @@ unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
 int ksys_chdir(const char __user *filename);
 int ksys_sync_file_range(int fd, loff_t offset, loff_t nbytes,
 			 unsigned int flags);
+int ksys_fchmod(unsigned int fd, umode_t mode);
 
 /*
  * The following kernel syscall equivalents are just wrappers to fs-internal
@@ -1009,4 +1010,10 @@ static inline long ksys_link(const char __user *oldname,
 	return do_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
 }
 
+extern int do_fchmodat(int dfd, const char __user *filename, umode_t mode);
+static inline int ksys_chmod(const char __user *filename, umode_t mode)
+{
+	return do_fchmodat(AT_FDCWD, filename, mode);
+}
+
 #endif
diff --git a/init/initramfs.c b/init/initramfs.c
index 5855ab632b4e..16c3c23076e2 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -344,7 +344,7 @@ static int __init do_name(void)
 
 			if (wfd >= 0) {
 				sys_fchown(wfd, uid, gid);
-				sys_fchmod(wfd, mode);
+				ksys_fchmod(wfd, mode);
 				if (body_len)
 					sys_ftruncate(wfd, body_len);
 				vcollected = kstrdup(collected, GFP_KERNEL);
@@ -354,14 +354,14 @@ static int __init do_name(void)
 	} else if (S_ISDIR(mode)) {
 		ksys_mkdir(collected, mode);
 		sys_chown(collected, uid, gid);
-		sys_chmod(collected, mode);
+		ksys_chmod(collected, mode);
 		dir_add(collected, mtime);
 	} else if (S_ISBLK(mode) || S_ISCHR(mode) ||
 		   S_ISFIFO(mode) || S_ISSOCK(mode)) {
 		if (maybe_link() == 0) {
 			ksys_mknod(collected, mode, rdev);
 			sys_chown(collected, uid, gid);
-			sys_chmod(collected, mode);
+			ksys_chmod(collected, mode);
 			do_utime(collected, mtime);
 		}
 	}
-- 
2.16.2

[RFC PATCH 32/35] syscalls: do not call sys_{f,}access{,at}() within the kernel

[Dominik Brodowski]

CC: Al Viro <viro@zeniv.linux.org.uk>
CC: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/internal.h            | 1 +
 fs/open.c                | 9 +++++++--
 include/linux/syscalls.h | 6 ++++++
 init/main.c              | 3 ++-
 4 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/fs/internal.h b/fs/internal.h
index 2474bf460f96..26f4f05b52ef 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -119,6 +119,7 @@ extern struct file *do_filp_open(int dfd, struct filename *pathname,
 extern struct file *do_file_open_root(struct dentry *, struct vfsmount *,
 		const char *, const struct open_flags *);
 
+long do_faccessat(int dfd, const char __user *filename, int mode);
 int do_fchmodat(int dfd, const char __user *filename, umode_t mode);
 
 extern int open_check_o_direct(struct file *f);
diff --git a/fs/open.c b/fs/open.c
index 6037f2bf418c..0fc8188be31a 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -350,7 +350,7 @@ SYSCALL_DEFINE4(fallocate, int, fd, int, mode, loff_t, offset, loff_t, len)
  * We do this by temporarily clearing all FS-related capabilities and
  * switching the fsuid/fsgid around to the real ones.
  */
-SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
+long do_faccessat(int dfd, const char __user *filename, int mode)
 {
 	const struct cred *old_cred;
 	struct cred *override_cred;
@@ -426,9 +426,14 @@ SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
 	return res;
 }
 
+SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
+{
+	return do_faccessat(dfd, filename, mode);
+}
+
 SYSCALL_DEFINE2(access, const char __user *, filename, int, mode)
 {
-	return sys_faccessat(AT_FDCWD, filename, mode);
+	return do_faccessat(AT_FDCWD, filename, mode);
 }
 
 int ksys_chdir(const char __user *filename)
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 87feef73c077..ac4ba9439e52 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1016,4 +1016,10 @@ static inline int ksys_chmod(const char __user *filename, umode_t mode)
 	return do_fchmodat(AT_FDCWD, filename, mode);
 }
 
+extern long do_faccessat(int dfd, const char __user *filename, int mode);
+static inline long ksys_access(const char __user *filename, int mode)
+{
+	return do_faccessat(AT_FDCWD, filename, mode);
+}
+
 #endif
diff --git a/init/main.c b/init/main.c
index b8649d1466e1..d0ded4322c6b 100644
--- a/init/main.c
+++ b/init/main.c
@@ -1087,7 +1087,8 @@ static noinline void __init kernel_init_freeable(void)
 	if (!ramdisk_execute_command)
 		ramdisk_execute_command = "/init";
 
-	if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
+	if (ksys_access((const char __user *)
+			ramdisk_execute_command, 0) != 0) {
 		ramdisk_execute_command = NULL;
 		prepare_namespace();
 	}
-- 
2.16.2

[RFC PATCH 33/35] syscalls: do not call sys_ftruncate() within the kernel

[Dominik Brodowski]

CC: Al Viro <viro@zeniv.linux.org.uk>
CC: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 arch/mips/kernel/linux32.c      | 2 +-
 arch/parisc/kernel/sys_parisc.c | 4 ++--
 arch/powerpc/kernel/sys_ppc32.c | 2 +-
 arch/s390/kernel/compat_linux.c | 2 +-
 arch/sparc/kernel/sys_sparc32.c | 2 +-
 arch/tile/kernel/compat.c       | 2 +-
 arch/x86/ia32/sys_ia32.c        | 2 +-
 fs/internal.h                   | 1 +
 fs/open.c                       | 2 +-
 include/linux/syscalls.h        | 6 ++++++
 init/initramfs.c                | 2 +-
 11 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/arch/mips/kernel/linux32.c b/arch/mips/kernel/linux32.c
index db895771ab06..740eee40c668 100644
--- a/arch/mips/kernel/linux32.c
+++ b/arch/mips/kernel/linux32.c
@@ -88,7 +88,7 @@ SYSCALL_DEFINE4(32_truncate64, const char __user *, path,
 SYSCALL_DEFINE4(32_ftruncate64, unsigned long, fd, unsigned long, __dummy,
 	unsigned long, a2, unsigned long, a3)
 {
-	return sys_ftruncate(fd, merge_64(a2, a3));
+	return ksys_ftruncate(fd, merge_64(a2, a3));
 }
 
 SYSCALL_DEFINE5(32_llseek, unsigned int, fd, unsigned int, offset_high,
diff --git a/arch/parisc/kernel/sys_parisc.c b/arch/parisc/kernel/sys_parisc.c
index 0b0e1cfb4bd9..59b315d6d194 100644
--- a/arch/parisc/kernel/sys_parisc.c
+++ b/arch/parisc/kernel/sys_parisc.c
@@ -298,7 +298,7 @@ asmlinkage long parisc_truncate64(const char __user * path,
 asmlinkage long parisc_ftruncate64(unsigned int fd,
 					unsigned int high, unsigned int low)
 {
-	return sys_ftruncate(fd, (long)high << 32 | low);
+	return ksys_ftruncate(fd, (long)high << 32 | low);
 }
 
 /* stubs for the benefit of the syscall_table since truncate64 and truncate 
@@ -309,7 +309,7 @@ asmlinkage long sys_truncate64(const char __user * path, unsigned long length)
 }
 asmlinkage long sys_ftruncate64(unsigned int fd, unsigned long length)
 {
-	return sys_ftruncate(fd, length);
+	return ksys_ftruncate(fd, length);
 }
 asmlinkage long sys_fcntl64(unsigned int fd, unsigned int cmd, unsigned long arg)
 {
diff --git a/arch/powerpc/kernel/sys_ppc32.c b/arch/powerpc/kernel/sys_ppc32.c
index 3871aa9267e6..f41cb34c84c8 100644
--- a/arch/powerpc/kernel/sys_ppc32.c
+++ b/arch/powerpc/kernel/sys_ppc32.c
@@ -107,7 +107,7 @@ asmlinkage long compat_sys_fallocate(int fd, int mode, u32 offhi, u32 offlo,
 asmlinkage int compat_sys_ftruncate64(unsigned int fd, u32 reg4, unsigned long high,
 				 unsigned long low)
 {
-	return sys_ftruncate(fd, (high << 32) | low);
+	return ksys_ftruncate(fd, (high << 32) | low);
 }
 
 long ppc32_fadvise64(int fd, u32 unused, u32 offset_high, u32 offset_low,
diff --git a/arch/s390/kernel/compat_linux.c b/arch/s390/kernel/compat_linux.c
index 82e99bf3b00e..572349852b75 100644
--- a/arch/s390/kernel/compat_linux.c
+++ b/arch/s390/kernel/compat_linux.c
@@ -307,7 +307,7 @@ COMPAT_SYSCALL_DEFINE3(s390_truncate64, const char __user *, path, u32, high, u3
 
 COMPAT_SYSCALL_DEFINE3(s390_ftruncate64, unsigned int, fd, u32, high, u32, low)
 {
-	return sys_ftruncate(fd, (unsigned long)high << 32 | low);
+	return ksys_ftruncate(fd, (unsigned long)high << 32 | low);
 }
 
 COMPAT_SYSCALL_DEFINE5(s390_pread64, unsigned int, fd, char __user *, ubuf,
diff --git a/arch/sparc/kernel/sys_sparc32.c b/arch/sparc/kernel/sys_sparc32.c
index c56f43893283..f8d357540748 100644
--- a/arch/sparc/kernel/sys_sparc32.c
+++ b/arch/sparc/kernel/sys_sparc32.c
@@ -65,7 +65,7 @@ asmlinkage long sys32_ftruncate64(unsigned int fd, unsigned long high, unsigned
 	if ((int)high < 0)
 		return -EINVAL;
 	else
-		return sys_ftruncate(fd, (high << 32) | low);
+		return ksys_ftruncate(fd, (high << 32) | low);
 }
 
 static int cp_compat_stat64(struct kstat *stat,
diff --git a/arch/tile/kernel/compat.c b/arch/tile/kernel/compat.c
index 24414d4d592d..d1fff2b0dade 100644
--- a/arch/tile/kernel/compat.c
+++ b/arch/tile/kernel/compat.c
@@ -48,7 +48,7 @@ COMPAT_SYSCALL_DEFINE4(truncate64, char __user *, filename, u32, dummy,
 COMPAT_SYSCALL_DEFINE4(ftruncate64, unsigned int, fd, u32, dummy,
 		       SYSCALL_PAIR(length))
 {
-	return sys_ftruncate(fd, ((loff_t)length_hi << 32) | length_lo);
+	return ksys_ftruncate(fd, ((loff_t)length_hi << 32) | length_lo);
 }
 
 COMPAT_SYSCALL_DEFINE6(pread64, unsigned int, fd, char __user *, ubuf,
diff --git a/arch/x86/ia32/sys_ia32.c b/arch/x86/ia32/sys_ia32.c
index 42badedd5ebc..3bac9e81a363 100644
--- a/arch/x86/ia32/sys_ia32.c
+++ b/arch/x86/ia32/sys_ia32.c
@@ -61,7 +61,7 @@ asmlinkage long sys32_truncate64(const char __user *filename,
 asmlinkage long sys32_ftruncate64(unsigned int fd, unsigned long offset_low,
 				  unsigned long offset_high)
 {
-       return sys_ftruncate(fd, ((loff_t) offset_high << 32) | offset_low);
+	return ksys_ftruncate(fd, ((loff_t) offset_high << 32) | offset_low);
 }
 
 /*
diff --git a/fs/internal.h b/fs/internal.h
index 26f4f05b52ef..49e0bf51576c 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -119,6 +119,7 @@ extern struct file *do_filp_open(int dfd, struct filename *pathname,
 extern struct file *do_file_open_root(struct dentry *, struct vfsmount *,
 		const char *, const struct open_flags *);
 
+long do_sys_ftruncate(unsigned int fd, loff_t length, int small);
 long do_faccessat(int dfd, const char __user *filename, int mode);
 int do_fchmodat(int dfd, const char __user *filename, umode_t mode);
 
diff --git a/fs/open.c b/fs/open.c
index 0fc8188be31a..77a4494f605d 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -162,7 +162,7 @@ COMPAT_SYSCALL_DEFINE2(truncate, const char __user *, path, compat_off_t, length
 }
 #endif
 
-static long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
+long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
 {
 	struct inode *inode;
 	struct dentry *dentry;
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index ac4ba9439e52..ebb8eb458415 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1022,4 +1022,10 @@ static inline long ksys_access(const char __user *filename, int mode)
 	return do_faccessat(AT_FDCWD, filename, mode);
 }
 
+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
diff --git a/init/initramfs.c b/init/initramfs.c
index 16c3c23076e2..237a975738ba 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -346,7 +346,7 @@ static int __init do_name(void)
 				sys_fchown(wfd, uid, gid);
 				ksys_fchmod(wfd, mode);
 				if (body_len)
-					sys_ftruncate(wfd, body_len);
+					ksys_ftruncate(wfd, body_len);
 				vcollected = kstrdup(collected, GFP_KERNEL);
 				state = CopyFile;
 			}
-- 
2.16.2

[RFC PATCH 34/35] syscalls: do not call sys_{,l,f}chown() within the kernel

[Dominik Brodowski]

CC: Al Viro <viro@zeniv.linux.org.uk>
CC: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 arch/s390/kernel/compat_linux.c |  6 +++---
 fs/internal.h                   |  2 ++
 fs/open.c                       | 23 +++++++++++++++++------
 include/linux/syscalls.h        | 14 ++++++++++++++
 init/initramfs.c                |  8 ++++----
 kernel/uid16.c                  |  6 +++---
 6 files changed, 43 insertions(+), 16 deletions(-)

diff --git a/arch/s390/kernel/compat_linux.c b/arch/s390/kernel/compat_linux.c
index 572349852b75..a1fa8051fe63 100644
--- a/arch/s390/kernel/compat_linux.c
+++ b/arch/s390/kernel/compat_linux.c
@@ -89,18 +89,18 @@
 COMPAT_SYSCALL_DEFINE3(s390_chown16, const char __user *, filename,
 		       u16, user, u16, group)
 {
-	return sys_chown(filename, low2highuid(user), low2highgid(group));
+	return ksys_chown(filename, low2highuid(user), low2highgid(group));
 }
 
 COMPAT_SYSCALL_DEFINE3(s390_lchown16, const char __user *,
 		       filename, u16, user, u16, group)
 {
-	return sys_lchown(filename, low2highuid(user), low2highgid(group));
+	return ksys_lchown(filename, low2highuid(user), low2highgid(group));
 }
 
 COMPAT_SYSCALL_DEFINE3(s390_fchown16, unsigned int, fd, u16, user, u16, group)
 {
-	return sys_fchown(fd, low2highuid(user), low2highgid(group));
+	return ksys_fchown(fd, low2highuid(user), low2highgid(group));
 }
 
 COMPAT_SYSCALL_DEFINE2(s390_setregid16, u16, rgid, u16, egid)
diff --git a/fs/internal.h b/fs/internal.h
index 49e0bf51576c..980d005b21b4 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -122,6 +122,8 @@ extern struct file *do_file_open_root(struct dentry *, struct vfsmount *,
 long do_sys_ftruncate(unsigned int fd, loff_t length, int small);
 long do_faccessat(int dfd, const char __user *filename, int mode);
 int do_fchmodat(int dfd, const char __user *filename, umode_t mode);
+int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,
+		int flag);
 
 extern int open_check_o_direct(struct file *f);
 extern int vfs_open(const struct path *, struct file *, const struct cred *);
diff --git a/fs/open.c b/fs/open.c
index 77a4494f605d..b3f3b2cd9f19 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -645,8 +645,8 @@ static int chown_common(const struct path *path, uid_t user, gid_t group)
 	return error;
 }
 
-SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
-		gid_t, group, int, flag)
+int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,
+		int flag)
 {
 	struct path path;
 	int error = -EINVAL;
@@ -677,18 +677,24 @@ SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
 	return error;
 }
 
+SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
+		gid_t, group, int, flag)
+{
+	return do_fchownat(dfd, filename, user, group, flag);
+}
+
 SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
 {
-	return sys_fchownat(AT_FDCWD, filename, user, group, 0);
+	return do_fchownat(AT_FDCWD, filename, user, group, 0);
 }
 
 SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group)
 {
-	return sys_fchownat(AT_FDCWD, filename, user, group,
-			    AT_SYMLINK_NOFOLLOW);
+	return do_fchownat(AT_FDCWD, filename, user, group,
+			   AT_SYMLINK_NOFOLLOW);
 }
 
-SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
+int ksys_fchown(unsigned int fd, uid_t user, gid_t group)
 {
 	struct fd f = fdget(fd);
 	int error = -EBADF;
@@ -708,6 +714,11 @@ SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
 	return error;
 }
 
+SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
+{
+	return ksys_fchown(fd, user, group);
+}
+
 int open_check_o_direct(struct file *f)
 {
 	/* NB: we're sure to have correct a_ops only after f_op->open */
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index ebb8eb458415..fd1dcdc7fb1b 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -963,6 +963,7 @@ int ksys_chdir(const char __user *filename);
 int ksys_sync_file_range(int fd, loff_t offset, loff_t nbytes,
 			 unsigned int flags);
 int ksys_fchmod(unsigned int fd, umode_t mode);
+int ksys_fchown(unsigned int fd, uid_t user, gid_t group);
 
 /*
  * The following kernel syscall equivalents are just wrappers to fs-internal
@@ -1028,4 +1029,17 @@ static inline long ksys_ftruncate(unsigned int fd, unsigned long length)
 	return do_sys_ftruncate(fd, length, 1);
 }
 
+extern int do_fchownat(int dfd, const char __user *filename, uid_t user,
+		       gid_t group, int flag);
+static inline long ksys_chown(const char __user *filename, uid_t user,
+			      gid_t group)
+{
+	return do_fchownat(AT_FDCWD, filename, user, group, 0);
+}
+static inline long ksys_lchown(const char __user *filename, uid_t user,
+			       gid_t group)
+{
+	return do_fchownat(AT_FDCWD, filename, user, group,
+			     AT_SYMLINK_NOFOLLOW);
+}
 #endif
diff --git a/init/initramfs.c b/init/initramfs.c
index 237a975738ba..0d3b001b0dc5 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -343,7 +343,7 @@ static int __init do_name(void)
 			wfd = sys_open(collected, openflags, mode);
 
 			if (wfd >= 0) {
-				sys_fchown(wfd, uid, gid);
+				ksys_fchown(wfd, uid, gid);
 				ksys_fchmod(wfd, mode);
 				if (body_len)
 					ksys_ftruncate(wfd, body_len);
@@ -353,14 +353,14 @@ static int __init do_name(void)
 		}
 	} else if (S_ISDIR(mode)) {
 		ksys_mkdir(collected, mode);
-		sys_chown(collected, uid, gid);
+		ksys_chown(collected, uid, gid);
 		ksys_chmod(collected, mode);
 		dir_add(collected, mtime);
 	} else if (S_ISBLK(mode) || S_ISCHR(mode) ||
 		   S_ISFIFO(mode) || S_ISSOCK(mode)) {
 		if (maybe_link() == 0) {
 			ksys_mknod(collected, mode, rdev);
-			sys_chown(collected, uid, gid);
+			ksys_chown(collected, uid, gid);
 			ksys_chmod(collected, mode);
 			do_utime(collected, mtime);
 		}
@@ -393,7 +393,7 @@ static int __init do_symlink(void)
 	collected[N_ALIGN(name_len) + body_len] = '\0';
 	clean_path(collected, 0);
 	ksys_symlink(collected + N_ALIGN(name_len), collected);
-	sys_lchown(collected, uid, gid);
+	ksys_lchown(collected, uid, gid);
 	do_utime(collected, mtime);
 	state = SkipIt;
 	next_state = Reset;
diff --git a/kernel/uid16.c b/kernel/uid16.c
index ef1da2a5f9bd..ea3cf87ff000 100644
--- a/kernel/uid16.c
+++ b/kernel/uid16.c
@@ -20,17 +20,17 @@
 
 SYSCALL_DEFINE3(chown16, const char __user *, filename, old_uid_t, user, old_gid_t, group)
 {
-	return sys_chown(filename, low2highuid(user), low2highgid(group));
+	return ksys_chown(filename, low2highuid(user), low2highgid(group));
 }
 
 SYSCALL_DEFINE3(lchown16, const char __user *, filename, old_uid_t, user, old_gid_t, group)
 {
-	return sys_lchown(filename, low2highuid(user), low2highgid(group));
+	return ksys_lchown(filename, low2highuid(user), low2highgid(group));
 }
 
 SYSCALL_DEFINE3(fchown16, unsigned int, fd, old_uid_t, user, old_gid_t, group)
 {
-	return sys_fchown(fd, low2highuid(user), low2highgid(group));
+	return ksys_fchown(fd, low2highuid(user), low2highgid(group));
 }
 
 SYSCALL_DEFINE2(setregid16, old_gid_t, rgid, old_gid_t, egid)
-- 
2.16.2

[RFC PATCH 35/35] syscalls: do not call sys_close() within the kernel

[Dominik Brodowski]

The few places which checked the return value did not care about the return
value re-writing in sys_close(), so simply use a wrapper to __close_fd().

CC: Al Viro <viro@zeniv.linux.org.uk>
CC: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
 fs/autofs4/dev-ioctl.c   | 2 +-
 fs/binfmt_misc.c         | 2 +-
 fs/file.c                | 1 +
 fs/open.c                | 2 +-
 include/linux/syscalls.h | 6 ++++++
 init/do_mounts.c         | 4 ++--
 init/do_mounts_initrd.c  | 2 +-
 init/do_mounts_md.c      | 8 ++++----
 init/do_mounts_rd.c      | 6 +++---
 init/initramfs.c         | 8 ++++----
 10 files changed, 24 insertions(+), 17 deletions(-)

diff --git a/fs/autofs4/dev-ioctl.c b/fs/autofs4/dev-ioctl.c
index b7c816f39404..26f6b4f41ce6 100644
--- a/fs/autofs4/dev-ioctl.c
+++ b/fs/autofs4/dev-ioctl.c
@@ -310,7 +310,7 @@ static int autofs_dev_ioctl_closemount(struct file *fp,
 				       struct autofs_sb_info *sbi,
 				       struct autofs_dev_ioctl *param)
 {
-	return sys_close(param->ioctlfd);
+	return ksys_close(param->ioctlfd);
 }
 
 /*
diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
index a7c5a9861bef..a41b48f82a70 100644
--- a/fs/binfmt_misc.c
+++ b/fs/binfmt_misc.c
@@ -241,7 +241,7 @@ static int load_misc_binary(struct linux_binprm *bprm)
 	return retval;
 error:
 	if (fd_binary > 0)
-		sys_close(fd_binary);
+		ksys_close(fd_binary);
 	bprm->interp_flags = 0;
 	bprm->interp_data = 0;
 	goto ret;
diff --git a/fs/file.c b/fs/file.c
index d304004f0b65..7ffd6e9d103d 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -638,6 +638,7 @@ int __close_fd(struct files_struct *files, unsigned fd)
 	spin_unlock(&files->file_lock);
 	return -EBADF;
 }
+EXPORT_SYMBOL(__close_fd); /* for ksys_close() */
 
 void do_close_on_exec(struct files_struct *files)
 {
diff --git a/fs/open.c b/fs/open.c
index b3f3b2cd9f19..aab4ad7d9c9a 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -1200,7 +1200,7 @@ SYSCALL_DEFINE1(close, unsigned int, fd)
 
 	return retval;
 }
-EXPORT_SYMBOL(sys_close);
+
 
 /*
  * This routine simulates a hangup on the tty, to arrange that users
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index fd1dcdc7fb1b..dda95f614916 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1042,4 +1042,10 @@ static inline long ksys_lchown(const char __user *filename, uid_t user,
 	return do_fchownat(AT_FDCWD, filename, user, group,
 			     AT_SYMLINK_NOFOLLOW);
 }
+
+extern int __close_fd(struct files_struct *files, unsigned int fd);
+static inline int ksys_close(unsigned int fd)
+{
+	return __close_fd(current->files, fd);
+}
 #endif
diff --git a/init/do_mounts.c b/init/do_mounts.c
index 89f18985fa90..a28dd42d1f84 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -492,7 +492,7 @@ void __init change_floppy(char *fmt, ...)
 	fd = sys_open("/dev/root", O_RDWR | O_NDELAY, 0);
 	if (fd >= 0) {
 		sys_ioctl(fd, FDEJECT, 0);
-		sys_close(fd);
+		ksys_close(fd);
 	}
 	printk(KERN_NOTICE "VFS: Insert %s and press ENTER\n", buf);
 	fd = sys_open("/dev/console", O_RDWR, 0);
@@ -503,7 +503,7 @@ void __init change_floppy(char *fmt, ...)
 		sys_read(fd, &c, 1);
 		termios.c_lflag |= ICANON;
 		sys_ioctl(fd, TCSETSF, (long)&termios);
-		sys_close(fd);
+		ksys_close(fd);
 	}
 }
 #endif
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index d30db6bbf014..50decd9999b7 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -111,7 +111,7 @@ static void __init handle_initrd(void)
 			error = fd;
 		} else {
 			error = sys_ioctl(fd, BLKFLSBUF, 0);
-			sys_close(fd);
+			ksys_close(fd);
 		}
 		printk(!error ? "okay\n" : "failed\n");
 	}
diff --git a/init/do_mounts_md.c b/init/do_mounts_md.c
index 3f733c760a8c..ebd4013d589e 100644
--- a/init/do_mounts_md.c
+++ b/init/do_mounts_md.c
@@ -191,7 +191,7 @@ static void __init md_setup_drive(void)
 			printk(KERN_WARNING
 			       "md: Ignoring md=%d, already autodetected. (Use raid=noautodetect)\n",
 			       minor);
-			sys_close(fd);
+			ksys_close(fd);
 			continue;
 		}
 
@@ -243,11 +243,11 @@ static void __init md_setup_drive(void)
 			 * boot a kernel with devfs compiled in from partitioned md
 			 * array without it
 			 */
-			sys_close(fd);
+			ksys_close(fd);
 			fd = sys_open(name, 0, 0);
 			sys_ioctl(fd, BLKRRPART, 0);
 		}
-		sys_close(fd);
+		ksys_close(fd);
 	}
 }
 
@@ -297,7 +297,7 @@ static void __init autodetect_raid(void)
 	fd = sys_open("/dev/md0", 0, 0);
 	if (fd >= 0) {
 		sys_ioctl(fd, RAID_AUTORUN, raid_autopart);
-		sys_close(fd);
+		ksys_close(fd);
 	}
 }
 
diff --git a/init/do_mounts_rd.c b/init/do_mounts_rd.c
index 5b69056f610a..f1aa341862d3 100644
--- a/init/do_mounts_rd.c
+++ b/init/do_mounts_rd.c
@@ -257,7 +257,7 @@ int __init rd_load_image(char *from)
 		if (i && (i % devblocks == 0)) {
 			printk("done disk #%d.\n", disk++);
 			rotate = 0;
-			if (sys_close(in_fd)) {
+			if (ksys_close(in_fd)) {
 				printk("Error closing the disk.\n");
 				goto noclose_input;
 			}
@@ -283,9 +283,9 @@ int __init rd_load_image(char *from)
 successful_load:
 	res = 1;
 done:
-	sys_close(in_fd);
+	ksys_close(in_fd);
 noclose_input:
-	sys_close(out_fd);
+	ksys_close(out_fd);
 out:
 	kfree(buf);
 	ksys_unlink("/dev/ram");
diff --git a/init/initramfs.c b/init/initramfs.c
index 0d3b001b0dc5..ce2bcad97cdf 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -373,7 +373,7 @@ static int __init do_copy(void)
 	if (byte_count >= body_len) {
 		if (xwrite(wfd, victim, body_len) != body_len)
 			error("write error");
-		sys_close(wfd);
+		ksys_close(wfd);
 		do_utime(vcollected, mtime);
 		kfree(vcollected);
 		eat(body_len);
@@ -574,7 +574,7 @@ static void __init clean_rootfs(void)
 	buf = kzalloc(BUF_SIZE, GFP_KERNEL);
 	WARN_ON(!buf);
 	if (!buf) {
-		sys_close(fd);
+		ksys_close(fd);
 		return;
 	}
 
@@ -602,7 +602,7 @@ static void __init clean_rootfs(void)
 		num = sys_getdents64(fd, dirp, BUF_SIZE);
 	}
 
-	sys_close(fd);
+	ksys_close(fd);
 	kfree(buf);
 }
 #endif
@@ -639,7 +639,7 @@ static int __init populate_rootfs(void)
 				pr_err("/initrd.image: incomplete write (%zd != %ld)\n",
 				       written, initrd_end - initrd_start);
 
-			sys_close(fd);
+			ksys_close(fd);
 			free_initrd();
 		}
 	done:
-- 
2.16.2

Re: [RFC PATCH 25/35] hostfs: rename do_rmdir() to hostfs_do_rmdir()

[Richard Weinberger]

Am Sonntag, 11. März 2018, 11:55:47 CET schrieb Dominik Brodowski:
> do_rmdir() is used in the VFS layer at fs/namei.c, so use a different
> name in hostfs.
> 
> CC: Jeff Dike <jdike@addtoit.com>
> CC: Richard Weinberger <richard@nod.at>
> CC: user-mode-linux-devel@lists.sourceforge.net
> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

Acked-by: Richard Weinberger <richard@nod.at>

Thanks,
//richard

Re: [RFC PATCH 25/35] hostfs: rename do_rmdir() to hostfs_do_rmdir()

[Richard Weinberger]

Am Sonntag, 11. M�rz 2018, 11:55:47 CET schrieb Dominik Brodowski:
> do_rmdir() is used in the VFS layer at fs/namei.c, so use a different
> name in hostfs.
> 
> CC: Jeff Dike <jdike@addtoit.com>
> CC: Richard Weinberger <richard@nod.at>
> CC: user-mode-linux-devel@lists.sourceforge.net
> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

Acked-by: Richard Weinberger <richard@nod.at>

Thanks,
//richard

Re: [RFC PATCH 13/35] syscalls: do not call sys_ioperm() within the kernel

[Andy Lutomirski]

On Sun, Mar 11, 2018 at 10:55 AM, Dominik Brodowski
<linux@dominikbrodowski.net> wrote:
> While at it, use SYSCALL_DEFINE3() instead of a hand-crafted syscall
> definition.

Great!

>  static void complete_change_console(struct vc_data *vc);
> @@ -420,12 +420,12 @@ int vt_ioctl(struct tty_struct *tty,
>                         ret = -EINVAL;
>                         break;
>                 }
> -               ret = sys_ioperm(arg, 1, (cmd == KDADDIO)) ? -ENXIO : 0;
> +               ret = ksys_ioperm(arg, 1, (cmd == KDADDIO)) ? -ENXIO : 0;
>                 break;
>
>         case KDENABIO:
>         case KDDISABIO:
> -               ret = sys_ioperm(GPFIRST, GPNUM,
> +               ret = ksys_ioperm(GPFIRST, GPNUM,
>                                   (cmd == KDENABIO)) ? -ENXIO : 0;
>                 break;
>  #endif

I wonder if we can just delete this code.

Re: [RFC PATCH 01/35] syscalls: define goal to not call sys_xyzzy() from within the kernel

[Andy Lutomirski]

On Sun, Mar 11, 2018 at 10:55 AM, Dominik Brodowski
<linux@dominikbrodowski.net> wrote:
> The syscall entry points to the kernel defined by SYSCALL_DEFINEx()
> and COMPAT_SYSCALL_DEFINEx() should only be called from userspace
> through kernel entry points, but not from the kernel itself. This
> will allow cleanups and optimizations to the entry paths *and* to
> the parts of the kernel code which currently need to pretend to be
> userspace in order to make use of syscalls.
>

> +
> +/*
> + * The kernel should not use call syscalls (i.e., sys_xyzyyz()) directly.
> + * Instead, use one of the following functions which work equivalent to
> + * the syscall they are named for.

"Instead, use one of the functions which work equivalently, e.g. do_xysyyz()"

Re: [RFC PATCH 00/35] remove in-kernel syscall invocations

[Linus Torvalds]

On Sun, Mar 11, 2018 at 3:55 AM, Dominik Brodowski
<linux@dominikbrodowski.net> wrote:
> Here is a first set of patches which reduce the number of syscall invocations
> from within the kernel.

This all looks ok to me. I think there may be some room for cleanup
and bikeshedding later (the "ksys_mmap_pgoff()" name made me go "that
sounds more like a real helper than a kernel syscall", for example),
but on the whole I think it's best to start with this kind of fairly
direct translation.

In fact, because it all looks *so* mechanical, I'd even be willing to
just pull this into 4.16, if that makes the real work that this
depends on easier?

Anyway, ack from me, qith the only question being how you want to
handle the patches. Direct pull request to me, go through the -mm
tree, or just keep them in your own git tree and then build upon it
and send it all later?

                       Linus

Re: [RFC PATCH 01/35] syscalls: define goal to not call sys_xyzzy() from within the kernel

[Ingo Molnar]

* Andy Lutomirski <luto@kernel.org> wrote:

> On Sun, Mar 11, 2018 at 10:55 AM, Dominik Brodowski
> <linux@dominikbrodowski.net> wrote:
> > The syscall entry points to the kernel defined by SYSCALL_DEFINEx()
> > and COMPAT_SYSCALL_DEFINEx() should only be called from userspace
> > through kernel entry points, but not from the kernel itself. This
> > will allow cleanups and optimizations to the entry paths *and* to
> > the parts of the kernel code which currently need to pretend to be
> > userspace in order to make use of syscalls.
> >
> 
> > +
> > +/*
> > + * The kernel should not use call syscalls (i.e., sys_xyzyyz()) directly.
> > + * Instead, use one of the following functions which work equivalent to
> > + * the syscall they are named for.
> 
> "Instead, use one of the functions which work equivalently, e.g. do_xysyyz()"

The previous sentence has a typo as well, should be:

  * Kernel code should not call syscalls (i.e., sys_xyzyyz()) directly.

or so.

Thanks,

	Ingo

Re: [RFC PATCH 02/35] syscalls: use kernel_wait4() instead of sys_wait4()

[Ingo Molnar]

* Dominik Brodowski <linux@dominikbrodowski.net> wrote:

> All call sites of sys_wait4() set *rusage to NULL. Therefore, there is
> no need for the copy_to_user() handling of *rusage, and we can use
> kernel_wait4() directly.
> 
> CC: Luis R. Rodriguez <mcgrof@kernel.org>
> CC: Al Viro <viro@zeniv.linux.org.uk>
> CC: Andrew Morton <akpm@linux-foundation.org>

Could you please fix the Cc: tags in all your patches, the canonical form is:

 s/CC:/Cc:

Thanks,

	Ingo

Re: [RFC PATCH 00/35] remove in-kernel syscall invocations

[Ingo Molnar]

* Dominik Brodowski <linux@dominikbrodowski.net> wrote:

> I'm a bit more unsure about these remaining patches. They use inline stubs
> named ksys_xyzzy() which (mostly) call fs-internal functions. Another
> alternative would be to define these in fs/*, but then we'd get more and
> more indirections.
> 
> 	syscalls: do not call sys_unlink() within the kernel
> 	syscalls: do not call sys_rmdir() within the kernel
> 	syscalls: do not call sys_mkdir{,at}() within the kernel
> 	syscalls: do not call sys_symlink{,at}() within the kernel
> 	syscalls: do not call sys_mknod{,at}() within the kernel
> 	syscalls: do not call sys_link{,at}() within the kernel
> 	syscalls: do not call sys_{f,}chmod{at,}() within the kernel
> 	syscalls: do not call sys_{f,}access{,at}() within the kernel
> 	syscalls: do not call sys_ftruncate() within the kernel
> 	syscalls: do not call sys_{,l,f}chown() within the kernel
> 	syscalls: do not call sys_close() within the kernel

>  72 files changed, 572 insertions(+), 274 deletions(-)

Just curious, have you done a before/after vmlinux /usr/bin/size comparison?
How do these changes impact generated code?

My expectation would be for there to be a noticeable decrease in text size.

Thanks,

	Ingo

Re: [RFC PATCH 35/35] syscalls: do not call sys_close() within the kernel

[Ingo Molnar]

* Dominik Brodowski <linux@dominikbrodowski.net> wrote:

> --- a/fs/open.c
> +++ b/fs/open.c
> @@ -1200,7 +1200,7 @@ SYSCALL_DEFINE1(close, unsigned int, fd)
>  
>  	return retval;
>  }
> -EXPORT_SYMBOL(sys_close);
> +
>  
>  /*

Nit: this introduces a stray newline.

> --- a/include/linux/syscalls.h
> +++ b/include/linux/syscalls.h
> @@ -1042,4 +1042,10 @@ static inline long ksys_lchown(const char __user *filename, uid_t user,
>  	return do_fchownat(AT_FDCWD, filename, user, group,
>  			     AT_SYMLINK_NOFOLLOW);
>  }
> +
> +extern int __close_fd(struct files_struct *files, unsigned int fd);
> +static inline int ksys_close(unsigned int fd)
> +{
> +	return __close_fd(current->files, fd);
> +}

Would be nice to reuse that stray newline after the __close_fd() prototype for the 
canonical stylistic separation of declarations from definitions.

It would also be very nice to add a short comment before ksys_close() that 
explains how it differs from sys_close(). This should reduce the amount of 
cargo-cult copying of existing ksys_close()/sys_close() patterns.

Thanks,

	Ingo

Re: [RFC PATCH 04/35] syscalls: do not call sys_getpgid() within the kernel

[Christoph Hellwig]

The subject (and lack of description) for this and the following patches
is rather confusing.

I'd expect something like:

---- snip ----
Subject: kernel: add a do_getpgid helper

And use it to avoid an in-kernel sys_getpgid call.

---- snip ----

instead.

On Sun, Mar 11, 2018 at 11:55:26AM +0100, Dominik Brodowski wrote:
> CC: Al Viro <viro@zeniv.linux.org.uk>
> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
> ---
>  kernel/sys.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/sys.c b/kernel/sys.c
> index f2289de20e19..ebb138b841c8 100644
> --- a/kernel/sys.c
> +++ b/kernel/sys.c
> @@ -1027,7 +1027,7 @@ SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid)
>  	return err;
>  }
>  
> -SYSCALL_DEFINE1(getpgid, pid_t, pid)
> +static int do_getpgid(pid_t pid)
>  {
>  	struct task_struct *p;
>  	struct pid *grp;
> @@ -1055,11 +1055,16 @@ SYSCALL_DEFINE1(getpgid, pid_t, pid)
>  	return retval;
>  }
>  
> +SYSCALL_DEFINE1(getpgid, pid_t, pid)
> +{
> +	return do_getpgid(pid);
> +}
> +
>  #ifdef __ARCH_WANT_SYS_GETPGRP
>  
>  SYSCALL_DEFINE0(getpgrp)
>  {
> -	return sys_getpgid(0);
> +	return do_getpgid(0);
>  }
>  
>  #endif
> -- 
> 2.16.2
> 
---end quoted text---

Re: [RFC PATCH 01/35] syscalls: define goal to not call sys_xyzzy() from within the kernel

[Dominik Brodowski]

On Sun, Mar 11, 2018 at 03:24:01PM +0000, Andy Lutomirski wrote:
> On Sun, Mar 11, 2018 at 10:55 AM, Dominik Brodowski
> <linux@dominikbrodowski.net> wrote:
> > +
> > +/*
> > + * The kernel should not use call syscalls (i.e., sys_xyzyyz()) directly.
> > + * Instead, use one of the following functions which work equivalent to
> > + * the syscall they are named for.
> 
> "Instead, use one of the functions which work equivalently, e.g. do_xysyyz()"

On Mon, Mar 12, 2018 at 08:27:49AM +0100, Ingo Molnar wrote:
> The previous sentence has a typo as well, should be:
> 
>   * Kernel code should not call syscalls (i.e., sys_xyzyyz()) directly.

Thanks for your feedback. Here's what I will do for v2, unless you find more
typos or areas for improvement:

	/*
	 * Kernel code should not call syscalls (i.e., sys_xyzyyz()) directly.
	 * Instead, use one of the functions which work equivalently, such as
	 * the ksys_xyzyyz() functions prototyped below.
	 */

Thanks,
	Dominik

Re: [RFC PATCH 00/35] remove in-kernel syscall invocations

[Dominik Brodowski]

On Mon, Mar 12, 2018 at 08:32:56AM +0100, Ingo Molnar wrote:
> 
> * Dominik Brodowski <linux@dominikbrodowski.net> wrote:
> 
> > I'm a bit more unsure about these remaining patches. They use inline stubs
> > named ksys_xyzzy() which (mostly) call fs-internal functions. Another
> > alternative would be to define these in fs/*, but then we'd get more and
> > more indirections.
> > 
> > 	syscalls: do not call sys_unlink() within the kernel
> > 	syscalls: do not call sys_rmdir() within the kernel
> > 	syscalls: do not call sys_mkdir{,at}() within the kernel
> > 	syscalls: do not call sys_symlink{,at}() within the kernel
> > 	syscalls: do not call sys_mknod{,at}() within the kernel
> > 	syscalls: do not call sys_link{,at}() within the kernel
> > 	syscalls: do not call sys_{f,}chmod{at,}() within the kernel
> > 	syscalls: do not call sys_{f,}access{,at}() within the kernel
> > 	syscalls: do not call sys_ftruncate() within the kernel
> > 	syscalls: do not call sys_{,l,f}chown() within the kernel
> > 	syscalls: do not call sys_close() within the kernel
> 
> >  72 files changed, 572 insertions(+), 274 deletions(-)
> 
> Just curious, have you done a before/after vmlinux /usr/bin/size comparison?
> How do these changes impact generated code?
> 
> My expectation would be for there to be a noticeable decrease in text size.

Unfortunately, no:

   text	   data	    bss	    dec	    hex	filename
10352515	6598692	13344972	30296179	1ce4873	vmlinux-v4.16-rc5
10352845	6598852	13344972	30296669	1ce4a5d	vmlinux-v4.16-rc5-patch23
10352942	6598948	13344972	30296862	1ce4b1e	vmlinux-v4.16-rc5-patch35

Thanks,
	Dominik

Re: [RFC PATCH 35/35] syscalls: do not call sys_close() within the kernel

[Dominik Brodowski]

On Mon, Mar 12, 2018 at 08:37:19AM +0100, Ingo Molnar wrote:
> 
> * Dominik Brodowski <linux@dominikbrodowski.net> wrote:
> 
> > --- a/fs/open.c
> > +++ b/fs/open.c
> > @@ -1200,7 +1200,7 @@ SYSCALL_DEFINE1(close, unsigned int, fd)
> >  
> >  	return retval;
> >  }
> > -EXPORT_SYMBOL(sys_close);
> > +
> >  
> >  /*
> 
> Nit: this introduces a stray newline.
> 
> > --- a/include/linux/syscalls.h
> > +++ b/include/linux/syscalls.h
> > @@ -1042,4 +1042,10 @@ static inline long ksys_lchown(const char __user *filename, uid_t user,
> >  	return do_fchownat(AT_FDCWD, filename, user, group,
> >  			     AT_SYMLINK_NOFOLLOW);
> >  }
> > +
> > +extern int __close_fd(struct files_struct *files, unsigned int fd);
> > +static inline int ksys_close(unsigned int fd)
> > +{
> > +	return __close_fd(current->files, fd);
> > +}
> 
> Would be nice to reuse that stray newline after the __close_fd() prototype for the 
> canonical stylistic separation of declarations from definitions.
> 
> It would also be very nice to add a short comment before ksys_close() that 
> explains how it differs from sys_close(). This should reduce the amount of 
> cargo-cult copying of existing ksys_close()/sys_close() patterns.

Thanks, have done that:

	/*
	 * In contrast to sys_close(), this stub does not check whether the syscall
	 * should or should not be restarted, but returns the raw error codes from
	 * __close_fd().
	 */

Is that ok?

Thanks,
	Dominik

Re: [RFC PATCH 04/35] syscalls: do not call sys_getpgid() within the kernel

[Dominik Brodowski]

On Mon, Mar 12, 2018 at 01:35:17AM -0700, Christoph Hellwig wrote:
> The subject (and lack of description) for this and the following patches
> is rather confusing.
> 
> I'd expect something like:
> 
> ---- snip ----
> Subject: kernel: add a do_getpgid helper
> 
> And use it to avoid an in-kernel sys_getpgid call.
> 
> ---- snip ----
> 
> instead.

Thanks, will expand the commit messages a bit.

	Dominik

Re: [RFC PATCH 00/35] remove in-kernel syscall invocations

[Dominik Brodowski]

On Sun, Mar 11, 2018 at 01:15:59PM -0700, Linus Torvalds wrote:
> On Sun, Mar 11, 2018 at 3:55 AM, Dominik Brodowski
> <linux@dominikbrodowski.net> wrote:
> > Here is a first set of patches which reduce the number of syscall invocations
> > from within the kernel.
> 
> This all looks ok to me. I think there may be some room for cleanup
> and bikeshedding later (the "ksys_mmap_pgoff()" name made me go "that
> sounds more like a real helper than a kernel syscall", for example),
> but on the whole I think it's best to start with this kind of fairly
> direct translation.
> 
> In fact, because it all looks *so* mechanical, I'd even be willing to
> just pull this into 4.16, if that makes the real work that this
> depends on easier?
> 
> Anyway, ack from me, qith the only question being how you want to
> handle the patches. Direct pull request to me, go through the -mm
> tree, or just keep them in your own git tree and then build upon it
> and send it all later?

Thanks for your feedback! As I think this deserves at least another round of
review and some testing by 0day, I've set up a git tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/brodo/linux syscalls-next

This will allow me to re-base and tweak the patches for a while, and add
some more similar patches on top. For example, besides the first set of
35+1 patches in the aforementioned branch "syscalls-next" there are a few
other patches -- including one you might find familiar -- in "syscalls-WIP"
which are not fully ready yet.

The patches in that repository also include the following changes since
yesterday's RFC:

- rebase to v4.15-rc5
	- sys_ioperm already got its SYSCALL_DEFINE3

- add ACK from Richard Weinberger

- modify CC -> Cc (suggested by Ingo Molnar)

- update comment in include/linux/syscalls.h (suggested by Ingo Molnar and
	Andy Lutomirski)

- separate declarations from definitions with newlines in
	include/linux/syscalls.h; add comment on ksys_close() (suggested by
	Ingo Molnar)

- expand commit messages (suggested by Christoph Hellwig)

- add patch 36: fs: add ksys_open() wrapper; remove in-kernel calls to
	sys_open()

Thanks,
	Dominik

Re: [RFC PATCH 35/35] syscalls: do not call sys_close() within the kernel

[Ingo Molnar]

* Dominik Brodowski <linux@dominikbrodowski.net> wrote:

> On Mon, Mar 12, 2018 at 08:37:19AM +0100, Ingo Molnar wrote:
> > 
> > * Dominik Brodowski <linux@dominikbrodowski.net> wrote:
> > 
> > > --- a/fs/open.c
> > > +++ b/fs/open.c
> > > @@ -1200,7 +1200,7 @@ SYSCALL_DEFINE1(close, unsigned int, fd)
> > >  
> > >  	return retval;
> > >  }
> > > -EXPORT_SYMBOL(sys_close);
> > > +
> > >  
> > >  /*
> > 
> > Nit: this introduces a stray newline.
> > 
> > > --- a/include/linux/syscalls.h
> > > +++ b/include/linux/syscalls.h
> > > @@ -1042,4 +1042,10 @@ static inline long ksys_lchown(const char __user *filename, uid_t user,
> > >  	return do_fchownat(AT_FDCWD, filename, user, group,
> > >  			     AT_SYMLINK_NOFOLLOW);
> > >  }
> > > +
> > > +extern int __close_fd(struct files_struct *files, unsigned int fd);
> > > +static inline int ksys_close(unsigned int fd)
> > > +{
> > > +	return __close_fd(current->files, fd);
> > > +}
> > 
> > Would be nice to reuse that stray newline after the __close_fd() prototype for the 
> > canonical stylistic separation of declarations from definitions.
> > 
> > It would also be very nice to add a short comment before ksys_close() that 
> > explains how it differs from sys_close(). This should reduce the amount of 
> > cargo-cult copying of existing ksys_close()/sys_close() patterns.
> 
> Thanks, have done that:
> 
> 	/*
> 	 * In contrast to sys_close(), this stub does not check whether the syscall
> 	 * should or should not be restarted, but returns the raw error codes from
> 	 * __close_fd().
> 	 */
> 
> Is that ok?

Yeah, looks good to me!

Thanks,

	Ingo

Re: [RFC PATCH 00/35] remove in-kernel syscall invocations

[Ingo Molnar]

* Dominik Brodowski <linux@dominikbrodowski.net> wrote:

> On Mon, Mar 12, 2018 at 08:32:56AM +0100, Ingo Molnar wrote:
> > 
> > * Dominik Brodowski <linux@dominikbrodowski.net> wrote:
> > 
> > > I'm a bit more unsure about these remaining patches. They use inline stubs
> > > named ksys_xyzzy() which (mostly) call fs-internal functions. Another
> > > alternative would be to define these in fs/*, but then we'd get more and
> > > more indirections.
> > > 
> > > 	syscalls: do not call sys_unlink() within the kernel
> > > 	syscalls: do not call sys_rmdir() within the kernel
> > > 	syscalls: do not call sys_mkdir{,at}() within the kernel
> > > 	syscalls: do not call sys_symlink{,at}() within the kernel
> > > 	syscalls: do not call sys_mknod{,at}() within the kernel
> > > 	syscalls: do not call sys_link{,at}() within the kernel
> > > 	syscalls: do not call sys_{f,}chmod{at,}() within the kernel
> > > 	syscalls: do not call sys_{f,}access{,at}() within the kernel
> > > 	syscalls: do not call sys_ftruncate() within the kernel
> > > 	syscalls: do not call sys_{,l,f}chown() within the kernel
> > > 	syscalls: do not call sys_close() within the kernel
> > 
> > >  72 files changed, 572 insertions(+), 274 deletions(-)
> > 
> > Just curious, have you done a before/after vmlinux /usr/bin/size comparison?
> > How do these changes impact generated code?
> > 
> > My expectation would be for there to be a noticeable decrease in text size.
> 
> Unfortunately, no:
> 
>    text	   data	    bss	    dec	    hex	filename
> 10352515	6598692	13344972	30296179	1ce4873	vmlinux-v4.16-rc5
> 10352845	6598852	13344972	30296669	1ce4a5d	vmlinux-v4.16-rc5-patch23
> 10352942	6598948	13344972	30296862	1ce4b1e	vmlinux-v4.16-rc5-patch35

Maybe it's due to the new helpers - still, the changes in size are very small so 
this isn't a showstopper.

Thanks,

	Ingo

Re: [RFC PATCH 13/35] syscalls: do not call sys_ioperm() within the kernel

[Greg Kroah-Hartman]

On Sun, Mar 11, 2018 at 11:55:35AM +0100, Dominik Brodowski wrote:
> While at it, use SYSCALL_DEFINE3() instead of a hand-crafted syscall
> definition.
> 
> CC: Thomas Gleixner <tglx@linutronix.de>
> CC: Ingo Molnar <mingo@redhat.com>
> CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> CC: Jiri Slaby <jslaby@suse.com>
> CC: x86@kernel.org
> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
> ---
>  arch/x86/include/asm/syscalls.h | 1 +
>  arch/x86/kernel/ioport.c        | 7 ++++++-
>  drivers/tty/vt/vt_ioctl.c       | 6 +++---
>  3 files changed, 10 insertions(+), 4 deletions(-)

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>