From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932835AbeCOTHS (ORCPT ); Thu, 15 Mar 2018 15:07:18 -0400 Received: from isilmar-4.linta.de ([136.243.71.142]:36332 "EHLO isilmar-4.linta.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932693AbeCOTGY (ORCPT ); Thu, 15 Mar 2018 15:06:24 -0400 From: Dominik Brodowski To: linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, viro@zeniv.linux.org.uk Cc: luto@kernel.org, mingo@kernel.org, akpm@linux-foundation.org, arnd@arndb.de Subject: [PATCH v2 19/36] kernel: add ksys_unshare() helper; remove in-kernel calls to sys_unshare() Date: Thu, 15 Mar 2018 20:05:12 +0100 Message-Id: <20180315190529.20943-20-linux@dominikbrodowski.net> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180315190529.20943-1-linux@dominikbrodowski.net> References: <20180315190529.20943-1-linux@dominikbrodowski.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Using this helper allows us to avoid the in-kernel calls to the sys_unshare() syscall. Cc: Al Viro Cc: Andrew Morton Cc: Ingo Molnar Signed-off-by: Dominik Brodowski --- 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 c6aa44b6a0a2..2c0fabc7d19d 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