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| author | Dominik Brodowski <linux@dominikbrodowski.net> | 2018-03-11 11:34:42 +0100 |
|---|---|---|
| committer | Dominik Brodowski <linux@dominikbrodowski.net> | 2018-04-02 20:16:06 +0200 |
| commit | 9b32105ec6b13d32d5db6a6e7992c97ce54b5ea7 (patch) | |
| tree | c3a07615fb95216020d87c65638c55deb47b45ac | |
| parent | 70f68ee81e2e9ad5105b8d2bd324e890e94c6ad9 (diff) | |
| download | linux-0-day-9b32105ec6b13d32d5db6a6e7992c97ce54b5ea7.tar.gz linux-0-day-9b32105ec6b13d32d5db6a6e7992c97ce54b5ea7.tar.xz | |
kernel: add ksys_unshare() helper; remove in-kernel calls to sys_unshare()
Using this helper allows us to avoid the in-kernel calls to the
sys_unshare() syscall. The ksys_ prefix denotes that this function is meant
as a drop-in replacement for the syscall. In particular, it uses the same
calling convention as sys_unshare().
This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
| -rw-r--r-- | drivers/base/devtmpfs.c | 2 | ||||
| -rw-r--r-- | include/linux/syscalls.h | 1 | ||||
| -rw-r--r-- | init/do_mounts_initrd.c | 2 | ||||
| -rw-r--r-- | kernel/fork.c | 7 |
4 files changed, 9 insertions, 3 deletions
diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c index 3f7ee954fd2cd..f7768077e817b 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 0a9942b3e718b..e724dda509e0d 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -961,6 +961,7 @@ int ksys_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg); off_t ksys_lseek(unsigned int fd, off_t offset, unsigned int whence); ssize_t ksys_read(unsigned int fd, char __user *buf, size_t count); void ksys_sync(void); +int ksys_unshare(unsigned long unshare_flags); /* * The following kernel syscall equivalents are just wrappers to fs-internal diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c index 03ec0c1b75530..d1d3e53bdeef9 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 */ ksys_open("/dev/console", O_RDWR, 0); ksys_dup(0); diff --git a/kernel/fork.c b/kernel/fork.c index b1e031aac9db7..f71b67dc156de 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 @@ bad_unshare_out: 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 |