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Merge branch 'remove-ksys-mount-dup' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/linux

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Pull ksys_mount() and ksys_dup() removal from Dominik Brodowski:
 "This small series replaces all in-kernel calls to the
  userspace-focused ksys_mount() and ksys_dup() with calls to
  kernel-centric functions:

  For each replacement of ksys_mount() with do_mount(), one needs to
  verify that the first and third parameter (char *dev_name, char *type)
  are strings allocated in kernelspace and that the fifth parameter
  (void *data) is either NULL or refers to a full page (only occurence
  in init/do_mounts.c::do_mount_root()). The second and fourth
  parameters (char *dir_name, unsigned long flags) are passed by
  ksys_mount() to do_mount() unchanged, and therefore do not require
  particular care.

  Moreover, instead of pretending to be userspace, the opening of
  /dev/console as stdin/stdout/stderr can be implemented using in-kernel
  functions as well. Thereby, ksys_dup() can be removed for good"

[ This doesn't get rid of the special "kernel init runs with KERNEL_DS"
  case, but it at least removes _some_ of the users of "treat kernel
  pointers as user pointers for our magical init sequence".

  One day we'll hopefully be rid of it all, and can initialize our
  init_thread addr_limit to USER_DS.    - Linus ]

* 'remove-ksys-mount-dup' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/linux:
  fs: remove ksys_dup()
  init: unify opening /dev/console as stdin/stdout/stderr
  init: use do_mount() instead of ksys_mount()
  initrd: use do_mount() instead of ksys_mount()
  devtmpfs: use do_mount() instead of ksys_mount()
This commit is contained in:
Linus Torvalds
2019-12-15 11:36:12 -08:00
parent 510c978899 8243186f0c
commit 2e6d304515
9 changed files with 63 additions and 41 deletions
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7
fs/file.c
View File

@@ -960,7 +960,7 @@ SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd)
return ksys_dup3(oldfd, newfd, 0);
}
int ksys_dup(unsigned int fildes)
SYSCALL_DEFINE1(dup, unsigned int, fildes)
{
int ret = -EBADF;
struct file *file = fget_raw(fildes);
@@ -975,11 +975,6 @@ int ksys_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;

10
fs/namespace.c
View File

@@ -3325,8 +3325,8 @@ struct dentry *mount_subtree(struct vfsmount *m, const char *name)
}
EXPORT_SYMBOL(mount_subtree);
int ksys_mount(const char __user *dev_name, const char __user *dir_name,
const char __user *type, unsigned long flags, void __user *data)
SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name,
char __user *, type, unsigned long, flags, void __user *, data)
{
int ret;
char *kernel_type;
@@ -3359,12 +3359,6 @@ out_type:
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);
}
/*
* Create a kernel mount representation for a new, prepared superblock
* (specified by fs_fd) and attach to an open_tree-like file descriptor.