Hi,

here are some patches related to
copy_struct_{from,to}_{user,sockptr}()
I collected during my work on an IPPROTO_SMBDIRECT
implementation wrapping the smbdirect code used
by cifs.ko and ksmbd.ko.

The first patch fixes copy_struct_to_user()
to behave like documented.

The 2nd patch fixes the case where
copy_struct_from_user() is called by
copy_struct_from_sockptr().

The 3rd patch introduces
copy_struct_{from,to}_bounce_buffer()
as a result of a discussion about the
IPPROTO_QUIC driver in order to
be future prove when handling msg_control
messages in sendmsg and recvmsg.
But I'll likely also use them in my
IPPROTO_SMBDIRECT driver.

The 4th patch makes copy_struct_from_sockptr()
a trivial wrapper switching between
copy_struct_from_user() and
copy_struct_from_bounce_buffer()

The 5th patch introduces copy_struct_to_sockptr()
which I'll also use in my IPPROTO_SMBDIRECT driver.

As future cleanup I was thinking about trick
to hide size_t ksize from the callers, similar
to what was done with kmalloc_obj(). Whould
others think that would be useful?

Stefan Metzmacher (5):
  uaccess: fix ignored_trailing logic in copy_struct_to_user()
  sockptr: fix usize check in copy_struct_from_sockptr() for user
    pointers
  uaccess: add copy_struct_{from,to}_bounce_buffer() helpers
  sockptr: let copy_struct_from_sockptr() use
    copy_struct_from_bounce_buffer()
  sockptr: introduce copy_struct_to_sockptr()

 include/linux/sockptr.h | 28 ++++++++----------
 include/linux/uaccess.h | 65 ++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 76 insertions(+), 17 deletions(-)

-- 
2.43.0

On Tue, 07 Apr 2026 18:03:12 +0200, Stefan Metzmacher wrote:
> here are some patches related to
> copy_struct_{from,to}_{user,sockptr}()
> I collected during my work on an IPPROTO_SMBDIRECT
> implementation wrapping the smbdirect code used
> by cifs.ko and ksmbd.ko.
> 
> The first patch fixes copy_struct_to_user()
> to behave like documented.
> 
> [...]

Applied to the vfs-7.2.misc branch of the vfs/vfs.git tree.
Patches in the vfs-7.2.misc branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs-7.2.misc

[1/5] uaccess: fix ignored_trailing logic in copy_struct_to_user()
      https://git.kernel.org/vfs/vfs/c/0a8d67b47a5c
[2/5] sockptr: fix usize check in copy_struct_from_sockptr() for user pointers
      https://git.kernel.org/vfs/vfs/c/e555ebefea0a
[3/5] uaccess: add copy_struct_{from,to}_bounce_buffer() helpers
      https://git.kernel.org/vfs/vfs/c/14e710721cd3
[4/5] sockptr: let copy_struct_from_sockptr() use copy_struct_from_bounce_buffer()
      https://git.kernel.org/vfs/vfs/c/62343ea38031
[5/5] sockptr: introduce copy_struct_to_sockptr()
      https://git.kernel.org/vfs/vfs/c/9899f22cc41d