From: David Carlier Date: Thu, 23 Apr 2026 12:56:48 +0000 (+0100) Subject: mm/memfd_luo: document preservation of file seals X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=7b0b68b2b95606e65594958686833e53423f58f2;p=thirdparty%2Flinux.git mm/memfd_luo: document preservation of file seals Commit 8a552d68a86e ("mm: memfd_luo: preserve file seals") started preserving file seals across live update and restoring them via memfd_add_seals() on retrieve, but the DOC header was not updated and still listed seals under "Non-Preserved Properties" as being unsealed on restore. Move the Seals entry to the "Preserved Properties" section and describe the actual behavior, including the MEMFD_LUO_ALL_SEALS restriction that both preserve and retrieve enforce. Fixes: 8a552d68a86e ("mm: memfd_luo: preserve file seals") Signed-off-by: David Carlier Reviewed-by: Pratyush Yadav Reviewed-by: Pasha Tatashin Link: https://patch.msgid.link/20260423125648.152113-2-devnexen@gmail.com Signed-off-by: Pasha Tatashin --- diff --git a/mm/memfd_luo.c b/mm/memfd_luo.c index 94ae113f68f6..59de210bee5f 100644 --- a/mm/memfd_luo.c +++ b/mm/memfd_luo.c @@ -50,6 +50,11 @@ * memfds are always opened with ``O_RDWR`` and ``O_LARGEFILE``. This property * is maintained. * + * Seals + * File seals set on the memfd are preserved and re-applied on restore. + * Only seals known to this LUO version (see ``MEMFD_LUO_ALL_SEALS``) may + * be present; preservation fails with ``-EOPNOTSUPP`` otherwise. + * * Non-Preserved Properties * ======================== * @@ -61,10 +66,6 @@ * A memfd can be created with the ``MFD_CLOEXEC`` flag that sets the * ``FD_CLOEXEC`` on the file. This flag is not preserved and must be set * again after restore via ``fcntl()``. - * - * Seals - * File seals are not preserved. The file is unsealed on restore and if - * needed, must be sealed again via ``fcntl()``. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt