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charset="UTF-8" X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: DF1A640006 X-Stat-Signature: bdgeoj4nxmjac13dbai7h8fx9673p9tb X-HE-Tag: 1788286048-845644 X-HE-Meta: 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 KmmrKKrs LfFA18gXkzr8vMICt3gPLKvmgVCJrdPtkG4OGkF2xtCfxRwyJGmXvJxLivSKseBWO1uRFR01sg8cTd7ulp3CwrTksOSYVUWlM9QRncruAiBH5cUM755ULrvX/rhHcpD+JvlR+HETs2JPrE6JihGunJBBeqlcFo+A4I/O26TaF56y713S9B+hX4DncRVV05VlHm4c2BGQ4g9IBv2FYH4GN9wnOv2Pltgs3+ZWBGeNyKZpFSgwG6oSebWgMc0riHoQ7ZKy5epQ/FCThtOYr1MYfhGsMfK/wBGlmkLAL+HlkqFuQO0nj4b3pr1Yvt9lAsH2huhBu1GNaOKCj7vQMfkzi3CZuynbJqlKB7cNcPaE8WoFHScErNTyiT48Mb4c78Q3r/R0TBZ5VTKJM0V3lXcIG+dxUVZCKcLOI/yWl6T/MnoSOqumevV2Nk9MZxAVRsqeZ20dGp+W8Ha3mF8AhWnei1O8JltNR0srDigiLtbmosCG+c4wu1fSZDaX2UytrdpXGvIGs5pMG3Ev8vgoYlRS3I/8ktosG6u6i7UaetpfDXMuUCjKo+06LDJTARiP4Y/c/Z/3Vmf/ZVZza+cBfBHdx1MO1q4X+YTQTeYx1OkxZzjBQ6nNXvHEnxQt1iINPG2+oH8uqiNVequAKSdM= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Relax the early validation checks in the Live Update preservation path to allow general shmem-backed files, completely dropping the requirement that the file be unlinked (!inode->i_nlink). This officially enables userspace to push standard, path-backed tmpfs file descriptors through the LUO session ioctl instead of being artificially restricted strictly to anonymous memfd pseudofiles. Signed-off-by: David Matlack --- mm/memfd_luo.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/mm/memfd_luo.c b/mm/memfd_luo.c index dcda5bf98646..107115c97bd8 100644 --- a/mm/memfd_luo.c +++ b/mm/memfd_luo.c @@ -9,14 +9,15 @@ */ /** - * DOC: Memfd Preservation via LUO + * DOC: Memfd and Tmpfs Preservation via LUO * * Overview * ======== * - * Memory file descriptors (memfd) can be preserved over a kexec using the Live - * Update Orchestrator (LUO) file preservation. This allows userspace to - * transfer its memory contents to the next kernel after a kexec. + * Memory file descriptors (memfd) and generic tmpfs files can be preserved + * over a kexec using the Live Update Orchestrator (LUO) file preservation. + * This allows userspace to transfer its memory contents to the next kernel + * after a kexec. * * The preservation is not intended to be transparent. Only select properties of * the file are preserved. All others are reset to default. The preserved @@ -24,16 +25,17 @@ * * .. note:: * The LUO API is not stabilized yet, so the preserved properties of a memfd - * are also not stable and are subject to backwards incompatible changes. + * or tmpfs file are also not stable and are subject to backwards + * incompatible changes. * * .. note:: - * Currently a memfd backed by Hugetlb is not supported. Memfds created + * Currently a file backed by Hugetlb is not supported. Memfds created * with ``MFD_HUGETLB`` will be rejected. * * Preserved Properties * ==================== * - * The following properties of the memfd are preserved across kexec: + * The following properties of the memfd/tmpfs file are preserved across kexec: * * File Contents * All data stored in the file is preserved. @@ -580,9 +582,7 @@ static int memfd_luo_retrieve(struct liveupdate_file_op_args *args) static bool memfd_luo_can_preserve(struct liveupdate_file_handler *handler, struct file *file) { - struct inode *inode = file_inode(file); - - return shmem_file(file) && !inode->i_nlink; + return shmem_file(file) || shmem_mapping(file->f_mapping); } static unsigned long memfd_luo_get_id(struct file *file) -- 2.55.0.966.g6673acef38-goog