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b=F2B/t0BtpaipEuqECr6q2CJUfcQms0HLxJ1OR2GUvVK3VTqXTupSVgtZ393faJZS7 dQHSzB5HL5WVRoPI4ukuPgq0d/qGc7gxjesKU+pdoSlachfAsOmjvl5EJQtZvZ98cf Gp2gxyG+vB+3v1oSUkc9y0Rh8oIjWfDS/aWB/NydQt1SjKfF7jsTWJZCSF9q4wDsww 7qizAlroyUkBBvubpL9dkVQsVt1+hSTdmt0fq6l7LUBAv8jv4z5PTv1UZZCFrnO2KG Rp3XuvFMJSQIO+AGJDB+u0tQRtAgTYNvF4hTXVH0vo5/zcIP1tQMXwmuCIG/0JvOKV Nn8gSvDHKY5+g== From: Pratyush Yadav To: Hugh Dickins , Baolin Wang , Andrew Morton , Pasha Tatashin , Mike Rapoport , Pratyush Yadav Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/3] memfd: export alloc_file() Date: Thu, 22 Jan 2026 16:18:39 +0100 Message-ID: <20260122151842.4069702-2-pratyush@kernel.org> X-Mailer: git-send-email 2.52.0.457.g6b5491de43-goog In-Reply-To: <20260122151842.4069702-1-pratyush@kernel.org> References: <20260122151842.4069702-1-pratyush@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 424C81C0008 X-Stat-Signature: 14oja17ghceo9raysqwwhf3yentyg9fs X-Rspam-User: X-HE-Tag: 1769095140-633626 X-HE-Meta: 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 tRPR6I88 QlNrXEeNpmxf/NzrZFMMMATHWzen34vr3xUM6Weu/seFDkNffNoPLKhAoC+21e8mRNk/vryiccUsTuSr0CIMyk1gUkNc5lGStqcn2rnIsv/EwLmXZvEaYRUSiJQuyfqqFP38W0i88tfiJaIYtGPhsEHO7mg6MU2mtJLhXy8dAN+ZZHfxxRGMnusOmYzgo5FL0IZRU9r9xa3TQ52FRzuIrm6j2L2iHWj4+xTdCxTvHPPUj1YXCTmPqO1JW73H5yjT0ytdJaFl+aMo2b1De9Mgr45H9FA== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: "Pratyush Yadav (Google)" The Live Update Orchestrator's (LUO) memfd preservation works by preserving all the folios of a memfd, re-creating an empty memfd on the next boot, and then inserting back the preserved folios. Currently it creates the file by directly calling shmem_file_setup(). This leaves out other work done by alloc_file() like setting up the file mode, flags, or calling the security hooks. Export alloc_file() to let memfd_luo use it. Rename it to memfd_alloc_file() since it is no longer private and thus needs a subsystem prefix. Signed-off-by: Pratyush Yadav (Google) --- include/linux/memfd.h | 6 ++++++ mm/memfd.c | 4 ++-- 2 files changed, 8 insertions(+), 2 deletions(-) diff --git a/include/linux/memfd.h b/include/linux/memfd.h index cc74de3dbcfe..c328a7b356d0 100644 --- a/include/linux/memfd.h +++ b/include/linux/memfd.h @@ -17,6 +17,7 @@ struct folio *memfd_alloc_folio(struct file *memfd, pgoff_t idx); * to by vm_flags_ptr. */ int memfd_check_seals_mmap(struct file *file, vm_flags_t *vm_flags_ptr); +struct file *memfd_alloc_file(const char *name, unsigned int flags); #else static inline long memfd_fcntl(struct file *f, unsigned int c, unsigned int a) { @@ -31,6 +32,11 @@ static inline int memfd_check_seals_mmap(struct file *file, { return 0; } + +static inline struct file *memfd_alloc_file(const char *name, unsigned int flags) +{ + return ERR_PTR(-EINVAL); +} #endif #endif /* __LINUX_MEMFD_H */ diff --git a/mm/memfd.c b/mm/memfd.c index ab5312aff14b..f032c6052926 100644 --- a/mm/memfd.c +++ b/mm/memfd.c @@ -456,7 +456,7 @@ static char *alloc_name(const char __user *uname) return ERR_PTR(error); } -static struct file *alloc_file(const char *name, unsigned int flags) +struct file *memfd_alloc_file(const char *name, unsigned int flags) { unsigned int *file_seals; struct file *file; @@ -520,5 +520,5 @@ SYSCALL_DEFINE2(memfd_create, return PTR_ERR(name); fd_flags = (flags & MFD_CLOEXEC) ? O_CLOEXEC : 0; - return FD_ADD(fd_flags, alloc_file(name, flags)); + return FD_ADD(fd_flags, memfd_alloc_file(name, flags)); } -- 2.52.0.457.g6b5491de43-goog