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b=sMIwuVuHQZ63VF+zCAo9oX2pCDZyMCYP5Wg8cjEsP3YQB9I0BpreQ9L/ablGpeUME oCs9zr+bX1CKb5waMw6erNYZisB571UuMGrkKaBNYOUMk6gCsaWyqrfsZ0hyGUqbfu ChqUNCDi1QwEeRwhkaCjZzXrvMknXrk6keOxrsSGvu4jHDYCbmMoFgOaz5ojW3ny5g 9rs0tggzMGM/Af2Y6UssYxHC4mq76M+pvKIUlV01l4H3Qwm2iNKqxRclRl6d7KvIaM 412Cjl2c8GJh/Gk8fEJh8XDHufdpHrLLofuGMQYXKBdLYLkz9loxs7BS19SxE6zL6o QKTJauwTCUg4Q== Date: Sun, 16 Nov 2025 20:25:29 +0200 From: Mike Rapoport To: Pasha Tatashin Cc: pratyush@kernel.org, jasonmiu@google.com, graf@amazon.com, dmatlack@google.com, rientjes@google.com, corbet@lwn.net, rdunlap@infradead.org, ilpo.jarvinen@linux.intel.com, kanie@linux.alibaba.com, ojeda@kernel.org, aliceryhl@google.com, masahiroy@kernel.org, akpm@linux-foundation.org, tj@kernel.org, yoann.congal@smile.fr, mmaurer@google.com, roman.gushchin@linux.dev, chenridong@huawei.com, axboe@kernel.dk, mark.rutland@arm.com, jannh@google.com, vincent.guittot@linaro.org, hannes@cmpxchg.org, dan.j.williams@intel.com, david@redhat.com, joel.granados@kernel.org, rostedt@goodmis.org, anna.schumaker@oracle.com, song@kernel.org, linux@weissschuh.net, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, gregkh@linuxfoundation.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, rafael@kernel.org, dakr@kernel.org, bartosz.golaszewski@linaro.org, cw00.choi@samsung.com, myungjoo.ham@samsung.com, yesanishhere@gmail.com, Jonathan.Cameron@huawei.com, quic_zijuhu@quicinc.com, aleksander.lobakin@intel.com, ira.weiny@intel.com, andriy.shevchenko@linux.intel.com, leon@kernel.org, lukas@wunner.de, bhelgaas@google.com, wagi@kernel.org, djeffery@redhat.com, stuart.w.hayes@gmail.com, ptyadav@amazon.de, lennart@poettering.net, brauner@kernel.org, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, saeedm@nvidia.com, ajayachandra@nvidia.com, jgg@nvidia.com, parav@nvidia.com, leonro@nvidia.com, witu@nvidia.com, hughd@google.com, skhawaja@google.com, chrisl@kernel.org Subject: Re: [PATCH v6 07/20] liveupdate: luo_session: Add ioctls for file preservation Message-ID: References: <20251115233409.768044-1-pasha.tatashin@soleen.com> <20251115233409.768044-8-pasha.tatashin@soleen.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251115233409.768044-8-pasha.tatashin@soleen.com> X-Rspamd-Server: rspam12 X-Rspam-User: X-Rspamd-Queue-Id: 73E761C0002 X-Stat-Signature: 3ux6dns19h6d7fenwguy7k118wckk4ea X-HE-Tag: 1763317555-516377 X-HE-Meta: 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 WDvpzswD SRf2f3Tyc9aPuHjAuETHN19SFXrkXDyNYm3MCUcrhFtkZjtFwYLF5LXOLgeFpYfgmsPUKB44SveTZKr4= 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: On Sat, Nov 15, 2025 at 06:33:53PM -0500, Pasha Tatashin wrote: > Introducing the userspace interface and internal logic required to > manage the lifecycle of file descriptors within a session. Previously, a > session was merely a container; this change makes it a functional > management unit. > > The following capabilities are added: > > A new set of ioctl commands are added, which operate on the file > descriptor returned by CREATE_SESSION. This allows userspace to: > - LIVEUPDATE_SESSION_PRESERVE_FD: Add a file descriptor to a session > to be preserved across the live update. > - LIVEUPDATE_SESSION_RETRIEVE_FD: Retrieve a preserved file in the > new kernel using its unique token. > - LIVEUPDATE_SESSION_FINISH: finish session > > The session's .release handler is enhanced to be state-aware. When a > session's file descriptor is closed, it correctly unpreserves > the session based on its current state before freeing all > associated file resources. > > Signed-off-by: Pasha Tatashin > --- > include/uapi/linux/liveupdate.h | 103 ++++++++++++++++++ > kernel/liveupdate/luo_session.c | 187 +++++++++++++++++++++++++++++++- > 2 files changed, 286 insertions(+), 4 deletions(-) ... > static int luo_session_release(struct inode *inodep, struct file *filep) > { > struct luo_session *session = filep->private_data; > struct luo_session_header *sh; > + int err = 0; > > /* If retrieved is set, it means this session is from incoming list */ > - if (session->retrieved) > + if (session->retrieved) { > sh = &luo_session_global.incoming; > - else > + > + err = luo_session_finish_one(session); > + if (err) { > + pr_warn("Unable to finish session [%s] on release\n", > + session->name); return err; and then else can go away here and luo_session_remove() and luo_session_free() can be moved outside if (session->retrieved). > + } else { > + luo_session_remove(sh, session); > + luo_session_free(session); > + } > + > + } else { > sh = &luo_session_global.outgoing; > > - luo_session_remove(sh, session); > - luo_session_free(session); > + scoped_guard(mutex, &session->mutex) > + luo_file_unpreserve_files(session); > + luo_session_remove(sh, session); > + luo_session_free(session); > + } > + > + return err; > +} -- Sincerely yours, Mike.