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[34.145.75.25]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2edb6a4013csm12795005ad.1.2026.11.10.10.29.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Nov 2026 10:29:57 -0800 (PST) Date: Tue, 10 Nov 2026 18:29:54 +0000 From: Samiullah Khawaja To: Pratyush Yadav Cc: Pasha Tatashin , Mike Rapoport , Andrew Morton , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v2 1/2] liveupdate: luo_file: allow keeping private_data from retrieve until finish Message-ID: References: <20261110175855.2437084-1-pratyush@kernel.org> <20261110175855.2437084-2-pratyush@kernel.org> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20261110175855.2437084-2-pratyush@kernel.org> X-Rspamd-Server: rspam06 X-Stat-Signature: g1cnbqbwc9go84upixekak5yedgfhckr X-Spam-Status: No, score=-23.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=4.0.1 X-Rspamd-Queue-Id: 2E21720011 X-Rspam-User: X-HE-Tag: 1794335400-463291 X-HE-Meta: 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 B4cNdloX YOTzzwBWgF42Aq1pC1yHoJ5HCtDF3YQe+kQPmL/B8WSaKrJz0tlRNwinl+xPN4I5ukJNMXJZwS3S7sqfDXTZyFEulW0TDvKDzSm9mgOzsLvQTx4Y5YULLPbnKM02EzF3gP3SGj7t6R+/StTfxcmmz6yJK5IoiqtvANVHAzwEWD7EhETuZbNN1UftWnEjTedbpR6U8iSEtP4sWxVuk1+HeYvSHcbWYQuq54eKI6uJpE3xelo4lynSejr0WZsJLIrRVur6g7AJRSlgWBG/V79iG3vzgyMuBe2hVOK5PFFpJsmIQk5sb2tsQomRAgx20cPfrCZ2pniqXy2BKhvKJNCXoSbYyNVgx+xx+3UNFHRMNgM0eXUJdsHQbwL5rB5a+s7Vu94LmpIiRs7hmEi3NmGoeYNLyonCR3nTsNKIFCLrRHamBeZ0jorp45UDauS4sH7WAKLnz/jPo6NfgoDCpIx9qbdhPemPkMUlFch6e Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Tue, Nov 10, 2026 at 06:58:52PM +0100, Pratyush Yadav wrote: >From: "Pratyush Yadav (Google)" > >The private_data field of struct liveupdate_file_op_args lets file >handlers keep runtime state that is not preserved. It is set by >.preserve() and passed to the later outgoing callbacks, up to >.unpreserve(). But in the new kernel, nothing set by .retrieve() is >kept, and .can_finish() and .finish() always get a NULL private_data. > >Handlers might need to keep runtime state from retrieve until finish. >For example, memfd will need to remember the folios it holds on to >until finish so it can release them there. > >Save the private_data set by a successful .retrieve() in the luo_file, >and pass it to .can_finish() and .finish(). The handler must free it in >.finish(). > >While at it, update a stale comment under struct >liveupdate_file_op_args. There is no 'data', but there is >'serialized_data' and 'private_data'. Refer to them instead. > >Reviewed-by: Pasha Tatashin >Signed-off-by: Pratyush Yadav (Google) >--- > include/linux/liveupdate.h | 11 +++++++---- > kernel/liveupdate/luo_file.c | 11 ++++++++--- > 2 files changed, 15 insertions(+), 7 deletions(-) > Reviewed-by: Samiullah Khawaja