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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-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261110_103001_044601_531DEDED X-CRM114-Status: GOOD ( 13.36 ) X-Spam-Score: -17.6 (-----------------) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" X-Spam-Status: No, score=-23.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIMWL_WL_MED,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=4.0.1 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