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[188.85.150.151]) by smtp.gmail.com with ESMTPSA id w21-20020a05600c015500b0040652e8ca13sm1888051wmm.43.2023.10.04.09.22.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 Oct 2023 09:22:07 -0700 (PDT) From: Juan Quintela To: Markus Armbruster Cc: qemu-devel@nongnu.org, peterx@redhat.com, leobras@redhat.com, farosas@suse.de, lizhijian@fujitsu.com, eblake@redhat.com Subject: Re: [PATCH v2 23/53] migration/rdma: Fix QEMUFileHooks method return values In-Reply-To: <20230928132019.2544702-24-armbru@redhat.com> (Markus Armbruster's message of "Thu, 28 Sep 2023 15:19:49 +0200") References: <20230928132019.2544702-1-armbru@redhat.com> <20230928132019.2544702-24-armbru@redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.3 (gnu/linux) Date: Wed, 04 Oct 2023 18:22:06 +0200 Message-ID: <87a5sywe6p.fsf@secure.mitica> MIME-Version: 1.0 Content-Type: text/plain Received-SPF: pass client-ip=170.10.133.124; envelope-from=quintela@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: quintela@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Markus Armbruster wrote: > The QEMUFileHooks methods don't come with a written contract. Digging > through the code calling them, we find: > > * save_page(): > > Negative values RAM_SAVE_CONTROL_DELAYED and > RAM_SAVE_CONTROL_NOT_SUPP are special. Any other negative value is > an unspecified error. > > qemu_rdma_save_page() returns -EIO or rdma->error_state on error. I > believe the latter is always negative. Nothing stops either of them > to clash with the special values, though. Feels unlikely, but fix > it anyway to return only the special values and -1. > > * before_ram_iterate(), after_ram_iterate(): > > Negative value means error. qemu_rdma_registration_start() and > qemu_rdma_registration_stop() comply as far as I can tell. Make > them comply *obviously*, by returning -1 on error. > > * hook_ram_load: > > Negative value means error. rdma_load_hook() already returns -1 on > error. Leave it alone. > > Signed-off-by: Markus Armbruster > Reviewed-by: Li Zhijian Reviewed-by: Juan Quintela Changed idea. Will include this and rebase mines on top.