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([2001:b07:6468:f312:ec64:483c:eca:9b27]) by smtp.gmail.com with ESMTPSA id o26sm15421208wro.83.2020.05.11.04.11.11 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 11 May 2020 04:11:11 -0700 (PDT) Subject: Re: [PATCH 3/4] device-core: use atomic_set on .realized property To: Maxim Levitsky , Stefan Hajnoczi References: <20200416203624.32366-1-mlevitsk@redhat.com> <20200416203624.32366-4-mlevitsk@redhat.com> <20200504104538.GC354891@stefanha-x1.localdomain> <948c2e2f293c08b6411030dc5ad91c23a2f773f0.camel@redhat.com> From: Paolo Bonzini Message-ID: <82d51a76-fd38-d72e-2d22-c4de1a76d5f9@redhat.com> Date: Mon, 11 May 2020 13:11:12 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <948c2e2f293c08b6411030dc5ad91c23a2f773f0.camel@redhat.com> Content-Language: en-US X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=205.139.110.120; envelope-from=pbonzini@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/11 00:05:06 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] 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_H2=-0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Fam Zheng , "Michael S. Tsirkin" , =?UTF-8?Q?Daniel_P=2e_Berrang=c3=a9?= , qemu-devel@nongnu.org, Eduardo Habkost Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 11/05/20 13:00, Maxim Levitsky wrote: > On second thought, I think both cases matter, after I examined the device removal case. > In device removal case, the device is first un-realized and then removed from the bus, > so just like in device hotplug case, the scsi_device_find can give you an unrealized device. > > I will change this patch to set .realized to false at the start (if needed) of the function and to true at the end (also if needed) > Will atomic_rcu_set work? or atomic_store_release? > (Both are the same thing, but former documents the purpose of using with RCU. atomic_rcu_set is more to store pointers, in this case you want to store the value after any other change to the struct so atomic_store_release is more appropriate. Paolo