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([2001:b07:6468:f312:7841:78cc:18c6:1e20]) by smtp.gmail.com with ESMTPSA id j11sm6554854wrq.69.2020.08.06.06.45.33 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 06 Aug 2020 06:45:34 -0700 (PDT) Subject: Re: [PATCH v3 2/3] async: always set ctx->notified in aio_notify() To: Stefan Hajnoczi , qemu-devel@nongnu.org References: <20200806131802.569478-1-stefanha@redhat.com> <20200806131802.569478-3-stefanha@redhat.com> From: Paolo Bonzini Message-ID: <1e47af10-47fb-0a2f-7aa2-8a426ec86361@redhat.com> Date: Thu, 6 Aug 2020 15:45:33 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <20200806131802.569478-3-stefanha@redhat.com> Content-Language: en-US Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=pbonzini@redhat.com 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=207.211.31.120; envelope-from=pbonzini@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/06 03:10:56 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, 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=-0.01, RCVD_IN_MSPIKE_WL=-0.01, 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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Fam Zheng , qemu-block@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 06/08/20 15:18, Stefan Hajnoczi wrote: > + atomic_set(&ctx->notified, false); > + > + /* > + * Write ctx->notified before reading e.g. bh->flags. Pairs with smp_mb in > + * aio_notify. > + */ > + smp_wmb(); Sorry I was not clear: the memory barrier has to be smp_mb(), but the comment has to say smp_wmb(). No need to repost for this. Paolo