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Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <2431994.1673453386@warthog.procyon.org.uk> References: <2431994.1673453386@warthog.procyon.org.uk> <20221226103309.953112-3-houtao@huaweicloud.com> <20221226103309.953112-1-houtao@huaweicloud.com> Subject: Re: [PATCH v2 2/2] fscache: Add the missing smp_mb__after_atomic() before wake_up_bit() MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <2432455.1673454299.1@warthog.procyon.org.uk> Date: Wed, 11 Jan 2023 16:24:59 +0000 Message-ID: <2432456.1673454299@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 X-BeenThere: linux-erofs@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Development of Linux EROFS file system List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Hou Tao , Jeff Layton , linux-kernel@vger.kernel.org, dhowells@redhat.com, linux-cachefs@redhat.com, houtao1@huawei.com, linux-erofs@lists.ozlabs.org Errors-To: linux-erofs-bounces+linux-erofs=archiver.kernel.org@lists.ozlabs.org Sender: "Linux-erofs" David Howells wrote: > What two values are you ordering? > > If we're using this to create a critical section, then yes, we would need a > barrier to order the changes inside the critical section before changing the > memory location that forms the lock - but this is not a critical section. Actually, that said, the ordering is probably between the bit being cleared and the task state. David