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[156.34.49.251]) by smtp.gmail.com with ESMTPSA id t17sm16094116qte.66.2019.05.22.15.52.20 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 22 May 2019 15:52:20 -0700 (PDT) Received: from jgg by mlx.ziepe.ca with local (Exim 4.90_1) (envelope-from ) id 1hTa5s-0004Hv-A7; Wed, 22 May 2019 19:52:20 -0300 Date: Wed, 22 May 2019 19:52:20 -0300 From: Jason Gunthorpe To: Jerome Glisse Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, Leon Romanovsky , Doug Ledford , Artemy Kovalyov , Moni Shoua , Mike Marciniszyn , Kaike Wan , Dennis Dalessandro Subject: Re: [PATCH v4 0/1] Use HMM for ODP v4 Message-ID: <20190522225220.GC15389@ziepe.ca> References: <20190411181314.19465-1-jglisse@redhat.com> <20190506195657.GA30261@ziepe.ca> <20190521205321.GC3331@redhat.com> <20190522005225.GA30819@ziepe.ca> <20190522174852.GA23038@redhat.com> <20190522201247.GH6054@ziepe.ca> <20190522220419.GB20179@redhat.com> <20190522223906.GA15389@ziepe.ca> <20190522224211.GF20179@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190522224211.GF20179@redhat.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000009, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, May 22, 2019 at 06:42:11PM -0400, Jerome Glisse wrote: > > > The way race is avoided is because mm->hmm will either be NULL or > > > point to another hmm struct before an existing hmm is free. > > > > There is no locking on mm->hmm so it is useless to prevent races. > > There is locking on mm->hmm Not in mm_get_hmm() > > So we agree this patch is necessary? Can you test it an ack it please? > > A slightly different patch than this one is necessary i will work on > it tomorrow. I think if you want something different you should give feedback on this patch. You haven't rasied any defects with it. Jason