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[54.240.9.36]) by mx.google.com with ESMTPS id o89si3159903qvo.208.2019.01.21.13.53.24 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 21 Jan 2019 13:53:24 -0800 (PST) Received-SPF: pass (google.com: domain of 01000168726760d6-6c4f2b48-870e-4a46-846b-3bb3d324000d-000000@amazonses.com designates 54.240.9.36 as permitted sender) client-ip=54.240.9.36; Authentication-Results: mx.google.com; dkim=pass header.i=@amazonses.com header.s=ug7nbtf4gccmlpwj322ax3p6ow6yfsug header.b=Q+BjbpDB; spf=pass (google.com: domain of 01000168726760d6-6c4f2b48-870e-4a46-846b-3bb3d324000d-000000@amazonses.com designates 54.240.9.36 as permitted sender) smtp.mailfrom=01000168726760d6-6c4f2b48-870e-4a46-846b-3bb3d324000d-000000@amazonses.com DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/simple; s=ug7nbtf4gccmlpwj322ax3p6ow6yfsug; d=amazonses.com; t=1548107604; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References:MIME-Version:Content-Type:Feedback-ID; bh=DcXpbnSbvxIdmq741qppTsLN32m9f2v4cydbcvErAV0=; b=Q+BjbpDBgsQD/11ROUV+6LLlGtEkEYWE1cAP3Xrim+rdMrlzz8/LqguRcZmbtPlL 2bNjHzrtqtpGEdkZMf6iCeUwWepSntlMaV138LRW2szfZ4BhieGFXzdTc1+Zkk9GaLp NrSg5DYlIFSs3WYwZ7KFyLiBbk4Ak8CxcaDiCQTU= Date: Mon, 21 Jan 2019 21:53:24 +0000 From: Christopher Lameter X-X-Sender: cl@nuc-kabylake To: Davidlohr Bueso cc: akpm@linux-foundation.org, dledford@redhat.com, jgg@mellanox.com, jack@suse.de, ira.weiny@intel.com, linux-rdma@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Davidlohr Bueso Subject: Re: [PATCH 6/6] drivers/IB,core: reduce scope of mmap_sem In-Reply-To: <20190121174220.10583-7-dave@stgolabs.net> Message-ID: <01000168726760d6-6c4f2b48-870e-4a46-846b-3bb3d324000d-000000@email.amazonses.com> References: <20190121174220.10583-1-dave@stgolabs.net> <20190121174220.10583-7-dave@stgolabs.net> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" X-SES-Outgoing: 2019.01.21-54.240.9.36 Feedback-ID: 1.us-east-1.fQZZZ0Xtj2+TD7V5apTT/NrT6QKuPgzCT/IC7XYgDKI=:AmazonSES X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Message-ID: <20190121215324.FqShdM648fdSj_tb3GaVgCPeDtuSzJzytaMiYpNZGDA@z> On Mon, 21 Jan 2019, Davidlohr Bueso wrote: > ib_umem_get() uses gup_longterm() and relies on the lock to > stabilze the vma_list, so we cannot really get rid of mmap_sem > altogether, but now that the counter is atomic, we can get of > some complexity that mmap_sem brings with only pinned_vm. Reviewd-by: Christoph Lameter