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[174.3.196.123]) by smtp.gmail.com with ESMTPSA id h128sm66270847pgc.15.2019.01.28.20.46.08 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 28 Jan 2019 20:46:08 -0800 (PST) Received: from jgg by mlx.ziepe.ca with local (Exim 4.90_1) (envelope-from ) id 1goLHj-00040F-Du; Mon, 28 Jan 2019 21:46:07 -0700 Date: Mon, 28 Jan 2019 21:46:07 -0700 From: Jason Gunthorpe To: Davidlohr Bueso Cc: akpm@linux-foundation.org, dledford@redhat.com, jack@suse.de, ira.weiny@intel.com, linux-rdma@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, dennis.dalessandro@intel.com, mike.marciniszyn@intel.com, Davidlohr Bueso Subject: Re: [PATCH 3/6] drivers/IB,qib: do not use mmap_sem Message-ID: <20190129044607.GL25106@ziepe.ca> References: <20190121174220.10583-1-dave@stgolabs.net> <20190121174220.10583-4-dave@stgolabs.net> <20190128233140.GA12530@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190128233140.GA12530@ziepe.ca> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 28, 2019 at 04:31:40PM -0700, Jason Gunthorpe wrote: > On Mon, Jan 21, 2019 at 09:42:17AM -0800, Davidlohr Bueso wrote: > > The driver uses mmap_sem for both pinned_vm accounting and > > get_user_pages(). By using gup_fast() and letting the mm handle > > the lock if needed, we can no longer rely on the semaphore and > > simplify the whole thing as the pinning is decoupled from the lock. > > > > This also fixes a bug that __qib_get_user_pages was not taking into > > account the current value of pinned_vm. > > > > Cc: dennis.dalessandro@intel.com > > Cc: mike.marciniszyn@intel.com > > Reviewed-by: Ira Weiny > > Signed-off-by: Davidlohr Bueso > > drivers/infiniband/hw/qib/qib_user_pages.c | 67 ++++++++++-------------------- > > 1 file changed, 22 insertions(+), 45 deletions(-) > > I need you to respin this patch/series against the latest rdma tree: > > git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma.git > > branch for-next > > > diff --git a/drivers/infiniband/hw/qib/qib_user_pages.c b/drivers/infiniband/hw/qib/qib_user_pages.c > > -static int __qib_get_user_pages(unsigned long start_page, size_t num_pages, > > - struct page **p) > > -{ > > - unsigned long lock_limit; > > - size_t got; > > - int ret; > > - > > - lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; > > - > > - if (num_pages > lock_limit && !capable(CAP_IPC_LOCK)) { > > - ret = -ENOMEM; > > - goto bail; > > - } > > - > > - for (got = 0; got < num_pages; got += ret) { > > - ret = get_user_pages(start_page + got * PAGE_SIZE, > > - num_pages - got, > > - FOLL_WRITE | FOLL_FORCE, > > - p + got, NULL); > > As this has been rightly changed to get_user_pages_longterm, and I > think the right answer to solve the conflict is to discard some of > this patch? .. and I'm looking at some of the other conversions here.. *most likely* any caller that is manipulating rlimit for get_user_pages should really be calling get_user_pages_longterm, so they should not be converted to use _fast? Jason