From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: [PATCH mm-unstable v1 10/20] RDMA/umem: remove FOLL_FORCE usage Date: Wed, 16 Nov 2022 20:45:21 -0400 Message-ID: References: <20221116102659.70287-1-david@redhat.com> <20221116102659.70287-11-david@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=yMw5fxGY1p2h/KXFfbAPV7iCUjQYbLBZtZUT7oyi98c=; b=c7vvvBExsKpv6O 7Bo2HAw9tcI4WNFQIIeBgGNI+AzKpGb4YfbjjpOnNoNclNLCB47VqzVVv+YTdVIz33RzfAElmrjTJ YsdAjrUsnwZoFXxniEXveNkAHm1c7QexPtepDOcMR+ZWKxqrP6+4Npy2mG/ojXokXe3a+34Nj8nVz T/9TxYXSh+AaTuZ2ColmsTilyQUtdut63dyJVTlW1XpwolG2PbfRRG/n1mvjw17H377Fm56hfnQ2c gPDFcmPoHuzfwJUWvJehLjdDIUaycfgcU6odfvp2ggEjXb4DqIrzZdWHaHicr6A0HHHu8bCmHUxhu 0rFSRTdIBOlG5uM3T7Hw==; DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=HEOs2OljVpzFekHebtNmxJNTS1biZDzbDC+7E+gbGXE=; b=NKUDG6/HRBHYArrki2ErKlKAFAloDP3syGXEvUqNJ9D2fVrZim0dI4zYfgnJWEKy+2 eIgPOs+mttvXhYUIJL/UppN4gHtQqcQpWlrONSgHhATtfRfLqa70r2Y5AFUtDhoXumLz QwAO0SpqErl+SpXb2isD+wqK260zhrI3m0OcjGKZmRIuadG54e+ieDR5HURAecTq4gww +4XuPNBvBD2G5dec/bz8Eh9V9EDh1RbiHGn8GIrcO4V8END9r1k5y0xfRAbT/lxmG9Cm d4SXiY9+ZupOQT/Gb+ZePnA6lwtOPkxvxI9tRVsC2WHBPZX7s+xnX8nZsTymxhqmYSZB 7vEA== Content-Disposition: inline In-Reply-To: <20221116102659.70287-11-david@redhat.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-um" Errors-To: linux-um-bounces+glud-user-mode-linux-devel=m.gmane-mx.org@lists.infradead.org To: David Hildenbrand Cc: linux-kernel@vger.kernel.org, x86@kernel.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, etnaviv@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-samsung-soc@vger.kernel.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-perf-users@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kselftest@vger.kernel.org, Linus Torvalds , Andrew Morton , John Hubbard , Peter Xu , Greg Kroah-Hartman , Andrea Arcangeli , Hugh Dickins , Nadav Amit On Wed, Nov 16, 2022 at 11:26:49AM +0100, David Hildenbrand wrote: > GUP now supports reliable R/O long-term pinning in COW mappings, such > that we break COW early. MAP_SHARED VMAs only use the shared zeropage so > far in one corner case (DAXFS file with holes), which can be ignored > because GUP does not support long-term pinning in fsdax (see > check_vma_flags()). > > Consequently, FOLL_FORCE | FOLL_WRITE | FOLL_LONGTERM is no longer required > for reliable R/O long-term pinning: FOLL_LONGTERM is sufficient. So stop > using FOLL_FORCE, which is really only for ptrace access. > > Tested-by: Leon Romanovsky # Over mlx4 and mlx5. > Cc: Jason Gunthorpe > Cc: Leon Romanovsky > Signed-off-by: David Hildenbrand > --- > drivers/infiniband/core/umem.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) Reviewed-by: Jason Gunthorpe Jason