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h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=liAKXVmo9AnwBPBY7iA753zrNtz/sl+uX7W/61C1NyJqXC89aVs9REWiHYda8qEgN xmyynk4NPZOifXJZETETOHztGukFxU3lXtEN1p8H9tPn+AA0QorG2Ixo+lXoV3F0dr 8BVHO6zk8ozWcfUhoZM6EebttFBs13w0tJ+ch7RfvstMS4M0Qeh4GNcRfxeuCzv0dR FxsTz2QwvTQvWDYlour0m/wRH00+iS2PkwtknrWfAqmtaDPLINTu2h5b+0fML9XqhH Ho8ibhn/skq6m+aOJlRTvexwXS2TJs/fo3DZ+pnOzeCYUloWiRejztd4VPqHYJ9zfj BIkx9ZIqs4fFw== Date: Mon, 9 Oct 2023 11:38:51 +0300 From: Mike Rapoport To: Axel Rasmussen Cc: Alejandro Colomar , Peter Xu , linux-man@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 01/10] userfaultfd.2: briefly mention two-step feature handshake process Message-ID: <20231009083851.GF3303@kernel.org> References: <20230919190206.388896-1-axelrasmussen@google.com> <20230919190206.388896-2-axelrasmussen@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230919190206.388896-2-axelrasmussen@google.com> X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 77637180022 X-Stat-Signature: obnsxo4unkpcs16guke1byh8zaseu5y8 X-Rspam-User: X-HE-Tag: 1696840788-138974 X-HE-Meta: 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 v18m8jqG sDKjrFfDU91efZjCYC78SF4gMD6Wo+EfKd93yUFXs+8t2RSPTsNne+1f5WayyEmfwgsmKXdZbwF5sDtvOwjIWTlnC6qyxV9bjEUnjuYnxxtAme+ahCMgpG++olYEQIeAf+ZVeEuCLm2PQ70UyF10Z+y7A2gM7KKxei6nlzzH3X5K8jhtSwm4Yc3zgetBHXQcG0gyp2VSCiQLDx2bW0fA9u4VQIOdlSb5l36bARqbmXxgV9dJFg/UdEV+efGeCEd7aV+UkymuBaQWFwK5ttw4ypGYDFw== 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: On Tue, Sep 19, 2023 at 12:01:57PM -0700, Axel Rasmussen wrote: > This process is critical for programs which depend on extra features, so > it's worth mentioning here. > > Future commits will much more fully describe it in ioctl_userfaultfd.2. > > Signed-off-by: Axel Rasmussen Reviewed-by: Mike Rapoport (IBM) > --- > man2/userfaultfd.2 | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/man2/userfaultfd.2 b/man2/userfaultfd.2 > index 40354065c..1b2af22f9 100644 > --- a/man2/userfaultfd.2 > +++ b/man2/userfaultfd.2 > @@ -200,8 +200,9 @@ the application must enable it using the > .B UFFDIO_API > .BR ioctl (2) > operation. > -This operation allows a handshake between the kernel and user space > -to determine the API version and supported features. > +This operation allows a two-step handshake between the kernel and user space > +to determine what API version and features the kernel supports, > +and then to enable those features user space wants. > This operation must be performed before any of the other > .BR ioctl (2) > operations described below (or those operations fail with the > -- > 2.42.0.459.ge4e396fd5e-goog > > -- Sincerely yours, Mike.