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[24.6.151.244]) by smtp.gmail.com with ESMTPSA id h10-20020a056a00218a00b006dde3053cdasm8574075pfi.133.2024.01.30.18.27.59 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 30 Jan 2024 18:28:01 -0800 (PST) Date: Tue, 30 Jan 2024 18:27:57 -0800 From: Joe Damato To: Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, chuck.lever@oracle.com, jlayton@kernel.org, linux-api@vger.kernel.org, brauner@kernel.org, edumazet@google.com, davem@davemloft.net, alexander.duyck@gmail.com, sridhar.samudrala@intel.com, kuba@kernel.org, willemdebruijn.kernel@gmail.com, weiwan@google.com, David.Laight@aculab.com, arnd@arndb.de, Jonathan Corbet , Alexander Viro , Jan Kara , Michael Ellerman , Nathan Lynch , Thomas Zimmermann , Maik Broemme , Steve French , Julien Panis , Jiri Slaby , Thomas Huth , Andrew Waterman , Albert Ou , Palmer Dabbelt , "open list:DOCUMENTATION" , "open list:FILESYSTEMS (VFS and infrastructure)" Subject: Re: [PATCH net-next v4 3/3] eventpoll: Add epoll ioctl for epoll_params Message-ID: <20240131022756.GA4837@fastly.com> References: <20240131014738.469858-1-jdamato@fastly.com> <20240131014738.469858-4-jdamato@fastly.com> <2024013001-prison-strum-899d@gregkh> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2024013001-prison-strum-899d@gregkh> User-Agent: Mutt/1.5.24 (2015-08-30) On Tue, Jan 30, 2024 at 06:08:36PM -0800, Greg Kroah-Hartman wrote: > On Wed, Jan 31, 2024 at 01:47:33AM +0000, Joe Damato wrote: > > +struct epoll_params { > > + __aligned_u64 busy_poll_usecs; > > + __u16 busy_poll_budget; > > + > > + /* pad the struct to a multiple of 64bits for alignment on all arches */ > > + __u8 __pad[6]; > > You HAVE to check this padding to be sure it is all 0, otherwise it can > never be used in the future for anything. Is there some preferred mechanism for this in the kernel that I should be using or is this as simple as adding a for loop to check each u8 == 0 ? Thanks.