From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Laight Date: Thu, 14 May 2020 09:51:00 +0000 Subject: [Ocfs2-devel] [PATCH 32/33] sctp: add sctp_sock_get_primary_addr In-Reply-To: <20200513180302.GC2491@localhost.localdomain> References: <20200513062649.2100053-1-hch@lst.de> <20200513062649.2100053-33-hch@lst.de> <20200513180302.GC2491@localhost.localdomain> Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: 'Marcelo Ricardo Leitner' , Christoph Hellwig Cc: "David S. Miller" , Jakub Kicinski , Eric Dumazet , Alexey Kuznetsov , Hideaki YOSHIFUJI , Vlad Yasevich , Neil Horman , Jon Maloy , Ying Xue , "drbd-dev@lists.linbit.com" , "linux-block@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-rdma@vger.kernel.org" , "linux-nvme@lists.infradead.org" , "target-devel@vger.kernel.org" , "linux-afs@lists.infradead.org" From: Marcelo Ricardo Leitner > Sent: 13 May 2020 19:03 > > On Wed, May 13, 2020 at 08:26:47AM +0200, Christoph Hellwig wrote: > > Add a helper to directly get the SCTP_PRIMARY_ADDR sockopt from kernel > > space without going through a fake uaccess. > > Same comment as on the other dlm/sctp patch. Wouldn't it be best to write sctp_[gs]etsockotp() that use a kernel buffer and then implement the user-space calls using a wrapper that does the copies to an on-stack (or malloced if big) buffer. That will also simplify the code be removing all the copies and -EFAULT returns. Only the size checks will be needed and the code can assume the buffer is at least the size of the on-stack buffer. Our SCTP code uses SO_REUSADDR, SCTP_EVENTS, SCTP_NODELAY, SCTP_STATUS, SCTP_INITMSG, IPV6_ONLY, SCTP_SOCKOPT_BINDX_ADD and SO_LINGER. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)