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[76.102.12.149]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-2ca7c3010e9sm237887eec.14.2026.04.01.09.34.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 01 Apr 2026 09:34:04 -0700 (PDT) Date: Wed, 1 Apr 2026 09:34:04 -0700 From: Stanislav Fomichev To: Breno Leitao Cc: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Kuniyuki Iwashima , Willem de Bruijn , metze@samba.org, axboe@kernel.dk, Stanislav Fomichev , io-uring@vger.kernel.org, bpf@vger.kernel.org, netdev@vger.kernel.org, Linus Torvalds , linux-kernel@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCH net-next v2 2/4] net: call getsockopt_iter if available Message-ID: References: <20260401-getsockopt-v2-0-611df6771aff@debian.org> <20260401-getsockopt-v2-2-611df6771aff@debian.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260401-getsockopt-v2-2-611df6771aff@debian.org> On 04/01, Breno Leitao wrote: > Update do_sock_getsockopt() to use the new getsockopt_iter callback > when available. Add do_sock_getsockopt_iter() helper that: > > 1. Reads optlen from user/kernel space > 2. Initializes a sockopt_t with the appropriate iov_iter (kvec for > kernel, ubuf for user buffers) and sets opt.optlen > 3. Calls the protocol's getsockopt_iter callback > 4. Writes opt.optlen back to user/kernel space > > The optlen is always written back, even on failure. Some protocols > (e.g. CAN raw) return -ERANGE and set optlen to the required buffer > size so userspace knows how much to allocate. > > The callback is responsible for setting opt.optlen to indicate the > returned data size. > > Signed-off-by: Breno Leitao > --- > net/socket.c | 48 +++++++++++++++++++++++++++++++++++++++++++++--- > 1 file changed, 45 insertions(+), 3 deletions(-) > > diff --git a/net/socket.c b/net/socket.c > index ade2ff5845a0..4a74a4aa1bb4 100644 > --- a/net/socket.c > +++ b/net/socket.c > @@ -77,6 +77,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -2349,6 +2350,44 @@ SYSCALL_DEFINE5(setsockopt, int, fd, int, level, int, optname, > INDIRECT_CALLABLE_DECLARE(bool tcp_bpf_bypass_getsockopt(int level, > int optname)); > > +static int do_sock_getsockopt_iter(struct socket *sock, > + const struct proto_ops *ops, int level, > + int optname, sockptr_t optval, > + sockptr_t optlen) If we want to eventually remove sockptr_t, why not make this new handler work with iov_iters from the beginning? The callers can have some new temporary sockptr_to_iter() or something? > +{ > + struct kvec kvec; > + sockopt_t opt; > + int koptlen; > + int err; > + > + if (copy_from_sockptr(&koptlen, optlen, sizeof(int))) > + return -EFAULT; > + > + if (optval.is_kernel) { > + kvec.iov_base = optval.kernel; > + kvec.iov_len = koptlen; > + iov_iter_kvec(&opt.iter, ITER_DEST, &kvec, 1, koptlen); > + } else { > + iov_iter_ubuf(&opt.iter, ITER_DEST, optval.user, koptlen); > + } > + opt.optlen = koptlen; > + > + /* iter is initialized as ITER_DEST. Callbacks that need to read > + * from optval (e.g. PACKET_HDRLEN) must flip data_source to > + * ITER_SOURCE, then restore ITER_DEST before writing back. > + */ Have you considered creating two iters? opt.iter_in and opt.iter_out. That way you don't have to flip the source back and forth in the handlers.