From 791333baf11dbf37dd8f566909f8c1d5b939bf04 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Wed, 10 Oct 2007 03:21:37 -0700 Subject: [PATCH] Fix zero length socket write() semantics. changeset e79ad711a0108475c1b3a03815527e7237020b08 from mainline. This fixes kernel bugzilla #5731 It should generate an empty packet for datagram protocols when the socket is connected, for one. The check is doubly-wrong because all that a write() can be is a sendmsg() call with a NULL msg_control and a single entry iovec. No special semantics should be assigned to it, therefore the zero length check should be removed entirely. This matches the behavior of BSD and several other systems. Alan Cox notes that SuSv3 says the behavior of a zero length write on non-files is "unspecified", but that's kind of useless since BSD has defined this behavior for a quarter century and BSD is essentially what application folks code to. Based upon a patch from Stephen Hemminger. Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/socket.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/net/socket.c b/net/socket.c index 0010da086acf..48bd793ecc1c 100644 --- a/net/socket.c +++ b/net/socket.c @@ -778,9 +778,6 @@ static ssize_t sock_aio_write(struct kiocb *iocb, const struct iovec *iov, if (pos != 0) return -ESPIPE; - if (iocb->ki_left == 0) /* Match SYS5 behaviour */ - return 0; - x = alloc_sock_iocb(iocb, &siocb); if (!x) return -ENOMEM; -- 2.39.5