From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael Kerrisk (man-pages)" Subject: Re: [PATCH/RFC] Re: recvmmsg() timeout behavior strangeness [RESEND] Date: Sat, 24 May 2014 08:13:18 +0200 Message-ID: <5380387E.50308@gmail.com> References: <20140512143451.GB13801@kernel.org> <20140521210535.GA5414@kernel.org> <20140523.150055.2214666905697701415.davem@davemloft.net> <20140523195522.GH2741@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-man-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, neleai-9Vj9tDbzfuSlVyrhU4qvOw@public.gmane.org, caitlin.bestler-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, nhorman-2XuSBdqkA4R54TAoqtyWWQ@public.gmane.org, eliedebrauwer-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, steve-TMeXKDtMCpxBDgjK7y7TUQ@public.gmane.org, remi.denis-courmont-xNZwKgViW5gAvxtiuMwx3w@public.gmane.org, paul-r2n+y4ga6xFZroRs9YW3xA@public.gmane.org, chris.friesen-CWA4WttNNZF54TAoqtyWWQ@public.gmane.org To: Arnaldo Carvalho de Melo , David Miller Return-path: In-Reply-To: <20140523195522.GH2741-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> Sender: linux-man-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: netdev.vger.kernel.org On 05/23/2014 09:55 PM, Arnaldo Carvalho de Melo wrote: > Em Fri, May 23, 2014 at 03:00:55PM -0400, David Miller escreveu: >> From: Arnaldo Carvalho de Melo >> Date: Wed, 21 May 2014 18:05:35 -0300 > >>> But after thinking a bit more, looks like we need to do that, please >>> take a look at the attached patch to see if it addresses the problem. > >>> Mostly it adds a new timeop to the per protocol recvmsg() >>> implementations, that, if not NULL, should be used instead of >>> SO_RCVTIMEO. > >>> since the underlying recvmsg implementations already check that timeout, >>> return what is remaining, that will then be used in subsequent recvmsg >>> calls, at the end we just convert it back to timespec format. > >>> In most cases it is just passed to skb_recv_datagram, that will check >>> the pointer, use it and update if not NULL. > >>> Should have no problems, but I only did a boot with a system with this >>> patch applied, no problems noticed on a normal desktop session, ssh, >>> etc. > >> This looks fine to me, but I have a small request: > >> + return noblock ? 0 : timeop ? *timeop : sk->sk_rcvtimeo; > >> I keep forgetting which way these expressions associate, so if you could >> parenthesize the innermost ?: I'd appreciate it. :) > > Ok, I actually wrote a sample program to verify that these ternaries did > what I meant 8) > > I'll finish the cset log and do this clarification change. > > Would be great to get Acked-by tags from the original reporter, Michael > and whoever had a look at this change, if possible. Michael, Elie? Arnaldo, I already sent you a reply (will reping on that one), but got no response. My light testing got the expected results, but I still had one question about the semantics. Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html