Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758891AbXFWQQd (ORCPT ); Sat, 23 Jun 2007 12:16:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753685AbXFWQQ0 (ORCPT ); Sat, 23 Jun 2007 12:16:26 -0400 Received: from nic.NetDirect.CA ([216.16.235.2]:46566 "EHLO rubicon.netdirect.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752378AbXFWQQ0 (ORCPT ); Sat, 23 Jun 2007 12:16:26 -0400 X-Originating-Ip: 72.143.66.27 Date: Sat, 23 Jun 2007 12:11:57 -0400 (EDT) From: "Robert P. J. Day" X-X-Sender: rpjday@localhost.localdomain To: Satyam Sharma cc: Arnd Bergmann , Florin Iucha , Linux Kernel Mailing List Subject: Re: "upping" a semaphore from interrupt context? In-Reply-To: Message-ID: References: <20070622173839.GB8398@iucha.net> <200706221934.18436.arnd@arndb.de> <200706231402.03617.arnd@arndb.de> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Net-Direct-Inc-MailScanner-Information: Please contact the ISP for more information X-Net-Direct-Inc-MailScanner: Found to be clean X-Net-Direct-Inc-MailScanner-SpamCheck: not spam, SpamAssassin (not cached, score=-16.8, required 5, autolearn=not spam, ALL_TRUSTED -1.80, BAYES_00 -15.00, INIT_RECVD_OUR_AUTH -20.00, RCVD_IN_SORBS_DUL 20.00) X-Net-Direct-Inc-MailScanner-From: rpjday@mindspring.com Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1649 Lines: 41 On Sat, 23 Jun 2007, Satyam Sharma wrote: > Hi Robert, Arnd, > > On 6/23/07, Arnd Bergmann wrote: > > On Saturday 23 June 2007, Robert P. J. Day wrote: > > > On Fri, 22 Jun 2007, Arnd Bergmann wrote: > > > > > > > > yes, but you should not. The use of semaphores is not recommended > > > > for new code, it should be replaced with either a mutex or a > > > > completion. > > > > > > can you clarify this? it sounds like you're saying that the current > > > implementation of semaphores is entirely superfluous. but surely it > > > isn't possible to replace all semaphores with either mutexes or > > > completions, is it? > > Semaphores being used as completions are superfluous, obsoleted by > completion handlers. Semaphores that are not counted (hence binary) > are superfluous, obsoleted by struct mutex. hang on, how is that true? as i read it, mutexes are more than just binary semaphores -- they have additional restrictions that regular semaphores don't. so i'm not convinced that binary semaphores can simply be replaced by mutexes, unless that's not what you meant here. rday -- ======================================================================== Robert P. J. Day Linux Consulting, Training and Annoying Kernel Pedantry Waterloo, Ontario, CANADA http://fsdev.net/wiki/index.php?title=Main_Page ======================================================================== - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/