Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755111Ab2BQDzq (ORCPT ); Thu, 16 Feb 2012 22:55:46 -0500 Received: from mail-qw0-f53.google.com ([209.85.216.53]:62808 "EHLO mail-qw0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752224Ab2BQDzp convert rfc822-to-8bit (ORCPT ); Thu, 16 Feb 2012 22:55:45 -0500 MIME-Version: 1.0 In-Reply-To: <201202160007.33131.rjw@sisk.pl> References: <201202070200.55505.rjw@sisk.pl> <201202150022.26072.rjw@sisk.pl> <201202160007.33131.rjw@sisk.pl> Date: Thu, 16 Feb 2012 19:55:44 -0800 Message-ID: Subject: Re: [RFC][PATCH 0/8] PM: Implement autosleep and "wake locks" From: =?ISO-8859-1?Q?Arve_Hj=F8nnev=E5g?= To: "Rafael J. Wysocki" Cc: Linux PM list , LKML , Magnus Damm , markgross@thegnar.org, Matthew Garrett , Greg KH , John Stultz , Brian Swetland , Neil Brown , Alan Stern Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2515 Lines: 53 2012/2/15 Rafael J. Wysocki : > On Wednesday, February 15, 2012, Arve Hj?nnev?g wrote: >> 2012/2/14 Rafael J. Wysocki : >> > On Tuesday, February 14, 2012, Arve Hj?nnev?g wrote: >> >> On Mon, Feb 6, 2012 at 5:00 PM, Rafael J. Wysocki wrote: >> >> ... >> >> but the wake-source timeout feature has some bugs or incompatible apis. An >> >> init api would also be useful for embedding wake-sources in other data >> >> structures without adding another memory allocation. Your patch to >> >> move the spinlock init to wakeup_source_add still require the struct >> >> to be zero initialized and the name set manually. >> > >> > That should be easy to fix. ?What about the appended patch? >> > >> >> That works, but I still have to call more than one function before I >> can use the wakeup-source (wakeup_source_init and wakeup_source_add) >> and more than one function before I can free it (__pm_relax, >> wakeup_source_remove and wakeup_source_drop). Is there any reason to >> keep these separate? > > Yes, there is. ?I think that wakeup_source_create/_destroy() should > use the same initialization functions internally that will be used for > externally allocated wakeup sources (to make sure that all wakeup source > objects are initialized in exactly the same way). > I agree with that, but is it useful to export these helper functions? >> Also, not copying the name when the caller provides the memory for the >> wakeup-source would be a closer match to the wakelock api. Most of our >> wakelocks pass a string constant as the name, and making a copy of >> that string is not useful. wake_lock_init is also safe to call from >> atomic context, but I don't know if anyone relies on this. > > OK, below is another go. ?It doesn't copy the name if wakeup_source_init() is > used (which also does the _add this time). ?I think, though, that copying > the name is generally safer, because someone might use wakeup_source_init() > with the name string allocated on the stack or otherwise temporary, which would > be a bug with the new version. > I prefer this version. I have not seen a bug where someone passed a temporary as the wakelock name, I assume since this will show up immediately in the stats file. -- Arve Hj?nnev?g -- 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/