Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756933AbYG2QVS (ORCPT ); Tue, 29 Jul 2008 12:21:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752703AbYG2QVH (ORCPT ); Tue, 29 Jul 2008 12:21:07 -0400 Received: from xenotime.net ([66.160.160.81]:53493 "HELO xenotime.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751955AbYG2QVG (ORCPT ); Tue, 29 Jul 2008 12:21:06 -0400 Date: Tue, 29 Jul 2008 09:21:02 -0700 From: Randy Dunlap To: Rusty Russell Cc: "Paul Menage" , "Linus Torvalds" , linux-kernel@vger.kernel.org, "Matthew Wilcox" , "Randy.Dunlap" , "Andrew Morton" , "Christoph Hellwig" Subject: Re: [PATCH] Introduce down_try() so we can move away from down_trylock() Message-Id: <20080729092102.14e6d964.rdunlap@xenotime.net> In-Reply-To: <200807292301.18733.rusty@rustcorp.com.au> References: <200807291015.02865.rusty@rustcorp.com.au> <6599ad830807281727r63a57a1g11972c5395828aae@mail.gmail.com> <200807292301.18733.rusty@rustcorp.com.au> Organization: YPO4 X-Mailer: Sylpheed 2.5.0 (GTK+ 2.12.0; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2586 Lines: 72 On Tue, 29 Jul 2008 23:01:17 +1000 Rusty Russell wrote: > On Tuesday 29 July 2008 10:27:15 Paul Menage wrote: > > On Mon, Jul 28, 2008 at 5:15 PM, Rusty Russell wrote: > > > +/** > > > + * down_try - try to down a semaphore, but don't block > > > + * @sem: the semaphore > > > > Is there a reason to avoid using a return type of "bool" for this? > > Probably, but not a good one. > > This incorporates Andrew's whitespace fix as well (ie: > introduce-down_try-so-we-can-move-away-from-down_trylock.patch and > introduce-down_try-so-we-can-move-away-from-down_trylock-checkpatch-fixes.patch) > > Introduce down_try() > > I planned on removing the much-disliked down_trylock() (with its > backwards return codes) in 2.6.27, but it's creating something of a > logjam with other patches in -mm and linux-next. > > Andrew suggested introducing "down_try" as a wrapper now, to make > the transition easier. Hi Rusty, Will you also be making updates to Documentation/DocBook/kernel-locking.tmpl ? > Signed-off-by: Rusty Russell > Cc: Andrew Morton > Cc: Christoph Hellwig > Cc: Matthew Wilcox > Cc: Stephen Rothwell > --- > include/linux/semaphore.h | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff -r 92664ae4130b include/linux/semaphore.h > --- a/include/linux/semaphore.h Wed May 21 14:54:40 2008 +1000 > +++ b/include/linux/semaphore.h Wed May 21 15:07:31 2008 +1000 > @@ -48,4 +48,18 @@ extern int __must_check down_timeout(str > extern int __must_check down_timeout(struct semaphore *sem, long jiffies); > extern void up(struct semaphore *sem); > > +/** > + * down_try - try to down a semaphore, but don't block > + * @sem: the semaphore > + * > + * This is equivalent to down_trylock(), but has the same return codes as > + * spin_trylock and mutex_trylock: 1 if semaphore acquired, 0 if not. > + * > + * down_trylock() with its confusing return codes will be deprecated > + * soon. It will not be missed. > + */ > +static inline bool __must_check down_try(struct semaphore *sem) > +{ > + return !down_trylock(sem); > +} > #endif /* __LINUX_SEMAPHORE_H */ --- ~Randy Linux Plumbers Conference, 17-19 September 2008, Portland, Oregon USA http://linuxplumbersconf.org/ -- 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/