From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id 5A162DDF09 for ; Thu, 10 May 2007 17:21:30 +1000 (EST) Subject: Re: [PATCH 2/3] Add hard_irq_disable() From: Benjamin Herrenschmidt To: Satyam Sharma In-Reply-To: References: <20070510052622.3E8D5DDF4B@ozlabs.org> <20070509224113.cca81a24.akpm@linux-foundation.org> Content-Type: text/plain Date: Thu, 10 May 2007 17:21:17 +1000 Message-Id: <1178781677.14928.221.camel@localhost.localdomain> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org, Andrew Morton , Rusty Russell , linux-kernel@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , > So you're saying that this mechanism forces the arch (that really > wants hard_irq_disable) to _#define_ hard_irq_disable (as a macro), > and if it implements it as an inline function, for example, then we're > screwed? No. The idea is to do like we did for a few other things already (according to Linus request in fact), which is to write static inline void hard_irq_disable(void) { .../... } #define hard_irq_disable hard_irq_disable This is nicer than having an ARCH_HAS_xxx > 1. Introduce some CONFIG_WANTS_HARD_IRQ_DISABLE that is #defined (or > left undefined) by the arch/.../defconfig (depending upon whether or > not that arch implements a hard_irq_disable() for itself or not) > > 2. Then pull-in that code into include/linux/interrupt.h somehow > (through some known / fixed header file, or through asm/system.h, or > anyhow -- it doesn't really matter) > > 3. And: > > #ifndef CONFIG_WANTS_HARD_IRQ_DISABLE > #define hard_irq_disable() do { } while(0) > #endif Well, last time I tried that, Linus NACKed it in favor of what I described above. > We don't need to standardize on some particular arch-specific header > filename in this case. True, that's my main problem here. Though really only the archs who actually implement something special here need to be careful. Ben.