Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262228AbVATQqE (ORCPT ); Thu, 20 Jan 2005 11:46:04 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262396AbVATQpv (ORCPT ); Thu, 20 Jan 2005 11:45:51 -0500 Received: from mx1.elte.hu ([157.181.1.137]:64215 "EHLO mx1.elte.hu") by vger.kernel.org with ESMTP id S262228AbVATQop (ORCPT ); Thu, 20 Jan 2005 11:44:45 -0500 Date: Thu, 20 Jan 2005 17:44:28 +0100 From: Ingo Molnar To: Linus Torvalds Cc: Peter Chubb , Chris Wedgwood , Andrew Morton , paulus@samba.org, linux-kernel@vger.kernel.org, tony.luck@intel.com, dsw@gelato.unsw.edu.au, benh@kernel.crashing.org, linux-ia64@vger.kernel.org, hch@infradead.org, wli@holomorphy.com, jbarnes@sgi.com Subject: Re: [patch 1/3] spinlock fix #1, *_can_lock() primitives Message-ID: <20050120164428.GA16342@elte.hu> References: <16878.9678.73202.771962@wombat.chubb.wattle.id.au> <20050119092013.GA2045@elte.hu> <16878.54402.344079.528038@cargo.ozlabs.ibm.com> <20050120023445.GA3475@taniwha.stupidest.org> <20050119190104.71f0a76f.akpm@osdl.org> <20050120031854.GA8538@taniwha.stupidest.org> <16879.29449.734172.893834@wombat.chubb.wattle.id.au> <20050120160839.GA13067@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.1i X-ELTE-SpamVersion: MailScanner 4.31.6-itk1 (ELTE 1.2) SpamAssassin 2.63 ClamAV 0.73 X-ELTE-VirusStatus: clean X-ELTE-SpamCheck: no X-ELTE-SpamCheck-Details: score=-4.9, required 5.9, autolearn=not spam, BAYES_00 -4.90 X-ELTE-SpamLevel: X-ELTE-SpamScore: -4 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1453 Lines: 48 * Linus Torvalds wrote: > I can do ppc64 myself, can others fix the other architectures (Ingo, > shouldn't the UP case have the read/write_can_lock() cases too? And > wouldn't you agree that it makes more sense to have the rwlock test > variants in asm/rwlock.h?): this one adds it to x64. (untested at the moment) This patch assumes that we are nuking rwlock_is_locked and that there is at least a s/rwlock_is_locked/!write_can_lock/ done to kernel/exit.c. Ingo Signed-off-by: Ingo Molnar --- linux/include/asm-x86_64/spinlock.h.orig +++ linux/include/asm-x86_64/spinlock.h @@ -161,7 +161,23 @@ typedef struct { #define rwlock_init(x) do { *(x) = RW_LOCK_UNLOCKED; } while(0) -#define rwlock_is_locked(x) ((x)->lock != RW_LOCK_BIAS) +/** + * read_can_lock - would read_trylock() succeed? + * @lock: the rwlock in question. + */ +static inline int read_can_lock(rwlock_t *rw) +{ + return rw->lock > 0; +} + +/** + * write_can_lock - would write_trylock() succeed? + * @lock: the rwlock in question. + */ +static inline int write_can_lock(rwlock_t *rw) +{ + return rw->lock == RW_LOCK_BIAS; +} /* * On x86, we implement read-write locks as a 32-bit counter - 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/