From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Lutomirski Subject: Are there u32 atomic bitops? (or dealing w/ i_flags) Date: Mon, 17 Dec 2012 17:10:21 -0800 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 To: linux-kernel@vger.kernel.org, Linux FS Devel Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org I want to change inode->i_flags access to be atomic -- there are some locking oddities right now, I think, and I want to use a new inode flag to signal mtime updates from page_mkwrite. The problem is that i_flags is an unsigned int, and making it an unsigned long seems like a waste, but there aren't any u32 atomic bitops. What should I do? Suck it up and waste four bytes on 64-bit machines? In general, having atomic flag words be long seems likely to waste bits on 64-bit architectures. --Andy