From mboxrd@z Thu Jan 1 00:00:00 1970 From: Frederic Weisbecker Subject: Re: [PATCH 7/8] percpu: add __percpu sparse annotations to hw_breakpoint Date: Tue, 26 Jan 2010 01:19:03 +0100 Message-ID: <20100126001901.GI5087@nowhere> References: <1264432935-10453-1-git-send-email-tj@kernel.org> <1264432935-10453-8-git-send-email-tj@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-kernel@vger.kernel.org, axboe@kernel.dk, rusty@rustcorp.com.au, akpm@linux-foundation.org, ebiederm@xmission.com, tytso@mit.edu, Trond.Myklebust@netapp.com, aelder@sgi.com, hch@infradead.org, viro@zeniv.linux.org.uk, davem@davemloft.net, netdev@vger.kernel.org, x86@kernel.org, mingo@redhat.com, dan.j.williams@intel.com, borislav.petkov@amd.com, ying.huang@intel.com, lenb@kernel.org, neilb@suse.de, cl@linux-foundation.org To: Tejun Heo Return-path: Received: from fg-out-1718.google.com ([72.14.220.154]:19578 "EHLO fg-out-1718.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751450Ab0AZATK (ORCPT ); Mon, 25 Jan 2010 19:19:10 -0500 Content-Disposition: inline In-Reply-To: <1264432935-10453-8-git-send-email-tj@kernel.org> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, Jan 26, 2010 at 12:22:14AM +0900, Tejun Heo wrote: > Add __percpu sparse annotations to hw_breakpoint. > > These annotations are to make sparse consider percpu variables to be > in a different address space and warn if accessed without going > through percpu accessors. This patch doesn't affect normal builds. > > per_cpu(nr_task_bp_pinned, cpu) is replaced with > &per_cpu(nr_task_bp_pinned[0], cpu). This is the same to the compiler > but allows per_cpu() macro to correctly drop __percpu designation for > the returned pointer. Ouch... It's unpleasant to see such workaround that messes up the code just to make sparse happy. I guess __percpu is an address_space attribute? Is there no way to force the address space change directly from the per_cpu() macro? Thanks.